The manufacturing process of freeform glass components for precision optics is usually based on contour CNC grinding and polishing operations. To predict the geometrical precision of the production process, a correlation between the geometrical error and the process parameters is required. This is even more important in the polishing operation which is the final stage of the process. In this work a model for material removal estimation in deterministic polishing of glass moulds is proposed and validated. The model is developed for CNC ball polishing of free-form surfaces, where the pad, made of a polyurethane layer superimposed to a rubber bulk, moves along a scanning path, in a suspension of cerium oxide. As many models in literature the removed material can be estimated by pressure and sliding velocity between polishing pad and workpiece. Adopting the Hertz theory these physical characteristics can be related to the CAD-CAM-CNC parameters, e.g. tool and workpiece shape, dimension and modulus of elasticity, feed rate, feed step, tool rotational speed and radial tool deformation. The model validation was performed on ground glass flat samples polished with different process parameters, measuring the removed material by a contact probe profilometer. The developed model shows a satisfactory estimation of removal material as a function of the process parameters.

A study on the material removal mechanisms in ball polishing

SAVIO, GIANPAOLO;MENEGHELLO, ROBERTO;CONCHERI, GIANMARIA;CERARDI, ANDREA
2011

Abstract

The manufacturing process of freeform glass components for precision optics is usually based on contour CNC grinding and polishing operations. To predict the geometrical precision of the production process, a correlation between the geometrical error and the process parameters is required. This is even more important in the polishing operation which is the final stage of the process. In this work a model for material removal estimation in deterministic polishing of glass moulds is proposed and validated. The model is developed for CNC ball polishing of free-form surfaces, where the pad, made of a polyurethane layer superimposed to a rubber bulk, moves along a scanning path, in a suspension of cerium oxide. As many models in literature the removed material can be estimated by pressure and sliding velocity between polishing pad and workpiece. Adopting the Hertz theory these physical characteristics can be related to the CAD-CAM-CNC parameters, e.g. tool and workpiece shape, dimension and modulus of elasticity, feed rate, feed step, tool rotational speed and radial tool deformation. The model validation was performed on ground glass flat samples polished with different process parameters, measuring the removed material by a contact probe profilometer. The developed model shows a satisfactory estimation of removal material as a function of the process parameters.
2011
11° euspen International Conference proceedings
11° euspen International Conference
9780955308291
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/171347
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
  • OpenAlex ND
social impact