FDM TPU Best Practices

Key differences and how to get the best results in printing parts with TPU 92A material.

TPU MATERIAL HANDLING
Proper storage of materials is critical.

• When removing TPU spools from the system, place the material spool in the Mylar bag
  immediately.
• For extended non-use periods greater than 48 hours, unload the material from the head
  and wind back onto the spool. Store in the material bay.
• (Environments with high humidity should unload the material after 36 hours)
• Note: If the machine has been idle with TPU material loaded for more than 48 hours,
  unload the filament and cut off 6 ft. (1.8 m) of the filament end and reload into the printer

PART ACCURACY

• Parts are produced within an accuracy of: +/- .254 mm (.010 in), or +/- .003 mm/mm (.003
  in/in), whichever is greater
• Accuracy is geometry-dependent. Achievable accuracy specification derived from
  statistical data at 95% dimensional yield.
• Putting printed parts into a support removal tank may cause swelling of up to 0.5%, which
  can result in the part being out of the accuracy tolerance initially.
• Depending on part size and geometry it may take up to 72 hours for a part to shrink
  back to pre-tanked size.
• Due to the nature of the elastomer material, the visual quality of parts, particularly fine
  feature details, may not be as high as it is for rigid materials such as ABS or ASA on the
  F123 platform

MODIFIED UPPER Y-BLOCK

• Same part as previously used but with a media blasted interior
• Reason for replacement: fixes loading issues. Only the upper half of each Y-block needs to be replaced

TPU 92A TIP OFFSET CALIBRATION CHANGES

1. Perform Auto tip offset calibration
2. Perform Manual tip offset calibration on X&Y only.
   1. TPU 92A adheres extremely well to QSR.
   2. The automatic Z tip calibration is sufficient and manual Z calibration is not
      necessary.

PART QUALITY
Ripples or waves in parts:

• If you experience any waves or ripples in parts, please verify the following:
• Tips and tip wipes are clean of any material debris.
• Clean tips/tip wipes if any debris is present
• Tip Wipes are adjusted to correct height
• Try reorienting part for better results

PART ORIENTATION
“Orient for stability”

• Normally, parts are oriented for function, aesthetics, speed, etc. with the expectation that
  parts will build successfully.
• With the FDM TPU 92A material, orienting for build success is the primary consideration.
  Then factors such as design intent and aesthetics can be considered.

PART ORIENTATION

• Try to minimize the Z extent
• Watch for vertical areas that can be unstable
• Insight users can further stabilize by increasing the self supporting angle (default is 55 degrees), switch to a different support style, and/or use stabilize walls

PART PACKING

• Place the purge part close to the first part in the pack or
  next to the tallest part.

Brian Maxwell
Field Service Engineer
Computer Aided Technology, LLC