1. Confirm before printing, and check whether the required jigs such as steel mesh, PCB and solder paste match;

2. Check whether there are foreign body residues such as tin slag in the steel mesh and whether the board surface is clean;

3. Confirm whether the brand and model of solder paste used are correct. Here we take the brand GKG Solder Paste Printing Machine as an example.

4. Confirm the tempering and stirring time (tempering for 4H and stirring for 5min);

5. The engineer can put the steel mesh and fixture into the printing machine and debug all the parameters before starting the operation. The program name is consistent with the actual machine type. The doctor blade angle is 60-70 degrees, the printing speed is 40-80mm/s, the doctor blade pressure is 3.0-5.0kg/cm2, and the demoulding speed is 0.3-2.0mm/s.. Automatic wiping frequency: 3-5PCS/ 1 time;

6. Check the PCB for deformation, damage, foreign matter and oxidation before putting it into use, and wipe the surface with a dust-free cloth;

7. After printing, check them one by one with a magnifying glass;

(1) Less tin: whether there is exposed copper foil on the pad, and less tin if the solder paste thickness does not meet the standard thickness;

(2) Soldering: There is solder paste between pads, especially between plugs, IC and PIN, so it is mainly checked;

(3) Multi-tin: the thickness of solder paste is greater than that of steel plate;

(4) Collapse and cusp: the solder pads of solder paste are unevenly distributed;

8. For products with poor quality, first scrape off the solder paste on the board surface with a soft scraper, then recover the solder paste with an empty bottle with a red label, then clean the residual solder paste on the board surface and in the hole with plate washing water, and then blow it clean with tools; (Clean the product with special tools)

9. Place the cleaned substrates separately, mark "△" on the edge of the plate with an oily pen until IPQC confirms it, and then put it in the oven for baking.

10. Manually clean the steel mesh. When wiping, the machine should be in manual state. Wipe from the bottom of the steel mesh with a dust-free paper dipped in a little cleaning liquid. After cleaning, use tools to blow the residual solder paste from bottom to top. Depending on the quality, if it is not good for three times in a row, report the project adjustment immediately, and then start normal production after OK.

1 1. When a good product is placed in the grid, an interlayer is placed. Complete the model and work order status in the process identification card;

12. The cumulative time of printed circuit boards shall not exceed 1 hour;

13. When adding solder paste, the rolling amount of the scraper shall prevail, and the solder paste leaked from both sides of the scraper shall be collected into the scraper in time;

14. Turn off the lighting in time during operation;

15. Engineers regularly check the wear of blades, and generally replace them once every six months.