How to Fixture a Part for an Industrial CT Scan Using Foam

Last Updated: February 27, 2021

Industrial CT scanning uses x-rays taken periodically while a part spins 360 degrees to create a 3D model of the part. Fixturing the part properly is required in order to decrease discrepancies between each x-ray taken. The following method relies on supplies that can be found at any hardware store to properly fixture your part.

Method 1

Method 1 of 2:
Indent Fixturing

1
Trace an outline around the part using permanent marker. Trace as closely to the part as possible.
2
Remove the part from the foam and begin to cut around the traced border with the knife. It is important to cut on a slight angle and only approximately 1" to 1 1/2" deep into the foam. Do not cut through the bottom of the foam.
3
Cut a grid pattern through the interior of the trace. Again cut only approximately 1" to 1 1/2" deep into the foam.
4
Use the flathead screwdriver to lift the foam out from the interior of the traced area one grid section at a time. Individual pieces of foam should break free with little effort.
5
Set the part down in the foam. The part should rest on a slight angle and be "snug" to the edges of the foam. If the part does not fit, cut a little more foam. Remember: You can always cut more foam away, but you cannot put the foam back. If you cut too much, you will have to restart with a new piece of foam.
6
Remove the excess foam. Leaving approximately 1" between the traced edge and the edge of the foam, cut off the excess foam.
7
Verify the part is securely fixed in the foam. Gently shake and push on the part to verify that it does not move within the foam.

Method 2

Method 2 of 2:
Wedge Fixturing

1
Cut out a rectangular and a circular piece of foam. These pieces will serve as the supports for the fixed part.
- The rectangular piece of foam should be approximately 9" x 11".
- The circular piece of foam should have a diameter of approximately 9"
2
Trace a 2" by 9" rectangle into the top of the circular piece of foam.
- A useful method is to use the rectangular piece of foam as a guide.
3
Cut into the traced out area on the circular foam in a grid shaped pattern. The grid pattern allows for the easy removal of the excess foam.
4
Remove the foam chunks from the cut out area. Use of a flathead screwdriver may be helpful here. Use the flat head to pry the foam chunks out.
5
File the cut out base of the circular foam. The base needs to be smooth and relatively flat.
6
Glue the rectangular piece of foam into the circular foam cutout. A little glue helps secure the two pieces of foam to each other.
7
Secure the part to the foam wedge using tape.
- Use as much tape as necessary. The part should not move when shaken or nudged.