The oil injection mold is manufactured using injection parts as a model, so mass-produced injection parts must be the same as the injection parts when manufacturing the injection mold to avoid the problem of flying oil (paint splashing) during injection. In order to obtain injection parts that are consistent with normal production, for large injection parts with thick walls, products with more than 1,000 injections are often used as the basic parts of the oil injection mold.
However, the accuracy of the injection molded parts will be different in different injection molding conditions. The dimensional accuracy of soft plastic parts such as PVC and other thick and hard plastic parts changes with the injection molding conditions. Therefore, in order to ensure that the paint does not splash when the injection parts are injected, the injection parameters must be adjusted carefully, and the injection parts should be adjusted to the same accuracy as required to manufacture the injection mold. Moreover, once adjusted, the parameters of the injection molding process cannot be changed at random, and the injection parts should be regularly tested for injection, to check the cooperation with the injection mold, and to adjust the parameters of the injection process in time according to the actual situation.
The conditions that can usually cause changes in the dimensional accuracy of injection molded parts are mainly injection pressure, injection time and cooling time. The mold temperature, melt temperature, injection speed and water immersion (if required) temperature will have a certain impact on the dimensional accuracy of injection molded parts, but the impact of the first three is not obvious. Therefore, in most cases, the first three injection conditions are adjusted to achieve the purpose of matching with the oil injection mold, and the latter conditions are taken into account when it is difficult.
In actual production, because thick plastic parts such as PVC are relatively soft when demoulding, they are easily affected by process conditions and change in accuracy. Therefore, even if there is a suitable oil injection mold, the injection conditions must be adjusted frequently. If the plastic parts of ABS and other hard plastics are not very thick, the shape of the injection molded parts is not easy to change, so it is usually not easy to fly oil when spraying oil. However, if there is a serious flying oil phenomenon, it may be necessary to redo the oil injection mold, because the amount of rigid plastic parts that can change the dimensional accuracy by adjusting the injection conditions is very limited. In this case, it is best to check whether the oil is flying due to the deformation of the injection part, otherwise the injection part may be deformed when the oil injection mold is made.
In addition, due to the instability of the injection molding machine, large-sized PVC injection parts are always difficult to maintain a good cooperation with the oil injection mold. Injection is difficult and the production speed is slow, so the technical cooperation of the oil injection department is also very important.
To learn more about our manufacturing capabilities and discover what makes us different, please visit our website. If you’re ready to jump into your next project with us. No matter your need, contact us now and we not only meet your requirements, but we actively look for ways to improve on your product and thus save you money and time in today’s competitive marketplace.