• Plastic injection molding service

Plastic injection molding service

The plastic is first heated in the heating barrel of the injection molding machine, and then under the push of the screw or piston of the injection molding machine, through the nozzle and the pouring system of the mold into the mold cavity, and finally in the cavity hardening finalize the design, this is the simple process of injection molding, and the mold used for injection molding is called injection molding mold.


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What is a plastic injection mold?

Plastic injection mold is a combined processing tool for compression molding, extrusion molding, injection molding, blow molding and low-foaming molding. The cavity-modifying die is a punch with a variable core, which is composed of a punch combination base plate, a punch component, a punch combination card board, a cavity cut-off component and a side section combination plate. Coordinated change of mold convex, concave mold and auxiliary forming system. Plastic injection molds can process a series of plastic parts of different shapes and sizes.

Molding machine used in manufacturing industry

A Plastic injection mold is a tool for producing plastic products. It consists of several groups of parts, and this combination has a molding cavity. During injection molding, the mold is clamped on the injection molding machine, the molten plastic is injected into the molding cavity, and cooled and shaped in the cavity, and then the upper and lower molds are separated, and the product is ejected from the cavity through the ejection system to leave the mold, and finally the mold is closed again. For the next injection, the entire injection process is cyclic.

Plastic injection mold classification

According to the different molding methods, the types of plastic processing molds corresponding to different process requirements can be divided, mainly including injection molding molds, extrusion molding molds, blister molding molds, and high-expanded polystyrene molding molds.

Plastic injection mold classification

1.Plastic injection (plastic) mold

It is mainly a molding mold that is most commonly used in the production of thermoplastic parts. The processing equipment corresponding to the plastic injection mold is a plastic injection molding machine. The plastic is first heated and melted in the heating barrel at the bottom of the injection machine, and then the screw Or driven by the plunger, it enters the mold cavity through the injection machine nozzle and the pouring system of the mold, and the plastic is cooled and hardened to form, and demolded to obtain the product. Its structure usually consists of forming parts, pouring system, guiding parts, pushing mechanism, temperature regulation system, exhaust system, supporting parts and other parts. The manufacturing materials usually use Plastic injection mold steel modules, and the commonly used materials are mainly carbon structural steel, carbon tool steel, alloy tool steel, high-speed steel, etc. The injection molding process is usually only suitable for the production of thermoplastic products. The plastic products produced by the injection molding process are very wide, ranging from daily necessities to various complex machinery, electrical appliances, and transportation parts. It is the most widely used processing method in the production of plastic products.

Plastic compression mould

2. Plastic compression mould

Including compression molding and injection molding two structural mold types. They are a type of mold mainly used to mold thermosetting plastics, and their corresponding equipment is a press molding machine. Compression molding method According to the characteristics of the plastic, the mold is heated to the molding temperature (usually 103°-108°), and then the measured compression molding powder is put into the mold cavity and the feeding chamber, the mold is closed, and the plastic is under high heat and high pressure. It is softened and viscous flow, and after a certain period of time, it will be solidified and shaped into the desired shape of the product. The difference between injection molding and compression molding is that there is a separate feeding chamber. Before molding, the mold is closed first. The plastic is preheated in the feeding chamber and is in a viscous flow state. Under the action of pressure, it is adjusted and squeezed into the mold cavity to harden and form. Compression molds are also used to form some special thermoplastics such as hard-to-melt thermoplastics (such as polyvinyl fluoride) blanks (cold pressing), resin lenses with high optical properties, slightly foamed nitrocellulose car steering wheels, etc. . The compression mold is mainly composed of cavity, feeding cavity, guiding mechanism, ejecting parts, heating system, etc. Injection molds are widely used in packaging electrical components. The materials used in the manufacture of compression molds are basically the same as injection molds.

3. Plastic extrusion mold

3. Plastic extrusion mold

A type of mold used to produce continuous-shaped plastic products, also known as extrusion molding head, is widely used in the processing of pipes, bars, monofilaments, plates, films, wire and cable cladding, profiles, etc. The corresponding production equipment is a plastic extruder, the principle of which is that the solid plastic is melted and plasticized under the conditions of heating and the screw rotation of the extruder, and is made into the same cross-section as the shape of the die through a die of a specific shape. Continuous plastic products. Its manufacturing materials are mainly carbon structural steel, alloy tools, etc., and some extrusion dies are also inlaid with wear-resistant materials such as diamond on the parts that need to be wear-resistant. The extrusion process is usually only suitable for the production of thermoplastic products, which is significantly different from injection molds and compression molds in structure.

4. Plastic blow mold

4. Plastic blow mold

It is a mold used to form plastic container hollow products (such as beverage bottles, daily chemical products and other packaging containers). The form of blow molding mainly includes extrusion blow molding and injection blow molding according to the process principle. , Injection stretch blow molding (commonly known as "injection stretch blow"), multilayer blow molding, sheet blow molding, etc. The equipment corresponding to blow molding of hollow products is usually called plastic blow molding machine, and blow molding is only suitable for the production of thermoplastic products. The structure of the blow mold is relatively simple, and the materials used are mostly made of carbon.

Plastic vacuum forming mold

5. Plastic vacuum forming mold

It is a kind of mold that uses plastic plates and sheets as raw materials to form some relatively simple plastic products. In the case of heating and softening, it is deformed and attached to the cavity of the mold to obtain the desired molded product, which is mainly used in the production of some daily necessities, food, and toy packaging products. Due to the low pressure during molding, the mold material is mostly made of cast aluminum or non-metallic materials, and the structure is relatively simple.

High-expanded polystyrene molding die

6. High-expanded polystyrene molding die

It is a kind of mold that uses expandable polystyrene (bead material composed of polystyrene and foaming agent) raw materials to form foam packaging materials of various desired shapes. The principle is that expandable polystyrene can be steamed in the mold, including two types of simple manual operation molds and hydraulic straight-through foam Plastic injection molds, which are mainly used to produce packaging products for industrial products. The materials for making such molds are cast aluminum, stainless steel, bronze, etc.

The structural elements to be considered in the design of plastic injection molds are

Parting surface, that is, the contact surface where the die and the punch cooperate with each other when the die is closed. The selection of its position and form is affected by factors such as product shape and appearance, wall thickness, molding method, post-processing technology, mold type and structure, demolding method and molding machine structure.

 Structural parts, that is, the sliders, inclined tops, straight top blocks, etc. of complex molds. The design of structural parts is very critical, which is related to the life of the mold, processing cycle, cost, product quality, etc. Therefore, designing the core structure of complex molds requires a higher comprehensive ability of the designer, and pursues simpler, more durable and more economical as far as possible. Design.

Mould accuracy, that is, avoiding jams, precise positioning, guide posts, positioning pins, etc. The positioning system is related to the appearance quality of the product, the quality and life of the mold. According to the different structure of the mold, different positioning methods are selected. The positioning accuracy control mainly depends on the processing. The internal mold positioning is mainly considered by the designer to design a more reasonable and easy-to-adjust positioning. Way.

Gating system, that is, the feeding channel from the injection molding machine nozzle to the cavity, including the main channel, the runner, the gate and the cold material cavity. In particular, the selection of the gate position should help the molten plastic to fill the cavity in a good flow state, and the solid runner and gate cold material attached to the product can be easily ejected from the mold and removed when the mold is opened (heat flow Except for Dao models).

 Plastic shrinkage and various factors that affect the dimensional accuracy of products, such as mold manufacturing and assembly errors, mold wear, etc. In addition, when designing compression molds and injection molds, the matching of process and structural parameters of the molding machine should also be considered. Computer-aided design technology has been widely used in Plastic injection mold design.

Material requirements for plastic injection mold manufacturing

Material requirements for plastic injection mold manufacturing

The working conditions of plastic injection molds are different from those of cold stamping molds. Generally, they must work at 150°C-200°C. In addition to a certain pressure, they must also be affected by temperature. According to the different use conditions and processing methods of Plastic injection molding molds, the basic performance requirements of steel for Plastic injection molds are roughly summarized as follows:

1. Sufficient surface hardness and wear resistance

The hardness of the Plastic injection mold is usually below 50-60HRC, and the heat-treated mold should have sufficient surface hardness to ensure that the mold has sufficient rigidity. Due to the filling and flow of plastic, the mold is required to bear large compressive stress and friction during work, and the mold is required to maintain the stability of shape accuracy and dimensional accuracy to ensure that the mold has a sufficient service life. The wear resistance of the mold depends on the chemical composition of the steel and the hardness of heat treatment, so increasing the hardness of the mold is beneficial to improve its wear resistance.

2. Excellent machinability

Most Plastic injection molding molds require certain cutting processing and fitter repair in addition to EMD processing. In order to prolong the service life of cutting tools, improve cutting performance, and reduce surface roughness, the hardness of Plastic injection mold steel must be appropriate.

3. Good polishing performance

High-quality plastic products require a small roughness value on the surface of the cavity. For example, the surface roughness value of the injection mold cavity is required to be less than Ra0.1~0.25, and the optical surface is required to be Ra<0.01nm. The cavity must be polished to reduce the surface roughness value. The steel selected for this purpose requires less material impurities, fine and uniform structure, no fiber orientation, and no pitting or orange peel defects during polishing.

4. Good thermal stability

The shape of the parts of the plastic injection mold is often complicated, and it is difficult to process after quenching. Therefore, it should be selected as far as possible with good thermal stability. When the mold is formed and processed after heat treatment, the linear expansion coefficient is small, the heat treatment deformation is small, and the dimensional change caused by the temperature difference. The rate is small, the metallographic structure and mold size are stable, and the processing can be reduced or no longer required to ensure the mold size accuracy and surface roughness requirements.

5, 45, 50 grades of carbon steel have certain strength and wear resistance, and are mostly used for mold base materials after quenching and tempering. High carbon tool steel and low alloy tool steel have high strength and wear resistance after heat treatment, and are mostly used for forming parts. However, high carbon tool steel is only suitable for the manufacture of formed parts with small size and simple shape due to its large deformation during heat treatment.

For the manufacture of complex, precise and corrosion-resistant Plastic injection molds, pre-hardened steels (such as PMS), corrosion-resistant steels (such as PCR) and low-carbon maraging steels (such as 18Ni-250) can be used, all of which have better performance. Machining, heat treating and polishing properties and high strength.

6. In addition, when selecting materials, it is necessary to consider preventing scratches and gluing. If there is relative movement between the two surfaces, try to avoid selecting materials with the same structure. with different surface structures.

Application of Plastic injection mold

Application of Plastic injection mold

The application of plastic injection molds can be said to be very extensive. From tea cups in daily necessities to forklifts used in industrial production and materials used in military and national defense, you can see parts and products produced by plastic injection molds.Here is some of their fields like household appliances, furniture, instruments, meters, building materials, fitness equipment, auto parts, auto parts, hardware, consumer electronics, medical equipment, etc.

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    • How to create a prototype?

      CNC machining and 3D printing are commonly methods of making prototypes. CNC machining includes metal parts CNC machining and plastic parts CNC machining; 3D printing includes metal 3D printing, plastic 3D printing, nylon 3D printing, etc.; The craft of duplication of modeling can also realize prototypes making, but it needs to cowork with CNC fine machining and manual grinding or polishing. Most of the prototype products need to be manually sanded and then surface treated before delivery so as to achieve the appearance effect and the strength of materials and other physical properties of the parts and components surface.

    • Can you provide one-stop service from product design to mass production to logistics?

      One-stop delivery service is our domination strength, we can provide product design, design optimization, appearance design, structural design, industrial design, hardware design, software design, electrical development, prototyping, mold design, mold manufacturing, duplication of modeling, Injection molding, die casting, stamping, sheet metal fabrication, 3D printing, surface treatment, assembly and testing, mass production, low-volume production,product packaging, domestic and offshore logistics and transportation, etc.

    • Can you provide the assembly and testing for prototypes andproducts?

      Product assembly and testing are essential to ensure the normal delivery of products. All prototyped products are required to pass strict quality inspections before they shipping; for mass-produced products, we provide IQC inspection, online inspection, finished product inspection, and OQC inspection

      And all test records are required to be archived.

    • Can the drawings be revised and optimized in prior to moulds making?

      All design drawings will be evaluated and diagnosed by our professional engineers before the molding. We will notify you as soon as there are design defects and hidden processing problems such as shrinkage. With your permission, we will   optimize the design drawings until it meet production requirement.

    • Can you provide the warehouse for our molds for store after injection molding manufacturing?

      We provide mold design and manufacture, product injection molding and assembly, whether it is plastic injection mold or aluminum alloy die-casting mold, we will provide storage services for all molds or dies.

    • How to guarantee the secuirty for our order during the shipping?

      Usually, we recommend you order an entire of transportation insurance for all logistics and transportation, so as to reduce the risk of loss of goods during transportation.

    • Can you arrange the door-to-door delivery for our ordered products?

      We provide door-to-door logistics services. According to different trades, you can choose transportation by air or by sea, or a combinated transportation. The most common incoterms are DAP, DDP, CFR, CIF, FOB, EX-WORKS…,

      In addition, you can arrange the logistics as your way, and we will assist you in completing the logistics and transportation from the factory to your designated location

    • What about the payment term?

      We currently support wire transfer(T/T), letter of credit(L/C), PayPal, Alipay, etc., Usually we will charge a certain percentage of the deposit, and the full payment needs to be paid before delivery.

    • What types of finishing or surface treatment for prototypes and mass products?

      The surface treatment of products includes surface treatment of metal products, surface treatment of plastic products, and surface treatment of synthetic materials. Our common surface treatments consist of :

      Sand blasting, Dry Sand Blasting, Wet Sand Blasting, Atomized Sand Blasting, Shot Blasting,etc.

      Spraying,Electrostatic Spraying, Fame Spraying, Powder Spraying, Plastic Spraying, Plasma Spraying, Painting, Oil Painting etc.

      Electroless Plating of Various Metals and Alloys,Copper Plating, Chromium Plating, Zinc Plating, Nickel Plating,Anodic Oxidation, Electrochemical Polishing, Electroplating etc.

      Bluing and Blackening, Phosphating, Pickling, Grinding, Rolling, Polishing, Brushing, CVD, PVD, Ion implantation, Ion Plating, Laser Surface Treatment ect.

    • What about the privacy for our design and product?

      The security of customer information and products is our priority consideration. We will sign the confidentiality agreements(such as NDA) with all customers and establish independent confidential archives. JHmockup has strict confidentiality systems and practice procedures to prevent leakage of customer information and product information from the source.

    • How long to custom and develp a product?

      The cycle of product development depends on what state the products are in when you deliver them.

      For instance, you already have a complete design plan including drawings, and now you need to verify the design plan through prototypes making; Or in case of your design has been made with a prototype in other places, but the effect is not satisfactory, then we will optimize your design drawings and then make a prototype to reverify it;Or,

      your product already has completed the appearance design, but there is no structural design, or even a complete set of electrical and software solutions, we will provide the corresponding design solutions to offset; Or, your product has been moulded, but the injection-molded or die cast parts cannot meet the function of the overall assembly or finished product, we will re-evaluate your design, mould, dies,materials and other aspects to create an optimized solution. Therefore, the cycle of product development cannot be simply answered, it is a systematic project, some can be completed in one day, some may take a week, and some may even be completed in several months.

      Please contact our professional engineers to discuss your project, so as to reduce your cost and shorten development timeline.

    • How to realize custom products?

      Customized service of products design and manufacturing is our key core capability. Different product customizations have different customization standards, such as partial product customization, overall product customization, partial customization of product hardware, partial customization of product software, and customization of product electrical control. The custom manufacturing and fabrication service is based on a comprehensive understanding of the customer’s product function, material strength, material processing technology, surface treatment, finished product assembly, performance testing, mass production, cost control and other factors before comprehensive evaluation and program design. We provide a complete supply chain solution. Probably your product does not use all the services at the current stage, but we will help you consider the scenario that may be needed in the future in advance, which is what differentiates us from other prototype suppliers.

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