pcb assembly,pcba china-STG Electronic co.,ltd.
It's not often that I see something really new and revolutionary. But that's the reason why I'm writing about the S-Series ProtoMat circuit board plotter from LPKF Laser & Electronics. While it uses plotter technology, the system is really a printed circuit board (PCBA China) generator that does not employ the chemicals normally associated with PCB creation. Combined with LPKF's ProConduct system for plated-through holes, designers can have prototype boards in one afternoon instead of shipping the design out to a prototype shop.
Most designers currently send work to prototype shops because the process for creating a board is fraught with chemicals and critical steps. Two-day turnaround times are possible with air shipments, and the LPKF solution beats that easily. LPKF's approach is very economical for prototypes and even very small production runs. It is also a good way to provide custom boards.
This is how it works.
Staying Between The Lines
The ProtoMat S62 is a self-contained circuit board generator that interfaces to a PC via a USB connection. It's a desktop unit that is relatively quiet. An internal vacuum system handles dust generated by the system. Overall, it's about as big and innocuous as a heavy-duty laser printer and not much harder to use.
You start by placing a blank circuit board in the ProtoMat S62. Next you import the Gerber files for your board design the ProtoMat software and let it run.
The S62 grabs the necessary milling tool. The system supports up to ten milling tools at a time. It then starts grinding away the surface copper. This is the same process used by most milling machines, but the depth is the same across the PCB Assembly. The job is only partially done if double-sided or multiple-layer boards are needed. In the PCB Assembly former case, the board is manually flipped and the process is repeated. In the latter case, a double-sided board is created for each pair of layers, and then the boards are stacked and pressed together. Holes are drilled, and then it's time to make plated through holes.
Making Plated Through Holes
The holes are not plated using the usual messy electroplating method. Instead, LPKF has the ProConduct process. It starts by covering both sides of the board with a removable film and drilling the holes. The board is then placed on a vacuum table and a squeegee is used to push silver polymer paste the pre-drilled holes . The board is flipped and the process repeated. Then the film is removed, leaving paste in the holes. After film removal, the board is placed an oven for 30 minutes . The heat converts the paste solid metal (silver) on the sides of the hole in about half an hour. Resistance is only 20 to 60 mO. Minimum hole size is 0.4 mm.
Time needed for the whole PCB generation process depends upon the size of the board and the complexity of the milling, but an average turnaround time for a double-sided board is a few hours, including plated through holes. That is hard to beat.