THE ROUGHNESS CONTROL Ra
The roughness control Ra
Description
One plastiform have the technical ability to perform indirect roughness Ra controls.
The P80 Ra, as its name suggests, is a product capable of copying the roughness of a surface (which is sometimes not accessible for measuring instruments) and transcribing it identically on the imprint.
When the Ra of the surface to be inspected is greater than or equal to 0.4 µm, the roughness can be measured directly on the impression using a roughness meter, and the result is faithful to the original. For a lower roughness, the inspection of the impression can be done with a laser metrology instrument, or a non contact roughness tester.
Methodology
Before making the impression, it is essential to clean the part thoroughly with the degreaser DN1 in order not to distort the roughness control. P80 is a pasty product that will not leak, so you can apply it to any type of surface. In addition, its polymerization time is 6 to 8 minutes, which will allow you to work the surface of the impression in order to facilitate roughness control. For example, we recommend roughness meter users to press the impression against the surface to be inspected with a flat object. This way, you will obtain a polymerized impression that is easy to positionnate.
Once the plastiform has cured, allow it 20 to 30 minutes before starting the roughness measurement, this will allow the product to reach its final hardness of 80 Shore A. This hardness is essential for accurate measurement.
Measuring the roughness of a part requires a rigorous application of the plastiform on the surface. We recommend that you follow the indications in the instructions for use when applying plastiforms. As P80 Ra is a pasty product, it is applied with an injector to a cleaned and degreased surface. Care must be taken not to create an air bubble, otherwise the roughness measurement will be false.
Ressources about that application
Plastiform roughness control procedure with contact
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