Test method and precautions of extrusion blow molding machine

Before the new mold blow molding or the machine to replace other mold production, the mold test is an essential part.The result of the test will directly affect the smooth production of the factory.Therefore, it is necessary to follow reasonable operation steps and record useful technical parameters in the process of mold testing to facilitate the mass production of products.

1. Understand the relevant information of the mold: it is best to obtain the design drawings of the mold, analyze in detail, and ask the mold technician to participate in the mold trial work.

2. First check the mechanical coordination action on the workbench: pay attention to whether there are scratches, missing parts and loose phenomena, whether the movement of the mold to the skateboard is true, whether the water channel and air pipe joints leak, if there is a limit on the opening of the mold, it should also be marked on the mold.If the above action can be done before hanging the die, it can avoid the time waste that occurs when the problem is found when hanging the die and then removing the die.

3. When determining the proper action of each part of the mold, it is necessary to choose a suitable trial mold blowing machine, and attention should be paid to the selection:(a) What is the maximum extrusion volume of the blow molding machine? (b) Whether the inner distance of the pull rod is placed in the lower mold? (c) Whether the maximum movement stroke of the movable template meets the requirements? (d) Whether other relevant tools and accessories for mold testing are ready.When hanging, attention should be paid to not to remove the hanging before locking all the clamping formwork and opening the mold, in case the clamping formwork is loose or broken so that the mold falls.After the mold is installed, the mechanical action 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. In the manual and low-speed mold closing action, pay attention to and listen to whether there are any smooth action and abnormal sound.

4. Improve the mold temperature: according to the performance of raw materials used in the finished product and the size of the mold, select the appropriate mold temperature control machine to increase the mold temperature to the required temperature in production (depending on the product requirements).After the temperature of the mold is increased, the action of each part should be examined again, because the thermal expansion of the steel may cause the mold clamping phenomenon, so pay attention to the sliding of each part, so as to avoid the tension and vibration.

 

If the factory does not implement the pilot plan rule, we recommend that only one condition at a time be adjusted in order to distinguish the effect of a single condition change on the finished product.

Moderate baking of the raw materials used (depending on the material).

As far as possible, the same materials will be used for the trial and future mass production.

Do not test the mold completely with the second material, if there is a color requirement, can arrange the color testing.

Internal stress and other problems often affect the secondary processing, should be in the test after the finished product is stable after the secondary processing mold in slow closing, to adjust the closing pressure, and action several times, check whether there is no unequal pressure closing mold, so as to avoid the finished product burr and mold deformation.

In order to avoid unnecessary time and confusion in mass production, it is necessary to have the patience to adjust and control the various processing conditions, to find the best temperature and pressure conditions, and to develop standard mold testing procedures that can be used to establish routine work methods.

1. Check whether the plastic in the cylinder is correct and whether it is baked according to the regulations (if different materials are used in mold test and production, different results may be obtained).

2. The material pipe should be cleaned thoroughly to prevent bad glue or miscellaneous material from being shot into the die, because the bad glue or miscellaneous material may jam the die.Check whether the temperature of the tube and the mold is suitable for the processing material.

 

3. Adjust the pressure and injection amount in order to produce a satisfactory appearance of the finished product, but do not run the edge, especially when there are some mold hole finished product is not completely solidifying, before adjusting various control conditions should think, because a slight change in the filling rate may cause a very large change in the filling of the mold.

 

4. Wait patiently until the condition of the machine and mold is stabilized.

 

5. Measure and record the important dimensions of continuous samples (wait until the samples are cooled to room temperature).

 

6. Comparing the size of each mold sample, attention should be paid to: (a) whether the size of the product is stable.(b) Whether there is a trend of increase or decrease in certain sizes indicating that the machining conditions are still changing, such as poor temperature control or oil pressure control.(c) whether the variation in size is within tolerance.

 

7. If the size of the finished product does not change very 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 size is within the allowable tolerance.To check the correct size of the die, make a note of the hole number which is measured continuously larger or smaller than the average.

8. Record and analyze data for modification of mold and production conditions and for reference in future mass production.