Plastic Cube

While your very first test cuts should be a simple geometric shape, this project is the perfect way to get familiar with your CNC mill or router. We will start with a cube cut out of soft plastic as it is more forgiving if you make a mistake.

The project consists of a simple .745" x .745" x .745" cube with a set of shallow 1/2" pockets cut into each side of the cube. 

If you cut the pockets shallow enough you will be able to break the small square in the center free and it will be trapped inside the center of the cube as shown here.

Parts

You will need the following components to make the plastic cube:

 

Clamping The Stock

The first challenge comes with trying to clamp the stock to your table. You can use the table clamps that came with the MF70 as shown here.

The problem with this method is that the cube will need to be swapped from side to side and getting it back into exact position will be problematic.

In addition, the clamps may get into the way of our milling operation.

By using a machine vise like the one shown here, you can very easily clamp the stock in place with 100% of the stock exposed for milling.

You will need to setup your vise before use

 

Vise Setup

You will need to setup your vise before you put it to use. This is a simple process that can be accomplished by using a test indicator attached to the head or mill base.

You place the indicator against the fence and move the table X-axis back and forth, adjusting the vise as needed.

 

Vise Stop

By using one of the table clamps you can create a small stop that will allow you to quickly move the stock into position on any of its sides.

 

Setting the X, Y, and Z Reference Points

Before loading the G-code and running the job, you will need to zero the X, Y, and Z axis.

To set the X-axis move the edge of the end mill against the left edge of the stock as shown here.  Once in position, set the X DRO to -.0625. (half the bits diameter)

Do the same thing for the Y-axis.  Set the end mill against the front edge of the stock and set the Y DRO to -.0625.

For the Z-axis set the end mill on top the stock as shown here, and set the Z-axis to 0.

 

Milling the Stock

The milling consists of placing a 1/2" wide pocket .19" deep into each side of the cube.

You can download the G-code, and drawing files here:

Plastic Cube Files

The actual size of my stock was .745" not .75". Files reflect this so if your stock is another size you will need to make adjustments.

Plastic Cube Milling Specifications

  • RPM: 10000
  • Feed Rate: 10 IPM
  • Depth of Cut: .03"
  • Plunge Rate of 10 IPM with a ramp of .25"

 

The Process

I urge you to cut several plastic cubes before moving on to aluminum. Experiment with making deeper or shallower pockets. If you make the pocket deeper the small internal cube can be removed. If the pocket is shallower the internal cube will be stock to the main cube at its corners.


Aluminum Cube

The aluminum cube is the logical next step in the project.  The process for milling the cube is identical to the plastic one with a few exceptions.

First, the stock is .5" x .5" x .5" instead of the .745" on the plastic cube.

The pockets are .4" wide and .105" deep. 

In addition, the depth of cut for each pass is .01" instead of the .03" used on the plastic cube.

Get the files here:

Aluminum Cube Files

Parts

You will need the following components to make the plastic cube:

Important!!

Wile you can start the milling process on the plastic cube and let it go from start to finish without worrying about clearing the chips, you cant do that when cutting aluminum. You have to make sure the chips are cleared or the end mill will have to do extra work cutting through the chips like a mulching mower. You will also want to add some lubricant to the cut as well.

Aluminum Cube Milling Specifications

  • RPM: 10000
  • Feed Rate: 10 IPM
  • Depth of Cut: .01"
  • Plunge Rate of 10 IPM with a ramp of .25"

 

Milling the Aluminum Cube

With a pocket depth of .105" the internal cube can be removed. Change the depth to .104" and the internal cube will remained attached to the main cube.

Other Cubes

Here is a larger cube I mad out of a foam block: