Correction of mould cavity geometry for warpage compensation

Kastelic, Tomaž (author), Starman, Bojan (author), Cafuta, Gašper (author), Halilovič, Miroslav (author), Mole, Nikolaj (author)

Warpage is one of the most challenging defects occurring in plastic injection moulded parts. Various approaches to overcome this issue have been proposed in the literature, but they all provide only partial solutions to the problem. This paper proposes a new method for the compensation and minimisation of warpage. The method is based on Mould Cavity (MC) correction. In contrast to other similar methods, here the MC correction is accomplished through a direct comparison of the local deviations of the warped part’s geometry to the desired geometry of the part. Modifying the MC shape accordingly yields parts with a lower shape discrepancy from the desired geometry compared to the nonadjusted shape. The key novelty of the paper is the development of software that iteratively adjusts the MC shape to minimise local deviations. In every iteration, the warped part is compared to the desired geometry in order to compute local deviations between both geometries. Computation is done first by determining the point normal vector of the warped geometry mesh and its piercing point through desired geometry mesh. Second, distance between the base point and the piercing point is calculated. After all local deviations are determined, the MC geometry is adjusted accordingly. Two case studies demonstrate the method’s capabilities. In the first case we present a curved thin-walled plate part. The maximum warpage value of 0.005 mm (0.7% of the initial maximum warpage) was reached after three iterations of MC geometry correction and remained stable afterwards. In the second case the method was tested on the box-shaped part. The maximum warpage dropped from initial 0.711 mm to 0.066 mm after three iterations.

• Language: English
• Keywords: computer simulation, injection moulding, warpage compensation, iterative mould cavity, geometry correction
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.11.2022
• Year: 2022
• Number of pages: Str. 1957–1971
• Numbering: Vol. 123
• PID: 20.500.12556/RUL-142937
• UDC: 004.94
• ISSN on article: 0268-3768
• DOI: 10.1007/s00170-022-10337-6
• COBISS.SI-ID: 127300355
• Publication date in RUL: 05.12.2022

Record is a part of a journal

• Title: International journal of advanced manufacturing technology
• Shortened title: Int. j. adv. manuf. technol.
• Publisher: Springer Nature
• ISSN: 0268-3768
• COBISS.SI-ID: 25636352

Secondary language

• Language: Slovenian
• Keywords: računalniška simulacija, injekcijsko brizganje, kompenzacija zvitosti, iteracijska korekcija, geometrija kalupne votline

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0263
• Name: Mehanika v tehniki

• Funder: ARRS - Slovenian Research Agency
• Project number: L2-3172
• Name: Razvoj tehničnih smernic za štirislojne zasteklitve