5.5.1 Grinding of plastics
Objective:
Grinding is a mechanical surface treatment method for removing the uppermost layers of the substrate and exposing the actual base substrate.
Suitability:
Grinding is in principle suitable for all thermosets. It is, however, only suitable for some elastomers and is generally unsuitable for thermoplastics.
Procedure:
- Prior to grinding the surface must always be thoroughly cleaned and degreased, to prevent “incorporation” of the contaminants into the surface and making them thereafter very difficult or impossible to remove.
- Manually with an abrasive block or using belt grinding machines
- Grain size from K 120 to 180 is best for adhesive bonding applications
- After grinding remove all grinding dust, etc. from the surface (e. g. using a disposable, white cloth soaked with cleaning agent)
Points to heed:
- Regularly change the abrasive paper
- Ensure the substrates are cleaned beforehand
- Ensure the surface has a uniform finish
- Remove all residues and dust from the surface after grinding
