We have a lot tutorials and articles online about how to design PCBs. However, as a designer, you may be curious that how to make your board. That is beyond the knowledge as an engineer or a designer, but design for manufacturing (DFM) knowledge will be quite helpful.
Seeed, as a leading company in the industry for more than 8 years and we have lots of experience to help designers from ideas to prototype, to even mass production. Seeed Fusion is a one stop prototype service can help you prototype PCB at low cost ( only $4.9 for 10pieces 10*10cm boards )
Here we are going to introduce you the whole PCB fabrication process in the factory. There are 20 steps for the PCB manufacturing. Here is the brief introduction of the process, Seeed will have a more specific manufacturing manual in this May to help you understand the fabrication.
1. Cut the raw material to a suitable size.
Most of customers used FR4 130-140 as the manufacturing material for prototype. The original size of the raw material is 41*45 inch. We will use the cutting machine to cut to board into 40*50 cm, which is suitable for manufacturing.
2. Drill hole
Please see attached picture of drilled board without copper. The min hole size in Fusion is from 0.2mm to 0.3mm. Normally, the average requirement for drill hole is 0.3mm. Strict equipment is needed for the factory if smaller hole size required.
3. Electroless plating copper
After the second step of drilling hole, there is no cooper inside the hole, which means the holes are not contacted. So we need to make sure the holes are contacted and our third step is electroless plating copper. After the third step, there will be copper inside the holes and they are contacted.
This step is completed with the assistance of automatic electroless plating copper production line.
4. Pressed film
There will be a blue dry film on the board in this step.Dry film is a very important carrier in PCB fabrication process.
Match the route film and the board with blue dried film in the exposure machine. With the lighting of the exposure machine, the film without route will be exposed totally. After this step, the route will be transferred to the dry film.
For the parts that are not exposed in last step, we will use the develop liquid in developer to develop. The develop liquid is useless to the parts that are exposed.
7. cathode copper（Electric copper ）
Put the board in the electric copper machine. The boards with copper will be electric and the part with dry film will not be influenced
8. Electric tin
Electric tin is to take away the copper which is protected by the dry film.
9. Film removal
This step is to take away the blue dry film.
We use liquid to etch the useless copper in the board.
11. Tin removal
We use liquid to take away the tin in the board.
12. AOI route scan
During the fabrication process,because of different issues, there may be unqualified boards. In order to make sure the break-over of the board, we used Automatic Optical Detector (AOI) to test the route.
13. Print solder mask
We print the solder mask in this step. Normally the color is green. Since November 2017, Fusion has cancelled the charge for different color. So you can have free color choices for your board in Seeed Fusion.
14. Solder mask exposure and develop
This step is to get away the mask in PADs. Put the solder resist film on the board and exposed in the exposure machine.
We print the designator or logo in the board in this step.
16. Surface finish
It means different surface finish in this step. Seeed Fusion offered 7 different surface finish to satisfy different requirement.
You will have mechanical file in your gerber to describe the shape of your board. In this step, we will use rim your board according to your file.
18. Flying Probe Test
This test is very significant during PCB fabrication since it is the last step of PCB fabrication with machine and it will make sure the unqualified board ( such as open circuit) will not be passed to the next step.
We still need to have visual inspection for the quantity, shape and silk screen.
20. Package and Ship
After we finish the 19 steps, we will pack your boards and ship.