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1、附录附1：外文文献翻译Practice vs. laboratory tests for plastic injection mouldingM. Van Stappen, K. Vandierendonck, C. Mol, E. Beeckman and E. De Clercq Abstract:Different types of anti-sticking coatings have been applied industrially on injection moulds for various types of plastics. Very often these tests a
2、re being done on a trial-and-error basis and results obtained are difficult to interpret. WTCM/CRIF has developed laboratory equipment where the injection moulding process can be simulated and demoulding forces and friction coefficients can be measured. These measurements were compared with surface
3、energy calculations of the coated surfaces and of the plastic materials in order to find a correlation. Using this approach it must be possible to make an easy and cheap selection of promising coatings towards plastic injection moulding. Another important advantage is that the understanding and mode
4、lling of the mouldplastic interface becomes possible. This new way of coating selection for plastic injection moulding has been demonstrated for various PVD coatings and verified for different industrial injection moulding applications. Author Keywords: Injection moulding; PVD coating; Modeling; Sur
5、face energy Article Outline 1. Introduction 2. Experimental details 3. Results and discussion 4. Conclusions References1. Introduction PVD coatings have found their way into industry for several applications like metal cutting and deep drawing. Their use in plastic injection moulds has given both po
6、sitive and negative results. The unreproducible character of the results hinders further implementation in industry. To valorise the intrinsically good coating properties like chemical inertness vs. plastics to enhance demoulding, more insight is needed into the mechanism of interaction between the
7、mould surface and the plastic material during injection moulding. To our knowledge, a systematic study of the influence of mould surface roughness, mould coating, properties of the polymer like Youngs modulus, surface energy, polarity, structures, etc. on possible binding mechanisms between the moul
8、d surface and the plastic material has never been carried out. This makes it practically impossible to understand demoulding mechanisms and, as a consequence of this, to select a proper coating for the injection mould. The purpose of this work was to try to simulate the injection moulding process in
9、 the laboratory and to correlate the results with surface energy measurements of the coated mould and of the plastic material. This could result in an approach to select the proper coating for a certain kind of plastic to be injected. 2. Experimental details Laboratory equipment has been built to me
10、asure demoulding forces and friction coefficients. The mould itself is made out of tool steel 1.2083 and has a diameter of 64 mm and a height of 30 mm (Fig. 1). The thickness of the moulded part is 2 mm. A pressure sensor measures the demoulding forces. The temperature inside the mould is measured b
11、y thermocouples as presented in Fig. 1. All moulds were hardened to a hardness of 56 HRC. Fig. 1. A cylindrical plastic part injection moulded around a mould.After a running-in period of 40 injections, the demoulding force was measured 10 times for each coatingplastic material combination. Surface e
12、nergy was measured on the surface of the coating and on the surface of the plastic material using the model of Owens and Wendt. A Digidrop GBX apparatus has been used based on water and di-iodomethane as testing liquids. To measure the total surface energy, the dispersive surface energy and the pola
13、r surface energy are measured. Injection moulding was carried out as follows. In the first application, a polyurethane plastic material with tradename DESMOPAN 385 S was injection moulded using uncoated moulds and moulds coated with, respectively, a TiN and a CrN coating. In the second application,
14、three types of polymers were tested on a TiN coated mould and an uncoated mould. Two elastomers (trade name HYTREL G 3548 W, which is a block-copolyester, and SANTOPRENE 101-73, which is a blend of polypropylene and EPDM), and EVOPRENE, which consists of polystyrene and butadiene.3. Results and disc
15、ussion The demoulding forces measured for the first application are given in Table 1. Table 1. Demoulding forces (N) for DESMOPAN The demoulding forces for the second application are given in Fig. 2. Fig. 2. Demoulding forces (in N) for three materials: HYTREL, EVOPRENE, SANTOPRENE.This demoulding b
16、ehaviour has also been observed in industrial practice, so the demoulding laboratory apparatus is a good simulation of reality. To explain these results, an attempt was made to find a correlation with the surface energy measurements. Both total surface energy as well as polar surface energy in mJ/m2 were compared for both coated surfaces and plastic materials.Fig. 3. Total surface energies (mJ/m2) of the different coati
