How to Design and 3D Print a Custom Armchair Caddy

Do you often find yourself juggling remotes, beverages, or gadgets while relaxing on your armchair? An armchair caddy can be a game-changer, keeping all your essentials within arm's reach. In this Instructable, I'll walk you through designing a personalized armchair caddy using Onshape—a free, cloud-based CAD software—and 3D printing it. This project combines digital design with practical functionality, resulting in a custom accessory tailored to your specific armchair dimensions. Feel free to go through the steps to design it or download the file and skip to step 7.

Materials:

1. Computer with internet access
2. Onshape Account (free at Onshape) or any 3D printing software
3. 3D Printer (e.g., Bambu Lab X1 Carbon or any other model)
4. 3D Printing Filament (PLA, ABS, or preferred material)
5. MicroSD Card or USB drive for file transfer

Tools:

1. Measuring Tape or ruler
2. Slicing Software (e.g., Bambu Studio, Cura, PrusaSlicer)
3. Cleaning Tools for the 3D printer (scraper, brush, etc.)

1. Open Onshape:
2. Log in to your Onshape account and create a new document.
3. Start a New Sketch:
4. Select the Top Plane and click on Sketch.
5. Draw a Center Point Rectangle:
6. Choose the Center Point Rectangle tool.
7. Click on the origin to start.
8. Set Dimensions:
9. Length: I chose to do 200 mm.
10. Width: Enter your Armrest Width + 10 mm (to account for the walls).
11. Extrude the Rectangle:
12. Click Extrude and select your rectangle sketch.
13. Depth: Enter 40 mm.
14. Operation: Ensure Solid and New are selected.
15. Click OK.

This forms the main body that will hang over the armrest.

1. New Sketch for Armrest Slot:
2. Select the Top Face of the extruded base.
3. Click on Sketch.
4. Draw Another Rectangle:
5. Use the Center Point Rectangle tool.
6. Length: Enter 200 mm.
7. Width: Enter Armrest Width.
8. Extrude Remove:
9. Click Extrude and select the new rectangle sketch.
10. Depth: Enter 30 mm.
11. Direction: Ensure it's set to Remove.
12. Click OK.

This creates a recessed area that fits snugly over your armrest.

1. Sketch the Top Platform:
2. Select the Top Face of the base again.
3. Click on Sketch.
4. Draw the Top Rectangle:
5. Use the Rectangle tool.
6. Dimensions: Enter 140 mm x 200 mm.
7. Extrude the Top Surface:
8. Click Extrude and select the new rectangle.
9. Depth: Enter 10 mm.
10. Offset: Set an Offset Distance of 30 mm (so it starts above the base).
11. Click OK.

This creates a flat surface for holding items.

1. Sketch the Holders:
2. Select the Top Face of the platform.
3. Click on Sketch.
4. Add Cup Holders (Circles):
5. Use the Circle tool.
6. Draw two circles with a diameter of 55 mm.
7. Position them appropriately on the platform.
8. Add Rectangular Holder:
9. Use the Rectangle tool.
10. Draw a rectangle with 75 mm length and 50 mm width.
11. This can serve as a key holder, ashtray, or storage for small items.
12. Extrude the Indentations:
13. Click Extrude and select the circles and rectangle.
14. Depth: Enter 8 mm.
15. Direction: Set to Remove.
16. This leaves a 2 mm base (since the platform is 10 mm thick).
17. Click OK.

These indentations will hold items securely without cutting through the platform.

1. Sketch Cable Holes:
2. On the same top surface, click on Sketch.
3. Draw Squares for Cables:
4. Use the Rectangle tool.
5. Draw two squares measuring 10 mm x 10 mm.
6. Position them where you'd like cables to pass through.
7. Extrude Through Holes:
8. Click Extrude and select the squares.
9. Depth: Enter 10 mm.
10. Direction: Set to Remove.
11. This cuts holes entirely through the platform.
12. Click OK.

These holes allow USB cables or chargers to pass through neatly.

1. Transform the Model (optional):
2. Click on Transform in the toolbar.
3. Select the entire model.
4. Rotate it 180 degrees.
5. This positions the widest part at the bottom, improving stability during printing.
6. Export the Model:
7. Right-click on the part name in the Parts list.
8. Select Export.
9. Set Export Options:
10. Format: Choose STL.
11. Units: Ensure it's set to Millimeters.
12. Resolution: Set to Fine or Custom for better quality.
13. Click Export to save the file to your computer.

1. Open Slicing Software:
2. Launch Bambu Studio or your preferred slicer.
3. Import the STL File:
4. Import your STL file to the software
5. Adjust Print Settings:
6. Material: Select the filament type you're using.
7. Layer Height: Standard is 0.2 mm, but adjust as desired.
8. Infill Density: Recommend 20% for strength but feel free to adjust it as desired.
9. Slice the Model:
10. Click Slice Plate to generate the sliced file.
11. Preview the Layers:
12. Review the sliced model to ensure there are no issues.
13. Export sliced file:
14. Click Export and save the file to your microSD card or USB drive.

1. Prepare the 3D Printer:
2. Load the filament.
3. Ensure the build plate is clean and leveled.
4. Transfer the G-code:
5. Insert the microSD card or USB drive into the printer.
6. Start the Print:
7. Navigate to the file and begin printing.
8. Monitor the Print:
9. Keep an eye on the first few layers for adhesion.
10. Periodically check the print's progress.
11. Remove the Print:
12. Once completed, carefully remove the caddy from the build plate.
13. Clean Up:
14. Remove any support material if used.
15. Sand any rough edges or surfaces if desired.
16. Test Fit:
17. Place the caddy on your armchair to ensure it fits snugly.
18. Check that all holders and pass-throughs function as intended.

Note: Printing may take several hours depending on your settings. It took 2.5 hours for me.

Creating this custom armchair caddy was both a practical and educational experience. Here's what I learned:

1. Design Precision: Accurate measurements are crucial for a perfect fit, emphasizing the importance of planning before designing.
2. CAD Skills: Using Onshape improved my proficiency in 3D modeling, from basic sketches to complex extrusions.
3. Functionality: Incorporating features like cup holders and cable pass-throughs tailored the caddy to my personal needs.
4. 3D Printing Considerations: Adjusting the model's orientation for stability during printing highlighted the relationship between design and manufacturing.
5. Problem-Solving: Overcoming challenges, such as ensuring the indentations didn't compromise the structural integrity, enhanced my critical thinking.

Overall, this project bridged the gap between digital design and tangible utility, resulting in a personalized accessory that enhances daily comfort.