Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool
The demolding of plastic parts remains a challenging aspect of injection molding. Despite various experimental studies and known solutions to reduce demolding forces, there is still not a complete understanding of the effects that occur. For this reason, laboratory devices and in-process measurement...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-03-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/5/1285 |
| _version_ | 1797614490053771264 |
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| author | Maximilian Schoenherr Holger Ruehl Thomas Guenther André Zimmermann Bernd Gundelsweiler |
| author_facet | Maximilian Schoenherr Holger Ruehl Thomas Guenther André Zimmermann Bernd Gundelsweiler |
| author_sort | Maximilian Schoenherr |
| collection | DOAJ |
| description | The demolding of plastic parts remains a challenging aspect of injection molding. Despite various experimental studies and known solutions to reduce demolding forces, there is still not a complete understanding of the effects that occur. For this reason, laboratory devices and in-process measurement injection molding tools have been developed to measure demolding forces. However, these tools are mostly used to measure either frictional forces or demolding forces for a specific part geometry. Tools that can be used to measure the adhesion components are still the exception. In this study, a novel injection molding tool based on the principle of measuring adhesion-induced tensile forces is presented. With this tool, the measurement of the demolding force is separated from the actual ejection step of the molded part. The functionality of the tool was verified by molding PET specimens at different mold temperatures, mold insert conditions and geometries. It was demonstrated that once a stable thermal state of the molding tool was achieved, the demolding force could be accurately measured with a comparatively low force variance. A built-in camera was found to be an efficient tool for monitoring the contact surface between the specimen and the mold insert. By comparing the adhesion forces of PET molded on polished uncoated, diamond-like carbon and chromium nitride (CrN) coated mold inserts, it was found that a CrN coating reduced the demolding force by 98.5% and could therefore be an efficient solution to significantly improve demolding by reducing adhesive bond strength under tensile loading. |
| first_indexed | 2024-03-11T07:12:40Z |
| format | Article |
| id | doaj.art-0f552598b9314ea69d0282274fbd08a0 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T07:12:40Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-0f552598b9314ea69d0282274fbd08a02023-11-17T08:28:42ZengMDPI AGPolymers2073-43602023-03-01155128510.3390/polym15051285Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding ToolMaximilian Schoenherr0Holger Ruehl1Thomas Guenther2André Zimmermann3Bernd Gundelsweiler4Institute of Design and Production in Precision Engineering (IKFF), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart, GermanyInstitute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9b, 70569 Stuttgart, GermanyInstitute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9b, 70569 Stuttgart, GermanyInstitute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9b, 70569 Stuttgart, GermanyInstitute of Design and Production in Precision Engineering (IKFF), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart, GermanyThe demolding of plastic parts remains a challenging aspect of injection molding. Despite various experimental studies and known solutions to reduce demolding forces, there is still not a complete understanding of the effects that occur. For this reason, laboratory devices and in-process measurement injection molding tools have been developed to measure demolding forces. However, these tools are mostly used to measure either frictional forces or demolding forces for a specific part geometry. Tools that can be used to measure the adhesion components are still the exception. In this study, a novel injection molding tool based on the principle of measuring adhesion-induced tensile forces is presented. With this tool, the measurement of the demolding force is separated from the actual ejection step of the molded part. The functionality of the tool was verified by molding PET specimens at different mold temperatures, mold insert conditions and geometries. It was demonstrated that once a stable thermal state of the molding tool was achieved, the demolding force could be accurately measured with a comparatively low force variance. A built-in camera was found to be an efficient tool for monitoring the contact surface between the specimen and the mold insert. By comparing the adhesion forces of PET molded on polished uncoated, diamond-like carbon and chromium nitride (CrN) coated mold inserts, it was found that a CrN coating reduced the demolding force by 98.5% and could therefore be an efficient solution to significantly improve demolding by reducing adhesive bond strength under tensile loading.https://www.mdpi.com/2073-4360/15/5/1285injection moldingmold tooldemolding measurementejectionejection forceadhesion force |
| spellingShingle | Maximilian Schoenherr Holger Ruehl Thomas Guenther André Zimmermann Bernd Gundelsweiler Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool Polymers injection molding mold tool demolding measurement ejection ejection force adhesion force |
| title | Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool |
| title_full | Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool |
| title_fullStr | Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool |
| title_full_unstemmed | Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool |
| title_short | Adhesion-Induced Demolding Forces of Hard Coated Microstructures Measured with a Novel Injection Molding Tool |
| title_sort | adhesion induced demolding forces of hard coated microstructures measured with a novel injection molding tool |
| topic | injection molding mold tool demolding measurement ejection ejection force adhesion force |
| url | https://www.mdpi.com/2073-4360/15/5/1285 |
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