Injection molding machine barrel cleaning

Injection molding machine barrel cleaning

The exits of buildup in injection machine barrel when we start to operator injection machine will influence the plastic product quality. So in order to guarantee the plastic product quality, injection machine barrel cleaning is very important.

  • Method of injection machine barrel cleaning

1)      If injection machine want to manufacture many kinds of product, we should manufacture the product with light color, low melt temperature and bad heat stability, thus changing the material, cleaning the barrel is very easy.

2)      When the new material temperature is higher than unused material temperature, we should increase the injection machine and nozzle temperature to the lowest process temperature which new material need.

3)      If the new material molding temperature lower than unused material in injection machine barrel, we should increase the injection machine barrel temperature, then cut the heating power when the unused material in a certain condition.

4)      For the injection machine barrel cleaning of unused material with heat sensitivity, like PVC,POM,PCTFEF3 and so on, to avoid plastic decompose, we can adopt two stages, that is using plastic with good heating stability to transition refueling cleaning first ,like PS,LDPE and so on, then use the new material to replace the transition cleaning material.

5)      Use cleaner to clean the injection machine barrel.

No matter change the material directly or transition refueling, they will cost many material. Using cleaner to clean the injection machine barrel can not only save the cost but the effect is good. It is suitable for the injection machine barrel cleaning which process temperature range from 180℃ to 280℃.

Good plastic injection molding parts made by good quality plastic mold

  •  Pattern of injection machine barrel cleaning

1)      Plunge type injection machine barrel cleaning

Since big quantity stores, cleaning the injection machine barrel is very difficult, we must use special injection machine barrel.

2)      Screw injection machine barrel cleaning

Generally, we use changing material cleaning directly, we should know the temperature range of unused material in injection machine barrel and the heating stability first, and then we can set specific cleaning pattern easily

Injection Molding Process

Injection Molding Process

The injection molding process parameters of two kinds of commonly used plastic reference,

A, high density polyethylene (HDPE)

Barrel temperature feeding zone 30 ~ 50 C (50 DEG C)

From 1160 to 250 C (200 DEG C), from 2200 to 300 C (210 DEG C), from 3220 to 300 C (230 DEG C)

From 4220 to 300 C (240 DEG C), from 5220 to 300 C (240 DEG C), the nozzle 220 ~ 300 C (240 DEG C)

Temperature is suggested in brackets as the basic set value, travel utilization rate was 35% and 65%, mold flow length and wall thickness ratio of 50:1 to 100:1

Melt temperature 220 to 280 DEG C, barrel temperature of 220 DEG C, mold temperature of 20 to 60 DEG C

With good flow property of injection pressure, avoid the use of high injection pressure 80 ~ 140MPa (800 ~ 1400bar); except for some thin wall packaging container can reach 180MPa (1800bar).

Holding pressure contraction degree is high, need long time on the product pressure is maintained, the dimensional accuracy is the key factor, the injection pressure is about.30% ~ 60%

Back pressure 5 ~ 20MPa (50 ~ 200bar); back pressure too low place is easy to cause the weight of the product and the dispersion.

High injection speed injection speed of thin-wall packaging containers need, secondary injection speed is often applied to the plastic products of other classes.

Screw speed high screw speed (line speed is 1.3m/s) is permitted, as long as meet the cooling time before the end of the completion of the plasticizing process can; screw torque requirements for low.

Measurement of travel of 0.5 ~ 4D (minimum to maximum); metering stroke4D for the melt dwell time is long enough to provide the residual material amount is very important for 2 ~ 8mm, depending on the measurement of travel and the screw diameter.

injection molding cost is depending on the molding process

The recovery rate can reach 100% recovery.

The shrinkage rate of 1.2 ~ 2.5%; easy to twist the high degree; shrinkage;never shrink after 24h (after shrinkage)

The gating system point gate; heating hot runner hot runner, insulation, cast in suit; cross-sectional area is relatively small, the thin section products have enough machine stoppage time without the need to use other materials for cleaning work of specialized PE temperature rise;

Barrel equipment standard screw, three section type screw standard us on the packaging container products, mixing section and shear section geometric shape special (L:D = 25:1), through the nozzle, a non-return valve.

Two, polypropylene (PP)

Barrel temperature feeding zone 30 ~ 50 C (50 DEG C)

From 1160 to 250 C (200 DEG C), from 2200 to 300 C (220 DEG C), from 3220 to 300 C (240 DEG C)

From 4220 to 300 C (240 DEG C), from 5220 to 300 C (240 DEG C)

The nozzle 220 ~ 300 degrees (240 degrees C)

Temperature is suggested in brackets as the basic set value, travel utilization rate was 35% and 65%, mold flow length and wall thickness ratio of 50:1 to 100:1

Melt temperature 220 to 280 DEG C, barrel temperature of 220 DEG C, mold temperature of 20 to 70 DEG C

With good flow property of injection pressure, avoid the use of high injection pressure 80 ~ 140MPa (800 ~ 1400bar);

Except for some thin wall packaging container can reach 180MPa(1800bar).

Holding pressure to avoid product shrinkage wall, take a long time for the product of holding pressure (about cycle time; 30%) about the injection pressure 30% ~ 60%.

Back pressure 5 ~ 20MPa (50 ~ 200bar).

The injection speed high injection speed of thin-wall packaging containers need (accumulator); secondary injection speed is often applied to the plastic products of other classes.

Screw speed high screw speed (line speed is 1.3m/s) is permitted, as long as meet the plasticizing process cooling time before the end of May.

Measurement of travel of 0.5 ~ 4D (minimum to maximum); metering stroke4D for the melt dwell time is long enough to provide is very important

Residue volume ranged from 2 to 8mm, depending on the metering stroke and screw speed.

Pre drying is not needed; if the storage condition is not good, at a temperature of 80 DEG C dried 1H can.

The recovery rate can reach 100% recovery.

The shrinkage rate of 1.2 ~ 2.5%; contraction degree is high; won’t shrink after 24h (after shrinkage).

The gating system point gate or multiple point gate; heating hot runner hot runner, insulation, cast in suit; the position of gate WIP thickest point, or prone to large shrinkage.

injection molding China company needs optimize the parameter from time to time to reduce the cost and keep same quality.

Machine stoppage time without the need to use other materials for cleaning work of specialized PP temperature rise;

Barrel equipment standard screw, three section type screw standard use on the packaging container products, mixing section and shear section geometric shape special (L:D = 25:1), through the nozzle, a non-return valve

What is Insert Molding

What is Insert Molding

While the injection molding as well as insert molding processes are more or less the same, the only difference is that the injection molding makes use of only thermoplastic materials. On the other hand, this process can make use of plastics as well as other metals in order to manufacture and produce even better or advanced products. This process has become so very popular these days that it gives various advantages to people. The application of this kind of molding is far, wide and advantageous to a lot of extent.

This can be called a highly advanced and better process in which the components or parts such as bushings, metal stampings, filtration materials, electromechanical parts as well as various distinct parts are joined or rather combined into one component only with the help of thermoplastic injection into ‘inserts’ or the placed parts. Read more

Plastic injection molding china

Plastic injection molding china

Plastic injection molding china is a technique through which plastic products are manufactured using the pressure of the molten plastic injected into the mold of plastic products. After cooling these moldings desired variety of plastic parts are obtained. There is specialized machinery for injection molding and the mold is acquired after the resin material is injected into a metal mold apparatus of the products having a certain shape. Often the final product is the resulting shape which requires no installation or processing. There is lot of detailing like convex portion, the ribs, threads that can be molded in the operation of the injection molding process. Read more