Sensitivity of operating conditions and material properties for thermoforming process

被引:8
作者
DiRaddo, RW [1 ]
Meddad, A [1 ]
机构
[1] Natl Res Council Canada, Inst Ind Mat, Boucherville, PQ J4B 6Y4, Canada
关键词
D O I
10.1179/146580100101540914
中图分类号
TB33 [复合材料];
学科分类号
摘要
The thermoforming process involves three stages: sheet reheat; forming; and solidification. A polymeric sheet is heated in an oven to the desired forming temperature distribution. The sheet is then deformed to take the shape of the mould cavity and subsequently solidified. The deformation of the sheet is assisted by the application of a pressure differential and/or the use of a moving plug. The sensitivity of process and material parameters on the final part has been studied. The two process parameters that most affect the final part thickness distribution are the heater settings (uniform and profiled) and the plug penetration depth. The effect of these operating conditions on the final part thickness distribution and on the material stretch distribution was determined. Two thermoforming grade materials with different material properties were studied: acrylonitrile/butadiene/styrene (ABS) and high density polyethylene (HDPE). The part considered was moulded in a box shape cavity mould. The effect of the level of uniform heater setting was found to be minimal for ABS, but more pronounced for HDPE. However, the ABS was found to be more sensitive to heater profiling than the HDPE. Increasing plug penetration was found to minimise the variance of the part thickness distribution, when considering uniform heater settings. Coupling of the plug penetration with profiling caused the minimal variation in the part thickness distribution to be obtained with an intermediate plug penetration. The effects of heater profiling were enhanced when a plug penetration was used. PRC/1626.
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页码:163 / 167
页数:5
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