热塑性塑料的电阻焊焊接工艺

采用导电炭黑(CB)填充的高密度聚乙烯(HDPE)复合材料加热单元来焊接HDPE样条。研究发现,炭黑填充量高于12%(质量分数,下同)时,复合材料的电阻率降到3Ω.cm以下;用炭黑含量为12%、16%及20%的加热单元来焊接HDPE时,合适的焊接电压分别为33 V、23 V和20 V。通过搭接焊和对焊,从剪切破坏强度和拉伸破坏强度两个方面来评价焊接性能。结果表明,当焊接时间在6 min左右时,三种不同炭黑含量的加热单元的焊接系数均超过0.9,焊接时间10 min左右时,焊接系数可以达到1,焊接性能优良。

Process of Resistance Welding for Thermoplastic-Matrix

Polyethylene laminates were welded by current-conducting heating element made by polyethylene/carbon black(CB) composites.The results indicate that resistivity of composites with CB fraction higher than 12% is lower than 3 Ω·cm.Moreover,infill system did not perform an intense positive temperature coefficient effect,which was positive to be used as heating element.Under 33 V,23 V and 20 V respectively,the temperature of heating elements with CB fraction of 12%,16% and 20% can be held in the range of 180 ℃ and 230 ℃ by pulsed power.Specimens were made by lap welding and abutting welding.The welding capability was evaluated from lap shear test and tensile test.It reveals that all series of current-conducting heating element can weld high density polyethylene(HDPE) laminates with superior mechanical properties in 5 minutes.