Control of part weight in injection molding of amorphous thermoplastics

被引:46
作者
Kamal, MR [1 ]
Varela, AE [1 ]
Patterson, WI [1 ]
机构
[1] McGill Univ, Dept Chem Engn, Montreal, PQ H3A 2B2, Canada
关键词
D O I
10.1002/pen.11483
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
Two methods are proposed for the control of part weight in injection molding. In the PT method, part weight control is achieved by controlling the temperature and pressure of the melt in the cavity at gate freeze time. This time is considered to occur when the cavity melt pressure starts to decrease from its peak value. For the purposes of control, the bulk melt temperature is estimated from measurements by surface thermocouples at strategic locations in the cavity, A cascade scheme is implemented for the control of bulk temperature from cycle to cycle. A self-tuning algorithm, with an observer, is employed for controlling the cavity pressure-time profile, to follow a set point trajectory during a cycle, In PWT control, the coolant temperature is controlled, while the peak cavity pressure is adjusted in a given cycle to compensate for bulk melt temperature deviations measured in the previous cycle. Both PT and PWT control reduce variance in part weight. PWT control appears to yield the best results.
引用
收藏
页码:940 / 952
页数:13
相关论文
共 24 条
  • [1] Astrom K. J., 1995, ADAPTIVE CONTROL
  • [2] DAVIS CC, 1991, SPE ANTEC TECHNICAL, V37, P474
  • [3] FUSSER HB, 1992, THESIS MCGILL U MONT
  • [4] SELF-TUNING CAVITY PRESSURE CONTROL OF INJECTION-MOLDING FILLING
    GAO, F
    PATTERSON, WI
    KAMAL, MR
    [J]. ADVANCES IN POLYMER TECHNOLOGY, 1994, 13 (02) : 111 - 120
  • [5] Cavity pressure dynamics and self-tuning control for filling and packing phases of thermoplastics injection molding
    Gao, F
    Patterson, WI
    Kamal, MR
    [J]. POLYMER ENGINEERING AND SCIENCE, 1996, 36 (09) : 1272 - 1285
  • [6] Cavity pressure control during the cooling stage in thermoplastic injection molding
    Gao, F
    Patterson, WI
    Kamal, MR
    [J]. POLYMER ENGINEERING AND SCIENCE, 1996, 36 (19) : 2467 - 2476
  • [7] GAO F, 1989, THESIS MCGILL U MONT
  • [8] Gao F., 1992, SPE ANTEC, V38, P1887
  • [9] HARRY DH, 1991, SPE ANTEC ANN TECHN, V37, P383
  • [10] Kamal MR., 1991, SPE ANTEC TECH PAPER, V37, P483