Measuring Impressions
We recommend non-contact measurement for every Plastiform impression, though contact measurement is possible on Rigid and some Medium products. To get accurate readings, check the surface first and position the impression without stress under stable workshop conditions.
Contact or Non-contact
A non-contact instrument never touches the impression, so it cannot deform it. Flexible impressions, 40 Shore A and below, are measured without contact only.
Contact measurement is possible with Rigid impressions, 80 Shore A and above. The probe or stylus must not compress or scratch the surface. For a Medium impression, between 40 and 80 Shore A, the technical sheet tells you if contact measurement is possible. A Rigid product can only be used on a shape with no removal constraint.
Which Instrument for Which Inspection
| Inspection | Instrument | Impression hardness |
|---|---|---|
| Dimensional, internal or external profile | Profile projector, vision system, scanner | Any. Non-contact is the priority for Flexible impressions |
| Visual surface finish | Microscope, vision system | Any. Non-contact preferred |
| Indirect roughness | Contact roughness tester or optical device | Rigid for contact |
Check the Impression First
Inspect the impression to make sure the surface is uniform, with no area that visibly did not polymerize. There must be no bubble in the measurement zone and no residue such as dust or a greasy trace. If you are working with P80 Ra, wait 30 minutes before you measure roughness.
Position the Impression
A complete impression rests on a support with no mechanical stress. A slice cut with the Double Blade Cutter lies flat on the measuring plate. Measure on a Profile Projector or Vision System gives the setup for both.
Position a Rigid Impression for Roughness
Fix the impression to a flat base with a thin layer of adhesive wax or putty so it does not slide under the stylus. The surface you measure must stay level and stable.
Keep the Conditions Stable
Let the impression and the part reach workshop temperature before you measure, and make sure polymerization is complete. Avoid stray reflections, since they visually shift the edges. Always use the same reference orientation.
Related Pages
- Dimensional Precision
- What Affects Measurement Accuracy
- Measure on a Profile Projector or Vision System
- Slice an Impression with the Double Blade Cutter
- Final Hardness
- Visual Surface Inspection with F30 Visual
- Measure with a Contact Instrument
- Read an Impression: A Negative of the Part