Some complex PCBs design be finished,you must take PCB to assembly plant when PCBs get back from PCB manufacturer.That assembly plant need you provide some necessary documents for production.Where the captain guy gave you talk about the PCB assembly when production of documents required,and what the representative of the file is useful.
PCB assembly processing required documents are the following:
Stencil file
Stencil file is solder paste file, it used in brush paste when PCB assembly, it can be automatically welded when PCB through high temperature furnace. But stencil file didn’t be included plug-in components information,it’s surface mount components information.What kind of stencil is? The following is a kind of stencil.
Above aperture is exposed for each surface mount components,no components area are covered. And the stencil is a certain thickness,the exposed holes are filled with solder paste when brush paste, then pcb pad coated with solder paste. The solder paste melting to stabilize assembly when soldering in high temperature.
Pick Place file
When assembly is processed with a machine.you have to tell the machine how to paste the components,which requires the coordinates of the document.Coordinate file also call pick place file,it has the coordinates of each components, layer, rotation angle and other information,the machine will be able to read this information,according to the requirements to paste components. Pick Place file are generally shown below:
| Designator | Footprint | Mid X | Mid Y | Ref X | Ref Y | Layer | Rotation | Comment |
| U2 | USON8_(3×4) | 1341.535mil | 276.575mil | 1294.291mil | 229.331mil | T | 90 | MX25R3235F |
| TP3 | TP-L_3D | 1066.929mil | 60.039mil | 1065.945mil | 60.039mil | B | 90 | JTAG_TMSC |
| TP5 | TP-L_3D | 1121.063mil | 125.984mil | 1120.079mil | 127.953mil | B | 90 | JTAG_TCKC |
| U4 | GNS302uLP_-_BS | 645.669mil | 308.563mil | 645.669mil | 618.111mil | B | 0 | GNS302uLP |
| U5 | YFP0025BABD | 641.732mil | 161.417mil | 641.732mil | 161.417mil | T | 360 | BQ25120YFPR |
| L3 | 0402L_3D | 535.433mil | 67.913mil | 535.433mil | 67.913mil | T | 90 | BLM15HG102SN1 |
| C27 | 0402C_3D | 482.284mil | 67.913mil | 482.284mil | 67.913mil | T | 270 | 10uF |
| u1 | PVQFN32_3D | 1143.701mil | 184.055mil | 1143.701mil | 184.055mil | T | 0 | CC2640RHB |
| C7 | 0402C_3D | 1024.606mil | 335.63mil | 1024.606mil | 335.63mil | T | 90 | 100nF |
| X2 | 2.0×1.2×0.6mm_crystal | 936.024mil | 135.827mil | 936.024mil | 135.827mil | T | 90 | 32.768KHz |
| C26 | 0402C_3D | 560.039mil | 264.764mil | 560.039mil | 264.764mil | T | 90 | 1uF |
| C25 | 0402C_3D | 721.457mil | 104.331mil | 721.457mil | 104.331mil | T | 270 | 1uF |
| U3 | LGA14 | 1349.409mil | 430.118mil | 1349.409mil | 430.118mil | T | 180 | LSM6DSL |
| L7 | 6-0805_L | 780.512mil | 185.039mil | 780.512mil | 185.039mil | T | 270 | 2.2uH |
| C1 | 0402C_3D | 1231.299mil | 346.457mil | 1231.299mil | 346.457mil | T | 90 | 100nF |
| C2 | 0402C_3D | 1066.929mil | 25.591mil | 1066.929mil | 25.591mil | T | 360 | 100nF |
| C6 | 0402C_3D | 1183.071mil | 346.457mil | 1183.071mil | 346.457mil | T | 90 | 100nF |
| C13 | 0402C_3D | 1390.748mil | 531.496mil | 1390.748mil | 531.496mil | T | 90 | 100nF |
| C16 | 0402C_3D | 1340.551mil | 531.496mil | 1340.551mil | 531.496mil | T | 90 | 100nF |
| C19 | 0402C_3D | 1380.906mil | 117.126mil | 1380.906mil | 117.126mil | T | 180 | 100nF |
| C20 | 0402C_3D | 1151.575mil | 25.591mil | 1151.575mil | 25.591mil | T | 360 | 1uF |
| C21 | 0402C_3D | 619.095mil | 266.732mil | 619.095mil | 266.732mil | T | 90 | 1uF |
| C22 | 0402C_3D | 710.63mil | 272.638mil | 710.63mil | 272.638mil | T | 360 | 10uF |
| C23 | 0402C_3D | 1380.906mil | 167.323mil | 1380.906mil | 167.323mil | T | 360 | 100nF |
| L2 | 6-0805_L | 1282.48mil | 40.354mil | 1282.48mil | 40.354mil | T | 180 | 10uH |
| R3 | 0402R-v2_3D | 1297.244mil | 117.126mil | 1297.244mil | 117.126mil | T | 180 | 56K |
| R4 | 0402R-v2_3D | 561.024mil | 178.15mil | 561.024mil | 178.15mil | T | 270 | 56K |
| TP1 | TP-L_3D | 1245.079mil | 54.134mil | 1245.079mil | 54.134mil | B | 180 | JTAG_TDI |
| C4 | 0402C_3D | 1380.906mil | 70.866mil | 1380.906mil | 70.866mil | T | 360 | 10uF |
| C5 | 0402C_3D | 1380.906mil | 26.575mil | 1380.906mil | 26.575mil | T | 360 | 10uF |
There are components labels.X,Y coordinates,rotation angle,where level.
Component bitmap file
The component bit map file,in fact is the component silkscreen. It’s provided to operate workers to comparison in the production processing.Inspect if there’s any wrong of assembly.The component bitmap is shown below:
PCB assembly fixture file:
PCB assembly fixture file, it’s used in covering surface mount components and expose plug pin when PCB through reflow welding machine.Because in the production of the first process is surface mount welded,and then the plug-in welding.the plug-in soldering is done with wave soldering, it must be through wave furnace. The fixture is avoid surface mount components be assembled don’t fall when through wave furnace.
Top side of PCB fixture
Back side of PCB fixture
Panel drawing file
If PCB is made from panel,it also need provides panel file.Because the assembly manufacturers need panel drawing to make coordinates files.
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