Week 7: Computer-Controlled Machining
Date: March 5 - 11, 2026
What I Made This Week
I designed and milled a wooden shelf for my reptile habitat. I call it the Gecko Shelf.
The shelf holds a glass terrarium on top. It has three storage shelves on the bottom. The side panels have a "G" logo carved into them.
I designed press-fit joints. But the machining accuracy was not good enough. So I used wood glue to hold the parts together.
The completed Gecko Shelf with the terrarium placed on top
📋 Assignment
Group Assignment
✅ Do the lab's safety training ✅ Test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for the machine
📎 Group Work Page
Individual Assignment
✅ Make something big (approximately meter-scale) ✅ Design, mill, and assemble the parts
Extra Credit
- [ ] Make it without fasteners or adhesives
🔬 Group Assignment: Machine Testing
In the group assignment, we tested the Maslow CNC machine.
We checked the spindle speed, feed rate, and step-down depth. We also learned about safety rules for CNC milling.
The results helped me set the correct values for my own project. I used those values in KrabzCAM when I set up my toolpaths.
📎 See the full test results on the Group Work Page.
🪵 Individual Assignment: Gecko Shelf
Design Concept
I made a shelf to hold my reptile terrarium. The terrarium sits on the top section. Three shelves below store supplies.
The "G" logo is carved on the side and back panels.
Size: 394 × 359 × 1094 mm (width × depth × height) Material: 12 mm plywood Joinery: Press-fit slots + wood glue
Step 1: Design with JW-CAD
I used JW-CAD to draw all the parts.
Each part has press-fit slots cut into the edges. The slot width is 12 mm (same as the plywood thickness).
I also added dog-bone corners to the inside slots. A round end mill cannot cut sharp inside corners. Dog-bone shapes fix this problem.
JW-CAD: Initial 2D drawing with dimensions
JW-CAD: All parts laid out on one sheet for DXF export
After the design was done, I exported all parts as DXF files.
Part dimensions:
| Part | Size |
|---|---|
| Side panel (×2) | 359 × 1094 mm |
| Back panel | 394 mm wide |
| Shelf (×5) | 370 × ~350 mm |
| Slot width | 12 mm |
Step 2: CAM Setup with KrabzCAM
I used KrabzCAM to make toolpaths from the DXF files.
First, I loaded all parts at once. But the file was too big. So I tested with one shelf piece first.
I used the settings from the group assignment.
KrabzCAM: Toolpath for all parts loaded
KrabzCAM: Testing toolpath on one shelf piece first
Machining settings:
| Setting | Initial (Default) | Final (Used) |
|---|---|---|
| Tool diameter | 2 mm | 6.35 mm |
| Spindle speed | 10,000 rpm | 10,000 rpm |
| Feed rate | 400 mm/min | 1,800 mm/min |
| Step down | 0.5 mm/pass | 5 mm/pass |
| Final depth (profile) | 3 mm | 12.5 mm |
| Direction | Climb (CCW) | Climb (CCW) |
Step 3: Safety and Setup
Wood milling makes a lot of dust. The dust can cause fires and is bad for your lungs.
Before milling, I set up the dust collection system. The lab built a cyclone separator connected to a Makita vacuum cleaner. This system catches most of the wood chips.
Cyclone separator + Makita vacuum for dust collection
The machine I used is the Maslow CNC. It is a CNC router that moves by wire. Two motors pull wires to move the router head across the material.
The spindle is a DEWALT router. I set it to speed "2" (about 10,000 rpm).
DEWALT router spindle set to speed 2 (≈10,000 rpm)
Setting up the Maslow CNC on the plywood sheet
Step 4: Milling
I placed the plywood flat on the floor. Then I set the Maslow CNC on top of it.
The router moved along the toolpath and cut each part.
Maslow CNC milling the plywood
Maslow CNC positioned on the plywood — ready to start
Milling in progress — the vacuum removes wood chips
Another view of the milling process
Close-up of the router cutting a shelf piece
After each part was cut, I removed it from the sheet.
Shelf piece just after cutting — press-fit tabs are visible
Close-up of the cut edge — dog-bone corner shape is visible
All shelf pieces cut and stacked
Step 5: Assembly
The parts had errors of up to 5 mm. They did not fit well at first.
I sanded and trimmed the slots by hand. Then I pressed the pieces together and added wood glue.
Assembling the shelf — pressing the parts together
Step 6: Final Result
The shelf fits the terrarium perfectly.
The "G" logo is carved into the panels. Note: the logo ended up on the inside of the panel. This was a design mistake. Next time I will check the face direction before milling.
Gecko "G" logo carved into the side panel
Completed Gecko Shelf — terrarium placed on top
📦 Design Files
All files are in docs/files/week07/.
| File | Description |
|---|---|
| Gecko_Shelf.jww | JW-CAD main design file |
| Gecko_Shelf_Cut.dxf | DXF for CAM — all parts |
| Gecko_Shelf_Cut_Top_Plate.dxf | DXF — top plate |
| Gecko_Shelf_Cut_back.dxf | DXF — back panel |
| Gecko_Shelf_Cut_side.dxf | DXF — side panels |
| Gecko_Shelf_Cut_part.dxf | DXF — shelf pieces |
| Gecko_Shelf_Cut_side_Text.dxf | DXF — side panels with G logo |
🔗 Connection to Final Project
The Gecko Shelf is part of my Smart Reptile Habitat System.
The terrarium sits on the top of the shelf. The shelves below store control boxes and cables.
CNC milling let me make a strong, large-scale structure. This skill will help me build the housing for my final project.
🔧 Problems and Solutions
Problem 1: Cutting Error (up to 5 mm)
What Happened: The Maslow CNC cut parts with up to 5 mm of error. The parts did not fit together at first.
How I Solved It: I adjusted the parts by hand. I sanded and trimmed the slots until the pieces fit.
What I Learned: The Maslow CNC needs careful calibration before use. Next time, I will calibrate it more carefully. I will also cut a small test piece first to check the fit.
Problem 2: Logo Direction
What Happened: The "G" logo was carved on the inside of the panel. This was a design mistake — I set it on the wrong face.
How I Solved It: I assembled the shelf with the logo facing inward. It is still visible through the open side.
What I Learned: Always check which face is "up" when you set up the DXF in CAM software.
✅ Evaluation Checklist
Group Assignment
- [x] Safety training completed
- [x] Machine runout tested
- [x] Speeds, feeds, and materials tested
- [x] Results on group work page
Individual Assignment
- [x] Design completed (meter-scale: 1094 mm height)
- [x] CAM toolpaths set up
- [x] Milling completed
- [x] Parts assembled (press-fit, no screws)
- [x] Process documented with photos
Documentation
- [x] Design files in repository
- [x] Images compressed (under 500 KB)
- [x] Pushed to repository
💠Reflection
What Went Well
- The shelf is strong. The terrarium fits perfectly on top.
- The dust collection system worked very well.
- I finished the design and assembly in one week.
What I'd Do Differently
- Calibrate the Maslow CNC more carefully before cutting.
- Check the logo direction before milling.
- Cut one test piece first to check fit before milling all parts.
For Next Week — Electronics Production
- Review the Week 6 PCB design (Test Board)
- Plan the milling and soldering process
📚 References
Last updated: March 11, 2026