Quality Assurance
  Design Tips

Design Tips


To avoid delay please submit following information with your order:
Gerber Files that can go straight to production avoiding costly delays.
We can use Gerber files in either 274D or 274X format for all layers, including silkscreens and soldermasks.
If using 274D format, we require a separate aperture list/report File, this will tell us the pad and line sizes you used to design the board.
Tool file/chart, telling us which tool is what size and how many of each tool is used
Fabrication drawing or Manufacturing Requirements.
NC Drill file in ASCII format.

Readme file. It is a good idea to include a readme file with information such as; contact person¡¯ name, phone/fax number and other information about your board requirements, this would aid in quickly moving your job from pre-engineering to production floor. This file can be in either ASCII (*.TXT) or Microsoft Word (*.DOC) format
Note: We also can support CAD files, such as Protel series, PADS2007, AutoCAD.But we have to output Gerber Files before CAM process.


Design Tips
Hole Size and Pad Size:

For power and ground layers, make the clearance 26mil larger than the hole size. For component, solder and inner layers make the pad size 16mil larger than the hole size. It allows more room for drilling and decreases the chances for shorts. Soldermask pads should be 5mil larger than the soldering pad.


Draws and Flashes:
When designing a board, try to limit the amount of draws you use. Draws use a lot of memory and slows the programming time. Ex.: Use a flash for pads instead of draws. If for some reason we need to increase or decrease that pad size, it can easily be done by changing the D-code, if they are done with draws it could be a nightmare.


Silkscreen rules:
Keep silkscreen at least 6mil away from pads (except vias). The minimum line width is 4mil and the minimum letter height is 28mil. Ensure that no silkscreen falls on any pads this could affect the soldering process. Avoid printing component outlines, especially if you are using automatic assembly.


To speed programming - add a borderline to one of your files, this will give us a route reference for routing the PCB to size. On the other hand keep routing at least 15mil away from copper except the edge will be exposed copper or plated.

Cost Cutting Tips:
Surface treatment:

All surface treatment methods have their advantages and disadvantages; the decisive factor is, of course, their application. A short overview of the most common surface treatments is given below.

Note: All of surface treatments (except HASL) are ROHS compliant.

Hole sizes:
Try to design the hole size is bigger than 0.25mm, if not, it will add cost to the drilling operation . Also try to limit the aspect ration, high aspect ratios which makes plating difficult. Meanwhile, limit the number of different hole sizes. Review your design to see what flexibility you have with the hole sizes

Annular ring:
Try to provide at least a 10 mil annular ring. A smaller annular ring creates manufacturing difficulties which result in lower yield and higher cost.

Line width and spacing:
Our manufacturing cost increases significantly when line width and spacing is below 4mil, so you should avoid them if your application does not require such fine line and space.

Layer Stackup:
If you have flexibility in your layup specification, discuss with us, we have some cost effective suggestion using our standard materials. Ex.: we recommend your layer stackup like below pictures.

Panel size:
If you can be flexible with your panelized PCB panel size, consult us to discuss the size. This will allow us to arrange the maximum number of boards on our standard panel size. This have a major impact on cost especially in production quantities.

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Room 0523-0527,Building1,Wanjunhui business building,xixiang,BaoAn Dist,Shenzhen,China.
Tel:(860755) 2918 5755 ¡¡Fax:(860755) 8625 1678¡¡ Email: sales@bestechcircuits.com
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