TY - THES

T1 - On the evaluation of the visual impact of sink marks of injection molded parts

AU - Pacher, Gernot Alois

N1 - embargoed until null

PY - 2009

Y1 - 2009

N2 - The visual impact of sink marks is a very important criterion for the quality of injection molded parts. Due to highly functional part designs the formation of sink marks is inevitable in many applications. The aim of this work was to contribute to the development of measurement methodologies for the visual impact of sink marks on an injection molded part. Based on a concept developed and patented by the PCCL a parameter is calculated by utilizing intensity matrices of captured digital images and it corresponds to the perceived magnitude of sink marks. Furthermore, the surface topography was measured with a confocal microscope. Parameters describing size and shape of sink marks were calculated and correlated with the proposed visual impact parameter. Furthermore a field study was carried out to prove the significance of the proposed parameter. The proposed parameter for the visual impact is very accurate for even surfaces and isolated sink marks, which is supported by a field study and topographic measurements. Further improvements should consider uneven, warped surfaces and superimposed shrinkage phenomena as well. The results confirm the capability of the developed methodology, which will be adapted for the inline use in an injection molding process in the near future.

AB - The visual impact of sink marks is a very important criterion for the quality of injection molded parts. Due to highly functional part designs the formation of sink marks is inevitable in many applications. The aim of this work was to contribute to the development of measurement methodologies for the visual impact of sink marks on an injection molded part. Based on a concept developed and patented by the PCCL a parameter is calculated by utilizing intensity matrices of captured digital images and it corresponds to the perceived magnitude of sink marks. Furthermore, the surface topography was measured with a confocal microscope. Parameters describing size and shape of sink marks were calculated and correlated with the proposed visual impact parameter. Furthermore a field study was carried out to prove the significance of the proposed parameter. The proposed parameter for the visual impact is very accurate for even surfaces and isolated sink marks, which is supported by a field study and topographic measurements. Further improvements should consider uneven, warped surfaces and superimposed shrinkage phenomena as well. The results confirm the capability of the developed methodology, which will be adapted for the inline use in an injection molding process in the near future.

KW - Einfallstelle Spritzguss Wirksamkeit

KW - visuelle Oberflächenfehler

KW - sink mark visual impact injection molding surface defect

M3 - Master's Thesis

ER -