What Are The Requirements For Injection Molding Machines For Precision Injection Molding?

Precision injection molding machine refers to the molding machinery and equipment suitable for the molding production of precision plastic products. For a precision injection molding machine, how should we measure or judge?
Many precision injection molding machines are also required

① High injection pressure and fast injection speed.

② The clamping system has enough rigidity and precision. The so-called precision of closing refers to the uniformity, adjustability, stability and repeatability of the closing force, as well as the high precision of the opening and closing position of the mold.

③ The pressure, flow rate, temperature and measurement can be accurately controlled to the corresponding accuracy, and the multi-stage injection can be used to ensure the reproducibility of the molding process and the repeated accuracy of the product.
Precision injection molding machines can achieve the benefits of high pressure molding

A, improve the precision and quality of precision products.

Injection pressure has the most obvious effect on molding shrinkage. When the injection pressure reaches 392MPa, the shrinkage rate of molding is almost zero. At this time, the accuracy of the product is only affected by the mold control or the environment. Experimental results show that the mechanical strength of the parts can be increased by 3 ~ 33% when the injection pressure is 98 ~ 392MPa.

B, can reduce the wall thickness of precision products, improve the molding length.

Taking PC as an example, the ordinary injection pressure of 177Mpa can form products with wall thickness of 0.8mm, while the precision injection pressure of 392MPa can form products with thickness of 0.45mm or more. Ultrahigh pressure injection machines can obtain products with higher flow ratio.

C. Increasing injection pressure can give full play to the efficacy of injection speed.
Injection molding machine performance to achieve precision injection

Injection molding products have been used in various fields, widely used to replace high-precision metal parts, so as to put forward strict requirements on dimensional accuracy, mass accuracy, apparent mass and mechanical properties of injection parts. At the same time, the technological factors affecting the quality of injection molding products also put forward higher requirements.

The ideal control state of injection molding machine is to directly control product size, mass, apparent mass, mechanical properties and other variables as feedback signals for feedback control. However, the method of direct measurement and conversion of these non-electric quantities into electrical signals has not been solved for the time being, and can only be solved by controlling the controllable variables of the injection molding machine that affect the quality of the above-mentioned products. .

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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.






A mismatch between mold and injection molding machine

Causes:

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.

Solution:

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

Causes:

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.

Solution:

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.






The parts are difficult to fill and difficult to take

Causes:

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.

Solution:

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

Causes:

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.

Solution:

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

Causes:

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.

Solution:

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.