Commit bfa53bc9 authored by Jake Read's avatar Jake Read

stash before rename and cleanup

parent fcc4c27b
## DEX
Re-did the machine last week, now much simpler:
![dex](images/2019-09-27_DEX-CAD.png)
...
#### Some Force Maths (and a .xlsx file)
- want (?) from ex. nylon dogbone
- for this, w/ motor doing 1.5NM, how much reduction ?
Have this spreadsheet already, that's great. The D683 dogbone is ~ 8mm wide, and it would be great to test parts at 4 layers of 0.2mm - 0.8mm thick. That's skinny, but here we are: these are all under ~ 500N. OK.
For that oomph, with a 22T drive pinion, I'll want a 6:1 reduction and a NEMA23 motor (just a short stack) pushing 1.26NM through to a max. 660N linear force. OK, glad to have checked, nice to know about the N23 - I had been thinking of N17s - and will have to watch about getting that 6:1.
## uSSM #3
![img](images/ussm3_chassis.jpg)
......
# micro Stress vs Strain Machine
# The Displacement Exercise (DEX)
## 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.
### notes -
![dex](images/2019-09-27_DEX-CAD.png)
To finish,
- pinch cross-bearers (haha) +5mm away from pulley corners,
- mod the squat to walk around cross bearers: agnostic - use holes in series up the cross
- the feet are an assembly, with legs for delrin
- the hearth is an order, but not *so* tall
## Usage
DEX runs a [squidworks](https://gitlab.cba.mit.edu/squidworks/squidworks) controller.
![c1](images/2019-09-06_ussm-controller-01.png)
![c2](images/2019-09-06_ussm-controller-02.png)
#### 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 | Cost |
| Part | Spec | Count | Notes | PN / Link | Cost |
| --- | --- | ---: | --- | ---: | ---: |
| SHCS | M3x25 | x | Pinning T- and X-es together | x |
| SHCS | M3x16 | x | Pinning T- to the wall, and pulley endmatter | x |
| FHCS | M3x10 | x | Pinning blisters to faces, flush up and countersink | x |
| 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](https://www.vxb.com/20-625ZZ-Shielded-5mm-Bore-Diameter-Miniature-p/625zz20.htm) | $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](https://www.vxb.com/6806-2RS-Bearing-30x42x7-Sealed-p/6806rs.htm) | - |
| 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
......@@ -30,18 +103,9 @@ To export from Fusion, use Rhino for layout, export cut files as DXF, for the tr
fixturing moves / top to bottom
## Controller Progress
## Testing Notes
I can run tests now, pulling data back in raw 24-bit signed integers from the load cell amp, and counting single steps.
![c1](images/2019-09-06_ussm-controller-01.png)
![c2](images/2019-09-06_ussm-controller-02.png)
These from this small sample:
![sp](images/2019-09-06_ussm-controller-test.jpg)
I can save this / output it as a JSON object, and it should be trivial to get this data out to a database somewhere... just need to know how the object should be formatted / how the database should be connected to.
Use the D683 ASTM Dogbone - normally Type 5
## Controller Desires
......@@ -49,12 +113,3 @@ I can save this / output it as a JSON object, and it should be trivial to get th
- 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 ...
## Goals for October 18
- machine leaves lab, goes to CiC, runs tests
- tests: for annealed PLA
## Hardware desires
I want the totem USSM. To spec performance, it should certainly have enough oomph to pull apart 1.75mm filament, maybe 3mm (a good goal). Figure out how many N this is. Also, some reasonable size coupon of 3DP'd coupon.
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