How to media blast FDM parts
Common applications where media blasting is applicable:
• Smoothing and polishing for:
- Concept models
- End-use parts
• Surface preparation such as texturing and etching for:
- Mold masters
Consider your options.
Blast Media: Select a blast media with the desired level of abrasiveness.
• Aluminum oxide: harshest
Aluminum oxide is the most aggressive blast media for smoothing an FDM
part and can also be used to texturize or etch parts. This media is ideal
when preparing a surface for electroplating.
• Plastic: mild to harsh
For surface smoothing, this finely ground plastic media is recommended.
This media is available with abrasiveness ratings from mild to harsh (Figure 2).
• Sodium bicarbonate (soda): mildest
Soda is ideal for converting a glossy finish, like that which results from a
vapor smoothing operation, into a frosted, matte finish.
Prepare the part. Mask the areas of the part where a media-blasted surface is
undesirable. Masked areas may include parting surfaces of tools or
sharp, outside corners that could be rounded by media blasting.
Prepare Media Blaster. Load the desired blasting media.
Adjust the pressure. Start with a low pressure and gradually increase until it provides the desired results. However, do not exceed 207 kPa (30 psi) since higher pressures will produce divots on the part surface and cause the media to break down.
Media Blast Part. Place the part into the blasting chamber (Figure 3).
Position the spray gun at a 60° angle to the part surface.
Media blast the part using a continuous, sweeping motion similar to that for spray painting (Figure 4). To avoid damaging the part, use several light passes across the part’s surfaces. Do not dwell in one area.
Inspect the part. If additional media blasting is needed, repeat step above.
Remove debris and blast media residue.
Media Blasting procedure complete (Figure 5).