What are the common production failure problems of blow molding machines?

Today, we have sorted out some common production failure problems of blow molding machines and how to check and solve them.

I  The blow molding machine does not material

1. The startup temperature is low, which may be caused by the damage of the extrusion cylinder and components. Check whether the temperature of the extrusion cylinder and die head reaches the standard, whether the heating time is sufficient, and whether the heater is damaged. Replace in time.

2. If there is glue sticking at the feeding place, first lower the temperature before stopping the machine, and stop the machine when there is no glue at the feeding part of the screw. Just start the machine and find that you need to use a plastic rod or a wooden rod to squeeze down at the feed port; feed the material, so that the glue sticking to the feed part of the screw moves forward.

3. The problem of the transmission belt may be that the transmission belt is old or too slack, which leads to unstable discharge. Replace and adjust the belt tension to avoid the occurrence of slack and falling off and affect the feeding.

MEPER blow molding machine

II  There are black substances on the surface of blow molding products

There are many reasons for the existence of black minerals or short black streaks in the transparent parts of blow-molded products.

1. The retention time of the raw material in the blow molding barrel or the flow channel is too long, and the material properties change.

2. The blowing screw and barrel are severely worn, and the raw materials cannot be melted uniformly.

3. The mold cooling water is not good, causing the overall temperature deviation of the mold to be large.

4. The mold is poorly vented, and the air accumulates inside the mold cavity, causing burnt material.

III Surface bubbles

During the blow molding process, when the surface of the product is formed, the gas that cannot be discharged in time is trapped, resulting in defects on the surface of the blow molded product.

1. The blow molding material is wet, and the water vapor evaporates into the surface of the material.

2. The exhaust air of the mold is blocked or the exhaust is poor, and the gas cannot be discharged smoothly.

3. The blow molding cycle time is too short, and the cavity gas cannot be discharged quickly.

4. The machine production air pressure parameter setting is wrong.

5. The blowing screw rotates too fast.

6. The screw back pressure is too low.

7. There are volatile additives in the raw materials.

MEPER extrusion blow molding machine with IML

IV Product surface finish is low

1. The blow molding pressure is not enough, and the raw materials are not fully compacted.

2. The temperature of the barrel is too low, and the raw materials are not completely melted, resulting in a low finish of the produced products.

3. The temperature of the mold is insufficient, the product cannot be attached to the inner surface of the mold, and there are problems in the production process.

4. The raw materials are a little wet, and the fluidity is not good when entering the production process of the blow molding machine, which will also cause the surface finish to decrease.

V  The longitudinal wall thickness of the product is uneven

1. The self-weight sagging of the parison is serious. Reduce the melt temperature of the parison, increase the extrusion speed of the parison, replace the resin with a lower melt flow rate, and adjust the parison control device to improve this problem.

2. The diameter of the two longitudinal cross-sections of the blow-molded product is too different, which affects the production. To solve this situation, the product design can be appropriately changed and the bottom-blowing method is used.

VI  Horizontal unevenness of blow molded products

1. The parison extrusion is skewed, because of the failure caused by this reason, adjust the gap width deviation of the die in time to make the parison wall thickness uniform; before the mold is closed, the straightening shape is bad.

2. The temperature difference between the mold sleeve and the mold core of the blow molding machine is large. It is necessary to increase or decrease the heating temperature of the mold sleeve to improve the temperature deviation inside and outside the die.

3. The shape of the product is asymmetrical. Before closing the mold, pre-clamping and pre-expanding the parison to properly offset the parison in the direction of the thin wall can improve this problem.

4. If the inflation ratio of the parison is too large, it can be solved by adjusting and reducing the inflation ratio of the blow molded products.

MEPER Coex Blow Molding Machine

VII The outline or graphics of blow-molded products are not clear

1. Poor cavity exhaust, repair the mold in time, sandblast the cavity or add an exhaust groove.

2. The inflation air pressure is low, and the inflation air pressure of the blow molding machine is increased.

3. The temperature of the parison melt is too low, and the material is not plasticized properly. Increase the heating temperature of the extruder and the die appropriately, and add an appropriate amount of filler masterbatch if necessary.

4. The cooling temperature of the mold is low, and the mold has condensation phenomenon, so adjust the mold temperature to above the dew point temperature.

Regarding the common production failure problems of blow molding machines, let’s introduce these 7 kinds first. I hope the article of the editor will be helpful to you. To learn more about blow molding, remember to pay attention to us.