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1. Reasons and troubleshooting methods for main runner mould sticking during injection moulding.
(1) The cooling time is too short and the main runner has not yet solidified.
(2) The slope of the main runner is insufficient, and the draft angle should be increased.
(3) The mismatched size of the main runner bushing and the nozzle causes leakage.
(4) The main runner is rough and has no cooling wells and pulling hook.
(5) If the nozzle temperature is too low, the temperature should be raised.
We all know that although product will make hand board for verification before development and it will not start the mould project until the product is ok. But after mould test, it is still inevitable to be modified. Whether injection mould manufacturers should charge the fee of mould modification? How should the product developer avoid mould modification and reduce the cost of mould modification? There is a difference between modifying the mould and repairing the mould. The mould repair is caused by the reasons of injection moulding factory itself, and the mould needs to be repaired. The modification of mould is caused by the reason of customer factors, the product design need to be changed etc.
When the billet plastically degenerates in the cavity of injection mould, it flows and slides along the surface of cavity, causing violent friction between the surface of the cavity and the blank, resulting in failure of injection mould due to wear. Therefore, the wear resistance of the material is one of the most basic and important properties of injection mould. Hardness is the main factor affecting wear resistance. Generally, the higher the hardness of injection mould parts, the smaller the amount of wear and the better the wear resistance. In addition, wear resistance is also related to the type, number, morphology, size, and distribution of carbides in the material.
The manufacture of injection moulds generally has to undergo several processes such as forging, cutting, and heat treatment etc. In order to ensure the quality of injection moulds and reduce production costs, the materials should have good forgeability, machinability, hardenability, and grindability, it should also have small oxidation, decarburization sensitivity, and quenching deformation cracking tendency.
With the rapid development of plastic moulding manufacturing industry, how to reduce the long development cycle and high cost of injection moulds has become a new goal that everyone is pursuing.

Now China has a low level of casting and it is difficult to achieve mixed casting. For the flanged moulds, high hardness and wear-resistant materials such as GM series, MoGr alloys, and air-cooled steels are generally used in the working part materials. By adopting a mosaic structure and satisfying the high life requirements of injection mould, an integral insert or an integral insert can be selected according to the size of the parts required in the working part.
Precheck of injection mould
Before the mould is installed in the injection moulding machine, inspection should be conducted so that quality problems can be found in a timely manner. And then modify the injection mould to avoid removing after installed. When the injection mould fixing plate and the moving platen are separately inspected, attention should be paid to the direction mark so as to avoid wrong when mould clamping.

Oblique guided mould installation
When installing the mould, the two should closely cooperate with safety. If there is a mould for the lateral parting mechanism, the slider should be installed in a horizontal position, that is, the movable block is moved left and right.
Injection MouldInjection Moulded Parts
Injection mould fastening
After the mould positioning ring is installed in the positioning ring seat of fixing mould plate of injection moulding machine, the mould is closed at an extremely slow speed, so that the movable platen presses the mould gently, and then the pressed plate is used. The pressed plate must be loaded with a pad and must be installed up and down four. When the pressed plate is used, we must pay attention to adjust the height of the screw to the same with the mould foot, that is, the pressed plate should be flat. If the pressed plate is inclined, the die foot can't be pressed tightly. The side of the pressed plate won't be close to the mould to avoid damage to the mould by friction.

Correct the eject distance of eject-rod
After the injection mould is fastened, slowly start the mould until the movable platen stops receding, at this time, the position of eject-rod should be adjusted to the position of between the ejector plate and the movable mould platen on the mould, and there is a gap that not less than 5mm, which is to prevent damage to the injection mould, and can ejecting the injection moulded part.

Ajustment of closed-mould tightness
In order to prevent overflow, but also ensure that the cavity is properly vented, when adjusting the clamping mechanism of hydraulic injection, mainly based on visual observation and experience, that is, when closing the mould, the elbow firstly fast and then slow, that is not very natural and also it is not too reluctant to straighten out, and the closeness of the mould is just right. For the moulds with mould temperature requirements, mould tightness should be corrected after the mould temperature is improved.

Access to cooling water
After connecting the cooling water, check whether it is unblocked or leaking.

In the plastic injection moulding process, when adopt multiple gates or there is holes and inserts in the cavity, and the thickness of injection moulded parts changes greatly, the plastic melt will flow to more than two directions in the injection mould, when the two strands plastic melt meets, it will form a weld line in injection moulded part.

According to the different production methods, the weld line can be divided into hot-melt lines and cold-melt lines. From the apparent point of view, the weld line has a curved shape, but also approximate to a straight line. From the product thickness section view, the weld line is on the outer surface, there is also a depth in the surface layer is a V-shaped groove marks, and even some through the entire wall thickness section.
EDM is suitable for a wide range of materials. Due to the high local energy of the pulse discharge, any hard, brittle, high-melting conductive material can be EDM processed. Since the energy density during pulse discharge is relatively high, it is convenient to process special materials and complex shaped workpieces that are difficult or impossible to process by ordinary machining methods, and are not affected by the material hardness and heat treatment conditions. Since the duration of the pulse discharge is extremely short, the range of heat conduction and diffusion after discharge is relatively small, so the range of the material affected by heat is very small.
Outdoor products exposed to strong light, the light fastness (sun-proof) grade requirement of the colorant used is an important indicator, if the light fastness grade is poor, the injection moulded plastic parts will quickly fade in the use. Organic pigments undergo molecular structure changes and small amounts of decomposition at a certain temperature. Especially for PP, PA and PET injection moulded parts, the processing temperature is above 280°C. When choosing the colorant, it is necessary to pay attention to the heat resistance of pigment. Acid and alkali resistance: The fading of colored injection moulded plastic parts is related to the chemical resistance (acid and alkali resistance, revivification of resistance to oxidation) of colorants.
Parting line is an important factor in the injection mould structure, it is also an important step before the injection mould begins. However, because different product structures are also different, it is also a very complicated issue. When we choose, we must try to grasp the main factors and give up the secondary factors. As much as possible to reduce the complexity of the injection mould structure, increase injection mould strength and injection mould life.
With the development of society, and with the enhancement of design and injection mould manufacturing, and the realization of new technology of injection mould, injection mould quality has received more and more attention. Injection mould quality is improved with the improvement of injection mould technology.
3D Design of Injection Mould
The driving and driving forces (pressing force, clamping force of injection mould, drop weight of the material, extrusion force, etc.) of the injection mould processing movement are provided by the power transmission mechanism of forming machine tool and equipment.
The driving of injection mould processing, such as aluminum alloy profiles, plastic profiles, sheets, or films, generally use extrusion moulding process. The mould is fixed on the head of machine, the material passes through the mould in the form of extrusion, and relative movements act on the mould to produce a various of moulded parts. For example, the plastic profile do spiraling movement relies on the screw of the continuous extrusion machine. The plastic is extruded into the mould and passed through the profile of the mould, and the shaping material is cooled and shaped. Extruded profiles are pulled forward by the traction mechanism for continuous forming machining.
Although the use of hot runners in plastic injection moulds is relatively small, everyone should not be unfamiliar, giving the impression that moulds are expensive. Why is there such a hot runner technology? What are the advantages of hot runner technology? What is the role of plastic injection mould manufacturing process? What is the problem with the general process?
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