Common defects and solutions for plastic products produced by injection molds

The shortcomings and anomalies of the injection molds are finally reflected in the quality of the injection molded products.

The shortcomings of injection molding products can be divided into the following points:

(1) insufficient product injection;

(2) Product overflow;

(3) product dents and bubbles;

(4) The product has a seam;

(5) The product is brittle;

(6) plastic discoloration;

(7) The product has silver wire, markings and flow marks;

(8) The product is turbid at the gate;

(9) product warpage and shrinkage;

(10) The product size is not allowed;

(11) The product is pasted into the mold;

(12) Material paste flow path;

(13) The nozzle is flowing.

JK-mold Injection product testing

The reasons for this and the ways to overcome it are described below.

1. How to overcome the insufficient injection of injection mold products

Insufficient product injection is often due to the fact that the material has solidified before it has filled the cavity, and of course there are many other reasons.

(1) Equipment reasons:

1 hopper interrupted material;

2 The hopper neck is partially or completely blocked;

3 insufficient feed;

4 The feeding control system is not operating properly;

5 The plasticizing capacity of the injection molding machine is too small;

6 The injection cycle caused by the equipment is abnormal.
(2) Reasons for injection molding:

1 The injection pressure is too low;

2 the injection pressure loss during the injection cycle is too large;

3 The injection time is too short;

4 The total pressure of injection is too short;

5 The injection rate is too slow;

6 The flow in the cavity is interrupted;

7 filling rate is not equal;

8 The injection cycle caused by the operating conditions is abnormal.

(3) Temperature reasons:

1 increase the temperature of the barrel;

2 increase the nozzle temperature;

3 Check the millivoltmeter, thermocouple, resistance heating coil (or far infrared heating device) and heating system;

4 increase the mold temperature;

5 Check the mold temperature control unit.

(4) Mold reasons

1 The flow path is too small;

2 The gate is too small;

3 nozzle hole is too small;

4 The gate location is unreasonable;

5 the number of gates is insufficient;

6 cold material is too small;

7 insufficient exhaust;

8 The injection cycle caused by the mold is abnormal;

(5) Material reasons: The material fluidity is too poor.

2. How to overcome the flashover of injection mold products:

The overflow of the product is often caused by the defects of the mold. Other reasons are: the injection force is greater than the clamping force, the material temperature is too high, the exhaust gas is insufficient, the feeding is excessive, and the mold is stained with foreign matter.

(1) Mold problem:

1 cavity and core are not closed;

2 cavity and core offset;

3 templates are not parallel;

4 template deformation;

5 The mold plane falls into the foreign object;

6 insufficient exhaust;

7 The vent hole is too large;

8 The injection cycle caused by the mold is abnormal.

(2) Equipment problems:

1 The projected area of ​​the product exceeds the maximum injection area of ​​the injection machine;

2 The presser template installation adjustment is incorrect;

3 The mold is not installed correctly;

4 The clamping force cannot be kept constant;

5 The injection molding machine template is not parallel;

6 The rod is deformed unevenly;

7 equipment caused by abnormal injection cycle

(3) Injection molding conditions:

1 clamping force is too low

2 The injection pressure is too large;

3 injection time is too long;

4 The total pressure of injection is too long;

5 The injection rate is too fast;

6 filling rate is not equal;

7 the flow in the cavity is interrupted;

8 The feed amount control is too large;

9 The injection cycle caused by the operating conditions is abnormal.

(4) Temperature problem:

1 The barrel temperature is too high;

2 The nozzle temperature is too high;

3 The mold temperature is too high.

(5) Equipment problems:

1 increase the plasticizing capacity of the injection machine;

2 make the injection cycle normal;

(6) Cooling conditions:

1The part is cooled too long in the mold to avoid shrinking from the outside to the inside and shorten the cooling time of the mold;

2 Cool the parts in hot water.
More details can be found at: https://plasticmolds.en.alibaba.com
Or send an email to a410093181@gmail.com