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]
1,Please visit : www.smthelp.com
2, Find us more: https://www.facebook.com/autoinsertion
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 SMT workshop planning? It turned out to be so useful.
How SMT workshop planning!
And only after the plant began production found that some areas have not planned beforehand, need to be adjusted, resulting in a waste of human and financial resources and valuable production time.
Therefore, it is important to check in advance SMT factory layout, especially for new SMT factory business, because there is no experience in SMT plant layout, the need to pay attention to the elements is not very clear, if we find a problem in the layout after production point, will cause some unnecessary losses.
So, when doing layout SMT plant, what to pay attention to what matters in advance to do to prepare? Here actual cases where we work to and we explore this problem.
planning SMT line configure
the client recent planning new on two identical SMT production line, specific device configuration (see FIG. 1) and the size of the apparatus is as follows: According to Figure 1 can be seen, the maximum width of the production line equipment is 1.71 m, the length of all devices sum is 13.6 meters, will add future planning a production line (line bulk on equipment configuration).
Workshop length 36 m, width of 12 m, an area of 432 m2, on the ground floor of the factory. Currently common ground for the shop floor, and no established anti-static system, can not meet the requirements of SMT antistatic workshop, but two conductive ground terminals, can establish subsequent workshops antistatic SMT system. Further, there is no air conditioning workshop and humidifiers, can not meet the requirements of SMT workshop temperature and humidity control. There workshop ventilation system, back to meet the requirements of the reflow furnace equipment. Workshop sufficient power to meet the electricity needs of all equipment in the workshop. There are two entrances whole plant, as are required to meet the equipment, raw materials and semi-finished channel. Special materials warehouse in another workshop, the need for planning. Good lighting conditions in the workshop, to meet the brightness of the SMT shop lighting requirements all stations. Whole plant layout situation shown in Figure 2.
1, the current new move into production lines and related aids, regional positioning;
2, the whole plant to meet future erection and production requirements three production lines, without planning zone realignment;
3, each production line starting position as consistent as possible, so that the whole plant orderly arranged in three lines.
analysisthe customer’s request, we first analyzed how the production line positioning; and before locating the production line, we consider the following points:
1, SMT equipment should avoid column and they maintain a certain distance, the distance is equipment installed at least after a good feed material by a vehicle;
2, SMT crossing equipment required for frame division pitch, and the crossing equipment to extend outwardly after the device installed above the material 50 cm;
3, optimal spacing of the two lines spaced more than 1.2 meters between the outer frame;
4, check the wire tail is generally a repair plan area, quality control personnel can perform sampling line tail region.
Based on the above considerations, the length of each line should be at least 13.6 meters (without regard to the maintenance area and the tail, the case where the sampling area and the thread area kanban), the width should be 2.7 meters (SMT feeding both surfaces), specifically as shown in Figure 3.
Therefore, the production line is positioned in substantially considering plant shown in FIG. 4.
Some details of the requirements of SMT plant layout
after determining the approximate location of the production line, when the need to consider some details of SMT production line requirements, and then to determine the exact location and the location of other auxiliary equipment SMT line.
First, we analyzed the SMT line position and aids required for each area requirements: 1, fire extinguisher drop zone;
fire extinguishers to be placed around the side of the post and SMT plant, placed according to the requirements of fire regulations.
2, the car rack placement region; car rack replacement for SMT production line models and switching material, in order to facilitate production and to improve the efficiency of replacement materials, preferably the vehicle is placed near the rack placement machine.
3, stock units rest area;
stock table mainly used in the production process and dryer materials stock preparation before switching, therefore, to be placed near the preparation station placement machine, and the best car rack together, Preparation facilitates directly on the car frame after a good feed material.
4, the shelf rest area printing station;
printing station for positioning the shelf aids in the production of printing presses, such as wipes, paste, alcohol, etc., to be placed in the vicinity of the printing press to facilitate removal use, improve Productivity.
region comprising placing solder paste storage refrigerator, solder paste mixer, paste warmed cabinets, can be placed next to the plant as required or uprights placed around a fixed area of the plant, However, to facilitate the operator to take place.
6, visual inspection after the furnace area, maintenance area;
in order to facilitate visual inspection after reflow and rework semifinished product, a shelf generally placed in the furnace, designed for the visual inspection of the furnace and rework.
7, screen placement area;
drop zone comprises a mesh screen plate was placed cabinet, stencil cleaningmachine, inspection tools, screen, stencil for storing, cleaning and inspection screen tension, etc., while in the region as much as possible to facilitate the production screen to take place.
8, garbage drop zone;
Production waste mainly from two parts, wipes and the like used in one printing operation, the second is to replace the waste tray and waste material produced with the like. Garbage two parts is generated to be placed separately, specialized recycling, in particular waste presses used. Thus, waste area may be placed next to the press machine or patch, or set beside the column region refuse placed separately placed.
9, kanban placement region;
kanban including the SMT billboards and other signage quality management, may be centrally located on the entrance into the shop, and also set up the production line Kanban state in which each head of the line, in order to view the producers and managers, promptly understand the current state of production status and quality SMT workshop and so on.
10, product placement area;
include products produced finished products in two parts, to separate the two partial regions divided out, strictly distinguished, in order to avoid confusion.
11, SMT placement of spare areas;
Nozzle including the SMT spare parts, a motor, a belt, cylinder or the like, to be placed in a special area, to facilitate the production of access.
12, location area temperature and humidity;
temperature and humidity conditions in order to better understand the SMT plant, depending on the size of the workshop area, several appropriately set the temperature and humidity measurement area, generally placed on the production line next to the column or wall.
13, SMT workshop office area;
let engineers and technicians and management personnel in office SMT shop floor, which can solve the problem on technology and management encountered in the production, to ensure the smooth operation of the SMT production lines.
14, anti-static protection area;
entry into SMT workshop area must have good anti-static measures. You may delineate the area in front of the plant, including the replacement of static clothing, shoes, hats and so on each employee’s locker. Also, the establishment of regional designed to test the static ring in SMT workshop at the entrance, so that each employee to do static loop testing and record test results before going to work. Based on the above analysis, the results of this SMT plant layout is shown in Figure 5.
In addition, SMT workshop also meet other requirements: 1, anti-static processing;
shop floor must be anti-static treatment, a common anti-static conductive flooring and paint and other ordinary places, customers can choose according to the actual situation. In addition, anti-static system must be set up in the workshop, to meet the requirements of the entire anti-static SMT workshop.
2, air-conditioning and a humidifier; SMT workshop to meet the requirements of temperature and humidity control.
3, the material management requirements;
in the warehouse, with particular attention to the way the material is stored, reel packaging methods, the use of hook-type place, wetting elements employed Cabinets for placement shelves to be treated with anti-static manner.
4, patch equipment gas and electrical circuitry;
preferably introduced directly from the production line at the down side of the roof, is arranged below the gas passage in the device and circuit wrapped with wire groove.
5, the ventilation system requirements;
needs to be installed to meet the requirements of the three power lines of the blower, and the third exhaust port reserved line.
1, according to the size of production line and the size of the entire plant SMT, completed the reasonable position of the production line; and
2, for aids, regions, etc. SMT production lines need to make the corresponding position location; 3, according to the SMT the characteristics of the plant, some of the necessary factors to consider in planning, in particular, anti-static; 4, in accordance with the requirements of the current situation and future development of the factory has been take into consideration, unified planning.
For SMT plant layout, but also requires a combination of size and product requirements and other plants to consider a number of factors, but to stimulate here.
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.
1. Obtain the proper shop packet and check order for build information. Pull all parts if any parts are missing, fill out a shortage sheet and give a copy to the appropriate material coordinator.
2. Pull the latest Electrical and Mechanical prints.
3. The following procedure is for a 29″ Destacker. Attach leg and control box to main beam. Leg should be flush to left side of main beam. Control box should be 3″ from right side of main beam. Attach width units to main beam, 4-3/8″ from either end square to main beam and Parallel to each other.
4. The following procedure is for the 44″ and 58″ Destackers Attach leg and control box to main beam. Leg 7-5/8″ from left end control box 7-5/8″ from right end. Attach width units to main beam 8.975″ from either end. Square to main beam and parallel to each other.
5. Attach rear rail to width supports parallel to main beam 3/8″ overhand from either end of main beam.
6. Level conveyor from side to side and front to back, off rear rail
7. Attach front rail to width supports. Match level to rear rail, especially front to back. Make parallel to rear rail. Make ends even with rear rail.
8. Install motors, pulleys, UHMW and belts on rails.
WARNING Do not perform any preventive maintenance with power on unless specifically instructed otherwise. Failure to observe this warning may result in personal injury.
CAUTION When performing machine maintenance, wear a wrist strap connected to ground to prevent electrostatic discharge damage to printed circuit boards.
500,000 Cycles Check: Perform Maintenance:
Clean the clinch scrap tube with the pipe cleaner (40940101) twice daily (every 250,000 cycles).
3,000,000 Cycles Check: Perform Maintenance:
Check for excessive wear on the pins 1. Lubricate the cutter linkage pins with Magnalube and linkage. Replace if necessary. (40833809).
12,000,000 Cycles Check: Perform Maintenance:
Check for worn cutters and bushings on 1. Replace if necessary. the cut and clinch by observing the quality of the production board component leads. 2. Lubricate the clinch lead screw with Super Blue (BLKM07680). 3. Replace the O-rings and bumpers in the cutter cylinders on the cut and clinch assembly. 4. Lubricate the three surfaces of the notch in the rocker guide Kendall Super Blue (BLKM07680).
48,000,000 Cycles Check: Perform Maintenance: 1. Lubricate the anvil slides with Kendall Super Blue (40833838) and grease gun (47408201).
3. 2. Installation accessories, required energy and precautions
1) The source pressure is : 0.4Mpa~0.6Mpa
2)Taken the air over diameter for ?: 12mm, a quick joint is needed
3) The top of the equipment is designed ?: The 125mm exhaust port shall be connected to the outside by independent air duct
4) matters need attention: In order to ensure safe production, customers must ensure that the following security measures are installed in place. Otherwise, the company does not assume any responsibility for security
?It is at least 3 meters away from the electric equipment, away from fire source and heat source
?The ground wire must be connected, and the earth shall not be connected to any other electrified equipment
?The exhaust duct of this equipment shall not be connected to any equipment that can produce heat source. (such as reflow soldering wave soldering of SMT, etc.)
3.3 installation space
To facilitate the maintenance and replacement of spare parts for equipment operation, please leave more than one meter space around the equipment
4.0 Operations Guide
A Preparation before operation
4.1.1 connect the air source to the machine, the gas source is connected well, the display lamp is highlighted and the subsequent work can be continued
4.1.2 check if air pressure in the standard rating (04-0.6 MPa) range. Lower than 0.4mpa will affect the cleaning effect and reduce production efficiency (too low will not activate the machine).
Higher than 0.6mpa can result in damage to the mechanical gas system and all parts of the system.
Adjust the pressure method: pull upward gently to adjust the knob and rotate to the right————- Increase pressure
Go to the right ————– reduce stress
After reaching the required pressure, press the adjusting knob, air pressure lock and pressure to complete the gas connection, and the lamp is highlighted
4.1.3 check whether the top exhaust duct is unblocked or unblocked, which will result in damage to the environment and other consequences of the cleaning effect
4.1.4 check the glass viewport of the door panel through the liquid road to check the solvent reserves. The normal state is above the M position, and the machine can meet the various cleaning effects. The amount of liquid stored in this model is the maximum amount (40L).
4.1.5 if the solvent is not enough, please add adding method in time: see adding solvent method
4.1.6 the pump access panel is opened with a randomly attached triangle key to check whether the ball valves are in normal condition
Ball (the ball valve of pump outlet filter) A ball valve D (pump inlet connection of the reservoir fluid Xiang ball valve) opens, B ((the ball) of white PE tube pump discharge ball valve C (white PE tube pump inlet ball valve) closed
4.2 time setting
4.2.1The setting of the cleaning time (see figure below), gently rotate the timer protection cap to the left and pull up the cover.
General cleaning time is
Minutes, depending on the actual situation, will be different.
This timer is measured in seconds (S) with a range of 10-999 seconds (S).
It can be set to 0, otherwise the machine will not start and may damage the timer and other components.
4.2.2 setting of drying time
Operation method and cleaning time setting.
The general drying time is 4-6 minutes depending on the actual situation.There will be an elongation of the aqueous solvents.
4.2.3The cleaning and drying time are automatic reset.
That is, one set, multiple times (N times).
When the pressure is less than the required number, the timer can be reset and the device cannot be started.
At this point, the black reset button on the upper row of the timer can be reset manually.
4.2.4The counter’s use of this counter is the increment counter, each cleaning a steel net, automatically into the system,
One of them is going up.
The count range is 0-999999.
Mainly used for cleaning work statistics, timely replacement of consumables (filter element), etc.
The filter cartridge should be changed when cleaning up to 1500.
Specific visual cleaning products are different and different.
When the counter displays the number to reach the target number, press the 4.2.3 method to open the cover, then press the black reset button on the left of the timer and the counter is reset.
4.3 placement of steel mesh
4.3.1 press the inner door safety button to open the cleaning room
4.3.2 lift the steel net with http://topmednorx.com both hands, gently place the front in the cleaning room chute roller and push it gently forward to the sliding channel steel
Fixed fixture on the net.
The steel net is in the middle of the fixture and chute. The top of the steel net is at the top of the cleaning room
Steel mesh fixture middle.(see below.)
4.3.3 when placing the steel mesh, the steel mesh shall not be in contact with the door to avoid damaging the steel net and sealant
4.3.4After the steel net is placed, close the cleaning door.
The inner door should be kept in good condition, otherwise, the solvent will be expelled outside, causing machine damage or environmental damage, more likely to cause personal injury
4.3.5 after the inside door is closed, continue to close the outer security door.
The security door is closed and the light is on, so that the following operation can be continued.
If the security door is not closed, the lamp will be retracted and the machine will not be able to start.
After closing the door again, the machine can be started
As we know,reflow oven is the most important welding technology in surface mount technology. It has been widely used in many industries including mobile phones, computers, automotive electronics, control circuits, communications, LED lighting and many other industries. More and more electronic devices are converted from through hole to surface mount, and reflow oven replaces wave soldering is a obvious trend in welding industry.
So what is the role of reflow oven equipment in the increasingly mature lead-free SMT process? Let’s take a look at the whole SMT surface mount line:
The whole SMT surface mounting line consists of three parts, such as steel mesh solder paste printing machine, SMT machine and reflow oven furnace. For the machine, and compared with lead free, and no new demands on the equipment itself; for screen printing machine, and a lead-free solder paste in the physical properties there are some differences, so put forward some improvement on the device itself, but there is no qualitative change. the key of lead-free is in the reflow oven.
The lead paste (Sn63Pb37) melting point of 183 degrees, if you want to form a good weld must have the thickness of 0.5-3.5um intermetallic compounds in welding, intermetallic compound formation temperature is above the melting point of 10-15, the lead welding is 195-200. The maximum withstand temperature of the electronic device on the circuit board is generally 240 degrees. Therefore, for lead welding, the ideal welding process window is 195-240 degrees.
Because of the change of melting point of lead-free solder paste, lead-free welding has brought great changes for welding process. At present, the lead-free solder paste is Sn96Ag0.5Cu3.5 and the melting point is 217-221 degrees. Good lead-free solder must also be formed 0.5-3.5um thickness intermetallic compounds, intermetallic compound formation temperature is also above the melting point of 10-15 degrees, for lead-free welding, that is, 230-235 degrees. Since the highest temperature of lead-free solder electronic device will not change, therefore, for lead-free soldering, ideal welding process window is 230-245 degrees. The substantial reduction of process window brings great challenge to ensure welding quality, and also brings higher requirements to stability and reliability of lead-free wave soldering equipment. Because the equipment itself is coupled with the electronic device transverse temperature difference, due to differences in size of heat capacity will produce temperature difference in the heating process, so in the process control of lead-free reflow oven can be adjusted in the process of welding temperature window becomes very small, this is the real lead-free reflow to the difficulty.
Higher Quality, Lower Costs, Most Knowledgeable and helpful Engineers
Service Engineer Built Southern Machinery
Did you know that Southern Machinery was founded by a Veteran Service Engineer? Founder, Jason Wu spent over 12 years as a service engineer. Jason’s mode of operation is tailored to the engineering needs of your manufacturing system. If you need guidance with design, CAD, equipment configuration, training, just ask! Southern Machinery is not just a place to buy machines, but also a place to get your technical questions answered. So ask us! We want to help you solve your PCBA problems.
Do you have a question you need answered and can’t seem to locate the information you need? Ask us and we will feature your Q&A!