Tips to ensure the tooling trial successfully

Precautions before plastic tooling trial.

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 the mold technician to participate in the trial work.

2. First check its mechanical coordination on the workbench:

Pay attention to whether there are phenomena such as scratches, missing parts and looseness, to check the movement of the mold, whether there are leaks in the waterway and gas pipe joints, and the opening of the mold should be marked on the mold if it is limited. If the above actions can be done before the mold is hung, you can avoid discovering problems when hanging the mold and then wasting the man-hours when disassembling the mold.

3. When it is determined that the various parts of the mold are moving properly, it is necessary to

select a suitable trial mold injection machine, and pay attention when selecting

(a) Injection capacity

(b) Width of guide rod

(c) The largest journey

(d) Accessories

After everything is confirmed that there is no problem, the next step is to hang the mold. When

hanging, you should pay attention not to remove the hook before locking all the clamp templates

and opening the mold, so as to prevent the clamp plate from loosening or breaking and causing

the mold to fall.

After the mold is installed, you should carefully check the mechanical movements of each part of the mold, such as the movement of the slider, ejector pin, withdrawal structure and limit switch. And pay attention to whether the injection nozzle and the inlet are aligned.

The next step is to pay attention to the mold clamping action.

At this time, the mold closing pressure should be lowered. In manual and low speed mold clamping actions, pay attention to whether there are any irregular movements and abnormal sounds.

4. Increase mold temperature.

According to the performance of resin and the size of the mold, an appropriate mold temperature control machine is selected to increase the temperature of the mold to the temperature required for production. After the mold temperature increases, the movement of each part must be checked again, because the steel may cause a mold movement stuck due to thermal expansion, so pay attention to the sliding of each part to avoid strain and vibration。

5.If the experiment plan rules are not implemented in the factory, we recommend that only one condition can be adjusted at a time when adjusting the trial test conditions, in order to distinguish the impact of a single condition change on the finished product.

6. According to different raw materials, baking the resin properly.

7. Use the same raw materials as much as possible for both of tooling trial and mass production.

8. Do not try the mold completely with inferior materials. If there is a color requirement, you can arrange the color test together.

9. Problems such as internal stress often affect the secondary processing. After the trial mold is finished, the secondary processing should be carried out after the mold is closed at a slow speed. Adjust the mold closing pressure and move it several times to check for uneven clamping pressure to avoid burrs and mold deformation in the finished product。

After checking the above steps, lower the mold closing speed and mold closing pressure, and set the safety buckle and ejection stroke, and then adjust the normal mold closing and mold closing speed. If the limit switch of the maximum stroke is involved, the mold opening stroke should be adjusted slightly shorter, and the high-speed mold opening action should be cut off before this mold opening maximum 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 injection machine, the mechanical ejector rod must also be adjusted after full-speed mold opening to prevent the ejector plate or stripper plate from being deformed by force.

To avoid the short shot, breaking, deformation, burrs or even damage the mold, please check the following items before making the first shot:

(a) Whether the feeding stroke is too long or insufficient.

(b) Whether the pressure is too high or too low.

(c) Is the filling speed too fast or too slow?

(d) Whether the processing cycle is too long or too short.

If the processing cycle is too short, the K.O pin will push through the finished product .

If the processing cycle is too long, the weak parts of the mold core may be broken due to the shrinkage of the resin.

Of course, you can't anticipate all the problems that may occur during the mold trial process, but adequate consideration of timely measures in advance will certainly help you avoid serious and expensive losses.

Third, the main steps of tooling trial

In order to avoid unnecessary waste of time and trouble during mass production, it is indeed necessary to pay patience to adjust and control various processing conditions, find out the best temperature and pressure conditions, and formulate standard mold trial procedures, which can be used in establish daily working methods.

1.Check whether the plastic material in the barrel is correct and whether it is baked according to the regulations.

2.The cleaning of the material tube should be thorough to prevent the bad degrading material or miscellaneous materials from being injected into the mold. Test whether the temperature of the material tube and the temperature of the mold are suitable for the raw materials processed.

3.Adjust the pressure and injection volume to produce a finished product with satisfactory appearance.

But do not run off the flash, especially if there are some mold cavity products that have not yet fully solidified, you should think before adjusting various control conditions, because the mold filling rate changes may cause very large mold changes

4. Wait patiently until the conditions of the machine and the mold stabilize, that is, the medium-sized machine may also wait more than 30 minutes. You can use this time to view possible problems with the finished product.

5. The time for the screw to advance should not be shorter than the time for the gate plastic to solidify, otherwise the weight of the finished product will be reduced and the performance of the finished product will be damaged.

And when the mold is heated, the screw advance time also needs to be lengthened in order to compact the finished product.

6. Reasonably adjust to reduce the total processing cycle time.

7. Operate the newly adjusted conditions for at least 30 minutes to make it stable, and then at least continuously produce a dozen full-mold samples, mark the date and quantity on the container, and place them separately according to the mold cavity, so as to test the stability of the actual operation and derive reasonable control tolerances. (Especially valuable for multi-cavity molds).

8. Measure the continuous sample and record its critical dimensions (it should be measured when the sample is cooled to room temperature).

9. Compare the measured size of each shot, you should pay attention to:

(a) Whether the size is stable.

(b) Are there any trends in the increase or decrease of certain dimensions that indicate that the machine conditions are still changing, such as poor temperature control or oil pressure control.

(c) Whether the size change is within the tolerance range.

10. If the size of the finished product does not change much and the processing conditions are normal, you need to observe whether the quality of the finished product of each cavity can be accepted, and its size can be within the allowable tolerance. Write down the number of mold cavities that are measured continuously larger or smaller than the average value in order to check whether the mold size is correct.

Record and analyze the data as a need to modify the mold and production conditions, and as a reference basis for future mass production.

1. Make the processing time longer to stabilize the melt temperature and hydraulic oil temperature

2. To adjust the machine condition according to the size of all finished products is too large or too small. If the shrinkage rate is too large and the finished product seems to be insufficient in shot, you can also refer to increase the size of the gate.

3. The size of each mold cavity is too large or too small to be corrected. If the size of the mold cavity and the doorway are still correct, you should try to modify the machine conditions, such as mold filling rate, mold temperature and pressure of each part, and check whether the filling of same cavity is slow.

4. According to the matching situation of the finished product of each cavity or the displacement of the mold core, it can be corrected separately, and it may be possible to readjust the mold filling rate and mold temperature in order to improve its uniformity.

5. Check and modify the faults of the injection machine, such as the failure of the oil pump, oil valve, temperature controller, etc.

Even a perfect mold can't exert good working efficiency on poorly maintained machines.

After reviewing all recorded values, keep a set of samples for proofreading and comparing whether the modified samples have improved.

4. Attentions

Keep all the records of sample inspection during the mold trial process, including various pressures during the processing cycle, the temperature of the melt and the mold, the temperature of the material tube, the injection action time, the screw feeding time, etc.

In short, All data that will help to establish the same processing conditions smoothly in order to obtain products that meet quality standards should be saved.

At present, the mold temperature is often ignored during tooling trial in some factory, and the mold temperature is the most difficult to master in short-term trial and future mass production, and the incorrect mold temperature is sufficient to affect the sample size, brightness, shrinkage, flow pattern and lack of material.

Difficulties may occur in future mass production if the mold temperature controller is not used.