7. Computer-Controlled Machining

This week, I have to work on a CNC router. I’m excited to make some furniture. I started searching for ideas, and I decided to create a shelf to organize tools that I use constantly.

Group Task:

Group task

I use SolidWorks

These are the shapes in solid works and the assembly of my organizer.

I used VCarve to configure the cut of my piece.

1. First, I opened VCarve and created a new project.
   • Width (X): 1200 mm
   • Height (Y): 2440 mm
   • Thickness (Z): 15 mm (This is the material thickness).
   • I also set the machine origin at 0.

Steps

1. I imported my pieces in .DXF format using the “import vectors” option.
2. I placed each vector in the work area. It’s important to leave a margin or space on the border to avoid the machine cutting the clamps.
3. To close the vector of each part, it’s important to use the tool to join them.

Chamfer

1. I added dogbones. I used a femur bone shape to put in each piece (it's important that you only place it in the internal corners).I clicked on the internal corners and added the dogbone with a radius of 3.175 mm.
2. I selected the pieces that I wanted to cut. I started with the external part and then with the internal cuts.

Types of Cuts

• Profile Cut: To cut the outer contour of the pieces.
• Pocket Cut: For internal cutouts.

Cutting Parameters

• Material thickness: 15.3 mm (to ensure the tool will cut the material properly).

Feeds and speed of my tool

1. I set the cutting tool (end mill 1/4") and adjusted parameters such as feed rate and spindle speed.

I put these calculations in thinking about safe milling for a 1/4 in. diameter tool with 2 flutes. I defined a pass depth of 0.1 in. and a recovery of 40% to avoid overloading the tool. I set the spindle speed at 18,000 rpm, based on the recommended table for this type of cutter and material. I set the feed rate at 3.6 inches per second, following the recommended parameters. In addition, I set the down speed at 25% of the feed rate (1.56 in/sec), because the cutter is not designed to cut aggressively downward, so it's best to go slow and safe on the downstroke.

2. I placed tabs on the pieces to prevent them from detaching during cutting.
3. I configured 6 passes in the software

Final Steps

1. I used the simulation tool to check that the toolpaths were correct and there were no errors.
2. Finally, I saved the file in the machine's format.

1. I placed my material on the sacrificial bed and secured the board properly.
2. I deactivated the emergency button and pressed the green button.

3. I let the machine return to the origin.
4. I set the starting point to 0 for the X and Y axes first, and then I did the same for the Z axis (I adjusted the Z origin and turned the tool until the drill bit started to scratch the material).
5. To load the file, I inserted the USB, went to the "Files" button, selected the USB, chose the file, and pressed play.

1. First, I sanded each piece with a sander.
2. Then, I used a hammer to join my pieces.
3. My pieces fit well.
4. To give my shelving a good finish, I varnished it.

This is the result:

Files

• Solid works files
• Download VCarve file
• Download G-Code files
• Download dxf files

Conclusion

I liked this week very much, at first I was afraid to use the machine, but by making the right adjustments I was able to make my furniture. Now I understand better how to make press-fit pieces and the importance of testing to make sure your pieces fit well.