Platic Injection Moulding Model

A plastic injection moulding model is a special tool used in the plastic injection molding process. According to the design shape and size of plastic products, through a specific structural design, it allows molten plastic materials to fill the mold cavity under the pressure of an injection molding machine. After cooling and solidification, plastic products consistent with the shape of the mold cavity are formed. In short, it is the core equipment for mass production of plastic products, determining the precision, appearance and performance of plastic products.

P&M Platic Injection Moulding Model Introduction

A、Classification of Plastic Injection Moulding Models

1. Classification by Mold Structure

（1）Two-Plate Mold

The two-plate mold is one of the simplest in structure and most widely used types in plastic injection moulding models. Its mold structure is mainly composed of two parts: the fixed mold and the moving mold. The gating system is usually arranged on the fixed mold side, and the mold cavities are respectively located on the fixed mold and the moving mold. When the mold is closed, the fixed mold and the moving mold fit closely, and molten plastic is injected into the cavity through the gating system; when the mold is opened, the moving mold moves with the injection molding machine, the plastic product is separated from the fixed mold together with the moving mold, and then the product is ejected from the moving mold through the ejection mechanism. Two-plate molds are suitable for plastic products with simple structure and low requirements on dimensional accuracy, such as plastic boxes and cups in daily necessities.

（2）Three-Plate Mold

The three-plate mold adds a sprue plate (also called a gate plate) on the basis of the two-plate mold, so the entire mold is composed of three parts: the fixed mold base plate, the sprue plate, and the moving mold base plate. Its biggest feature is that the gating system and the plastic product can be automatically separated when the mold is opened, without subsequent manual trimming of the gate, which improves production efficiency. The gating system of the three-plate mold is arranged between the sprue plate and the fixed mold, and the mold cavity is located between the fixed mold and the moving mold. When the mold is opened, first the sprue plate is separated from the fixed mold, and the gating system condensate is left on the sprue plate side; when the mold is opened further, the fixed mold is separated from the moving mold, the plastic product moves with the moving mold, and finally the product is ejected by the ejection mechanism. Three-plate molds are suitable for scenarios that require pin gate feeding and have high requirements on product appearance, such as electronic product casings and precision parts.

2. Classification by Plastic Product Output

（1）Single-Cavity Mold

A single-cavity mold has only one mold cavity, and only one plastic product can be produced in each injection molding process. This type of mold has a simple structure, short design and manufacturing cycle, and low cost. It is suitable for small-batch production, trial production, or large and complex plastic products, such as large plastic turnover boxes and automobile bumpers. Since only one product is produced each time, the pressure distribution of the mold is uniform, which can better ensure the precision and quality of a single product.

（2）Multi-Cavity Mold

A multi-cavity mold contains two or more mold cavities, and multiple plastic products can be produced simultaneously in one injection molding process, which can significantly improve production efficiency and reduce the production cost per unit product. It is widely used in mass-produced small plastic products, such as plastic bottle caps, buttons, and electronic component casings. When designing a multi-cavity mold, it is necessary to ensure uniform feeding and consistent cooling of each cavity to ensure the consistency of the size and performance of all products. A balanced gating system is usually adopted to allow molten plastic to fill each cavity simultaneously and uniformly.

B、Structural Composition of Plastic Injection Moulding Model

1. Gating System

The gating system is a channel that introduces molten plastic from the injection molding machine nozzle into the mold cavity, mainly composed of the sprue, runner, gate, and cold slug well. The sprue is the part connecting the injection molding machine nozzle and the runner, and its size and shape need to match the nozzle to ensure the smooth flow of plastic; the runner is used to distribute the plastic in the sprue to each cavity; the gate is a small channel connecting the runner and the cavity, which controls the injection speed and pressure of the plastic, and at the same time facilitates the separation of the gating system and the product when the mold is opened; the cold slug well is used to collect the low-temperature plastic at the front end during the injection molding process to prevent cold material from entering the cavity and affecting the product quality.

2.Molding Parts

Molding parts are key components that directly contact the molten plastic and determine the shape and size of the plastic product, mainly including the cavity and core. The cavity is the part in the mold that forms the outer surface of the plastic product, and its shape is consistent with the outer contour of the product; the core is the part that forms the inner surface of the product or structures such as holes and grooves. Molding parts need to have high hardness, wear resistance, and high-temperature resistance to withstand the pressure and friction of the plastic melt and ensure dimensional stability during long-term use. Common materials for molding parts include mold steels such as P20, 718H, and H13. Appropriate materials are selected according to the material and precision requirements of the product, and corresponding heat treatment (such as quenching and tempering) is performed to improve their performance.

3. Guiding and Positioning Mechanism

The guiding and positioning mechanism is used to ensure that the fixed mold and the moving mold can be accurately aligned during the mold closing and opening process, preventing product size deviation or mold damage due to misalignment. It mainly includes guide pillars and guide bushes. Usually, the guide pillars are installed on the moving mold side, and the guide bushes are installed on the fixed mold side. A precision fit (such as H7/f7) is adopted between the guide pillars and guide bushes. When the mold is closed, the guide pillars are inserted into the guide bushes to provide guidance for the movement of the mold; at the same time, some molds are also equipped with positioning pins or positioning blocks to further improve the positioning accuracy of the fixed mold and the moving mold, which is especially suitable for molds with high requirements on product precision.

4. Ejection Mechanism

The function of the ejection mechanism is to eject the cooled and solidified plastic product from the mold cavity (usually the moving mold) after the mold is opened, so that the product can be taken out. Common ejection mechanisms include ejector pins, ejector sleeves, ejector plates, and ejector blocks. Ejector pins are the most commonly used ejection components, with a simple structure and easy installation, suitable for most plastic products; ejector sleeves are suitable for cylindrical or annular products, which can make the product bear uniform force and avoid deformation; ejector plates (also called ejection plates) are suitable for large-area, thin-walled or complex-shaped products, ensuring that the product does not deform through overall ejection; ejector blocks are used for local ejection of products with special shapes. The design of the ejection mechanism needs to be based on the shape, structure and material characteristics of the product to ensure uniform ejection force and reasonable ejection position, and avoid damaging the product.

5. Cooling System

The cooling system is used to take away the heat of the molten plastic in the mold cavity, so that the plastic can be cooled and solidified quickly, shortening the molding cycle, improving production efficiency, and at the same time ensuring the dimensional accuracy and appearance quality of the plastic product. The cooling system is usually a cooling water channel opened on the fixed mold and moving mold of the mold. The position, shape and size of the water channel need to be designed according to the shape and thickness of the product to ensure uniform cooling of all parts of the product. Generally speaking, the cooling water channel should be as close to the cavity surface as possible and keep a certain distance from the cavity contour to avoid affecting the mold strength; for thick-walled products, it is necessary to appropriately increase the number of water channels or extend the cooling time to ensure sufficient cooling inside the product; for thin-walled products, the distance between water channels can be appropriately reduced to speed up the cooling rate. The cooling medium usually uses water, and in some cases, other media such as oil are also used.

C、Design Key Points of Plastic Injection Moulding Model

1.Product Structure Analysis

Before mold design, it is necessary to conduct a detailed analysis of the structure of the plastic product, including structural features such as the shape, size, wall thickness, fillet, hole, and groove of the product. First, the wall thickness of the product should be uniform to avoid excessive differences in wall thickness, because uneven wall thickness will lead to inconsistent plastic cooling rates, generate internal stress, and then cause defects such as product deformation and shrinkage cavities; second, reasonable fillets should be set at the corners of the product, which can not only avoid stress concentration and improve the strength of the product, but also facilitate plastic flow and mold processing; in addition, for the holes and grooves on the product, their position, size and depth need to be considered to ensure that the mold can be formed smoothly, and at the same time facilitate subsequent ejection and removal.

2. Material Selection Adaptation

The selection of mold materials needs to be compatible with the material characteristics of the plastic product. If the plastic product uses a material with strong corrosion (such as PVC), the mold molding parts should choose mold steel with good corrosion resistance (such as H13) and undergo surface treatment (such as chrome plating) to prevent the mold from being corroded; if the plastic product requires high surface finish (such as transparent plastic parts), the mold molding parts need to undergo high-precision polishing treatment, and at the same time choose materials with good polishing performance (such as 718H); for molds used in mass production, the molding parts should choose materials with high wear resistance to extend the service life of the mold; for molds used in small-batch production or trial molding, materials with lower cost (such as P20) can be selected to reduce production costs.

3. Process Parameter Matching

Mold design needs to fully consider injection molding process parameters, such as injection pressure, injection speed, mold temperature, cooling time, etc., to ensure that the mold structure can adapt to the requirements of these process parameters.

P&M Platic Injection Moulding Model(Specification)

Customization Process

Factory&About US

NingBo Plastic Metal Product Co.,Ltd (P&M) is located in Yuyao, the so-called Mould City, Plastic Kingdom, in the southern tip of Hangzhou Bay Bridge,north of Shanghai, the east of Ningbo Port,tight double line of State Road 329 on land, sea and air trafic into a network to facilitate transport.

By the abundant technical strength,scientific management methods and good after-sales service, product deeply trusted and welcomed by customers from all over the world. P&M holds improved system of development and production, to achieve mold design, plastic products manufacturing and automatic production. Our main products is design and manufacturing of plastic mold, plastic product, metal product. 90% products of our enterprise are exported to America, Europe, Germany, Japan, Australia, etc. For many years, the company has been committed to the research of raw materials. The company has its own trademark and dozens of patents, providing more convenient technical support for mold making and product production. P&M started domestic business from 2008,named Shundi Mould Factory. And opened the international market from 2014. We always adhere to the principles of quality first and time first. While providing customers with the highest quality products, try to maximize the production efficiency and shorten production time. We are proud to tell every customer that our company has not lost any customer since its establishment.If there is a problem with the product, we will seek a solution actively and take responsibility to the end.

P&M adheres to market-oriented to the quanlity of life and focus on quality service and continuous development of new products,determined to establish a better corporate image,and our friends at home and abroad to carry a wide range of business exchanges and cooperation, create brilliant.

Packing

Packaging according to your needs

1. By air ,it takes 3-7 days for delivery.

The goods can be shipped by DHL , Fedex , UPS .

2. By sea ,the delivery time is based on your port.

To South East Asian Countries takes about 5-12 days.

To Middle east countries takes about 18-25 days.

To European countries takes about 20-28 days.

To American countries takes about 28-35 days.

To Australia takes about 10-15 days.

To African countries takes about 30-35 days.

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FAQ

1.Who are we?

We are based in Zhejiang, China, start from 2014,sell to North America(30.00%),Southern Europe(10.00%),Northern Europe(10.00%),Central America(10.00%),Western Europe(10.00%),Mid East(10.00%),Eastern Europe(10.00%),South America(10.00%). There are total about 51-100 people in our office.

2.How can we guarantee quality?

Always a pre-production sample before mass production;

Always final Inspection before shipment;

3.What can you buy from us?

Mould, Plastic Product, Metal Product, Dental Product, CNC machining.

4.Why should you buy from us not from other suppliers?

We main do all kinds of 3d design, 3d printing and plastic metal molds tooling and products. We have our own engineer and factory. One-stop supply: 3d design - 3d printing - mold making - plastic injection.

5.What services can we provide?

Accepted Delivery Terms: FOB,CFR,CIF,EXW,FCA,DDP,DDU;

Accepted Payment Currency: USD, EUR;

Accepted Payment Type: T/T,L/C,PayPal,Western Union,Escrow;

Language Spoken:English,Chinese,Spanish,French,Russian.

6.What are the characteristics of your service?

1. Your inquiry related to our products or prices will be replied within 24 hours.

2. Well-trained and experienced staffs to answer all your enquiries in fluent English.

3. Offering the support to solve the problem in the application or selling period.

4. Competitive prices based on same quality.

5. Guarantee samples quality same as mass production quality.