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29
CNC Machine.md
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@ -173,20 +173,30 @@ This section outlines the full workflow for using the CNC machine, from preparat
#### 3. Toolpaths: Cut #### 3. Toolpaths: Cut
- Choose **2D Profile Toolpath**. - Choose **Profile Toolpath**.
- Set: - Set:
- **Start Depth:** 0 mm - **Start Depth:** 0 mm
- **Cut Depth:** 13 mm (12 mm material + 1 mm into sacrificial sheet) - **Cut Depth:** 13 mm (12 mm material + 1 mm into sacrificial sheet)
- Select **Outside/Right** for vector machining to preserve size.
- Tool Settings (6 mm bit): - Tool Settings (6 mm bit):
- Spindle Speed: 8000 RPM - Spindle Speed: 8000 RPM
- Feed Rate: 80 in/min - Feed Rate: 80 in/min
- Plunge Rate: 15 in/min - Plunge Rate: 15 in/min
- Click **Calculate**, then **OK** to confirm warnings. - Specify the Number of Passes:
- Press "Edit Passes"
- Number of Passes: 2
- First Pass Depth: 6.5mm
- Second Pass Depth: 13mm
- Specify Machine Vectors:
- Select **Outside/Right** for vector machining to preserve size.
- Select **Inside/Left** for
- Select **On** for
- Tabs: ++++++++
- Click **Calculate**, then read the warnings, if it is within your expectations click **OK** to confirm.
--- ---
#### 4. Toolpaths: Pocket and Tabs #### 4. Toolpaths: Pocket
- **Pocket Toolpath:** - **Pocket Toolpath:**
- Used to hollow out an internal region. - Used to hollow out an internal region.
@ -202,6 +212,13 @@ This section outlines the full workflow for using the CNC machine, from preparat
--- ---
#### 5. Preview Toolpaths
Preview Visible Toolpaths
Click on the 3D View tab
Reset Preview
Preview Visible Toolpaths
#### 5. ShopBot 3 Setup #### 5. ShopBot 3 Setup
- Open **ShopBot 3** software. - Open **ShopBot 3** software.
@ -216,11 +233,11 @@ This section outlines the full workflow for using the CNC machine, from preparat
#### 6. Z-Axis Calibration #### 6. Z-Axis Calibration
- Clip the wire to the drill bit. - Clip the wire to the collet nut or the spindle body of the CNC machine.
- Place the **metal calibration plate** on the surface of the sheet. - Place the **metal calibration plate** on the surface of the sheet.
- Run the **Z-zeroing command** (machine lowers bit to touch the plate). - Run the **Z-zeroing command** (machine lowers bit to touch the plate).
- System detects contact and sets Z = 0. - System detects contact and sets Z = 0.
- Remove the clip and plate after calibration. - After calibration, remove the clip and plate, then return them to their original location with the clip still attached to the plate.This ensures smooth CNC operation.
--- ---

2
Cycloidal Gearbox.md
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@ -37,6 +37,8 @@ To clearly illustrate the internal mechanics, structural design, and assembly st
- Included Media - Included Media
- **Assembly Video** – starts with an exploded view and step-by-step buildup - **Assembly Video** – starts with an exploded view and step-by-step buildup
<iframe width="560" height="315" src="https://www.youtube.com/embed/ylcnBYmR19A?si=1Pg3t_qRczJDjIow" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
<iframe src="https://1drv.ms/v/c/62d760a9f409a919/IQSXz1cAg1KlSb5fDzi06m4CAZDB0oQq2RIVgFQe7C54sDk" width="640" height="480" frameborder="0" scrolling="no" allow="autoplay" allowfullscreen></iframe> <iframe src="https://1drv.ms/v/c/62d760a9f409a919/IQSXz1cAg1KlSb5fDzi06m4CAZDB0oQq2RIVgFQe7C54sDk" width="640" height="480" frameborder="0" scrolling="no" allow="autoplay" allowfullscreen></iframe>
- **Disassembly Video** – shows teardown process in reverse order - **Disassembly Video** – shows teardown process in reverse order

342
Laser Cutting.md
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@ -1,266 +1,136 @@
# Two-Disc Cycloidal Gearbox Design # 🔲 How to Use the Laser Cutting Machine
#### 1. Project Description *(This page provides step-by-step instructions for students on how to prepare and operate the laser cutter. Insert images where noted to enhance clarity and guidance.)*
The two-disc cycloidal gearbox is designed to convert high-speed, low-torque input from a stepper motor into low-speed, high-torque output. It utilizes two synchronized cycloidal discs that rotate in opposite phases, interacting with drive pins to transmit motion to an output shaft.
This configuration minimizes backlash and distributes load across multiple contact points, offering smooth and powerful transmission. The system is fully enclosed and features multiple mounting options for external attachments.
#### 2. Application & Use Cases
##### Applications
- Robotics joints and arms
- CNC rotary tables
- Precision camera mounts
- Automated actuators
- Small-scale industrial machines
##### How to Use
- Mount the gearbox base to your motor using the provided holes.
- Connect the NEMA-17 motor shaft to the input via the motor shaft connector.
- Attach your load or mechanism to the output shaft area.
- Power the motor through a driver board and microcontroller (e.g., Arduino).
- Control the motion using programmed step sequences.
- Ensure lubrication (grease) between the discs and drive pins for smoother performance and longer lifespan.
#### 3. Engineering Drawings
##### Description
The design is a compact, scalable two-disc cycloidal gearbox intended for high-torque, low-speed applications. Its parametric structure makes it easy to adapt in size and material. The current prototype has a 90 mm diameter and 54 mm height.
To clearly illustrate the internal mechanics, structural design, and assembly steps, the following visuals are provided:
- Included Media
- Assembly Video – starts with an exploded view and step-by-step buildup
<p align="center">
<img src="images/insert.jpg" style="border: 2px solid black;" />
</p>
- Disassembly Video – shows teardown process in reverse order
<p align="center">
<img src="images/insert.jpg" style="border: 2px solid black;" />
</p>
- Transparent Body Image – reveals internal components without hiding the casing
<p align="center">
<img src="images/Transparent.png" style="border: 2px solid black;" />
</p>
- Visual Assets & Drawings
- Engineering Drawing Sheet
<p align="center">
<img src="images/2.png" style="border: 2px solid black;" />
</p>
- Cross-Sectional Analysis (x2)
<p align="center">
<img src="images/SubSectionAnalysis.png" style="border: 2px solid black;" />
</p>
<p align="center">
<img src="images/sectionanalysis2.png" style="border: 2px solid black;" />
</p>
- Isometric View
<p align="center">
<img src="images/1.png" style="border: 2px solid black;" />
</p>
#### 4. List of Materials & Components
- ##### Standard Components
| Part | Quantity | Approx. Size |
| ------------- | -------- | -------------------------------------------------- |
| Bearing | 2 | Ø65 mm (outer) × Ø50 mm (inner) × 7 mm (thickness) |
| Bearing | 4 | Ø32 mm (outer) × Ø20 mm (inner) × 7 mm (thickness) |
| Stepper Motor | 1 | NEMA-17 |
- ##### Bolts & Nuts (*with available size approximations*)
Note: If a bolt is slightly longer than needed, it can be trimmed using a saw. Nut sizes should fit snugly but not too tight.
1. (A) Connecting Base to Base Cover
- 7 × Flat Head Machine Screws (Type B)
- Size: M4 × 45 mm
- Head Diameter: ~7.5 mm
- 7 × M4 Hex Nuts
- Edge-to-Edge: ~6.9 mm
- Thickness: ~3.2 mm
2. (B) Drive Pins Area (Replaces 5 mm Pins)
- 4 × M3 × 50 mm Bolts (hex or socket head)
- Head Diameter: ~5.5 mm
- 4 × M3 Hex Nuts
- Edge-to-Edge: ~5.5 mm
- Thickness: ~2.4 mm
3. (C) Mounting Points on Top of the Gearbox
- 7 × M4 Hex Nuts
- Edge-to-Edge: ~6.9 mm
- Thickness: ~3.2 mm
4. (D) Shaft Connector
- 2 × M3 × 40 mm Bolts
- Head Diameter: ~5.5 mm
- 2 × M3 Hex Nuts
- Edge-to-Edge: ~5.5 mm
- Thickness: ~2.4 mm
5. (E) NEMA-17 Shaft Connector
- 1 × M3 × 6 mm Bolt (may require sanding)
- Head Diameter: ~5.5 mm
- 1 × M3 Hex Nut
- Edge-to-Edge: ~5.5 mm
- Thickness: ~2.4 mm
6. (F) NEMA-17 Connector
- 4 × M3 × 15 mm Bolts
- Head Diameter: ~5 mm
- ##### 3D-Printed Components
- Material: PLA (tested), PETG (recommended for durability)
- Parts: Housing, base cover, discs, shaft connectors, output caps, circlips
- Infill: Suggested 40% or more for torque applications
#### 5. Cycloidal Drive Strength Analysis
--- ---
##### **1. Motor Output Torque** #### 1️⃣ Preparing the File
**Software: SolidWorks / Illustrator / CorelDraw / etc.**
* **Motor Stall Torque**: 0.45 Nm - Export the design as a **DXF (.dxf)** file.
* **Gear Ratio**: 21:1 - Send the file to the designated **email account** (e.g., instructor's Gmail or lab email).
* **Estimated Efficiency**: 85% - On the laser cutting computer, **download** the file and **import it into RDWorks**.
$$
\text{Output Torque} = 0.45 \times 21 \times 0.85 = \boxed{8.03 \, \text{Nm}}
$$
--- ---
##### **2. Load Handling Capability (Based on PLA Disc)** #### 2️⃣ Setting Up in RDWorks
📌 *Insert screenshot of RDWorks interface here*
###### PLA Parameters: - **Arrange the parts** on the virtual sheet using directional arrow buttons.
- **Assign colors** to each part depending on whether it’s for cutting, engraving, or marking.
- **Double-click the selected color** from the left color bar to adjust settings:
- Input appropriate **Speed** and **Power** values based on material type and thickness.
- Alternatively, use **Parameter Library** to select preconfigured material profiles.
* **Yield Strength of PLA**: 50 MPa ✅ After setting all values, click **“Download”** to transfer the file to the machine.
* **Safety Factor**: 3 → Allowable stress = 16.7 MPa
* **Contact Area (per lobe)**: 5 mm²
* **Lobes in contact**: 4
* **Radius from center to lobe force point**: 33.5 mm = 0.0335 m
* **Infill Density**: 25%
###### Calculations:
* **Force per lobe**:
$$
F_{\text{lobe}} = 16.7 \times 10^6 \times 5 \times 10^{-6} = 83.5 \, \text{N}
$$
* **Total force from 4 lobes**:
$$
F_{\text{total}} = 4 \times 83.5 = 334 \, \text{N}
$$
* **Torque handling at 33.5 mm radius**:
$$
\tau = 334 \times 0.0335 = 11.2 \, \text{Nm}
$$
* **Account for 25% infill**:
$$
\tau_{\text{safe}} = 11.2 \times 0.25 = \boxed{2.8 \, \text{Nm}}
$$
--- ---
##### **3. Drive Pin Strength (Bolts with PLA Sleeves)** #### 3️⃣ Operating the Laser Cutter
📌 *Insert image of laser cutter with labeled parts here*
###### Assumption: 1. **Turn on** the machine and main power switch.
2. **Insert the material** (e.g., 3mm plywood, 6mm acrylic).
* Bolts used instead of precision 5 mm mild steel pins 3. Flip the **light knob** to activate internal lighting.
* Outer diameter maintained at **5 mm** using **PLA sleeves** 4. On the machine panel:
* Inner bolt shaft assumed 4 mm (typical M4 bolt shank) - Press **“File”** and select the file
* Steel Yield Strength: 260 MPa - Press **“Enter”** to load it into memory
5. Use **arrow keys** to move the laser head to the desired starting point.
- **Cross-sectional Area (4 mm bolt)**: 6. Adjust the **Z-axis** (height) of the laser:
- Use a **spacer tool** (e.g., LEGO brick) for low thickness.
$$ - For thicker materials, keep around **2mm distance** between the laser head and the material.
A = \frac{\pi D^2}{4} = \frac{\pi \cdot 4^2}{4} = 12.57 \, \text{mm}^2 7. Press **“Origin”** to set the starting position.
$$ 8. Press **“Frame”** to preview the cutting boundary.
9. Once confirmed, press **“Start”** to begin cutting.
- **Force per bolt**:
$$
F_{\text{bolt}} = 260 \times 12.57 = 3,268.2 \, \text{N}
$$
- **Total force (4 bolts)**:
$$
F_{\text{total}} = 4 \times 3,268.2 = 13,072.8 \, \text{N}
$$
- **Torque capacity**:
$$
\tau = 13,072.8 \times 0.0335 = \boxed{437.9 \, \text{Nm}} \quad \text{(Safe✅)}
$$
> Note: **PLA sleeves** do not contribute significantly to strength — they act as spacers or guides. Only **steel bolts** are load-bearing.
--- ---
##### **4. Max Load at 50 mm Arm** #### 🛡️ Safety & Efficiency Tips
📌 *Insert image of safety guidelines and PPE here*
$$ - Always wear **safety goggles** during operation.
F = \frac{\tau_{\text{safe}}}{r} = \frac{2.8}{0.05} = 56 \, \text{N} - Never leave the machine **unattended** while it's running.
$$ - Use **tape or weights** to hold down curled or uneven sheets.
- Use **Frame preview** to avoid cutting beyond the material area.
$$ - **Organize parts efficiently** on the sheet to reduce material waste.
\text{Mass} = \frac{56}{9.81} = \boxed{5.7 \, \text{kg}}
$$
--- ---
##### Final Summary Table #### ✍️ Engraving Notes
| Category | Value | Safe? | - Use **lower power and higher speed** for engraving.
| --------------------------- | -------- | ------------------------ | - Perform a **small test area** first to avoid burning the material.
| Motor Stall Torque | 0.45 Nm | ✅ | - Ensure the surface is flat and clean for consistent engraving quality.
| Output Torque | 8.03 Nm | ❌ Exceeds PLA safe limit |
| PLA Torque Limit | 2.8 Nm | ✅ |
| Bolt + PLA Pin Torque Limit | 437.9 Nm | ✅ (way overbuilt) |
| Max Load (at 50 mm arm) | 5.7 kg | ✅ |
--- ---
##### Final Conclusion #### 🧪 Cutting Efficiency Test Example
📌 *Insert photo of test squares with labels*
The **cycloidal drive system is likely to fail at the PLA disc lobes under full output torque**, especially if printed with only **25% infill**. Although the **bolts (with PLA sleeves)** acting as drive pins are structurally sufficient, the **PLA disc is the mechanical weak point**. **Objective:**
Determine the optimal speed and power settings for clean cuts on 2.45mm plywood without manual force.
##### If tested: ---
* The drive **will function under light loads (below \~5.7 kg at 50 mm arm)**. **Test Parameters:**
* Under full load or high-torque demand, **plastic deformation or cracking is expected at the lobes**.
* The bolts will hold without issue, but **localized PLA wear or failure around the lobes and sleeves is likely.**
##### Recommendations: - **Speeds (mm/s):** 15, 20, 30, 40
- **Powers (%):** 15, 27, 40, 52, 65
* Increase **infill to at least 75%** or use a stronger material like **PETG**. ⚠️ *Do not exceed 70% power. It may damage the machine.*
* Consider **fillet reinforcement** around lobes to distribute stress.
* Reduce gear ratio or torque output if high load isn't needed. ---
**Successful Cutting Combinations:**
| Speed (mm/s) | Power (%) |
|--------------|------------|
| 15 | 40 |
| 20 | 30 |
| 10 | 52 |
| 20 | 52 |
| 30 | 52 |
| 15 | 65 |
| 20 | 65 |
| 30 | 65 |
| 40 | 65 |
---
**Conclusion:**
Higher power settings (52–65%) combined with moderate to low speeds produced clean cuts. This combination allows the laser sufficient energy and time to fully penetrate the material without excessive scorching.
---
#### 🔍 Focal Point Experiment
📌 *Insert photo of inclined test setup with cuts*
**Objective:**
Understand how varying the laser's focal height (Z-axis) affects the quality of cuts.
---
**Setup:**
- A wooden plate was placed at an **inclined angle** on the cutting bed.
- The laser cut along the slope, testing multiple focal heights.
---
**Observations:**
- When **too far**, the beam was unfocused, producing wide and burnt edges.
- When **too close**, the beam was concentrated but often failed to cut through fully.
- The **ideal distance** created precise, clean lines without burn marks.
---
**Conclusion:**
The laser’s **focal point** plays a crucial role in cut quality. Proper Z-axis alignment ensures effective energy concentration, minimizing burns and maximizing precision.
---
#### 📎 Add Barcode Below
📌 *Insert a QR code here that links directly to this documentation page on your website*
---