Custom Plastic Injection Mold Manufacturing Service In China

OEM Services: Injection Mold Design Services, Mold Engineering, Plastic Mold Manufacturing Services, Injection Molding Services, Mold Export
Project name: Custom export plastic injection mold, HASCO standard injection steel mold manufacturing
Steel name: NAK80
Material: Nylon PA66
Processing technology: CNC, drilling, EDM, wire cutting, grinding, assembly, fitting, injection molding test
injection molding trail production sample

The Injection Mold Overview

Sungplastic is a professional injection molding and plastic injection mold manufacturer. This is an actual case of an injection mold exported to Italy. The customer operates an injection molding factory with 16 injection molding machines. He sources injection molds from China and performs injection molding mass production locally.

According to customer requirements, this steel mould needs to be manufactured in accordance with HASCO standards. Therefore, even if we design the thread at the water inlet and outlet, we will follow the BSF pipe thread PT1/4. If in the future, during the mass injection molding production process in the customer’s factory, their operators injure the mold thimble or some accessories during injection molding, the customer can easily purchase HASCO standard mold parts locally for replacement and repair. Customers from the United States and Brazil are different, and they require DME standards. Therefore, the export mold manufacturing standard is an important indicator for us in the mold evaluation stage.

According to the requirements, the mold base adopts conventional C45 mold steel, and the mold core material chooses NAK80. NAK80 steel has good machinability, polishing and etching properties. It has been pre-hardened to 285-330HB (30-36HRC) before leaving the factory. It has the characteristics of good processing dimensional stability, no need for heat treatment, and the mold life is generally up to 500,000 times, so we often use this steel to make thermoplastic injection molds.

mold engineering of plastic injection mold

Review the mold design and mold engineering

The challenge of mold design: This plastic part is a plastic cover on the mechanical equipment, and the product designer designed many hollow heat dissipation windows. As an external accessory, it has high requirements on the appearance of the product and requires fine lines.

The first difficulty: The visible edge of the heat dissipation window cannot leave a parting surface.

Therefore, we need to make raised bone positions on the front mold core of the mold, so that they can be in good zero-distance contact with the plane of the rear mold core. In this way, during the mold opening stage of injection molding, the front mold core will have a large pulling force on the plastic product. Therefore, in the initial mold design stage, we need to consider that the rear mold core should have enough tension to firmly fix the molded plastic parts on the rear mold core when the mold is opened. Otherwise, the displacement of plastic parts during the mold opening stage will damage the appearance of the product.

The second difficulty: the design of the injection point gates.

Because the customer requires that the outer surface cannot be designed for injection gates, we need to design latent plastic injection gates and design the injection position on the inner surface of the product. In order to achieve sufficient injection volume and plastic flow balance in the molten state, we need to inject melt plastic from both sides at the same time, so our engineers design a three-plate mold. The injection molding flow channel is relatively complicated. The large nozzle flow channel diverts to the fine nozzle, and the fine nozzle flow channel touches the parting surface. Finally, the small nozzle flow channel is transformed into submarine injection gates to enter the product cavities.

The third difficulty: control the joint line and air mark of the product appearance.

This product is designed with a lot of heat dissipation windows, and the hollow design will definitely divert the molten plastic and then combine it at the other end. This requires our engineers to carry out mold flow analysis.
plastic mold injection gates 1
plastic mold injection gates 2
Do you see the difference between this and the plastic feed position above? Yes, after mold flow analysis, we concluded that two injection points in the second picture can better control the parting line at the hollow window structure to a minimum state. Please see the analysis results below.
mold flow 1
injection mold flow analysis
Remarks: The above display is only a partial illustration of the mold flow analysis report. As a professional plastic injection mold manufacturer, we can provide a complete and comprehensive analysis report according to the needs of customers. The detailed mold flow analysis report is an important guiding document for our mold manufacturing.

Injection mold processing

Injection mold processing steps mainly include: purchasing professional mold bases, steel materials, drilling water holes, mould cores preliminary processing, CNC, milling, grinding, design and making copper electrodes, EDM, wire cutting, assembly, mold fitting, polishing, sand texture.
Here are the most important CNC processing technology and discharge EDM processing technology used in mold manufacturing:

CNC machining

Usually the CNC we refer to in mold manufacturing refers to CNC milling machine processing. Let it be an automatic milling machine equipped with a digital control system. It combines modern new technologies such as machinery, automation, and computer programming control. CNC machining is based on the programmed software program, usually G code, so that the machine tool drives the tool to follow the path specified by the program. The control system controls the tool feed, spindle speed, coolant and other functions according to different position coordinate requirements. CNC machining solves complex and precise machining problems. It has been widely used in modern industry and greatly improved the production efficiency of enterprises.
In mold manufacturing, our CNC processing generally needs to be divided into two steps. The first step is to determine the reference position, roughing the mold core steel, using larger cutters and larger feed rates to quickly and efficiently process the mold core steel to the design size. At this time, the finished mold core parts can already see the shape of the product. The second step is to switch to a smaller tool and process some necessary dimensions in place with high speed and slow feed. This is what we call fine CNC machining. During the processing, the debris is much smaller, and the processed surface will be much finer.
CNC machining mold base


EDM” is the abbreviation of “Electrical Discharge Machining”, also known as electro-erosion machining. EDM is processed by the electro-corrosion effect of pulse discharge between the tool electrode and the metal workpiece. Since the splashing sparks can be seen during the processing, it is called EDM. The same principle is also used It is used in EDM drilling, EDM cutting (wire cutting), etc. We often use these processing technologies in mold manufacturing.
Here, we explain more about what the tool electrode requires in electrical discharge machining. For the processing of injection moulds, we usually use red copper to make tool electrodes and use CNC machining to process the required shape on the red copper, and we get the tool electrodes.
EDM electrodes

Mold fitting and Injection molding trial production

Mold fitting work is the most important step in the whole mold building. In the process of mold fitting, we can know whether all the previous processing is OK and whether the required tolerance is met. Red lead/blue lead can help us understand the front and rear die contact.
injection mold fitting
In view of the characteristics of this injection mould, we took an extra precautionary measure before the mould trial. We roughen the surface of the rear mould in advance so that the injection moulded part is not easy to follow the front mould when the mould is opened during the mould trial, commonly known as sticking the front mould. This rough texture helps hold the plastic part in place on the rear mould core.
The next step is T0 mold trial. The middle position of the resulting T0 sample developed trapped air and joint line defects. How to solve this problem? In the process of remodelling, enhancing the exhaust is the main direction. We cut holes and insert small plug-ins in the corresponding places where the air is trapped for exhaust, and process more exhaust grooves on the front mold. After changing the mold, we immediately conducted a T1 trial mold. The final T1 samples met the customer requirements.
plastic injection molding production
injection molding trail production sample

Sample delivery and export mold

After getting Golden samples, we sent samples to customers for confirmation. We are very happy that the customer replied that the quality of the sample exceeded his expectation, “This is not only good. I like it very much.”.
At this point, we can arrange custom-made fumigation-free wooden boxes and pack the mould for shipment. There is no need for customers to worry about the transportation. We will arrange for international freight companies to deliver the moulds to the customer’s factory safely and on time. It is ok if the customer has their own agent, we can send the packaged wooden box with the mould to their warehouse.
steel mold wooden package

The Influence of Injection Mold on Mass Injection Production

As a professional plastic injection mold manufacturer with 20 years of experience, we fully understand that injection moulds are the key to mass injection molding production.

The injection mold starts from the design, and the rationality of the mould design will have a decisive impact on whether the mass production of injection moulding will be smooth in the future. Whether the mould design is reasonable or not, it requires us to use mould flow analysis software to simulate the plastic filling process and generate a series of parameters to judge.

Another is the impact of mold manufacturing and processing tolerances for injection molding. Our CNC centre will be well maintained every week to ensure machining accuracy. The processing of EDM is also divided into rough work and fine work to ensure that the final size meets the requirements. Two-dimensional and three-dimensional testing instruments are used at any time to detect various processing steps in the mould manufacturing process.

The final decision on whether the quality of the injection mold is OK or not is the mold test. Fix the injection mold on the injection molding machine, and then adjust the injection molding temperature, pressure, time and other parameters to obtain perfect injection molding parts step by step. Getting a good sample means that the set of molds has passed half the test. The other half of the test is the next small batch trial production. Keeping the injection molding parameters unchanged, the mold can run stably for 50 shots or even 100 shots, and the quality of the obtained plastic products is consistent with the tested samples, so we can say that this set of molds has completely passed the test.

Choose an excellent Chinese Plastic injection mold manufacturer as your partner

In the mold customization and plastic injection moulding service industry, China’s mold manufacturing and plastic molding companies are committed to providing high-quality, efficient, and cost-effective services to customers from all over the world. Sungplastic is one of the factories with many years of manufacturing experience.

Sungplastic’s services include: custom export moulds, custom injection moulds, custom plastic injection moulding services, custom overmolding, custom blow molding, custom rubber silicone products, plastic product development, rapid prototyping, small batch processing customization, mould parts manufacturing
Service industry: automobile industry, electronics, machinery, tools, medical treatment, LED lighting, household appliances, consumer goods, sports and fitness, pet supplies, etc.

Wide range of injection molding materials: Materials include difficult-to-process engineering resins, rubber replacement and metal replacement plastics, ABS, Acrylic, TPE, TPU, PC, PE, PP, PVC, Polyethylene, Nylon (PA), PS, PPS, PI, PEI, PPS, PES, Ultem, Radel, PEEK, Ryton, Lexan, Valox and other engineering plastics with additives.

Mold processing services: multi-cavity mold, hot runner mold, plastic mold, silicone rubber mold, mold maintenance.

Injection molding processing services: plastic injection molding, rubber injection molding, overmolding injection molding, insert injection molding.

Other additional services: fast prototype manufacturing, aluminium mold test mold manufacturing, 3D printing services, CNC machining, and metal stamping.

When you choose Sungplastic, you get a professional plastic injection mold manufacturer partner through the entire production cycle. Timely, professional, and effective communication is always with you, taking your product from concept or drawing to reality.
We hope you enjoy this plastic injection OEM case study overview and may have gained some ideas and insights to help you with your next project. Do you have a great idea that you also want to make a reality? When you send an RFQ today and upload your CAD files to, we’re always ready to provide a free quote and project research.

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