PCB design glossary
CPL
AKA: component placement list, pick and place file, pos file
Component Placement List — the X/Y positions and rotations of every part on a PCB, used by pick-and-place machines.
A CPL (also called a pick-and-place file) gives each component's reference designator, position (X, Y), rotation, and layer. Assembly houses feed it into pick-and-place machines so the robots know where to put parts.
CPL and BOM together are the minimum a turnkey assembly house needs from you alongside the Gerber files.
What a CPL contains
Each row describes one placed part. JLCPCB's format, for example, uses the columns Designator, Mid X, Mid Y, Layer and Rotation. Other assemblers use similar columns under different names.
- Designator: matches the BOM and the silkscreen.
- X and Y: the part's centre, usually in millimetres from the board origin.
- Layer: top or bottom.
- Rotation: the part's angle in degrees.
Why parts end up rotated wrong
The most common assembly problem with a CPL is rotation. Libraries do not agree on a part's zero orientation, so a part that is correct in your EDA tool can be placed 90 or 180 degrees off by the assembler. Assembly services show a preview before production; check the polarity of diodes, electrolytic capacitors and ICs in that preview, and correct the rotation there or in the file.
- Bottom-side parts are mirrored, and tools disagree on how to report their X and rotation.
- The origin must be the one the assembler expects: often the board's lower-left corner.
- Parts marked do-not-populate should be left out of the CPL or marked clearly.
Work it out with a free tool
Placement files that match the layout
A board designed in PCBEditor exports its pick-and-place file alongside the Gerbers, drill file and BOM, so the assembler's positions and rotations come from the same layout.
See the online editor