< and [summer 2020](https://roberthart56.github.io/SCFAB/SC_lab/S-12machine/index.html) intro fab classes.
- Notes on building the [Ender](https://gitlab.cba.mit.edu/classes/865.21/site/-/tree/master/people/robhart/ender3)3D printer, and [Genmitsu](https://gitlab.cba.mit.edu/classes/865.21/site/-/tree/master/people/robhart/genmitsu) mini CNC.
### Projects for this term.
Machines are central to what I would like to do and teach in fablabs. First, PCB making is one of the most important superpowers that the fablab enables, and it should be easy for beginners to do successfully, and simple to set up in any lab. The ability to setup and reconfigure machines to do creative things is very important (think Nadya's Fab Academy 2015). This should work well, and both software and hardware should be accessible to beginners. This spring, I'm working at home, and developing tools and capabilities with resources similar to a small fab lab.
- Simple [PCB machine](./simple_pcb/index.html) that can be made with limited tooling. Explore methods for simple and precise mechanisms:
- Cams, Sliding elements, Flexures
- Spindles, or other actuators.
- Control software/firmware.
- Vinyl cutter. I have a small vinylcutter that I'd like to control with my own boards and software.
- Projects with [plastic recycling machines.](https://preciousplastic.com/)
- Use 3D printer as PCB mill? Tool change could be easy with the Ender-3.
- [Musical instrument keyboard simulation](./keyboard/index.html)
### Goals and capabilities
- Get [clank](./clank/index.html) running, understand its control, evaluate it.
- Learn how to use the A4950 in greater detail. Make fabbable driver boards.
- Learn how to make a simple, reconfigurable, beginner-friendly networked machine.
---
### March 10.
- [PCB machine](./simple_pcb/index.html).
- Made sliding axes - not practical.
- Plan to make simple machine with bearings or flexure.
- Polar machine? One axis flex?
- [Clank](./clank/index.html) and networked steppers. Clank is working well - new spindle coming soon.
- Will make Fabstep and use it.
- Make a fabbable head and ESC, or reuse fabstep.
- Make a stepper board with tiny1614.
- Musical instrument [keyboard.](./keyboard/index.html)
- Make prototype key with sensor.
- find a solenoid.
- make a solenoid.
###March 18 updates.
- [PCB machine](./simple_pcb/index.html).
- Spoke with Jake about his idea for a [simpler PCB rotor.](https://gitlab.cba.mit.edu/jakeread/micro-spindle/)
- I hope to make and document a prototype (with proper credit to Jake).
- [Clank](./clank/index.html) and networked steppers. Clank is infirm. Jake will send new RS4xx chips, since the behavior of the machine is consistent with destroyed comm. Jake has ready for me new rotor parts which I will install.
- I plan to repair and further characterize Clank.
- Next PCB job is to make a stepper board with tiny1614.
- Will make Fabstep (make consistent with latest Clank software?) and use it.
- Musical instrument [keyboard.](./keyboard/index.html)
- made a solenoid.
- made a PCB with hall sensor for distance sensing
- On a model wood key, connected the sensor and solenoid to make a rough approximation of a harpsichord action.
###March 25 updates.
- [PCB machine](./simple_pcb/index.html).
- Made a prototype of Jake's (micro-spindle)[https://gitlab.cba.mit.edu/jakeread/micro-spindle] that spins well. Runout at zero speed is undetectable with my methods. Tested above 20kRPM.
- In the process, I destroyed an ESC. Will order new ones, and explore steppers to drive, as well as DC motors.
- Next steps: speed control, try circuit milling, characterize better.
- [Clank](./clank/index.html) and networked steppers. Parts are here for spindle. Waiting for a Digikey order for the RS485 chips.
- Musical instrument [keyboard.](./keyboard/index.html). No news here this week. Working on analog version.
### April 7 updates.
- [micro-spindle](https://gitlab.cba.mit.edu/jakeread/micro-spindle) progress. My work documented [here](./micro-spindle/index.html). Made a circuitboard. Straight lines look good and have little runout. Corners are a problem.
- [Clank](./clank/index.html). Got spindle assembled, and Clank making good circuits with ~ 0.001 urnout.
- Musical instrument [keyboard.](./keyboard/index.html). Progress on kit woodworking. When I return to solenoid making, it would be good to document and measure force vs position, with both crude methods available at home, and more sophisticated methods at Harvard or CBA. Explore experience of Sam and others in this area, use COMSOL. Seems like this is an area where craft and DigFab relate well.
### April 14 updates
* [Micro-spindle.](./micro-spindle/index.html) Some progress. I'll be ready to show next week, after documenting, reviewing with Jake and Zach, and doing another design round. Some versions are very quiet. Direct driving of bit is possible, but needs added stiffness.
* With driver as constraining bearing, much wiggling. * Two-bearing approach with bit inside bearings. Beautiful results, but diameter tolerances are an issue!
* Surrounding bit with six steel bearings. Improved stability.
* Drive bearings rather than bit. Need to add upward z-force.
* Drive bit with angled o-ring wheel. OK, but support is lacking for bearings.
* For micro-spindle, I'm interested in a six-bearing approach, driving via two bearings, and using a tilted idler to provide upward z-force.
* Clank. Working well. I will do a quick study this week of resolution and backlash using a dial indicator.
### April 22 updates.
* [Micro-spindle.](./micro-spindle/index.html) More progress. Made several iterations, learned a bit. After discussing with Jake, will pursue the six-bearing, OD driven model.
* I would like to:
* use this spindle to make some simple h-bridge stepper boards,
* make a version of the Flex-table PCB mill design that Quentin has shown,
* create a z-axis with cams,
* and employ Neil's Urumbu idea to drive the system.
### April 22 updates.
* [Micro-spindle.](./micro-spindle/index.html). Surfaced sac. layer and created a stepper driver PCB (barely) with last iteration. I will order some parts and make a more stable version with built-in z-force and a good thrust bearing.
### May 6 updates.
* [Micro-spindle.](./micro-spindle/index.html). Built a six-bearing spindle, driven on OD of bearings with the usual o-ring driver. Added z-actuation using an eccentrically-driven large bearing.
### Preparation for [final presentation.](./micro-spindle/Final/index.html)
Progress on making a micro-spindle.
* 3D printed bearing mount for spindle - no shimming needed.
* Characterize and document board-making with this spindle.
* Stepper motor driver using NEMA8 and NEMA11 motors.
* Stepper motor board with attiny1614
* Cast polyurethane driver wheel.
Keyboard-based machine. First iteration and characterization of DIY solenoid.
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