Before blow molding a new mold or when the machine is replaced with other molds, trial molding is an essential part. The quality of the mold trial results will directly affect the smoothness of subsequent production in the factory.
Therefore, reasonable operating steps must be followed during the mold trial process and useful technical parameters must be recorded during the mold trial process to facilitate mass production of the product.
This article will introduce in detail the mold trial methods and precautions of the blow molding machine.
1. Understand the relevant information of the mold:
It is best to obtain the design drawings of the mold, analyze them in detail, and ask a mold technician to participate in the mold trial work.
2. First check its mechanical coordination on the workbench:
Pay attention to whether there are scratches, missing parts, loose parts, etc., whether the movement of the mold to the sliding plate is correct, whether there are leaks in the water pipe and air pipe joints, and if there are any restrictions on the opening of the mold, it should also be marked on the mold.
If the above actions can be done before hanging the mold, it can avoid the waste of man-hours caused by discovering problems during the mold hanging and then disassembling the mold.
3. After confirming that each part of the mold is functioning properly, it is necessary to select a suitable trial mold blow molding machine. When selecting, pay attention to:
(a) What is the maximum extrusion capacity of the blow molding machine?
(b) Whether the inner distance of the tie rod is placed in the lower mold
(c) Whether the maximum movement range of the movable template meets the requirements
(d) Are other related mold trial tools and accessories ready? After everything is confirmed to be OK, the next step is to hang the mold. When hanging, be careful not to remove the hanging hook before locking all clamping templates and opening the mold. To prevent the clamping template from loosening or breaking and causing the mold to fall. After the mold is installed, the mechanical movement of each part of the mold should be carefully checked.
The next step is to pay attention to the mold closing action. At this time, the mold closing pressure should be lowered. During the manual and low-speed mold closing action, pay attention to see and listen for any irregularities or abnormal sounds.
4. Increase the mold temperature:
According to the performance of the raw materials used in the finished product and the size of the mold, an appropriate mold temperature controller is selected to increase the temperature of the mold to the temperature required for production (depending on product requirements). After the mold temperature increases, the movement of each part must be checked again, because the thermal expansion of the steel may cause the mold to jam, so attention must be paid to the sliding of each part to avoid strain and vibration.
If the experimental plan rule is not implemented in the factory, we recommend that only one condition be adjusted at a time when adjusting the mold trial conditions in order to distinguish the impact of a single condition change on the finished product.
Depending on the raw materials, the raw materials used should be roasted moderately (depending on the materials).
Trial molds and future mass production use the same raw materials as much as possible. Do not test the mold entirely with defective materials. If there is a color requirement, you can arrange a color test together.
Problems such as internal stress often affect secondary processing. Secondary processing should be carried out after the mold is tried and the finished product is stable. After closing the mold slowly, adjust the mold closing pressure and operate it several times to check whether there is mold closing pressure. Uneven phenomenon to avoid burrs and mold deformation in the finished product.
In order to avoid unnecessary waste of time and trouble during mass production, it is indeed necessary to have patience to adjust and control various processing conditions, find the best temperature and pressure conditions, and develop standard mold trial procedures that can be used Establish daily working methods.
1. Check whether the plastic in the barrel is correct and whether it is baked according to regulations (if different raw materials are used for mold trial and production, it is likely to produce different results).
2. Be sure to clean the material tube thoroughly to prevent improperly decomposed rubber materials or impurities from being injected into the mold, because inferior decomposed rubber materials and impurities may jam the mold. Check whether the temperature of the material tube and the temperature of the mold are suitable for the raw materials being processed.
3. Adjust the pressure and injection volume in order to produce a finished product with a satisfactory appearance. However, burrs should not be allowed. Especially when some mold cavity finished products have not yet completely solidified, you should think about it before adjusting various control conditions because the mold is filled. A slight change in the rate may cause significant changes in mold filling.
4. Wait patiently until the conditions of the machine and mold stabilize.
5. Measure consecutive samples and record their important dimensions (the samples should be measured after they have cooled to room temperature).
6. Compare the measured dimensions of each mold sample and pay attention to (a) whether the product dimensions are stable.
(b) Whether certain dimensions have an increasing or decreasing trend indicating that the machine processing conditions are still changing, such as poor temperature control or oil pressure control.
(c) Whether the change in dimensions is within the tolerance range.
7. If the dimensions of the finished product do not change much and the processing conditions are normal, it is necessary to observe whether the quality of the finished product of each mold is acceptable and the dimensions are within the allowable tolerance. Record the mold cavity numbers that are continuously larger or smaller than the average value to check whether the size of the mold is correct.
8. Record and analyze data to meet the needs of modifying molds and production conditions, and as a reference for future mass production.
