| 摘要 |
PURPOSE:To shorten the change-over time of raw material and at the same time make the loss of raw material due to changing-over as small as possible by a method wherein the maximum number of injections by present raw material is calculated so as to leave the minimum necessary weight of material to be secured as back raw material in an injection cylinder at the final shot of project production by the present raw material. CONSTITUTION:The maximum number S of injections by present raw material A under the condition that the present raw material A can be secured in an injection cylinder 12 is obtained by the following formula: S=integer satisfying (W0-Wl)/w on the basis that (1) W0 is the total weight of the raw material A left in the interior of the injection cylinder 12 at the time when a raw material charging port 11 is closed, (2) Wl is the minimum necessary weight of the raw material A to be present in the interior of the injection cylinder 12 as back raw material and (3) (w) is the weight of the present raw material A injected at every one shot by a screw 13. Further, when the cumulative number of injections by the present raw material A reaches (N-S), the supply of the present raw material A to the raw material charging port 11 is stopped. Next, when the cumulative number of injections by the present raw material A reaches N, the next raw material is supplied to the raw material charging port 11 in exchange for the present raw material. In this case, N is the number of injections of the present raw material A in project production. |
