PCB screen printing screen board production process can be generally divided into two aspects: net, net drying;

PCB silkscreen material suppliers are all too familiar with these two steps.

Specific operation instructions:

Due to the repeated use of net frame, there are residual viscose, net yarn and other sundries around the net frame, must be removed, so as not to affect the adhesion of net yarn and net frame.

Place the screen frame on the platform (level) to check whether the screen frame deformation, such as deformation should be leveled.

Will be cleaned up, not deformed mesh frame and mesh then surface thin and uniform coated with a layer of Nanbao right fat (without adding hardener) to enhance the net after the mesh and mesh frame adhesion.

After Di is coated with glue for about 10 minutes, place the net frame on the net drawing table, and adjust the relative position and height.

Choose mesh, loosen around the clip, the net tiled on the frame, and then the net evenly clamped into the mouth, can not have wrinkles, pay attention to the four corners to have more loose net, the clip must be locked, there can be no gap between the clip and the clip (automatic lift frame, manual net as an example)

Net pulling: the first Di tension is 26, standing for 5 minutes, the tension is 24; Second tension 28, stand for 5 minutes tension 26; The third tension is 32, and the tension is 30 after 5 minutes. For the fourth time, the 5-point tension was 32. After standing for 20 minutes, the gluing tension was 30. After curing for 15 minutes, the net tension is 28. After standing for 72 hours, the screen plate can be made (taking the screen plate used in one meter × one meter automatic production line as an example).

The glue will be modulated with xiaomao brush brush evenly over the surface of white gauze net frame and then, not to glue off the net version of the middle part, the glue after 8 minutes to dry, scraper glue on the coating surface will be available in the local press close to agreement was not fully fit the 10 minutes after the glue is completely dry (open air blast should be adopted to strengthen drying) can only be let down the nets.

Remove the screen around the redundant mesh, and indicate the date in the screen frame, mesh and net tension (in order to observe the tension changes) in order to prevent the infiltration of white water, in the inner corner of the net frame sealed with red glue, and then with waterproof tape in the net frame and net gauze then above the surface, also prevent the infiltration of the potion.

Wash net: use grinding net cream to grease (new net), ghost paste to figure (old net), in addition to the pulp powder to net pulp, blue oil, with anti-white water to wash sundry, with detergent to wash the net, and then with high pressure water gun rinse clean, and then clean with pure water.

Baking net - oven setting temperature should be less than 48 degrees C.

Water film: clean the net and then clean it with pure water. Select the water film according to the project film piecing figure increase about 20%, press one end of the water film on the net with a triangle ruler, then slowly scrape up with a triangle ruler, gently press and scrape with a rubber scraper, wipe the excess water to dry

Use net pulp: baking sheet and sizing, use box, containing pulp to the boxes to the Internet, including green oil three times, about every 10 minutes to the last) (bottom oil, oil is secondary, welan first 50 k water film on the tear film, again top 20 times the net pulp, three times every time scraping adopt automatic sizing machine (we have), sizing after drying.

Mesh selection of general line, green oil, bottom oil, surface oil with 120T, 100T, 110T mesh, carbon oil 51T, blue glue 24T photosensitive line and heat curing green oil with 77T.

Film selection line with 18K water film (no net pulp due to the Internet with net pulp due to uneven: dog teeth, fat oil, wave), green oil, bottom oil, surface oil selection of net pulp, carbon oil selection of 50K water film.

The required engineering graphics film is pasted on the selected position of the screen board and placed on the lighting machine for lighting. The selection of time (3000W spotlight) is 60-80 seconds for the line, 80-100 seconds for the green oil, 40-60 seconds for the bottom character oil, 350-400 seconds for the carbon oil and blue glue

Pressurized water flushes net, dry.

With blue oil (screen paste) seal graph filin outside the net edge, dry.

Check, repair network, write the completion date and the corresponding number and record, save.

Of course, this is just the general operation steps, the ancients said that all the books are better than no books, if the actual operation strictly according to this method, it is extremely unwise, we should live to learn and use, so as to make continuous progress, to make better products.

There are many specifications for PCB screen printing technology, which can not be done casually. These specifications promote the development of PCB screen printing technology. Let's take a look at the following specifications:

All components, mounting holes and positioning holes have corresponding silk screen labels. In order to facilitate the installation of the board, all components, mounting holes and positioning holes have corresponding silk screen labels. The installation holes on the PCB are silkscreen printed with H1 and H2... Hn for identification.

Silk screen characters are displayed from left to right and from bottom to top. For polar devices such as electrolytic capacitors and diodes, ensure that the directions are consistent within each functional unit.

The solder plate of the device and the tin channel to be lined with tin have no screen printing, and the device position number should not be blocked by the device after installation (except the PCB with high density that does not need screen printing).

In order to ensure the welding reliability of the device, it is required that there is no screen printing on the welding pad of the device. In order to ensure the continuity of tin lining, tin lining is required to have no silk screen; In order to facilitate device installation and maintenance, the device position number should not be blocked by the device after installation. Screen printing can not be pressed on the through hole, pad, so as not to open blocking welding window caused by part of the screen printing loss, affecting training. The silkscreen spacing is greater than 5mil.

The polarity of the polar component is clearly shown on the screen printing diagram, and the polarity direction mark is easy to identify.

PCB light drawing file number is correct, each layer should be correct output, and have a complete layer output.

The identifiers of the components on the PCB must be consistent with those in the BOM list.

A directed connector whose direction is clearly indicated on the screen.

Where space on the PCB board allows, there should be 42*6 bar code screen frame on the PCB. The bar code should be positioned to facilitate scanning.

The screen printing position of PCB board name, date, version number and other information shall be clear. PCB file should be board name, date, version number and other board information screen printing, clear position, eye-catching.

PCB must have manufacturer's complete information and antistatic label.

In addition, ink is also crucial. In the choice of ink dry film manufacturers should also be careful.