Skill Builder: Milling Acrylic/Plywood

Overview

You will become familiar with desktop milling set ups, milling acrylic/plywood, and creating 2.5D parts from .svg files.  Take a look at SVG Workflow for more information.

You will need to download the Bantam Tools software and tool libraries for acrylic and plywood.

 

What You Will Need

Digital Calipers

1/8″ diam flat end mill

Double Sided Tape

Acrylic/Plywood

Othermill/Bantam Tools Milling Machine

Tool libraries for Acrylic and Plywood.

 

Note: The documentation was originally done on the Version 1 Othermill with sheet aluminum.

 

Safety

Make sure all clear panels are in place on the mill before any cutting operation.  Be careful with metal burs, they can be sharp.  Always wear goggles when near the mill while it is cutting.  Never leave a running mill unattended.  If something goes wrong hit the emergency stop button.

 

The Process

Prepare your .svg file.  For this example I am using drive_wheel.svg.  The solid black areas will be treated as engravings and the outer circle will be treated as a cutout.

 

Attaching End Mill

The OtherMill uses a collet and collet nut to hold end mills in place.

Tap the collet nut a few times on the workbench to clear it from any dust.  Snap the collet into the nut and thread it into place on the spindle.  Place the end mill into the collet and hand tighten.  Use the two wrenches to tighten all the way.  And replace the wrenches on the magnets on the front of the machine.

 

Measure Your Material

Using digital calipers, measure the length, width, and thickness of the material.  Record these number and add .002″ to the thickness.  This will allow for any inconsistencies in material thickness.

 

Mount Material to Bed

Use double sided tape to mount your material to the mill bed.  Be generous with the amount of tape you use (but do not overlap the tape), you don’t want the material to move.  Make sure the mill bed is free from dust and material before you mount the material.  Mount the material in the front left corner of the bed, this is the origin for the X and Y axis.  Hold the material in place firmly for a few moments to ensure a solid attachment.

 

Home Machine and Determine Z axis Origin

If you just turn on the OtherMill it will need to calibrate and re-home itself.  Click the homing button to do this.

To set Z axis origin the mill must be secured in the spindle.  The mill must be over a free portion of the bed — not over material — and in the “Safety Zone”.  The mill must be connect to a computer with OtherPlan for these operations to be performed.

 

Setup Material

In OtherPlan, setup the material.  Choose the type of material and input the dimensions you measured earlier.   Again, it is very important that you measure material thickness accurately.  It is a good habit to add a small bit of wiggle room to your material thickness.  For example, if the material is measured to be .125″ thick, enter .127″ as the material thickness.  This should addition will make up for any inconsistencies in thickness.

 

Change the Tool

You will need to set the tool that you are using in OtherPlan.  Select the tool you have mounted in the spindle and set the Z axis origin.

 

Operations

You will have the options to perform Engravings, Cutouts, or both.  Cutouts will cut all the way through the material but you can set the depth of the engravings.  Note: engravings typically take a long time to perform.

 

Begin Cut

When all is set correctly you can click “Start Cutting” or “Cut Visible” to begin your job.  Never leaving a running mill unattended.  You can press the pause button and start the job up again .

When the operations are complete you can remove the parts and excess material from the bed.

Use the vacuum to clean up the mill when you are doing cutting.  Remove your end mill.

 

Clean Up Part

Most likely you will need to sand or file your part after it has been removed from the mill.  Light sanding with 220 grit sand paper should take care of most of it.  For this circular part, using a screw and a nut, I chucked it up in a drill and sanded while spinning it.

 

Make sure to clean up the shop when you are done and return all tools, bits, and attachments to their proper place.  Always vacuum out the Othermill.