Save money on PCB fab and how to cut the board apart with CNC mill (or table saw, press drill).

For lab geeks or hobbyist who often sends out small quantity PCB fab orders but doesn’t care about a little bit extra work, this  post will help save a decent amount of money on PCB manufacture cost by putting multiple design images on a single board. PCB fab houses usually charge a fixed amount of money per order with no regard to what is actually on the design file such as Gerber. This produces a money-saving opportunity by putting more than one design images (sometimes is also called “array”) on a single board file , and you will only be charged by just “one” order. Some PCB houses doesn’t allow this kind of thing by explicitly saying “No array allowed”. For those don’t care about this, this is actually a win-win situation because the PCB house wins your deal with no extra manufacture cost, and you save money!

If you are an Altium Desinger user, putting multiple images on a PCB design file is fairly easy. First of all, you need to have all your sub design files ready. Then, create an empty PCB and go to menu -> Place – > Embedde Board Array/Panelize. Shown in the snapshot below, you will be asked for the location of each sub design files, the size of the grid and the distance between each image. You must leave sufficient space between each images for the cutting tool to eat through. I would recommend 1/8″ ~ 1/4″ for safety, otherwise, the cutting tools are getting close enough to damage your traces.

After a couple days of anxious waiting, you receive the finished boards from the awesome PCB house, which only charged you only single order of money!

But, there comes a little bit of the extra work — you have to cut it apart before soldering the components on. I have tried different kinds of tools to cut the board apart such as table saw, press drill and CNC. All of them worked pretty well depending on different task requirements. Here are some thoughts:

• Table saw:
  Cheap to own in your house, low in cutting accuracy, hard to cut straight. Recommended for dimensionally non-critical boards. Make sure to use the diamond blades. Highly recommend the “Mini table saw” from Harbor Freight. Link: http://www.harborfreight.com/4-inch-mighty-mite-table-saw-93211.html

• Drill press:
  I actually never tried a press drill to mill apart the PCB board. But based on the experience from the CNC machine, I would assume that a press drill should produce pretty high accuracy if it comes with a compound table.
• CNC:
  Undoubtedly, this incredible piece of machine produces the best ever cutting results with an accuracy of 0.0001″. It  is also capable of cutting any shape of outline if programmed properly. Here is a video clip of it: