The Displacement Exercise (DEX)
DEX is a small materials testing machine that should be capable of running tensile and compressive tests at up to 600N of force. The machine can be manufactured by anyone with access to a laser cutter with at least a 24x12" bed, and nearly any FDM 3D Printer. A bill of materials of purchased parts required to complete the machine is below.
Usage
DEX runs a squidworks controller.
Controller TODOs:
- serverside squidworks: machine contained system
- server config for bootstrap entire system ! (/url-to-program-location)
- setup and config-it
- assign meaning to charts and graphs
- save tests as .json objects (optionally) develop program for reading
- save images of tests (genpurp canvas save tool?)
Circuit TODO:
- draw / fab temp and humidity sensor (looks like Bosch BME280 828-1063-1-ND)
- better implementation of load cell amplifier ?
Building a Displacement Exercise
Hardware TODOs:
-
temp. 3DP for N23-backside mount (w/ old circuits)
-
bring fixturing here
-
make queue of prints, tomorrow is JS servers + vfpt, next day is final build (route, etc)
-
to close doc:
-
BOM, McMaster
-
this list of bits (incl fixturing), then fusion -> repo
-
done 4 now, cut long tail
-
print:
-
5x new idlers (w/ improved bearing seat distance)
-
fixturing,
-
n23 mount
-
desktop psu (pdbs hello?)
BOM
Part | Spec | Count | Notes | PN / Link | Cost |
---|---|---|---|---|---|
Delrin (Acetal) Cast Sheet | 24x18", 0.25" Thick | 1 | Advise to buy two in case of mistakes | x | x |
PLA 'Tough' | x | ~ 300g | Many 3DP Mechanical Bits | x | x |
625ZZ Bearings | 5x16x5mm Deep Groove Roller Bearings | 24 | x | 625ZZ VXB | $40 |
Bearing Shims | - | - | - | - | - |
Carriage Shoulders | - | (12) | - | - | - |
Idler Shoulders | - | 5 | - | - | - |
Reduction Shoulder | - | 1 | - | - | - |
Feet | - | 3 | - | - | - |
NEMA 23 Stepper Motor | - | 1 | - | - | - |
GT2 Pinion | 20T | 1 | - | - | - |
GT2 Closed Loop Belt | 280T | 1 | - | - | - |
GT3 Open Loop Belt | ~ 1M - | 1 | - | - | - |
6806 Bearing | 30x42x7mm Deep Groove Roller Bearings | 2 | x | 6806-2RS VXB | - |
M3 Inserts | - | - | - | - | - |
M4 Inserts | - | - | - | - | - |
M5 Inserts | - | 4 | - | - | - |
SHCS | M3x25 | x | Pinning T- and X-es together | x | - |
SHCS | M3x16 | x | Pinning T- to the wall, and pulley endmatter | x | - |
SHCS | M3x20 | x | Pinning T- to one another (?) | x | - |
SHCS | M3x25 | x | Pinning edge-idlers together, | x | - |
SHCS | M3x45 | 8 | Pinning the 'squat' together | x | - |
FHCS | M3x10 | x | Pinning blisters to faces, flush up and countersink | x | - |
FHCS | M3x25 | ? | - | - | - |
Dowel | 5x8mm | ? | - | - | - |
Feet | - | - | - | - | - |
Loadcell(s) | - | - | - | - | - |
CAD Notes
- fusion / parameters
Tools for Fabrication
- laser, 3dprinter
- soldering iron for inserts
- arbor press is nice, but not necessary
Dependencies
This repo is for the machine itself, it implements / uses / depends on the projects below:
- pdbs
- router
- stepper driver
- loadcell circuit (find amp, make board?)
MFG Notes
I used the trotec w/ 80 watts power, doing two passes per cut at 0.25 speed and 100 power. The colors to setup with are:
Black, Red, Blue, Cyan, Green, Magenta
To export from Fusion, use Rhino for layout, export cut files as DXF, for the trotec the best move is to export as 'R12 Natural'. This will keep segments together.
...
fixturing moves / top to bottom
Testing Notes
Use the D683 ASTM Dogbone - normally Type 5
Controller Desires
- cyclic loading
- direct upload -> materiom (generic: databases) ... MQTT (and nodered)
- https://cookbook.nodered.org/mqtt/ (and: https://cookbook.nodered.org/)
- add to data: humidity, temperature, location, time ...