C. PCB Technical Questions
1: What is solder mask?
Answer: Solder mask is the film covering most of the copper area except the pads. If you have access to any electronics devices - you will see that the copper circuit is actually protected by a lacquer like layer - this is the solder mask, the color is normally green.
2: What is Silkscreen?
Answer: Silkscreen is actually a process of screening ink using a stencil prepared by lithographic method. Purpose of this is to apply a nomenclature to aid in assembly. It is those little white labeling of component that makes manual assembly significantly easier. Although not an absolutely needed feature, it is nice to have when you have many components and would like to know what goes where.
3. Why should circuit boards be electrically tested?
Answer: Electrical test is very important after the processes of PCB manufacturing, because this is the only way for any PCB manufacturer to ensure the PCB board shipped have zero shorts or opens. Visual inspection can never be 100% effective. Especially, if the defect is under the solder mask, electrical test is the only way to catch it.
4. What should be shown in drill file: Drill diameter or finished hole diameter?
Answer: Please provide finished hole diameter in your drill files.
5. What is your standard specification PCB?
Answer: The following is used for our standard specification boards: FR4, 1.6mm thickness, 1oz copper weight, white silkscreen, green solder mask, HASL/HAL(Lead free) finished.
6. What solder mask do you use for PCBs?
Answer: We use LPI solder mask for the standard process of PCBs.
7. Are there any other color options for the solder mask?
Answer: Although green is the standard color we use for PCB soldermask process, we can also provide the following colors: red, white, blue, black, yellow, etc, please check our capability column.
8. How to reduce the cost of circuit boards?
Answer: The PCB price is related with many factors, such as layer counts, raw material, board thickness, copper thickness, surface treatment, min hole size, total hole quantity, min trace width/spacing etc.
If you want to get the lower price, please avoid using small holes(less the 7.8mil) and fine lines(less than 4mil).
9. Can I put multiple designs in the same board layout?
Answer: We don't recommend this. It will result in additional engineering costs.
10. To what acceptability standards do you build?
Answer: All our printed circuit boards are built based on the acceptance standard of IPC-A-600 Class2.For special requirements, we can also produce PCB compliant with IPC Class3.
11. Can you manufacture my PCBs from a picture file?
Answer: No, We can not accept BMP, GIF, TIFF or JPG pictures as the manufacturing file as these formats are not good for PCB manufacturing. But you can use these files to request a quotation. If you send us actual PCBs, we can copy it for you.