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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At present, laser marking machine is suitable for most materials produced in various industries, so it is widely used in a variety of materials, such as metals, glass, ceramics, plastics, leather, etc. can be permanently marked with high quality. There is no force on the workpiece surface, no mechanical deformation and no corrosion on the material surface. So how to choose a laser marking machine? Let’s discuss something today.
1，The quality of laser: As laser is the crucial part of the whole machine, its quality determines the machine’s quality. In general, the imported laser will be better, its beam quality is good, the electro-optic conversion rate is high, and the domestic laser is slightly inferior, but the homemade laser can also meet the needs of any industry.So if you have a limited budget,then the homemade laser is a good choice.
2. The cooling device.The cooling equipment of machine can be judged from the following aspects: (1) What’s the cooling water velocity? (If the speed of cooling water is fast, the heat dissipation will fast as well) (2) Whether the water pipe of the cooling system leaks, if dew, will also affect the power of the laser.
3. The quality of laser lens. The better laser lens, the more reflected laser beam, and the smaller the laser loss, which is conducive to increasing the electro-optic conversion rate of laser marking machine. There are two kinds of lenses: the imported one and homemade one, the homemade also divided into imported materials and homemade materials. The service life and use effect will being effected by its price .
4. Laser operating software. You need to confirm whether the software is original genuine development, pirated software will often appear light leakage, power consumption, performance instability, short service life, high maintenance costs. 5. After-sales service. You need to acknowledge if the supplier can offer this service like deliver, training, debugging and so on.
Laser marking machine has 3 main parts: laser, galvanometer and laser software.
There are many types of laser marking machines. First of all, you should make clear the scope of production, processing materials and processing capacity of our enterprises, and then determine the type and quantity of equipment to be purchased.
When the PCB board goes through the machine, it brushes off the surface dust and particles and sucks the dust away through the suction device
Necessity of Using PCB Cleaning Machine
Our independent research and development of PCB surface cleaning machine, before the solder paste printing, the printed circuit board surface dust, glass fiber and surface stains and other clean, the PCB surface has been sticking 0402 or 0201 components can also be carried out clean.
Structure and Function
1. When the PCB board goes through the machine, it brushes off the surface dust and particles and sucks the dust away through the suction device
2. PCB board import and export parts with the elimination of static electricity devices to reduce the negative effects of the patch produced by static electricity, and electrostatic damage
3. When the dust transition cleaning brush wheel needs to be cleaned, the brush structure is pulled straight out of the cleaning, easy to use, each cleaning can clean about 300 PCB
1. Function modular design, according to different work needs to switch, great flexibility
2. Panasonic PLC control system, easy to operate touch screen control interface.
How to produce SMT high quality products? (for aviation, aerospace, medical products) SCM5600D off-line automatic PCBA cleaning machine is an energy-saving environmental protection, batch cleaning, integrated high-end cleaning machine. It can automatically complete cleaning, rinsing, drying process by just push the start key.
Mainly used for aviation, aerospace, medical, new energy, automotive electronics and other products . This machine can effectively clean residual rosin flux, water-soluble flux , No-clean flux / solder paste ball and other organic and inorganic pollution materials on SMT / THT PCBA.
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.