Milkymist One SMT/DIP Process Flow

Here collected info is came from visiting smt factory during producing Milkymist One RC1 pcba.

• Auto/Semi-Auto PCB Carrier Machine

• Print Solder Paste

Printing machine is to print solder paste on the solder paste layer through stencil. Normally you don't need to specify a well-known brand solder paste to pcb maker, as long as request them to use a leed-free paste. But they all have famous brands' ones, for example;

• Produce Stencil

Stencil is a material for the process of printing soldering paste of smt stage. There are two methods to produce stencil: One is made by geber file, the other is made by pcb optical scanning.

 by gerber file: the smt factory will request customer to get final gerber file which is exact mapping with instant pcb produced from 
 pcb maker not from customer's routing files. This approach is more significant to mass production without much
 variable tolerances.

 by optical scanning: the smt factory also can use the instant pcb sample to let stencil maker to do a scan to copy and produce it.

For Milkymist One RC1 we make this by file which is brought from New Heart Corporation. Thus is also this time RC1 pcb maker. For an EMS or SMT business, they almost frequently build oriented-business with stencil makers like http://www.cksmt.com.tw or http://www.laser.com.tw/. In Taiwan for example the quotation about pcba assembly including outsourcing stencil made on smt factory side.

The stencil file is somehow the same as the layer SOLDER PASTE in gerber files generated in PADS, OrCad or Altiem Designer tools. Sometimes for economic goals in mass production effectively, gerbers in PANEL structures rather than single gerber. Eg., 2 pieces, 4 pieces, or even more pieces in one panel. That's the reasons that must use FINAL SOLDER PASTE layer film/file produced by pcb maker.

• Feeders

• Pick and Placement

 high speed AI machine

 medium speed AI machine

 low speed AI machine

• IPQC

• Inspection before IR-Reflow

• IR-Reflow Measurement

• IR-Reflow

• X-Ray Inspection

• Through Holes Insertion (DIPs Process)

• OQA