Non-selected bid for "Challenge 3: Reimagine Supportive Tech"

A project log for Minamil: a minimal CNC mill - HaDPrize 2021

Minamil: a minimal 3-axis CNC mill that works. Build from laser-cut hardboard with a screwdriver (mostly). Mill fine-pitch PCBs.

Paul McClayPaul McClay 08/23/2021 at 01:100 Comments

This was my shot at "Challenge 3: Reimagine Supportive Tech"...

It was a little Procrustean. Others hit closer to the mark. Leaving this here for the history.

1. Discuss the challenge the project addresses.

This entry addresses Challenge 3: Reimagine Supportive Tech

Create technology that acts as ... more inclusive ... beginner-friendly tech for aspiring engineers!
Many projects across the maker community begin life as the solution to a problem. How can we fill a gap in hardware? ... How can we bring more people into the fold through more accessible and entry-level projects? ...
Your solution should make it easier for others to build electronics or make electronics devices more accessible; modular, hackable, or affordable.
This could look like:
* Creating beginner-friendly projects or jumping off points into STEM education

Within a focus on electronics

A trend toward making new ICs available only in fine pitch SMD packages increasingly defeats many low-cost circuit assembly techniques apart from making custom PCBs to a level of precision that challenges homebrew etching. This makes new electronics components increasingly more exclusive, less beginner-friendly, less affordable, and less accessible to beginners and STEM students. While several services now provide high quality PCBs in small quantities at low prices, the "low" cost includes weeks of waiting for delivery to most locations. Such long cycle times quash fearless iteration for beginners and students.

Beyond electronics

3-axis CNC milling, the traditional "CAM" of CAD/CAM, resists commoditization and remains a complex and often difficult art. Learning generally requires perseverance and access to costly equipment. Pandemic lockdowns keep students away from institutional teaching facilities. Even at the low end of "hobby" mills, costs in hundreds of USD and dedicated space requirements exclude many potential beginners or home-study students.

2. Discuss how the project will alleviate or solve the problem that the project addresses.

This project presents a 3-axis CNC mill of novel design that can mill very fine PCB features, and provide entrée to real 3-axis milling, at much lower cost than any other ready-to-assemble option that I have found to date. 

Specifically in regard to electronics, this project significantly drops the cost of milling PCBs for immediate use and with precision suitable for very fine SMD pin pitches required for access to increasingly many new electronics components available only in fine pitch packages.

Generally in regard to CNC machining, this project significantly drops the cost of entry to learn full 3d CAM by building and using a real machine to make real parts from usefully strong materials.

The mill presented in this project features:

3. Publish at least one (1) image illustrating how the project might be used. This may be a sketch, schematic, flow chart, rendering, or other type of image.

Above, log entries, and Gallery

4. Link to any repositories (e.g., Github).


primary: Low(est?) Cost Reproducible 3-axis CNC Mill

refers to: A Cheap Compact Linear Motion Slide

Onshape (CAD)

primary: Minamil - a minimal CNC mill

imports from: pmc's cheap linear slide



5. Document all open-source licenses and permissions as well as any applicable third-party licenses/restrictions.


6. Submit the project to the 2021 Hackaday Prize using the “Submit project to...” option found on the published Project Profile.

Submitted 30 July 2021

Is this a unique solution to a particular challenge facing the world today?

That’s a biggie! Let’s suppose that many potential solutions to particular challenges facing the world today involve prototyping with progressively shrinking electronic components. People trying new ideas without industrial support face a particular challenge of access to costly tools to make circuit boards with precise tiny features for shrinking components.

Accessible options for individuals include “isolation routing” circuit boards from copper-clad PCB stock using a sufficiently precise CNC machine. Existing capabilities and costs include thousands or hundreds of dollars

The unique sub-$100 diy CNC mill presented here offers greater capability to cut finely detailed circuit boards for lower cost than existing “lowest cost” CNC routers.

Other options have different advantages and disadvantages:

Oh yeah, and it's a little 3-axis CNC mill that can make other parts for building up a complete prototype, or provide a solid start for learning the CAM end of CAD-CAM.

How thoroughly documented were the design process & design decisions?

tl;dr: tried an idea for a least possible step up from a CD/DVD optical deck and it worked so I kept going -- here's the one big read.

I think I can fairly say: documented more thoroughly, or at least with more words, than most people will want to read.

Or a little more selectively:

How easily can this design be implemented by other people in future projects?

"Easy" is a primary project goal!

To be clear, I expect this to continue as a DIY project rather than a turn-key consumer item ready to chug out all the best parts on delivery. By "easy" I mean easy for hack-ish people with aptitude for assembling something from pieces, and then learning a tool that returns delayed gratification for initial patience. That said, making it easier for more people to get started on the 3d CNC “subtractive” learning curve for real, including milling PCBs, is also a primary project goal.

And here's the how:

How complete is the project?

Two answers:

  1. It works well right now!
  2. I think this project has lots of potential for further development!
    • validate buildability
    • improve build documentation - try video
    • given rising price of the specific CH-SM1545 motor and falling prices of similar but longer generics: adjust dimensions to fit the longer screws which are no longer much more expensive and apparently available from more sources. (oh, heck yeah - price bumped again)
    • optimize flat part details to reduce commercial laser cutting cost
    • adapt for more expensive but faster-cutting material, e.g. acrylic, to net reduce commercial laser cutting cost
    • try again 2x motors for X & Y - first try effective when synced but too easy to un-sync; try again with limit switches & soft limits