SMD Stencil Creation
1 Required Software (Linux)
- Eagle (free edition is enough)
- Python version 2.4 or later
apt-get install python
- SimpleParse version 2.1.0 or later
apt-get install python-simpleparse
- gerbmerge 1.8 or higher
https://github.com/fightingwalrus/gerbmerge http://downloads.sourceforge.net/project/salix-sbo/13.37/gerbmerge/gerbmerge-1.8.tar.gz https://github.com/provideyourown/gerbmerge
- gerbv (a Gerber File Viewer)
apt-get install gerbv
2 Introduction
We want to fill an SMD stencil with as many PCBs to make optimal use of the space.
The top and bottom cream layers together with the board outlines are exported through Eagle as CAM job and then processed with gerbmerge and manual absolute placement to create one combined gerber file that can be sent to an SMD stencil manufacturer.
3 External Manuals & References
http://www.gedasymbols.org/user/stefan_tauner/tools/gerbmerge/doc/index.html
4 1. Export Gerber Files from Eagle
Eagle CAM Job to create required gerber files (plus a few others that we don't need for the stencils):
Note: Make sure the bottom cream side has the "mirror" checkbox checked when running the job.
The three essential files/layers we need are:
- Cream Top (*.tcream.ger)
- Cream Bottom (*.bcream.ger)
- Board Outline (*.boardoutline.ger)
5 2. Create gerbmerg configuration files
create an empty file called "empty" (gerbmerge requires a drill file or will throw an error - but is happy with an empty one)
create job.cfg with the following content (file names are left in for demonstration purpose):
[DEFAULT] projdir = . [Options] AllowMissingLayers = 1 PanelWidth = 12.9 PanelHeight = 18.5 [DummyTop] BoardOutline=axiom_beta_interface_dummy_v0.12.dimensions.ger Drills=empty *topcopper=axiom_beta_interface_dummy_v0.12.tcream.ger [DummyBottom] BoardOutline=axiom_beta_interface_dummy_v0.12.dimensions.ger Drills=empty *topcopper=axiom_beta_interface_dummy_v0.12.bcream.ger [StencilTemplate] BoardOutline=stencil02.gtp Drills=empty *topcopper=stencil02.gtp