-
-
Notifications
You must be signed in to change notification settings - Fork 35
Design guide
This page is under development, please help expand it
So you want to design a new Fabricatable Machine? Awesome! Bellow you you find an overview of guiding principles when designing Fabricatable Machines.
We coined the term "fabricatable" for this project. It means that something is designed to be as easy as possible to fabricate, also for someone with little skills or training in machine building. Digital manufacturing helps vastly with this, because design complexity and locating features can be built into the shared design files (for instance parts simply click together thanks to milled slots and similar, instead of needing careful alignment with touch dials and calipers). This means that a lot of the hard work has been done in CAD instead of through manual fitting and handiwork. Now millions of people can download the files and "inherit" the predigested design work done in CAD. If one of those million downloaders make a design improvement, and submit it with a pull request, millions of people can again benefit from the improved design with minimal effort or time spent.
Yet digital manufacturing can be demanding handiwork as well. Milling angled surfaces or two-sided features is easy for an experienced fabricator, but can be a show-stopper for a first time machine builder. Additionally the fancy two sided features could cost more in professional manufacturing, or decrease the project start motivation of a seasoned pro. Here are some core tips for how to design fabricatable:
- Prefer 2D over 3D geometry
- Use open software, if your can't then make sure you publish both source files and files that can be imported into other design programs like .step, .dxf and .svg.
- Keep assembly simple
- Avoid or reduce the need for handicraft finishing and assembly skills
- Design for fabrication tools that most people have access to (like standard fab lab machines)
- Keep the Bill of Materials (BOM) short and easy. Think about which materials and dimensions most people have access to. If there is only one global vendor of a special part, you might have made a nightmare sourcing job for someone on the other side of the world.
- Try to maximize the amount vitamins that can be self made instead of store bought
- Don't underestimate the power of human laziness. If it is a lot of work, few people will want to do it. Keep it super simple.
Additionally it is good to reflect on balancing these three design properties, they are usually in juxtaposition. If you increase the score of one, you will usually decrease the score of to the two other. The ultimate fabricatable machine has a very high combined score from all three properties:
- Maximum degree of DIY, can be made in the wild anywhere
- Low handiwork skills and prior experience needed, and low money and time investment needed.
- High performance and low maintenance
We have published files and generators for different types of fabricatable axes that you can use to put together custom machine designs. The fabricatable axes are built up form individual modules that you can use to building new axis types or other custom machine parts.
Try to use these geometric features to help build a relationship and visual identity between all the fabricatable machines:
- Sharp external corners should have a 4mm chamfer + 2mm radius fillets
- If a large chamfer is not suitable, use only a 2mm radius fillet
- Embed our logo and your own name in the files (for instance on the front gantry face, cabinet wall etc.)
- No chain is stronger than its weakest link. Balance the design, there is no point putting a 9kg 3kw spindle on a gantry made from wood. Likewise it is often not necessary to make a make a super sturdy construction if all you need is to move a laser source around in the air.
- Golden section of wheel placement
- Prefer supported rails over unsupported rails
- Make it a friendly machine, think of the user experience in getting to know the machine and in daily use.
All fabricatable machines have a name starting with the letter "H". This helps build a family of machines and forces playful and creative names. If you are stuck, try to think of a word that describes the properties or intentions of your machine. For instance "Hattori", a small and agile machine that was intended to do high speed machining in metal, was named after the sword smith Hatori Hanzo in Kill Bill. Also don't be shy about simply switching the first letter of a word describing your design, like the Hootstrap bootstrapping machine and the HRBL-shield for the GRBL firmware.
- Don't be shy about making pull requests
- Give credit when you base components of your design on someone elses work
- Document on this wiki
The work on this repository is published under a Creative commons Attribution-ShareAlike 4.0 license.
- Freecad for machine design and CAM
- Inkscape for vector graphics and documentation
- GIMP for editing image documentation
- Machines that make at CBA MIT
- MIT FUNdaMENTALS of machine design
- Numerical control on Wikipedia
Page started by Jens Dyvik on 11th May 2020