In order to prevent the finished product from short shot, breakage, deformation, burrs and even damage to the mold. If the processing cycle is too short, the thimble will push through the finished product or peel off the ring and crush the finished product. This type of situation can take you two or three hours to get the finished product out. If the processing cycle is too long, the weak parts of the mold core may be broken due to the shrinkage of the rubber compound. Of course, it is impossible for you to predict all the problems that may occur during the mold trial process, but taking adequate and timely measures in advance will help you avoid serious and expensive losses.
1. Understand the relevant information of the mold:
It is best to obtain the design drawing of the mold, analyze it in detail, and invite a mold technician to participate in the mold trial work.
2. Check its mechanical coordination on the workbench first:
Pay attention to whether there are scratches, missing parts and looseness, whether the sliding movement of the mold is correct, whether there is leakage of the water channel and air pipe joints, and if the opening of the mold is limited, 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 when the mold is found when the mold is hanging, and then the mold is disassembled.
3. When it is determined that each part of the mold moves properly, it is necessary to choose a suitable mold trial injection machine. When choosing, you should pay attention to:
(a) What is the maximum injection volume of the injection molding machine
(b) Whether the inner distance of the tie rod is placed in the lower mold
(c) Whether the maximum moving stroke of the active template meets the requirements
(d) Whether other related tools and accessories for mold testing are ready
After everything is confirmed that there is no problem, the next step is to hang the mold. When hanging, you should pay attention to locking all the clamping templates and not removing them before opening the mold, so as to prevent the clamping template from loosening or breaking and causing the mold to fall. After the mold is installed, carefully check the mechanical actions of all parts of the mold, such as the sliding plate, the ejector pin, the retraction structure and the limit switch, whether the actions are correct. And pay attention to whether the injection nozzle and the feeding port are aligned.
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 actions, pay attention to see and listen to whether there are any unsmooth movements and abnormal sounds. The process of hoisting the mold is actually relatively simple. The main point that needs to be careful is that it is difficult to adjust the center of the mold gate and the nozzle. Usually, the center can be adjusted by means of test paper.
4. Increase mold temperature:
According to the performance of the raw materials used in the finished product and the size of the mold, select an appropriate mold temperature controller to increase the temperature of the mold to the temperature required for production. After the mold temperature is raised, it is necessary to check the movements of each part again, because the steel may cause a mold jam phenomenon due to thermal expansion, so it is necessary to pay attention to the sliding of each part to avoid strain and vibration.
5. If the experiment plan rule is not implemented in the factory, we suggest that only one condition can be adjusted at a time when adjusting the test conditions, so as to distinguish the influence of a single condition change on the finished product.
6. According to the different raw materials, moderately bake the raw materials used.
7. Try to use the same raw materials as possible for future mass production.
8. Do not test the mold completely with inferior materials. If there is a color requirement, you can arrange a color test together.
9. Problems such as internal stress often affect the secondary processing. After the mold is tested and the finished product is stable, the secondary processing should be added. After the mold is closed at a slow speed, the mold closing pressure should be adjusted well, and the action should be performed several times to check whether there is a fit. Unequal mold pressure to avoid burrs and mold deformation in the finished product.
After the above steps are checked, lower the closing speed and closing pressure, and set the safety lever and ejection stroke, and then adjust the normal closing speed and closing speed. If the limit switch of the maximum stroke is involved, the mold opening stroke should be adjusted to be slightly shorter, and the high-speed mold opening action should be cut off before the maximum mold opening stroke. This is because the high-speed action stroke is longer than the low-speed one in the entire mold opening stroke during the mold installation. On the plastic machine, the mechanical ejector rod must also be adjusted to act after the full-speed mold opening action to prevent the ejector plate or the peeling plate from being deformed by force.
Please check the following items before making the first mold injection:
(a) Whether the feeding stroke is too long or insufficient.
(b) Whether the pressure is too high or too low.
(c) Whether the filling speed is too fast or too slow.
(d) Whether the machining cycle is too long or too short.