Main content of lean factory design The traditional way of plant layout begins with equipment and tooling, and finally considers the flow of processes. Unlike traditional factory layouts, lean factory design layout begins with the customer and then designs the process flow around the workforce. Lean factory design should comprehensively apply the knowledge of lean production ideas, system engineering, enterprise management, etc., and use parallel technology, information technology and other means to determine the factory design plan that meets the requirements of lean production concept. The main design contents are as follows:
(1) Production line layout based on lean thinking The design of the best production line must be independent of the current legacy workflow and should reduce or eliminate large amounts of moving time for products and materials. According to the assembly requirements, placing the part loading process on the assembly point where the material of the production line is consumed will reduce the movement and waiting time.
(2) Lean logistics system design According to the lean production point of view, logistics is not a value-added link. Therefore, the goal of lean logistics system design is to minimize the logistics and strive to minimize the waste in the logistics process while meeting the production requirements. To break the limitations of the profession, try to set up and no intermediate inventory area, and completely follow the process flow layout. All ideas that minimize the amount of movement and optimize the flow of the product should be tested. Ultimately, a practical and appropriate approach should be taken to finalize the production line in order to maximize the benefits of the production process. .
(3) Lean selection and arrangement of equipment It is necessary to fully consider the relationship between the various production links, and on the basis of realizing the capacity requirements, try to achieve a balanced production capacity and reflect the idea of lean flow. At the same time, the choice of equipment is not based on the most advanced standards, but the small size, low investment, flexibility and other indicators are put in the first place, in order to meet the needs of flexible production in the future.
(4) Lean staffing Traditional factories use the “scheduled system” staffing, but this method increases the cost of the enterprise and reduces the response speed of the enterprise under the multi-variety and small-batch production methods. Lean factory design, it is recommended to use the least staff to achieve the same production needs, through the training of employees, so that it has a variety of skills, so that with the change in production, flexible arrangements for operators.
(5) Lean selection of auxiliary equipment Although the fixtures and tools required for production assistance are not resource equipment, they must be considered for lean production. It must be designed to accommodate the movement of the required materials, such as the passage of the automatic loading and unloading trucks and large material containers. It is necessary to design the station to be more compact, but at the same time, the operator should be considered to be as ergonomic as possible.
In addition, the design of the lean factory should also include the planning of the public facilities of the factory, the design of the information system, etc., and should be carried out according to the specific needs of the factory and the actual situation of the enterprise. The goal of lean plant design is to minimize waste and overload in the work process while enhancing visual communication on site.
After the PCB is manufactured, it has a shelf life. If the shelf life is exceeded, the PCB needs to be baked. Otherwise, it is easy to cause the PCB to explode when the PCB is produced on the SMT. Baking can eliminate the internal stress of the PCB, which is to stabilize the size of the PCB. The baked board has a relatively large improvement in warpage. Advantages of baking: After baking, the moisture in the pad can be dried, the welding effect is enhanced, and the welding and repair rate are reduced. Disadvantages of baking: The color of the PCB board may change, affecting the appearance. The main purpose of PCB baking is to remove moisture and remove moisture from the PCB.
First, the specification of PCB management
1, PCB unpacking and storage
(1) PCB board seal can be directly used online within 2 months of unopened manufacturing date (2) PCB board manufacturing date is within 2 months, the date of unpacking must be marked after unpacking (3) PCB board manufacturing date is within 2 months, after opening, it must be used within 5 days.
2, PCB baking
(1) If the PCB is sealed and unsealed for more than 5 days within 2 months of the date of manufacture, please bake at 120 ± 5 °C for 1 hour. (2) If the PCB is more than 2 months from the date of manufacture, please bake at 120 ± 5 °C for 1 hour before going online. (3) If the PCB is more than 2 to 6 months from the date of manufacture, please bake at 120 ± 5 °C for 2 hours before going online. (4) If the PCB is more than 6 months to 1 year before the date of manufacture, please bake at 120 ± 5 °C for 4 hours before going online. (5) The baked PCB must be used within 5 days (input to IR REFLOW). After the bit is used, it needs to be baked for another hour before it can be used. (6) If the PCB exceeds the manufacturing date of 1 year, please bake at 120 ± 5 °C for 4 hours before going online, and then send it to the PCB factory for re-spraying before it can be used.
3, PCB baking method
(1) Large PCB (16 PORT and above including 16 PORT), placed in a flat format, with a maximum of 30 sheets in a stack, and the oven is opened within 10 minutes after baking. The PCB is placed in a flat and natural cooling (requires pressure to prevent the bay fixture) (2) Small and medium-sized PCB (8PORT below 8PORT) is placed flat, the maximum number of stacks is 40 pieces, the number of uprights is not limited, the oven is opened within 10 minutes after baking, and the PCB is placed flat and naturally cooled (requires pressure protection) Banwan fixtures)
Second, the preservation and baking of PCBs in different regions
The specific storage time and baking temperature of the PCB are not only related to the production capacity and manufacturing process of the PCB manufacturer, but also have a great relationship with the region.
The PCB made by the OSP process and the pure immersion gold process generally has a shelf life of 6 months after packaging, and is generally not recommended for the OSP process.
The storage and baking time of PCB has a great relationship with the area. The humidity in the south is generally heavier. Especially in Guangdong and Guangxi, there will be “returning to the south” weather every year in March and April. It is very wet at this time. The PCB must be used up within 24 hours of exposure to air, otherwise it will be easily oxidized. After normal opening, it is best to use up to 8 hours. For some PCBs that need to be baked, the baking time is longer. In the northern regions, the weather is generally dry, the PCB storage time will be longer, and the baking time can be shorter. The baking temperature is generally 120 ± 5 ° C baking, baking time is determined according to the specific circumstances.
If you need to know more about PCB drying and PCB-baked-machine machin, please contact us.
Southern Machinery (SMTHELP), which specializes in SMT machines and spare parts. SMTHELP has more than 20 years of experience in the electronics processing equipment industry. Customers all over the world, and win the trust and praise of customers. Long-term customers include BOSCH in Spain and India, DIXION in India, Panasonic in Mexico, Samsung and Cliptechin Brazil.
With the SMTHELP industry experience, philosophy and professional team, adhere to the “One-Stop Solution” belief to serve customers in the electronics processing industry, providing customers with cost-effective, high quality spare parts and equipment with stable performance from China, saving customers time And cost. truly one-stop solution services.
In SMT PCB production, solder paste printing is a critical step. Since the solder paste is used to directly form the soldering joint, the quality of solder paste printing affects the performance and reliability of the surface mount assembly. Quality solder paste printing guarantees a quality solder joint and final product. Statistics demonstrate that 60% to 90% of soldering defects are related to solder paste printing defects. So it is very important to understand what causes defects in solder paste printing. ItemFactorsAnalysis1Solder PastePowder formationThe irregular shape of solder powder will easily clog stencil apertures. This will cause a big slump after printing. It can also cause solder ball and short bridge defects after reflow.
A spherical shape is best, especially for fine-pitch QFP printing.Particle SizeIf the particle size is too small, the results will be poor paste adhesion. It will have a high oxygen content and cause a solder ball after reflow.
The particle size should be controlled to about 25 ~ 45 μm in order to meet the requirements for fine-pitch QFP soldering, If the partical size desired is 25 to 30 μm, it should applied with less than 20 μm solder paste for an ultra fine-pitch IC.FluxFlux contains a thixotropic agent, which allows the solder paste to have pseudoplastic flow characteristics. Since the viscosity decreases when the paste passes through the stencil apertures, the paste can be applied to the PCB pads rapidly. When the external force stops, the viscosity will recover to ensure no deformation occurs.
The flux in the solder paste should be controlled to between 8 and 15 percent. A lower flux content will result in excess amount of solder paste applied. Conversely, a high flux content will result in an insufficient amount of solder applied.2StencilThicknessA stencil that is too thick will cause a solder bridge short.
A stencil that is too thin will cause an insufficient solder to be applied.Aperture sizeWhen the stencil aperature size is too big, a solder bridge short can occur.
When the stencil aperature size is too small, and insufficient solder paste will be applied.Aperture shapeIt is best to use a circular-shaped stencil aperture design. Its size should be slightly smaller than the PCB pad size, preventing a bridging defect during reflow.3Printing parametersBlade Angle Speed & PressureThe blade angle affects the vertical force applied on the solder paste. If the angle is too small, the solder paste will not be squeezed into the stencil apertures. The best blade angle should be set around 45 to 60 degrees.
A higher the printing speed means that less time will be spent in applying the solder paste through the stencil aperture surface. A higher printing speed will cause insufficient solder to be applied.
The speed should be controlled to around 20 ~ 40 mm/s.
When the blade pressure is too small, it will prevent the solder paste from being cleanly applied to the stencil.
When the blade pressure is too high, it will result in more paste leakage. The blade pressure is typically set at about 5N ~ 15N / 25mm.4Printing process controlPCB moistureIf the PCB moisture is too high, the water under the solder paste will quickly evaporate, causing the solder to splash and creating solder balls.
Dry the PCB if it was fabricated over 6 months ago. The recommended drying temperature is 125 degrees for 4 hours.Paste storageIf the solder paste is applied without a temperature recovery period, the water vapour in the surrounding environment will condense and penetrate the solder paste; this will cause the solder to splash.
Solder paste should be stored in a refrigerator at 0 to 5 degrees.Two to fours hours before use, place the paste in a normal temperature environment.
1 program composition 1) NC PROGRAM: Z-axis components are placed at X, Y positions at θ angle 2) PCB PROGRAM: substrate length, width, thickness and PIN spacing 3) ARRAY PROGRAM: Z specified components 4) PART LIBRARY: Component Information 5) MARK LIBRARY: tag information 2 NC PROGRAM 1) File name: P— [0-9, A-Z, +, -,.] 2) X, Y coordinates 3) Z No: ZA+ZB, K TYPE and Q TYPE, in single and double FEEDER at 8mm width The difference between K TYPE and Q TYPE: * PIN, no PIN * PITCH: K-21.5mm Q-20mm * ORG: FULL is 1, K-Z1, Q-Z2 when HALF FEEDER: HALF must be used when mixing single and double Z No: Single input K TYPE: Product number, Q TYPE: Even 4) θ angle: θ1, θ2 two, θ3 origin return Θ1:0° 90° 180° 270° Θ2: [set angle – θ1] + correction angle Reverse time is – 5) S&R: STEP REPEAT, PATTERN REPEAT On time is + 6) NO MOUNTING: 0-normal patch, 1-non-patch 7) SKIP BLOCK: 0 – unconditional execution, 1 to 9 – conditional jump, 7 – unconditional jump 8) MARK: 0 – no MARK, 1 – individual MARK, 2-PCB MARK, 3-PATTERN MARK 9) LAND TEACHING: 0-NO, 1-LAND TEACHING [Recommended for the second leg of each side] 10) BAD MARK: 0-NO, 1-BAD MARK [SENSOR] 2-BAD MARK [PCB CAMERA] 11) PROGRAM OFFSET: X=, Y=, move the first point of the patch to the camera center The machine automatically finds PROGRAM OFFSET 12) Z ORG is normally 1 and Z No can be set * NC PROGRAM sequence S&R->BAD MARK->MARK/PROGRAM->ROGRAM OFFSET->MARK 3 ARRAY PROGRAM 1) File name: P— [0-9, A-Z, +, -,.] 2) Z No: Fixed cannot be changed 3) SHAPE CODE: shape coding [machine] 4) PARTS NAME: component name [person] 5) VACUUM OFFSET: NOZZLE↑ +, NOZZLE↓ – [-3～3mm] 6) MASTER Z No.: master, slave Z axis 4 PCB PROGRAM 1) File name: P— [0-9, A-Z, +, -,.] 2) X: PCB length 3) Y: PCB width 4) T: PCB thickness [NO USED] 5) Whether the PIN is used: 0-not used, 1-automatic adjustment 6) Hole spacing: X-10 7) Conveyor speed: 1[H]~8[L] speed, X, Y table speed when fully automatic control 5 MARK LIBRARY 1) SHAPE CODE: shape coding, — X, Y: MARK size PCB material: 0-copper foil, 1-solder PATTERN: shape TYPE: 0-shade, 1-binarization 6 PARTS LIBRARY 1) Shape coding: SHAPE CODE [—, 0-9, A-Z, +, -,.] 2) Component type CLASS: 1 to 99 [1 to 19 transmission recognition, 20 to 99 reflection recognition] Reflection recognition: blue light is absorbed on the orange reflector, and the surface of the component is reflected [Figure A] By recognizing: the white light of the halogen lamp shines on the orange reflector, and the reflector reflects the light. Depending on the component, the edge of the component is reflected to the camera [Figure B] * High reflection recognition accuracy, high passability through recognition, LED off when used * For identification θ: CHIP angular deviation > 35° NG, QFP angular deviation > 25° NG TYPE: For component color, normal condition is 1 [black best] 3) SHUTTER [Shutter]: 0-on, 1-in [Generally open] Closed left and right to ensure component identification [Figure D] 4) Component dimensions SIZE: up, down, left, right Hand-drawn tape to see the reverse side of the component is the same as the camera [Figure C] 5) Component thickness THICKNESS: T-component body thickness 6) Thickness tolerance TOL: T<1 is 20% T≥1 is 15% 7) HEAD SPEED: 1[H]~8[L] X, Y TABLE SPEED: 1[H]~8[L] 8) NOZZLE SELECT: 1~5 9) CAMERA: 0-S, 1-L 10) Component feed direction FEED DIRECTION: 0 to 7, 45° interval 11) Packing method: 0-PAPER [including 32mmPEELING] 1-EMBOSS 2-BULK 12) PUSHPIN: 0-NO USE 1-USE only for 8mm bandwidth 13) Number of feeds FEED COUNT: 1~4 spacing 12mm 14) Auxiliary feed: NO USE 15) Component error correction RECOVERY: 0-NO, 1-YES, 2- large parts are sucking 16) CHIP STAND: 0-NO, 1-YES [Components stand up, thickness sensor is detected, LINE SENSOR application] 17) VACUUM OFFSET: absorbing, for components [-3mm~+3mm] 18) LEAD OUT SIZE: Up/Down Left/Right 19) LEAD PITCH: leg spacing 20) LEAD PITCH TOL: tube leg tolerance 21) LEAD COUNT: Up/Down Left/Right Legs 22) Electrode part ELECTROD: The length direction of the element is the length direction of the electrode [Fig. E] The width direction of the component is the width direction of the electrode 23) CUT LEAD: cut tube legs SIDE: 1~4, there are cut legs on the side COUNT: Cut off: POSTION: Position [Figure F]
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Depth analysis: What are the factors that affect the thickness of SMT press solder paste printing? In the solder paste printing machine, sometimes the printed solder paste is very thin, which causes the product to fall off due to too little solder paste after the furnace is finished. So how is this phenomenon caused? Below I will analyze some specific reasons for everyone.
First, the quality of the steel plate — stencil printing is contact printing, so the stencil thickness and opening size determine the amount of solder paste printing, too much solder paste will produce bridging, too little solder paste will occur solder deficiency or solder joint, template The shape of the opening and the smoothness of the opening also affect the quality of the release. The template opening must have the bell mouth down, otherwise the solder paste will be taken from the chamfered corner of the bell when the mold is released. DEK accessories
Second, the printing process parameters — solder paste is a thixotropic fluid, with viscosity, when the scraper moves forward at a certain speed and angle, push the solder paste to roll in front of the scraper, the need to inject solder paste into the mesh or leak hole The pressure, the viscous friction of the solder paste causes the solder paste to shear at the intersection of the squeegee and the stencil, and the shear force reduces the viscosity of the solder paste, which facilitates the smooth injection of the solder paste into the mesh. There is a certain constraint between the speed of the blade, the pressure of the blade, the angle of the blade and the stencil, and the viscosity of the solder paste. Therefore, only by properly controlling these parameters can the printing quality of the solder paste be ensured.
How to remove the misprinted solder paste on the PCB surface?
Prepared by Ming
email@example.com This article describes that paying attention to some details can often prevent common problems in assembly processes and equipment selection.
Question: Can I use a small spatula to remove misprinted solder paste from the board? Will this get the solder paste and small tin beads into the holes and small gaps?
Answer: Using a small spatula to remove the solder paste from the misprinted board may cause some problems. It is generally practicable to immerse the misprinted board in a compatible solvent, such as water with an additive, and then remove the small tin beads from the board with a soft brush. I prefer to soak and wash repeatedly instead of violent dry brush or shovel. After the solder paste is printed, the longer the operator waits to clean the misprint, the harder it is to remove the solder paste. Misprinted boards should be placed in the soaking solvent immediately after the problem is discovered, as the solder paste is easily removed before it is dried.
Avoid wiping with a strip of cloth to prevent solder paste and other contaminants from smearing on the surface of the board. After soaking, brushing with a gentle spray can often help remove unwanted tins. It is also recommended to dry with hot air. If a horizontal stencil cleaner is used, the side to be cleaned should face down to allow the solder paste to fall off the board.
As usual, note that some details can eliminate undesirable conditions, such as misprinting of the solder paste and removal of the solder paste from the board. It is our goal to deposit the right amount of solder paste at the desired location. Stained tools, dry solder paste, and misalignment of the stencils and plates can cause undesirable solder paste on the underside of the stencil or even the assembly. During the printing process, the template is wiped with a certain pattern between printing cycles. Ensure that the template is seated on the pad, not on the solder mask, to ensure a clean solder paste printing process. On-line, real-time solder paste inspection and inspection prior to reflow after component placement are process steps that reduce process defects prior to soldering.
For fine-pitch stencils, if damage is caused between pins due to thin stencil cross-section bending, it can cause solder paste to deposit between the pins, causing printing defects and/or short circuits. Low viscosity solder paste can also cause printing defects. For example, high operating temperatures or high blade speeds can reduce the stickiness of the solder paste during use, resulting in printing defects and bridging due to excessive solder paste deposition.
In general, the lack of adequate control of materials, solder paste deposition methods and equipment are the main causes of defects in the reflow soldering process.
Question: What type of assembly board depaneling equipment provides the best results?
Answer: There are several sub-board systems that offer a variety of techniques for slab assembly boards. As a rule, there are many factors that should be considered when selecting such a device. Regardless of whether there is routing, sawing or blanking to separate individual panels from the composite panel, stable support during the splitting process is the most important factor. Without support, the resulting stress can damage the substrate and solder joints. Distorting the plate, or stressing the assembly during the splitting, can result in hidden or significant defects. While sawing often provides minimal clearance, shearing or die cutting with tools can provide cleaner, more controlled results.
In order to avoid component damage, many assemblers attempt to maintain component solder joints at least 5.08 mm from the edge of the board when the splitter is required. Sensitive ceramic capacitors or diodes may require extra care and consideration.
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0201 assembly, from difficult to conventional placement
This article explains and discusses the guiding principles governing 0201 placement in both high-volume and high-mix assembly operations.
By Ming Gan, firstname.lastname@example.org
Although generally considered to be a relatively recent development, printed circuit boards (PCBs) have been available since the early 1950s. Since then, the demand for smaller, lighter, and faster electronic products has driven electronic components, PCB, and assembly equipment technology toward SMT. The earliest general acceptance of SMT occurred in the early 1980s, when machines such as the Dynapert MPS-500 and FUJI CP-2 entered the market. At that time, 1206 (3216) resistors and capacitors were the most popular placement components. However, in one or two years, 1206 gave way to 0805 (2125) as the most common component package for SMT placement. During this time, both machines and components evolved rapidly. As the machine became faster and more flexible, the 0603 (1608) component began to evolve. At this point, many assembly machine manufacturers went back to the R&D, research and development lab to re-evaluate the technology used to accommodate these newer, smaller components. Higher resolution cameras and smaller vacuum nozzles are among the variations that these components bring to the assembly equipment. The emergence of 0402 (1608) packaging poses further challenges in all aspects of PCB assembly. In terms of machine development, vacuum nozzles have become smaller and more fragile. A new focus is placed on the component’s feeder, which acts as a unit for improvement, giving the machine more accurate parts. With the advent of 0402 components, process challenges have increased to those that need to be addressed for successful component placement. Solder paste printing becomes even more critical – stencil thickness and solder paste mesh are increasingly important process considerations. The technology required for such placement also involves significant new costs. The combination of these factors creates a new form of packaging that is the slowest to adopt in the history of the electronics industry. In total, for almost five years, 0402 packaging was widely accepted in the industry – and many assembly plants today never put a 0402 sheet. Now, I entered 0201. Over the past year and a half, 0201 placement has been a key topic of discussion throughout the industry. Due to the size, weight and power consumption requirements, many OEM board assemblers need to incorporate even smaller components and technologies into their products. Contract manufacturers (CM, contract manufacturer) must also have new technologies to keep the assembly process up to date and provide customers with a complete range of services. For machine builders, the challenge is to develop more resistant to obsolete assembly equipment in an era of dynamic technological change.
0201 placement challenge The placement of the 0201 component is more challenging than the component intervention in front of it. The main reason is that the 0201 package is approximately one-third of the corresponding 0402 size. The previously acceptable machine placement accuracy immediately became a limitation of the introduction of 0201. In addition, the traditional industrial tapeding specification allows for too much movement for reliable 0201 placement, and the level of process control must be increased to make the 0201 placement a production reality. Although these obstacles are very large, they are far from insurmountable. Of course, they need all the determination, because the technology necessary for the 0201 placement requires a lot of money and top management’s promise of research and development (R&D).
The key to reliable 0201 placement At FUJI, the aggressive R&D program has produced the ability to make all circuit assembly machines compatible with 0201 at 100% speed, with a minimum suction reliability of 99.90%, a target suction reliability of 99.95%, and minimal placement reliability. It is 99.99%. In the beginning, every aspect of the design was evaluated for its ability to work on a complete 0201 program, and the combination of single elements of closely related machine component parameters proved critical to success. These parameters include:
Figure 1 Component feeder table. The R&D program concluded that the ability to precisely position the carriage table – and make minimal adjustments to compensate for the inaccuracy of the tape – is a key factor in achieving component pickup reliability above 99.95%.
To achieve this, the feeder table must be precision machined to ensure repeatable positioning of the individual feeders and combined with a high-resolution semi-closed-cycle servo system using a two-track linear moving guide. This design allows for minor adjustments – based on the results of the suction accuracy as judged by the vision system. This ensures that the component is as close as possible to the center. Component feeder. The feeder must be manufactured to extremely tight tolerances to ensure repeatability of the suction position, regardless of component height and a large number of possible component positions. The mechanism used to position and lock the feeder in position must be durable and precise, yet be user friendly. In addition, the materials used to make the feeder must be high in strength and light in weight to allow for ergonomic operation while ensuring precise, repeatable delivery of the carrier tape. The feeder drives the sprocket. The drive sprocket plays a key role in the ability of the machine to position the component tape. The shape, taper and length of the drive sprocket teeth significantly affect the ability of the feeder to position the tape. Other factors have also been investigated, such as the diameter of the drive sprocket and the number of belts in contact with the sprocket. Changes to the basic sprocket design resulted in improved positioning accuracy, with earlier designs increasing by 20% in the X direction and 50% in the Y direction.
Figure 2 sucks the head. After properly feeding the component, the next step is to draw the component onto the vacuum nozzle and bring it to the board. Vacuum nozzles are compliant to absorb shock during pick-and-place components, compensate for small variations in solder paste height, and reduce the risk of component breakage. For these reasons, the nozzle must be able to move within its fixture.
Material selection, material hardness, machining tolerances, and thermal characteristics must all be understood to construct a reliable suction head. The nozzle must move freely within its holder without sacrificing accuracy (Figure 1). The nozzle shaft is assembled. The nozzle shaft is also a key design element – eliminating overdrive by keeping the entire nozzle in direct alignment with the shaft assembly. Overpressure is caused by the inertia generated when the head is moved up and down. If the nozzle and the shaft are not in a straight line, there is a little whip – or overpressure. Overpressure causes a change in positioning accuracy, which is determined by the speed of movement, the weight of the nozzle, and the weight of the component. By eliminating overpressure, direct alignment reduces the number of negative factors associated with component pick-and-place placement (Figure 2). Figure 3 nozzle design. Variations in the design of the nozzle are an important factor in allowing the 0201 component to be received. In order to draw a 0.6×0.3 mm component, the nozzle must have an outer diameter of no more than 0.40 mm. This forms a long, thin nozzle shaft that is fragile but must also maintain precision to maintain high reliability of suction. Changes from the linear axis to the tapered design increase the nozzle strength and allow the nozzle to resist bending (Figure 3). Matrix structure. All machines generate vibrations during operation. The base frame design is a key first step in reducing the speed and motion effects of vibration and harmonic resonance. By using a cast iron base frame and state-of-the-art structural technology, vibration and harmonic resonance can be reduced to a controllable level within the machine, so that negative effects can be dealt with. Up to standard Through all six key factors, the obstacles to reliable 0201 placement have been eliminated. As a result, R&D’s focus has shifted to newer, smaller components, and 0201 is no longer considered a leading edge component packaging technology. For 0201 component placement, the accepted process window is approximately 75 μm X and 75 μm Y at 3 。. To achieve 6 贴 placement reliability, the X and Y tolerances must be reduced to 50 μm. The latest high-speed placement equipment has a rating of 66μm with an actual standard deviation of approximately 35~45μm. As the 0201 component becomes more widely used and the manufacturing process becomes tighter, improved accuracy can be achieved. The difference in component size between suppliers poses a challenge to 0201 feeding and placement. Bulk feeding is being opened and should be available in 2001. Although the machine now has this capability, only a small percentage of users will be ready to take the 0201 placement in the next 12 to 24 months. This is similar to the introduction of a ball grid array (BGA) and 0402 components, in which the machine’s capabilities are ahead of the process state.
Challenge ahead While the placement of 0201 components is now a standard feature of new placement equipment, additional work is needed to improve the overall process for the end user. The relationship between machine builders, component suppliers, board manufacturers, formwork factories, and solder paste manufacturers needs to be strengthened to create a more seamless development process. The end result will be a unified understanding of the process and a better working relationship that will benefit end users, especially by making new production technologies faster and more efficient.
Bulk material handle method and process on SMT production line
SMT patch bulk material problems have plagued many SMT people, as we all know, once the placement machine starts, there will definitely be a problem in the SMT production line. For a variety of reasons, many bulk materials are produced, thrown, or are originally bulk materials, or other reasons. Some bulk materials, such as resistors, capacitors, inductors, etc., are not easily distinguishable and have little value in themselves, and there is no value for reuse. However, for large devices, especially some imported chip components, they are of high value and can be distinguished and distinguished, so they are generally reused. However, for scattered components, if the original package is a tray or a suitable tray, the problem may be solved better. Otherwise, it may be more difficult to handle. Southern Machinery today will talk about the handling of bulk material in the SMT production line. Method and process. First, the bulk material handle process
Collecting materials – material personnel sorting materials – using electrostatic bags to pack – paste material specifications – technicians based on bulk material springboard – hand paste bulk material – QC confirmation
Second, the definition
Bulk material: refers to the components that are separated from the original packaging during the production process due to machine throwing, or loading and unloading materials.
Third, job responsibilities
Material staff: responsible for the collection, classification, identification, storage, placement, and placement information of bulk materials, and the material loss rate is calculated according to the order.
QC in front of the furnace: responsible for the manual placement of bulk materials, the front back grain and material code confirmation, PCBA mark, and the classification of bulk materials.
Technician: Responsible for programming, patch production, monitoring patch quality distribution and timely improvement.
QC after the furnace: It is responsible for checking and checking the first piece of all the machines, and the quality is abnormal. Immediate feedback is provided to the front station to improve and track.
Fourth, the work content
In the production process, the material may be thrown due to equipment and other factors, so the operator should check the material step before the patch and after the shift, and check the throwing box and the trash can each time the garbage is dumped. Collect the bulk material and report to the supervisor about excessive bulk material anomalies.
According to the shape of the components, the bulk material is classified according to the shape of the components, and the back code of the components is checked to determine the material code. Then, the checked bulk materials are packed in anti-static bulk box or bulk bag, and the material code identification is performed to confirm the signature of the person. .
When using machine mounting, the operator should first check whether the components are consistent with the normal materials, confirm the material number, and then load the FEEDER tape.
The first piece of material feeding / mid-way refueling, the technician firstly inspects the materials that will be short of materials in the machine half-hour in advance, and collects the materials of the same item number in the component preparation area, and check them correctly, and submit them to the quality department QC/materials. The staff will check again and confirm the total signature of the refueling sheet.
Automatic wave soldering machine is currently the mainstream of electronic products welding process, compared with other manual welding with a variety of manual, has unparalleled advantages, and thus widely used by electronics manufacturers. The automatic claw wave soldering machine produced by our company is the most advanced using modern high-tech technology.
The new design of crystallization:
(1) Unique automated preparation program;
(2) Perfect work/adjustment function;
(3) The temperature is controlled by the temperature control table of WINPARK. The speed is high and the precision is high. It is suitable for long-distance transmission in harsh industrial environments and has high reliability.
(4) The chain speed is controlled by the frequency conversion speed control motor, which is easy to adjust.
(5) Solder joints are of high quality, easy operation and good service. They are reliable products in this industry.
Thank you for your inquiry and use this machine, thank you very much! Before use, please read this manual carefully. It will provide you with all the functions of the machine thoroughly, and it will be fully utilized in production.
a) Confirm that the machine is connected to three-phase ac380v, 5- line power supply and ensure the machine is grounded properly.
b) Open the total air switch and the switch in the electric control box, then open the power switch on the operator panel.
c) The machine Time control switch is lit, at this time presses the manual/The automatic switch icon, the time control switch displays On state, touch screen lit
d) Touch ( enter ) the button until you enter the operating interface, please refer to the instructions.
3.2time-controlled switch operation instructions
Instructions for use (Time controller is not used for a long time, every three months need to charge once, the charge times <12 hours)
1. first use, or long time after use, when the controller is not displayed, please after the power, with small items in the lower left corner of the hole open.
2. when powered on, the timer is 24-hour system, please hold the “clock” key for 5 seconds, the monitor will display AMin the upper left corner, indicating that it has been the hour system. Press 5 seconds and return to the hour system, at which time AM display is turned off.
(12 hours When AM is the morning, PM means the afternoon)
3. Set switch time: (if the set opening and closing time is the same, the time controller relay suction for a second ) set steps:
Set up a project
Press (SET) (??)
Enter timed setting (show 1 on)
Press (Week) (??)
set every day the same, or week 1-5 the same, week Six Sunday the same, or daily different (if the same daily, you can not press this key, this time does not show the week, while correcting the clock also
No need to press this key)
Press(time) (?)(? )
Set Time to open
Enter the timer setting (show 1 off)
Press(time) (? )(? )
Time to set off
Press (week) (??)
If the date of the set off is the same as open, you may not press this key
Repeat 2-6 steps
Set the 2-8 times switch time
End Time setting
* If you do not need 8 switch timing, press (clock) key can be into the clock correction.
* If set error or cancel set this press (clear)(??) key, and then restore the original settings once again
* Display without setting (–:–)
4.1Press Live (Clock ) and repeatedly press (week ) to the same day. ( if the daily set switch time is the same, can not press this key, direct correction time, points)
4.2Press and hold (the clock) and adjust the time by (time) or (minutes).
5.when you have completed the above operation, pressThe Open/Auto/ off ” key, be sure to base your current time on the set of self
controls the time switch, causes the monitor the most downlink to display as (on / off ) or at off(auto / off)
Indicates that the timer is in automatic control and in the open state
Indicates that the timer is in automatic control and is off state
Indicates that the contact is in a connected state but the timer does not switch on the set switch time
Indicates that the switch time is invalid in the long shutdown state.
6.check: Press (set) key to check whether the time set is correct.
7.Modify : please press (clear ) The key at the setting , then reset the time and week of the timing switch.
8.End check: Press (clock) to finish checking and setting, display clock.
9.Manual control: Press (ON/off/off) key, can realize random switch
1.Open The setting of time, can not cross set, should be set according to the order of time.
2.Implement timing Switch Controlsystem Time to set the state in the auto , that is, show on / off (on) or from Move / Close ( at off).
3.The use of the environment should be in line with the environmental requirements of the controller, to avoid vibration, shock, corrosion, dust, electrostatic, high-temperature, high-temperature, direct sunlight environment to use.
4.Please store it in the rated voltage and temperature and humidity condition.
5.maximum current refers to the maximum current when resistive load, lamp current = rated current x20%, motor current = rated power Flow x30%, please use in the specified voltage and current range, if exceed the specified capacity, please contact the AC contactor.
Chapter 4 Interface Operation
4.1 when the machine electric source button is opened , touch the screen into the Welcome interface ( figure 1 ), waiting about Ten seconds, after the completion of the PLC , the machine automatically open tin furnace heating function.
Figure 1 Startup initial interface
4. 2 Click to touch the screen into the Secretary to introduce the painting surface, such as ( figure 2) Click into the system
Figure 2 Company Introduction
4. 3 Click into the system , touch the screen into the machine to manipulate.the painting surface , as 3.
This painting surface controls all the operation of the machine,
including the manual mode and the self – moving die style.
4.3.1 : Manual mode: Touch screen left upper corner display manual (click to Automatic), manual mode, click Transport, open the chain claw
transport function; Click Preheat, turn on preheat function (must turn on transport to turn on preheating); Preheat temperature to reach, click on the peak, according to the actual product to open the crest, unicast or double wave (long leg wave soldering only a valid), generally only in the back of the red glue patch components need to open the double wave, at this time the peak has been running , the technical personnel can adjust the crest height according to the actual situation; Click on the spray, click the spraying, spray has been working, at this time can adjust the spray size, close to spray, the spray becomes automatic state.
4.3.2 : Automatic mode: Click on the touch screen in the upper left hand corner of the manual switch to Automatic mode, point Open Transport, preheating, as needed to open the crest, spray fog. In the manual mode after adjusting the machine state, at this time the machine can be normal production, when the circuit board into the machine, machine automatic spray, automatic spray, automatic wave soldering.
4. 4 Click on the machine in the lower right corner of the EEG map , the machine into the set interface , as shown in Figure four , this screen is used to set the machine‘s shipping parameters. Spray Distance: This parameter sets the automatic spray time when PCB The board is
transported to the top of the sprinkler start spray, recommended set value to 7 , if PCB
The office has not reached the top of the nozzle has been opened Start Spray, then change
this parameter large, conversely, if PCB after the board is over the nozzle before
beginning to spray, then the parameter is adjusted small;
Spray coefficient: This parameter is not set;
Wave Distance: This parameter is automatic Qipo parameter, when the PCB board is
transported to the front of the tin Furnace, automatic Qipo, this parameter and spray
distance set the same way;PCB board in distance tin furnace 20cm
The peak effect is the best when it is opened.
Wave time: This parameter is the peak after the automatic start of the operation time, it is recommended to set the 50-80.
Figure 4 parameter setting screen
4. 5 Click Control Screen left -pointing arrow chart , into the machine– like monitoring Screen , this screen is used to monitor the operation Status of PLC .
Fig . 5 The status monitor drawing surface
Chapter 5 Installation Adjustment and Commissioning
5.1 Machine Adjustment
After the machine positioning, the level adjustment, first the Foot Cup, so that the rubber wheel off the ground water leveling ruler on the machine to adjust, must make it in a horizontal state.
Adjustment of rail height
(Note: Tin furnace before shaking out, the first tin furnace trolley and rack fixed connection code loosened, and then the tin furnace height lowered, so that the tin furnace nozzle and titanium Claw in the height of a certain gap to avoid damage collision.) The tin furnace can be smoothly shaken out. Note: The foot wave soldering furnace to disconnect the titanium claw first
5.2 Adjustment of Plate feeder
Installation of the machine to install the first access to the plate feeder, the board will be connected with screws fixed, with two
PCB Board to adjust the docking plate, a piece of PCB into the titanium claw inside clamping, a PCB board placed in the plate feeder, two PCB board docking up, By adjusting the plate to the side of the four screw wire To adjust the height of the board connection, so that the two PCB board height parallel, through the adjustment of the machine, such as plate connected to the side of the rice screws to adjust the parallel to the plate feeder and titanium Claw, two fast PCB The joint of the plate butt is completely kissed so that the plate feeder has been installed and adjusted.
Adjustment of 5.2 guideway width
The width of the guide rail can be adjusted according to the different width of the printed board, the printed board Pinto on the Import board, and the printed board side to the fixed edge of the import plate, the rotation width adjustment handwheel to the printed circuit board can be placed on the guide, and can be moderately pushed to the conveyor chain claw mechanism
1. Can not hold too tight or loose, too tight will cause the chain claw and plate deformation; Taisong may appear drop board or PCB side stop affect the quality of welding.
2. before adjusting the width of the chain to check whether the two sides of the solder furnace nozzle plate, if you can touch, it is necessary to increase the guide or reduce the tin furnace, so that the chain claw higher than tin furnace spout Guide.
5.2 Adjustment of Tin Furnace
The height adjustment of the tin furnace can be completed by the tin Furnace trolley lift, and the height standard is approximately 6mm~8mmfrom the top edge of the nozzle by the base board component foot.
5.3 Conditioning of preheating box
The position of the preheating box is fixed before leaving the factory, and can not be easily changed, the preheating box should ensure the bottom
The temperature of the face is between the 80?-180?.
5.4 adjustment of flux spray height
The spray height adjustment is done by adjusting the nozzle height and adjusting the appropriate air pressure and gas.
Loosen the screw that the nozzle is connected with the shaft, the nozzle can be moved up and down, and appropriate adjustments can be made according to the actual needs.
* The adjustment of the volume of wash claw liquid. (see chart below)
4.- Chain Claw
The claw pump has a switch control in the touch screen and requires alcohol in the alcohol box and turns on the drive Chain to open
Claw Washer is to ensure that the chain claw clean, to achieve solder quality one of the factors. The device uses a loop-back -flow design, the chain claw through the alcohol moist brush cleaning, flow through the control valve. The capacity of the alcohol box should be Paute 2/3 or more, otherwise the pump will burn, every two days will wash the claw box out of the tin slag clean.
Note: Do not turn the adjustment switch too large and the alcohol overflow machine, so as not to cause a fire.
after the equipment is installed, the equipment should be fully checked, and after the system and mechanism are working normally, then put into normal use.
* Prepare Equipment
flux approx . 20L
Cleaning Lotion about 12L
Solder lead -free solder 400kg
Electric Stove 3Kw 1
Stainless steel tank 1
* Molten Tin
The solid solder is poured into the stainless steel container in batches, heated to the furnace to fully melt ( about the? ), and then poured into the tin tank of the equipment, when the solder liquid surface is about 8mm from the tin Groove mouth , Stop feeding start-up equipment, the tin furnace temperature preset for 245?, to tin furnace temperature, start the crest, adjust the crest height, check whether the crest is normal. Josi surface is low, at this time can be the bar-shaped solder directly into the tin furnace, adjust the tin surface to fit. Note:a. Tin Tank for the first time, the Solid Tin Bar ( block ) material directly into the tin furnace to melt, In case a large amount of heat can not be passed to the solid solder in time, resulting in high-temperature burning tin trough and heating pipe. b. Before dissolving the tin, the tin trough and the stainless steel container should be cleaned to prevent the impurity from polluting the solder.
* Check Flux Spray Condition
The flux is injected into the rosin groove, connected to the gas source and activated. “Spray Fog ” , check whether the spray is normal. the proportion of flux in accordance with the requirements of manufacturers and actual use of the situation, can be 0.80~0.87 within the scope of appropriate adjustments. ( manufacturers are best to provide free cleaning flux)
Check the transmission, adjust the body is normal, respectively, start the transport, washing claws, cooling, preheating and so on, check is normal, commissioning completed.
Chapter 6 Inverter Description
(See VFD-M Manual and temperature control sheet , This manual is presented in conjunction with the instructions )
Chapter 7 Spray Type Rosin Furnace
7.1 composition of rosin furnace
Rosin furnace is made of stainless steel, sealed containers, flux stored in this will not evaporate and absorb moisture in the air, and maintain a stable solvent composition, and with high-precision import nozzle and Germany or the United States rod-free cylinder, imported light eye, is currently the most ideal welding equipment users. The structure is shown in the figure below.
7.2 correct use of rosin furnace
the height of the rosin spray can be adjusted (see spray height adjustment), can also adjust the solenoid valve on the airflow regulator or pressure regulator on the air conditioner, the factory has been adjusted so easy to change, to avoid making into the spray system chaos, when working when the substrate through the input photoelectric tube, time control system started, and began to delay spraying and spraying tin until the substrate through the rosin furnace 3-5 seconds to stop spraying.
Note: The flux must be clean-free dapoxetine type, which is characterized by the plate surface after welding without ultrasonic cleaning, clean and beautiful board.
7.3 instructions for the use of nozzles
I, the safe operation of the case of special attention to the following matters:
7.3.1. Take appropriate precautions before use to prevent injury to the human body or damage to the product.
7.3.2. Do not point an open flame or close to an open fire place, to avoid static electricity.
7.3.3. In the installation or maintenance process should be all fittings with raw tape, such as the connection slack, in the gas
Under the pressure of the body, various liquids will be sprayed into the body.
7.3.4. When connecting the air pipe and the solvent pipe, please select different material and pay attention to the pressure of the hose can not exceed the regulation, do not use the damaged old trachea.
7.3.5. Often clean the nozzle on the solvent, the residue on the road, may cause trouble, is in the direction of people can not press the switch.
7.4.1. after Regular cleaning nozzle to ensure smooth nozzle.
7.4.2. always keep the liner slide clean and lubricated, no solvent immersion, so as not to affect the rod the normal use of cylinders.
Chapter 8 Preheater
8.1 the role of Preheater
The role of preheater is to increase the expansion rate on solder pads by preheating the flux activation and
To promote the evaporation of the PCB flux solvent, thus obtaining the best soldering effect. In addition, the circuit board after preheating, reduce the PCB and tin furnace temperature difference, to avoid the thermal impact of electronic components and circuit board sudden thermal deformation.
the optimum temperature for preheating is 120~180?. The temperature is too high can cause undesirable consequences; too low temperature affects welding quality.
8.2 The construction of preheating box
the preheating system is composed of imported blackbody heating pipe. The Preheating box and the guide rail are connected by screws to facilitate the inspection and maintenance of the line.
The best preheating temperature on the circuit board is 120-180 ?, the temperature of the preheating box is passed by the high accuracy temperature probe to the preheating electronic thermostat to adjust, can accurately control the preheating box temperature, protect the circuit board, achieve the most ideal preheating effect.
8.3 Daily Maintenance and Precautions
8.3.1 The temperature of the circuit board’s bottom surface is often tested to ensure that 120~180? between the two to ensure the best solder effect.
8.3.2. Check whether the circuit wire aging, in order to prevent current interruption.
8.3.3. Clear the flux residue in the drawer of preheating box, lest the set will cause fire.
Chapter 9 Tin Furnace
Tin furnace structure using stainless steel production. By the wave generator, nozzle filter, impeller, motor and other groups
Yes. The use of pump-type principle to form a crest.
Tin furnace structure is reasonable, high technical content, the use of Japanese and American tin Furnace advantages of the development of high standard tin furnace. Its characteristics:
1 reduce the tin oxidation to a minimum.
2 nozzle wave smooth, tin surface can be adjusted vertically to adapt to different PCB board welding requirements,
3) External heating effectively avoids the phenomenon of explosion tin, good insulation performance, tin furnace durability does not deform.
Tin furnace body is by corrosion-resistant stainless steel plate welding into, heating tube installed in the tin furnace two outside. Use
Plate to radiate heat, so that the temperature uniformity of the tin furnace, the overall heat balance does not deform, spray cavity set up without clogging nets,
Can keep the peak smooth and smooth, and not plug, thus reducing maintenance, improve efficiency.
9.2 correct use of tin furnace
Tin Furnace high and low and in and out of the mobile can be used to set up the joint hand wheel and lifting screw adjustment , adjust the tin Furnace crest can be adjusted by the frequency converter, the higher the impeller speed, tin furnace crest is higher;
Solder temperature controlled by the thermocouple in the tin Furnace. First of all, the expected solder temperature set, usually the normal solder temperature is 230-250 ?.
In the back of the tin furnace with a row of tin Tsui, used to clear the tin furnace. The tin furnace to the back of the removal, cleaning and maintenance, before the tin furnace removed, must first be the guide rail high or tin furnace to reduce a certain height to avoid the rail chain claw and tin furnace collision caused by the chain claw deformation.
In the demolition of the furnace, referring to the structure shown above, the nozzle removed first, the motor frame and impeller out, loosen the furnace liner fastening bolts, you can remove the furnace.
9.3 Daily maintenance and precautions
9.3.1. Regularly check the amount of tin to control the “spray tin wave.”
9.3.2 . measure soldering temperature with mercury thermometer ( standard temperature0?). If the preset solder temperature is unstable , it can be adjusted in the temperature control table.
9.3.3. Depending on the resulting oxide, add antioxidant grease. (Anti-oxidation grease and flux supporting use)
9.3.4. Frequently remove oxides from tin furnaces.
9.3.5. Check the tin furnace motor coupling on the machine rice and impeller shaft coupling machine meter and its operation, to ensure its normal operation.
9.3.6. Pay attention to check the wire has no aging, as well as the parts of the screws, nuts are loose.
9.3.7. Spray nozzle every day after work with alcohol automatic cleaning, lest block.
Chapter 10 Maintenance and precautions
1. Often the fuselage, transport, claw pump, cooling fan, such as motor housing cleaning to facilitate the cooling and insulation.
2. Regular inspection of electrical control box in the electrical appliances and fastening the screws on its terminals, such as the discovery of contact ablation, suction and not flexible, etc., should be dealt with in a timely manner.
3. Regular inspection of preheater, tin furnace heating pipe joints, such as the discovery of head loosening, poor contact, insulation aging and other phenomena should be tightened, clean and replace.
4. Regular inspection of equipment to protect the grounding device is good.
5. In the operation of the equipment, pay attention to monitor the shell temperature of each motor, overheating phenomenon should be stopped check.
6. When the general switch on the power supply, should first stop the tin Furnace, preheating and wave crest and other large current load before entering
7. After the main power switch trip, you must find out the cause of the failure, before the closing.
8. In the process of melting solder and injecting high temperature liquid solder into the welding furnace, wear protective articles to prevent
9. Flux, Wash claw liquid are flammable materials, use should pay attention to fire safety.
Ten after working every day, you need to clear the flux residues in the preheater to prevent accumulation. cause an open flame.
11. The limiter can not be added lubricating oil, so as to avoid the transmission chain claw not go.
12. Anti-oxidation wax (oil) should be used with flux to avoid fire.
13. Each transmission part should maintain the good lubrication, except the angle adjustment mechanism may use the ordinary ointment, other all uses the High-temperature ointment lubrication.
14. The tightness of each transmission chain should be checked and adjusted regularly.
15. Regular inspection of tin furnace speed motor lubrication and operation, to ensure its normal operation.
– Tin furnace Nozzle should be based on the peak stability, the peak when the exception to clean the nozzle, so as not to affect welding quality.
18. Spray nozzle should always check the tightness of its connection.
Chapter 11 Wiring
This equipment needs external 3? , ac380v,50HZ power supply ( three-phase five wire system ), power supply capacity
The quantity is not less than 20KVA, the equipment shell should protect the grounding, the grounding resistance ?4?, the grounding conductor is not less than
4mm2, the incoming line should be no less than 6mm2?
Chapter 12 General Trouble shooting
To ensure high quality, the devices used in the equipment are advanced industrial countries of high-quality products, such as million
In the event of an accident, please check each of the items listed in one table. If you are still unable to resolve, please contact the company directly.
All action buttons are invalid
1. Time is not in the state of timing
2. The tin temperature is not up to the set value
1. Set the scheduled boot time before the current time.
2. Wait until the temperature of the tin furnace, then operation.
Control power LED not lit
1. Power supply Missing phase
2. Fuse on the bottom plate of the electric vessel
1. Overhaul power supply.
2. Check whether there is a short-circuit phenomenon in the lights, etc.
In addition to the failure, replace the new insurance pipe (4A).
Power supply Total Switch tripping
1. Load and line occurrence short-circuit phenomenon
2. Power supply Total Switch Contact bad
1. Check the load and related lines, troubleshooting short-circuit.
2. Check the wiring area of the power supply master switch for appearanceloosening, heating, oxidation and whether the switch contact point is outcontact is bad, ablation and other phenomena, or to be seized
repaired or replaced.
Tin Furnace or preheating
Slow warming of the device
1. Power supply is too low
2. Additional Hotline(tube)partially damaged
1. Improve the quality of power supply.
2. Replace the hotline(tube).
Transport Claw not running
1. Transport motor shaft end of the drive chain skid, Force nut Loose
2.chain speed set to “0”
3.fx-2da or inverter damage
1. Fixed nut for fastening drive sprocket.
2.chain speed set to not “0” position.
3.fx-2da or inverter.
Failure and solder welding problem analysis
Press the button to press,But the LEDs are not lit
1. Total switch not open, emergency stop switch not open
Clean copper foil and component ends;PCB, components for long-term storage, research flux is no problem, for new flux.
Out of the tin pillar
1. Copper foil surface, component ends of oxidation and pollution
2. Solder welding of flux is not good
3. The chemical changes of the coating flux and copper foil4. Flux metamorphism
Clean copper foil surface, fully preheat, Preheat temperature standard: Aldehyde circuit board to
– ?, epoxy circuit board120 to?
(Solder surface temperatureadjustment flux, eutectic solder , temperature for250~260? circuit boardand tin liquid contact do not exceed the road plate thickness of the 1/2. Reduce the height of the tin liquid to adjust the speed of transmission , research circuit board design, in
Circuit board coating Protective film.
The occurrence of the lap
1. Copper foil surface, component ends of the oxidation of pollution
Use of PCB Pallets in Wave Soldering Patch components are used more and more on the circuit board, but there are still some perforated components between them. For this kind of board, selective soldering is the best solution, but not every company has enough funds to purchase selective soldering equipment, or the number of this type of circuit board is too small, specifically to buy selective soldering equipment is not Cost-effective. Manual welding is prohibited in certain industries such as the automotive industry
Therefore, in PCB wave soldering, using trays to block those patch components is a good method: reliable, fast production, and adaptability to high-capacity requirements.
The benefits of using trays: Lead-free soldering requires higher soldering temperatures. Therefore, the circuit board is more easily bent during welding. The tray provides maximum protection of the circuit board during soldering and prevents bending.
Similarly, in the automotive and consumer electronics industries, many special-shaped circuit boards have emerged for the needs of applications. It is sometimes difficult to transport these shaped plates with conventional chain rails and mesh belts, and placing the circuit board plates in trays allows any type of circuit board to be shipped.
By soldering some of the bottom components through the tray, it is also possible to use PCB wave soldering equipment for selective soldering of the product.
Since most trays are thick (sometimes 15 mm), solder certainly does not flow to the top of the board. The oxide layer on the solder surface will also be washed away by the edge of the tray before the board reaches the peak, so that when the solder starts, the tin is relatively clean.
By adding some stiffening strips to the tray, it can increase its hardness to withstand high-strength welding. It is also possible to install heat-absorbing blocks, component fixing devices and some other auxiliary devices on the upper part.
The use of pallets also helps standardize the width of the product line, soldering different circuit boards on the same production line, and can use bar code readers and other identification tools to quickly change process programs for different boards.
Although there are many advantages to using trays in lead-free soldering, it can also cause solder balls.
Requirements for pallet materials: In order to maximize the service life of the trays, the trays must be made of materials that can withstand high temperatures and harsh process conditions, especially for lead-free soldering.
To meet these requirements, the material used to make the tray must meet the following characteristics: • High dimensional stability • Good thermal shock resistance • Can remain flat after repeated use • Corrosion resistance (flux and cleaning agent) • Does not absorb moisture
The use of the tray brings the process problems: The flux system must be able to spray the circuit board completely with flux. Poor tray designs can lead to “shadow effects” in flux spraying: Some parts of the board have insufficient flux or no flux at all. The flux must be sprayed onto the board and spread through the capillary action.
Before the tray touches the crest, it must be heated in the preheating unit. A typical preheating configuration is a combination of heat pipes and hot air forced convection. If the temperature drops before contact with the peak, the tray will have an endothermic effect, making the welding process difficult to control.
The use of trays requires a wave height of up to 0.5 inches (12.5 mm). In the case of such a high pump speed, the use of nitrogen can help reduce dross. When using pallets in lead-free soldering, Vitronics Soltec’s perturbed “smart wave” can also promote tinning of the perforated component.
In addition, we must pay special attention to keeping the circuit board in the pallet flat. If there is a gap between the circuit board and the tray, the flux will flow into the gap, and the solder will flow to the board when passing through the peak. This will cause solder residue on the board.
The gap between the circuit board and the tray may cause solder residue on the circuit board
Circuit board and tray design recommendations: Avoid placing larger components near the piercing element as this can cause shadowing effects and tin difficulties.
Leave proper clearance around the pins and edges of the through-hole components so that solder can flow. These tin guides will guide the solder to the seat of the tray opening, while also greatly improving the solder flowability.
The tin slot at the tail of the tray allows the solder to flow smoothly back to the tin tank
The opening of the tray should be as large as possible to facilitate the flow of solder. This will reduce some of the welding defects, such as: short circuit and solder balls. At the same time, it is also beneficial to the solder filling of the through hole, because the large opening also means that there is more energy to enter the welding area.
How to prevent static electricity in the process of SMT placement machine?
In the SMT production line, we will encounter the problem of static electricity, from the friction between the clothes and the dry air to the dry air, which is the end of the duckweed. If the condition is suitable, it is a few volts and the peak is hundreds of kilovolts, so anti static is the need to do in our work, today, the south. Give some measures to introduce mechanical anti electrostatic patch SMT.
Static electricity has three: static clothing, antistatic shoes (conductive shoes), electrostatic hand rings, antistatic shoes and electrostatic hand rings to guide the human body to avoid accumulation in the human body. Ordinary clothes will have great electrostatic voltage in the walk (>1000V). And antistatic clothing does not happen when it moves. This is the main role of antistatic clothing, long strip antistatic clothing can not shield the inside of the clothing produced static (after wearing still >1000V), grid – like antistatic clothing can be shielded (<200V), the static electricity generated through the floor and the grounding line of various parts of the plant to the outside of the general grounding wire.
1, strengthen the consciousness of the workers on the anti static operation
2, reduce the poor production caused by static electricity
3, prevent static electricity from causing damage to the product
二，Scope of application: all SMT production lines
The generation of static electricity is not perceived, but the static electricity produces the voltage of tens of thousands of volts. When the static electricity comes into the tip (the static release point, such as the human finger), it releases all the energy in a moment, causing the contact material to be struck by electric shock, causing the capacitance, IC, line road and so on to be destroyed and burned, so that the product is strict. In the case of heavy damage, static electricity measures should be taken. .
四，The contents of the operation
（一）Prevention and treatment of human static electricity
1, the workers should wear electrostatic clothing, work shoes;
2, the operator should take electrostatic gloves when working.
3, the operator should take an electrostatic ring in the operation.
（二）Prevention and control of static electricity
Make use of electrostatic materials to produce production tools.
2, the storage place to prevent static electricity;
（三）Prevention and control of static electricity of a worktable / mobile vehicle
1, the anti static film should be pasted on the work table.
2, the operation platform / mobile vehicle must have antistatic grounding chain.Prevention of equipment static electricity: good grounding wire
（四）Prevention and control of material static electricity
When the material is taken, the operator should use the antistatic method: with electrostatic gloves and electrostatic rings.
2, the material storage should be anti static measures: material cabinet to paste electrostatic film, grounding chain.
3, there should be anti-static measures in temporary storage area: installing grounding chain.
（五）Prevention and control of static electricity related to production: anti static measures should be taken when using items related to production: static wires and antistatic films.
The online operators should strictly abide by this rule
The online operators are supervised by the team leader, and the engineers are supervised by the engineers.