Maus C Build Process
Release status: Early development
| Description | Micron-scale 3D Printer
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Contents
Under Construction
Overview
This document covers the construction of the Maus C is a μRepRap design, featuring an XY Table based on complementary flexures hence the 'C'. It is intended to be controlled by any CNC Controller capable of being interactively operated, and other than fasteners and wire is mostly 3D printed. A Bill Of Materials is being created.
Assemblies
Major components of the system are:
- Optics
- CNC Control System
- Axis Drivers
- XY Flexures
- Stage
- Probe
- Support And Enclosure
Optics
The prototype as built requires two USB Microscopes, self-illuminating, 30mm dia. One of 10Mpixel resolution to observe the print area, the other can be of lesser quality and is used to gauge the approximate probe height. It is convenient if one can be obtained to fit a 16mm pole on a stand via a height adjustment system, but this is not essential.
CNC Control System
The CNC Controller needs to drive 3 x NEMA17 400 step/rev motors with 5mm diameter output shafts approximately 23mm long. The shafts can be round or have a flat. For I/O the CNC Controller needs to support Z Touch, Normally Open max & min limit inputs, and have one spare output capable of driving a 20mA UV LED.
Required Tools
You will require:
- Screwdriver to fit chosen M3 fasteners
- Needle-nosed pliers
- Small wire cutters
- Electric drill
- 3mm HSS drill bit
- Medium flat file
- Fine awl or similar long pointy tool with blunt edges
- Lighter or similar heat source
You may find useful:
- Magnifying glasses
- Wire stripper
- Tweezers
- Haemostat
- Dental tool with a hook and probe
- Large clamp
- Portable bench vise
- Soft-faced mallet
- Caffeinated beverage
3D Printed Components
Parts are printed in plain PLA or eSun PLA+, 0.2mm layers, 2 perimeters, 4 top/bottom layers, 20% grid infill, no support or brim. PLA with additives to give unusual finishes such as matt, roughened, metallic etc. will definitely not work. Cheap 'PLA' tends to have a very low actual PLA content, so stick with a reputable brand. Maus C print sheets required from the repository (TBA but can be compiled from Github source) are:
- Axis Driver (three of)
- Maus Complementary A
- Maus Complementary B
- Maus Probe
Note: The prints may be tidied, but if you see lose filaments around any of the flexures, just leave them. It is highly likely that the flexure will be damaged if you attempt to remove them.
Assembling The Modules
The gist of each section is to prepare any parts requiring hand tooling, insert captive parts, then assemble.
Axis Driver
The 3D printed parts for an Axis Driver are all on one 3D print sheet. The mechanism's essentials are a spacer and mount for a NEMA17 stepper, a coupling and drive screw that fit a lever arm and bearing block, and a structural box with a parallelogram-like flexure on the end. Three of these are needed, and they are identical.
Part Preparation
Two fasteners need to be prepared, and these are the most complex machining operations in the assembly process. That said, they're not hugely sophisticated. Also, some wiring.
Select the most pristine M3 x 50mm screw available. Wrap the thread with a non-gummy soft tape and secure in a drill chuck with the head sticking out. Run the drill and simultaneously file the side of the screw head. The objective is to reduce the diameter of the screw head to less than 5.5mm - the width of an M3 nut from flat to flat. Be very careful not to damage the thread. If you damage it, pick another screw and start again. This 50mm screw will be used for the Drive Screw. It is VERY IMPORTANT that the screw thread not be bent, scuffed, scratched, spindled, or mutilated in any way.
Fit the 3mm drill bit to the drill. Hold an M3 nut in pliers or a vice and cleanly drill the thread out of the nut. This nut will be used for the Bearing Block.
Take the limit switch wires you will be using on the CNC Controller for this axis. Bare both ends approximately 10mm. Take a 50mm length of 28ga wire, place it alongside the switch wire so the ends are flush. Bend the switch wire and 28ga wire out at 45 degrees to ensure a tight twist, and twist together 8 times or so. Trim off any uneven ends on the twist. Fold the twist down against the insulation on the switch wire, point the 28ga wire forward, and shrink heatshrink over the twist.
Assembly
Drive the bottom (flat) end of the conical Flexible Coupling onto the NEMA motor shaft until the shaft contacts the flat shelf inside the coupling's cavity. This is recessed approximately 7mm, and you may find it convenient to mark this off on the shaft. Gentle pressure from a clamp will suffice, or a more percussive approach may be taken with careful deployment of a soft-faced mallet.
the author got this far, it's hard, give 'em a break
