injection mold

Common Defects Of Injection Molds And Their Solutions

An injection mold is a tool for producing plastic products and for giving them a complete structure and precise dimensions. Read on for more information about common problems and solutions for injection molds.


injection mold


A mismatch between mold and injection molding machine


1. Positioning ring position is not correct, size is too big or too small.

2. Wrong position and size of the ejector hole of the mold; wrong position and size of the forced pull reset hole.

3. Mold width size is too big; mold height size is too small.


1. Adjust the ejector hole position and size; adjust the reset hole position and size.

2. Replace the positioning ring; adjust the position and size of the positioning ring.

3. Change the tonnage of a large injection molding machine; increase the thickness of the mold.


Bad quality of parts


1. The fit-gap is too large.

2. Poor glue walking, trapped air.

3. Ejector pin is too small, uneven ejection.

4. Too small bevel, burr, hardness is not enough.

5. Uneven injection pressure, insufficient strength of product form.

6. Processing error.

7. Far from the gate, low mold temperature.


1. Trim the gate, pressure uniformity, strengthen the product strength.

2. Reasonable adjustment of clearance and grinding work part of the parting surface.

3. Improve the gate, increase the mold temperature.

4. Add local glue, add exhaust.

5. Re-processing.

6. Increase the ejector pin, evenly distributed.

7. Repair burr, increase slope, nitriding.


injection mold


The parts are difficult to fill and difficult to take


1. The pouring system is blocked, the runner cross-section size is too small, the gate arrangement is unreasonable, and the gate size is small.

2. The limit stroke of the mold is not enough, the extraction stroke of the mold is not enough, the ejecting stroke of the mold is not enough.


1. Check whether the limit, core extraction, and ejection strokes meet the design requirements and adjust the strokes that do not meet the requirements.

2. Check the runner and gate of each section of the pouring system, and fix the parts concerned.


Mold opening and closing ejecting reset action is not smooth


1. Slanting ejector, ejector pin sliding is not smooth.

2. Mold frame guide column, guide sleeve sliding is not smooth, with too tight

3. Reset spring elasticity or pre-pressure is not enough.


1. Increase or replace the spring.

2. Repair or replace the guide pillar, guide bush.

3. Check and repair the slanting top, ejector pin.


Mold water transportation is not working or water leakage


1. Water sealing rubber ring and water pipe joint are not sealed enough.

2. The mold water channel is blocked and the inlet and outlet water pipe joints are connected in the wrong way.


1. Check the cooling system inlet and outlet water pipe joints connection and each section of the waterway, repair the relevant parts.

2. Check the water sealing rubber ring and water pipe joints, repair or replace the parts.


WIT MOLD is a very professional mold design and mold manufacturer located in southern China and has passed the ISO2009:2015 international quality Our injection molding process can be customized according to your unique project. If you are interested, please feel free to contact us.

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