Optimization case of abreast smt nozzle style placement machine

Optimization case of abreast smt nozzle style placement machine 

1.SMT Feeder position considerations: For abreast nozzle of placement machine feeder position is slightly different from the turret style,

The arrangement principle is as follows:

(1) The classification is based on components, the same type of components is arranged together, as far as possible to achieve simultaneous sampling. Side-by-side nozzle, between the two nozzles have a fixed distance (such as GSM is 20mm width), this distance is just with the station 8 mm feeder is equal, in order to save the picking time, the best way is to patch the first nozzle at the same time to absorb the components, such as less than 12 mm components are arranged together, 16 mm components are arranged together, greater than 20mm Of the components are arranged together.

(2) The same type of components placed in the order on the feeder, should first place the most components of the number of components, followed by the placement of a relatively large number of components, and finally placed fewer components components. Components placed as much as possible to patch position The placement of the material and the placement of the total travel the shortest principle, such as the placement of the location of the central part of the board, the feeder position is preferentially installed in the middle of the printed circuit board near the middle of the station, you can save the head back and forth moving time. In addition, for the board to install a larger number of components, in order to save time to pick up a feeder can be changed to a number of feeder, while picking, while the same time, Extend the refueling time, save machine downtime.

(3) it will be placed in the placement of the components are not far apart, the placement of the patch to reduce the moving distance.

2. Programming considerations.
(1) Minimize the number of nozzle replacements. The components are arranged in the same type, and the nozzle can draw such components at the same time. When the type of suction nozzle is completed, replace the next nozzle type and avoid frequent replacement of the nozzle. When more than one make-up placement programming, you can make the puzzle expansion as a whole board placement, reduce the number of nozzle replacement.

(2) To reduce the loading and unloading head before and after the material to move back and forth distance in the element reclaiming material, as far as possible in the machine for a feeding platform for material, such as only in the back of the material station to take, to avoid before and after the material caused by the increase in moving time .

(3) To Consider the ccd camera ,and the general placement machine has two sets of cameras, the first group installed in the patch head, the components picked up, the patch head in the process of moving to complete the flight identification to the middle of time, The camera is usually handled with components smaller than a certain size, for example, less than 20mm. The second group is mounted on a part of the machine and the suction nozzle picks up the components and needs to be identified on the camera. This will take part of the movement time , Usually this type of camera to identify the larger high-precision components, such as more than 20mm components. In programming, try to make multiple nozzles to pick up, identify and mount at the same time as far as possible not to absorb the need for two kinds of camera identification components , To spend more time to identify the entire placement of the head to wait for all the nozzle to complete, to absorb the next set of components.

(4) Tray discs to consider. General multi-function machines, all with a number of waffle Tray disk. Mounter is usually a Tray disk to move to the patch picking position, after drawing components, and then replace another Tray disk , Because Tray mobile replacement speed is slower than the placement speed, multi-nozzle side by side patch, if the adsorption components did not reach all, need to wait for the arrival of the next Tray disk components, so a waste of time. Programming should be considered, in the replacement Tray Disk time, patch head do not have to wait, to install other components, and then go to absorb  ic tray components.

How to avoid SMT Nozzle will be blown away?

How to avoid SMT Nozzle will be  blown away?

Is there any problem with smt Nozzle being collided in normal operations? So how to  avoid smt  Nozzle will be flying out? 

The solution is as follows：

1) SMT feeder did not install the case, the operator also manually adjusted the fly off the shift, the results close to the feeder problems need to be re-installed .

2) The operator needs to strengthen the training process.

3) check the height of the rail, it is possible to block part of the screw did not lock the floating high.

4) view the next alarm records, PT and the machine can see, you get the parameters of the material to be set correctly, Nozzle play with the order of the patch does not matter!

Above situation is the problem summary for SMT Nozzle .

General Knowledge of SMT Technology

General Knowledge of SMT Technology 

1. SMT full name is Surface mount (or mounting) technology, the Chinese means for the surface adhesion (or placement) technology.

2. In general, SMT workshop temperature of 25 ± 3 ℃.

3. Paste
(1) Paste printing, the required preparation of materials and tools Paste, steel plate, scraper, clean paper, clean paper, cleaning agent .
(2) Paste Ingredients include: metal powder, dissolved, flux, anti-flood agent, active agent, the main component of tin powder and flux, the volume ratio of about 1: 1, the weight ratio   
(3) flux in the constant temperature area began to carry out chemical cleaning action. flux in the welding of the main role is to remove the oxide ﹑ destruction of molten tin surface tension to prevent re-oxidation. Rosin-based flux can be divided into four types: R ﹑ RA ﹑ RSA ﹑ RMA.
(4)lead solder Sn / Pb ratio of 63/37, the melting point of 217 ℃. Lead-free solder Sn / Ag / Cu is 96.5 / 3.0 / 0.5, the melting point of 217 ℃.
(5)Paste removed from the refrigerator in Kaifeng use, must go through two important processes back to gentle mixing. The purpose of the temperature is to let the temperature of the cold paste back to room temperature, to facilitate printing. If you do not return to the temperature in the PCB into the reflow after easy to produce tin beads.
(6）Paste access principle is first-in first out.
(7）currently on the market selling solder paste, the actual only 4 hours of sticky time.

4. steel mesh
(1) steel mesh common production methods: etching, laser, electroforming.
(2) Commonly used SMT steel mesh material for the stainless steel. The thickness is 0.15 mm (or 0.12 mm).
(3) SMT general steel mesh openings than the PCB PAD small 4um can prevent the phenomenon of poor solder ball.

5.PCB
(1) often used PCB material FR-4.
(2) PCB vacuum packaging is the purpose of dust and moisture.
(3) PCB warpage specifications do not exceed 0.7% of its diagonal.

6.components
commonly used passive components (Passive Devices) are: resistors, capacitors, inductors, diodes, and so on, and these components are used to pick up the nozzle suction nozzle, referred to as the nozzle or suction nozzle. active components (Active Devices are: transistors, ICs, etc.
components of the control box relative humidity and humidity <10%.
 After the unpacking of the MD, the humidity on the card indicates that the IC is moisture and hygroscopic if it is greater than 30%

7. heating furnace
Reflow furnace temperature curve of the curve of the maximum temperature of 215 ℃ the most appropriate.
tin furnace test, the tin furnace temperature 245 ℃ more appropriate.
RSS curve for the temperature → constant temperature → return → cooling curve. ideal cooling zone curve and the return curve curve mirror relationship.

8. patch red plastic
SMT patch red plastic is a poly-thin compounds, and solder paste is different from its heat after curing, the freezing point temperature of 150 ℃, then, red plastic from the paste directly into a solid body.
SMT patch red plastic with viscosity flow, temperature characteristics, wetting characteristics. According to this feature of red plastic, so in the production, the use of red plastic is to make the parts firmly attached to the PCB surface, to prevent its fall.

For use on presses or dispensers:
① To keep the quality of the patch glue, please store in the refrigerator (5 ± 3 ℃) storage.
② from the refrigerator before use, should be placed at room temperature back to temperature 2 to 3 hours.
③ You can use toluene or ethyl acetate to clean the hose.

Dispensing:
① in the point of the hose to join the plug, you can get a more stable dispensing volume.
② recommended dispensing temperature of 30-35 ℃.
③ When dispensing the hose, please use a special glue sub-machine to separate, to prevent the glue into the glue.

Scraper: Recommended scraping temperature of 30-35 ℃ Note: red plastic removed from the cold environment, before reaching room temperature can not be used.
To avoid contamination of the original product, do not use any of the patch of plastic back into the original packaging.