# sv06-belt-recovery-stress-tests

Belt tension recovery and motion stability test models for bed-slinger 3D printers (e.g., SV06-class machines).

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![](img/DSC_5098.webp)
## Purpose

These models are designed to help recover from situations where printer motion accuracy has been degraded, typically due to:

* Adjusting belt tension without a reference baseline
* Experiencing layer shifts during prints
* Replacing belts or modifying mechanical components

This project provides:

* Parametric OpenSCAD models
* A structured test procedure
* Guidance for interpreting failure modes

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## When To Use This

Use these tests if you observe:

* Sudden layer shifts (e.g., 3-5 mm offsets)
* Inconsistent dimensional accuracy
* Audible belt skipping or motor stutter
* After adjusting belt tensioners

Here's an example of a case for a hand held radio where the top suddendly shift at the 20mm height.
![](img/20260318_215156_Wed.png)
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## Models Included

### 1. Cube (Baseline Test)

* Dimensions: 40 × 40 × 40 mm
* Purpose:

  * Verify basic printer stability
  * Detect gross mechanical issues

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### 2. Y-Bar (Axis Stress Test)

* Dimensions: 20 × 150 × 50 mm
* Purpose:

  * Stress the Y-axis (bed movement)
  * Detect belt slip under momentum and direction reversal

**Important:**

* Orient the 150 mm dimension front-to-back on the bed

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### 3. Tower (Long-Duration Test)

* Dimensions: 18 × 18 × 120 mm
* Purpose:

  * Reveal issues that appear only over time
  * Detect cumulative drift, resonance, or late-stage layer shifts

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## Print Procedure (Recommended Order)

Run each model as a **separate print job**:

1. **Cube**

   * Confirms system is not fundamentally broken

2. **Y-Bar**

   * Directly tests axis tension and inertia behavior

3. **Tower**

   * Tests stability over time and height

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## Suggested Slicer Settings (Orca Slicer)

### Cube

* Layer height: 0.20 mm
* Perimeters: 3
* Infill: 20-25% (grid or gyroid)

### Y-Bar

* Layer height: 0.20 mm
* Perimeters: 3
* Infill: 15-25% (grid recommended)

### Tower

* Layer height: 0.20 mm
* Perimeters: 3
* Infill: 0-10%
* Brim: optional (only if adhesion is an issue)

See the settings folder for settings used in Orca Slicer.

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## Belt Tension Guidance

This project assumes GT2 belts (typical for most hobby printers).

### Frequency Method (Recommended)

Using a phone-based spectrum analyzer:

* Target range: **90-110 Hz**
* Reference: ~110 Hz ? ~2 lb tension (Voron baseline)

Procedure:

1. Move bed so belt span ~ 150 mm
2. Pluck belt
3. Measure frequency
4. Adjust tensioner
5. Repeat until stable

### Notes

* Too loose:

  * Low frequency (<70 Hz)
  * Layer shifts likely

* Too tight:

  * High frequency (>120-130 Hz)
  * Motor strain, possible missed steps

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## Interpreting Results

### Good Result

* Clean vertical alignment
* No sudden offsets
* Consistent layer stacking

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### Failure Modes

#### Sudden Layer Shift

* Cause:

  * Belt too loose
  * Pulley slipping
* Action:

  * Increase tension slightly
  * Check motor pulley set screws

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#### Repeated Shift at Same Height

* Cause:

  * Mechanical obstruction
  * Cable snag
* Action:

  * Inspect motion path
  * Check wiring harness clearance

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#### Gradual Lean / Drift

* Cause:

  * Frame or axis alignment issue
* Action:

  * Inspect rails, wheels, or rods

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#### Ringing / Ghosting (No Shift)

* Cause:

  * High acceleration
* Action:

  * Reduce acceleration (not a belt issue)

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## Notes on Methodology

These tests intentionally:

* Emphasize repeated motion in one axis
* Increase inertial load with height
* Create conditions where marginal tension fails visibly

This approach isolates motion system issues rather than general print quality.

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## OpenSCAD Usage

Generate models:

```bash
openscad -D 'model="cube"'  -o cube_$(date +%Y%m%d_%H%M).stl  stress_test_models.scad
openscad -D 'model="ybar"'  -o ybar_$(date +%Y%m%d_%H%M).stl  stress_test_models.scad
openscad -D 'model="tower"' -o tower_$(date +%Y%m%d_%H%M).stl stress_test_models.scad
```

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## Provenance

Generated with:

* OpenSCAD
* Orca Slicer (recommended)
* Frequency-based belt tuning derived from:

  * Voron Design tuning methodology

This project was developed with ChatGPT.
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## License

Recommend: MIT or CC-BY 4.0 for broad reuse.

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## Contributing

Improvements welcome:

* Additional test geometries
* Axis-specific stress models
* Automated calibration workflows

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