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PCB Fabrication
Table of Contents
- General processing reminders
- Process Guides
- Process Capabilites
- Process Specifications and Tolerances
General Processing Reminders...
- Orient all your boards *before* creating any fiducials.
- 4 fiducials – always.
- Don't forget to save before generating the toolpath on the ProtoMat!
- Make sure that the two boxes are checked before selecting a ProtoLaser template.
- Do not forget the chemical safety gear when electroplating.
- Get a PI to change any bits in the ProtoMat!
Process Guides
- Kapton tape soldermasking (unverified)
HELP! –> First, go to the proper process guide and make sure you've followed our most up-to-date process. If that doesn't resolve the issue, see the Knowledge Base for processing issues/concerns/questions.
See our tips and tricks page for some advanced processing concepts (or just interesting tidbits).
The above guides targeted towards End Users and PIs (Peer Instructors) who want to know about the standard fabrication process often employed at The Hive, either before they are certified or afterwards. It is not intended to serve as a technical manual for any of these three tools or the software that controls them; for those, see the individual tool SOPs. It is also not intended to serve as a complete list of all processes that can be achieved with this tool suite. It is simply a step-by-step guide to our standardized processes.
Process Capabilities
The Hive has a suite of LPKF tools that enable students to fabricate 2-layer prototype-quality PCBs with fully-plated vias on campus. With additional setup, they can also apply soldermask and silkscreen for a production-quality finish, cut a solder paste stencil for part placement, and a reflow solder the components to the board. The tools have numerous additional capabilities beyond simple PCB fabrication, including 2.5D milling and exotic substrates. We encourage our users to explore new uses for the tools; however, as these options are beyond the scope of this document, if you’re interested in doing a non-standard process, we ask that you contact us beforehand.
The Hive's PCB fabrication tool suite has the following capabilities:
- Substrates: FR4, Rogers materials, polyamide, among many others. See the ProtoLaser help page for more details.
- Copper thickness/weight: No known limit, other than processing time.
- Slot: yes, but YMMV. See our fabs tips page for details.
- Electroplating: yes, standard processing time of 3 hours will plate approximately 16 um of copper. We also have a chemical-free non-electrical “plating” process with the ProConduct package. See our electroplater help page for details. Note that as of Feb 2022, the electroplater is still down. We continue to work with LPKF on a solution.
- Soldermask: we have the chemicals, which have an official process, but we don't officially support it. See the ProMask datasheet, below. We also have trialed an alternative masking process with Kapton tape, but YMMV. See this page for more details.
- Silkscreen: we have the chemicals, which have an official process, but we don't officially support it. See the ProLegend datasheet below.
- Stencils: we can make them! See our “How to make stencils” page for more!
- Reflow: we have a fully operational reflow oven, optimized for lead-free solder paste. See “How to reflow” for more information.
- Our knowledge base is pretty extensive as well, so check that for answers to many questions and processing help.
The full suit includes the following:
Process Specifications and Tolerances
If you’re board passes OshPark’s specs (OshPark .dru file), it can be made using our process (see their website for details). However, our process can, in fact, go beyond that in some ways.
| Specification | Minimum/Theoretical | Recommended |
|---|---|---|
| Trace width | 2 mils (0.05 mm) | 10 mils (0.25 mm) |
| Trace spacing (“pitch”) | 1 mils (0.025 mm) | 6 mils (0.15 mm) |
| Polygon isolation | 10 mils (0.25 mm) | 30 mils (0.75 mm) |
| Drill hit | 6 mil (0.15 mm) | 15 mil (0.4 mm) |
| Drill X/Y resolution | +/- 0.01 mil (0.25 μm) | |
| Drill repeat accuracy | +/- 0.2 mil (5 μm) | |
| Laser repeatability | 0.08 mils (2 μm) | |
| Drill hit | 0.05 mil (1.2 μm) | |
See our Knowledge Base and Tips and Tricks pages for additional information.