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# The Displacement Exercise (DEX)
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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.
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![dex](images/2019-09-27_DEX-CAD.png)
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![dex](images/2019-10-03_dex-together.jpg)

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## Usage

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DEX runs a [squidworks](https://gitlab.cba.mit.edu/squidworks/squidworks) controller, which is in development but is pulling data from samples successfully.
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![c1](images/2019-09-06_ussm-controller-01.png)
![c2](images/2019-09-06_ussm-controller-02.png)

#### Controller TODOs:
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- 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?)
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#### 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

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### CAD 

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#### Hardware Documenting TODO
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- mcmaster order
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- CAD shuffle and export
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### BOM
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Part numbers are from [McMaster Carr](http://mcmaster.com) unless otherwise linked.

| Part | Spec | Count | Notes | PN / Link | Cost / Per |
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| --- | --- | ---: | --- | ---: | ---: |
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| Delrin (Acetal) Cast Sheet | 24x12", 0.25" Thick | 2 | Fits on 24x18" w/ no mistakes | 8573K35 | $50.49 / 1 |
| PLA 'Tough' |  | ~ 300g | Many 3DP Mechanical Bits | [Matter Hackers M6E9T65K](https://www.matterhackers.com/store/l/light-blue-pro-series-tough-pla-filament-175mm-1kg/sk/M6E9T65K) | $52.00 / 1kg |
| 625ZZ Bearings | 5x16x5  | 24 | - | [VXB 625ZZ](https://www.vxb.com/20-625ZZ-Shielded-5mm-Bore-Diameter-Miniature-p/625zz20.htm) | $24.95 / 20 |
| Bearing Shims | 5x10x0.5 | 37 | - | 98055A098 | $8.62 / 50 |
| Carriage Shoulders | M4x5x6 | 12 | - | 92981A146 | $2.16 / 1 |
| Reduction Shoulder | M4x5x10 | 1 | - | 92981A030 | $2.32 / 1 |
| Idler Shoulders | M4x5x20 | 5 | - | 92981A042 | $2.33 / 1 |
| NEMA 23 Stepper Motor | > 56mm Can Length | 1 | Spec Shaft with Pinion | [Stepper Online](https://www.omc-stepperonline.com/nema-23-stepper-motor/nema-23-bipolare-1-8deg-1-26nm-178-4oz-in-2-8a-2-5v-57x57x56mm-4-fili.html) | $14.83 / 1 |
| GT2 Pinion | 20T | 1 | Spec Shaft with NEMA 23 | [Amazon](https://www.amazon.com/Saiper-GT2-Teeth-6-35mm-Synchronous/dp/B07MGMBX3N/) (or) [RobotDigg](https://www.robotdigg.com/product/226/20-Tooth-2GT-Pulley-10pcs-per-lot) | $9.96 / 5 |
| GT2 Closed Loop Belt | 280T, 6mm Wide | 1 | - | [Amazon](https://www.amazon.com/280-2GT-6-Timing-Belt-Closed-Loop/dp/B014SLWP68/) (or) [RobotDigg](https://www.robotdigg.com/product/283/260mm-264mm-268mm-280mm-284mm-288mm-or-294mm-gt2-endless-belt) | $15.88 / 10 |
| GT3 Open Loop Belt | ~ 1m, 9mm Wide | 1 | - | [Amazon](https://www.amazon.com/Ochoos-Timing-Rubber-Backlash-5Meters/dp/B07MWD9D7V/) (or) [RobotDigg](https://www.robotdigg.com/product/597/3GT-9mm-or-6mm-wide-open-ended-belt) | $15.00 / 1 |
| 6806 Bearing | 30x42x7mm | 2 | x | 6806-2RS [VXB](https://www.vxb.com/6806-2RS-Bearing-30x42x7-Sealed-p/6806rs.htm) | $12.95 / 1 |
| M3 Inserts | Tapered, 3.8mm Tall | ~ 300 | - | 94180A331 | $12.92 / 100 |
| M4 Inserts | Tapered, 4.7mm Tall | 16 | - | 94180A351 | $14.96 / 100 |
| M5 Inserts | Tapered, 6.7mm Tall | 4 | - | 94180A361 | $12.00 / 50 |
| M3 Washers | 18-8 Standard Flat | 300 | - | 93475A210 | $1.62 / 100 |
| SHCS | M3x16 | 100 | Pinning T- to the wall, and pulley endmatter | 91292A115 | $5.87 / 100 |
| SHCS | M3x20 | 100 | Pinning T- to one another (?) | 91292A123 | $6.78 / 100 |
| SHCS | M3x25 | 100 | Pinning T- and X-es together | 91292A020 | $7.23 / 100 |
| SHCS | M3x45 | 8 | Pinning the 'squat' together | 91292A025 | $12.21 / 50 |
| FHCS | M3x10 | 30 | Pinning blisters to faces | 92125A130 | $5.81 / 100 |
| FHCS | M3x25 | (?) | - | 92125A138 | $11.50 / 100 |
| Steel Dowel Pins | 5x8mm | 10 | - | 91585A506 | $8.40 / 25 |
| Feet | M4 Stud, 15x15mm | - | - | 93115K881 | $1.78 / 1 |
| **Approximate Mechanical Total** | | | | | **$446.80** |
| Loadcell(s) | 10, 30, or 50kg | 1 | Choose Range for Sensitivity | [Amazon 50kg](https://www.amazon.com/Pressure-Force-S-type-Sensor-Cable/dp/B01F6IOW3G/) [Amazon 30kg](https://www.amazon.com/Pressure-Force-S-type-Sensor-Cable/dp/B01F6IOWDG/) [Amazon 10kg](https://www.amazon.com/Pressure-Force-S-type-Sensor-Cable/dp/B01F6IOW4K/) | $39.00 / 1|
| Loadcell Amplifier | HX711 | 1 | - | [Sparkfun 13879](https://www.sparkfun.com/products/13879) | $9.95 / 1 |
| Power Supply | 350W 24V LRS-350-24 | 1 | - | [Amazon](https://www.amazon.com/MEAN-WELL-LRS-350-24-350-4W-Switchable/dp/B013ETVO12/) | $32.25 / 1 |
| **Rough Control Total: Incomplete** | | | | | **81.20** |
| **All Up** | | | | | **$528.00** |
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**CIC Build**
McMaster Order includes everything except:
- PLA
- Delrin
- 625ZZ's
- M4 Inserts
- M5 Inserts
- Belt / Pulleys / Motors
- LoadCell, PSU

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### 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?)
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### MFG Notes
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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:
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Black, Red, Blue, Cyan, Green, Magenta
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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.
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...
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fixturing moves / top to bottom
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## Testing Notes
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Use the D683 ASTM Dogbone - normally Type 5.

![dogbones](images/astm_d-638_bonesizes.jpg)
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## Controller Desires
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- 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 ...