How to distinguish whether the plastic part is injection molded or die casting

Distinguish between injection molding and die-casting of plastic parts

1.The injection pressure of the die-casting mold is large, so the template is required to be relatively thick to prevent deformation.

2.The gate of the die-casting mold is different from that of the injection mold, and it needs to be divided into cones to break down the high pressure of the material stream.

3.Die casting mold cores do not need to be quenched, because the temperature in the mold cavity exceeds 700 degrees during die casting. Therefore, each molding is equivalent to quenching. The mold cavity will become harder and harder, and the general injection mold will be quenched to HRC52 or above.

4.The die-casting mold should be nitrided in the cavity to prevent the alloy from sticking to the mold cavity.

5.Generally, the corrosion of the die-casting mold is relatively large, and the outer surface is generally blued.

6.Compared with injection molds, the mating gap of the movable mating part of a die casting mold (such as the core puller slider) is larger, because the high temperature of the die casting process can cause thermal expansion. If the gap is too small, the mold will be stuck.

7.The parting surface fit requirements of the die-casting mold are higher, because the alloy fluidity is much better than that of plastic. It is very dangerous for the high-temperature and high-pressure material flow to fly out of the parting surface.

8.The injection mold generally relies on the thimble, the parting surface, etc. can be exhausted, and the die-casting mold must open the exhaust groove and slag collection bag (collect the cold material head).

Plastic die casting: In the die casting process, a thermoset resin material is added to a separate cavity, often called a trough, and then forced into one or more closed molds for polymerization (curing). The forehearth, also called the injection channel and runner, allows the material to flow from the chute to the mold cavity, and passes through the flow restrictor or gate before entering the mold cavity.

Many cavities have a single trough. The air in the chamber is replaced by the incoming material and discharged through a specially placed exhaust port. When the material is placed in the trough, the amount is measured in a compact measuring device and then preheated to close to the polymerization temperature.

Add only enough injection quantities at a time. The force that feeds the preheated raw material out of the trough is then fed to an injector that is mounted immediately on the trough to prevent spillage from the gap between the piston and the edge of the trough. The sealing sleeve is usually snapped into the injector for further leak prevention.

The surface of the trough, injector, gate, runner and mold cavity is maintained at a temperature of 280 380°F depending on the nature of the material, the design of the mold and the geometry of the part. When the die casting reaches the end of the curing period, the complete die casting is demoulded, including removing the gate, runner, injection channel and trough to form a solidified material pad (called residual material). In die casting, the preheating of the material is important.

The cold material flows slowly, and the material that enters the mold cavity first may polymerize before it reaches its end point. If this happens, the product quality is inferior, not only in appearance, but also in mechanical properties. There are some exceptions, such as small quantities at a time, or some low-viscosity materials.

It can be heated by a heat lamp or furnace, but the most effective and common method is to use a dielectric heater that is specially molded into plastic. Screw plasticizing heating of thermosetting materials is also commonly used nowadays. This equipment can be combined with molding equipment or can be self-contained, has the advantages of reduced volume and accurate measurement of feed volume, and must be combined with preform in other systems.

2.Plastic Injection Molding:Plastic injection molding is a method of plastic products, in which the molten plastic is injected into the plastic product mold by pressure, and the plastic parts are cooled and molded to obtain various plastic parts.

There are mechanical injection molding machines that are specifically designed for carrying out injection molding. The most commonly used plastic today is polystyrene.

The resulting shape is often the final product and no further processing is required before it can be installed or used as the final product. Many details, such as protrusions, ribs, and threads, can be molded in a one-step injection molding operation.

Injection molding can be divided into injection molding molding methods. and die casting.

So the difference is here, the size of the concept is different.

It's simple, look at the material. Thermoset plastics are die-cast, while thermosets are injection-molded. There is also a gate for injection molding, but not for die casting.

Generally speaking, injection molding refers to the molding of non-metallic materials, such as plastic parts; Whereas, die casting generally refers to the forming of metal materials.

Abbreviated as injection molding. A plastic processing method in which the plastic is plasticized in the heated barrel of the injection molding machine and then injected into the mold cavity of the closed mold by a plunger or reciprocating screw. This method can process products with complex shapes, precise dimensions or inserts, and has high production efficiency.

Most thermoplastics and some thermosets such as phenolic plastics can be processed in this way. The material used for injection molding must have good flow in order to fill the mold cavity to obtain the product. Since the 70s of the 20th century, there has been a type of injection molding with a chemical reaction, called reaction injection molding, which has developed rapidly.

Injection molding machine is referred to as injection molding machine (see color picture). It is composed of three parts: injection device, mold clamping device and injection mold. There are two representations of the specifications of the injection molding machine:

One is the maximum injection volume or weight per shot, and the other is the maximum clamping force. Other main parameters of the injection molding machine are plasticizing capacity, injection rate and injection pressure.

Injection molding. Injection unit is the main part of the injection molding machine. The plastic is heated and plasticized into a flowing state, and then injected into a mold under pressure. The injection methods are plunger, preplasticized and reciprocating screw. It has the advantages of uniform plasticization, small injection pressure loss, compact structure, etc., and is widely used.

Injection molding: It is a method of producing molding for industrial products. Products are usually molded using rubber and plastic.

Injection molding can also be divided into injection molding, compression molding and die casting. Injection molding machine (referred to as injection machine or injection molding machine) is the main molding equipment for making thermoplastics or thermosets into plastic products of various shapes using plastic molding molds, and injection molding is achieved through injection molding machines and molds.

Injection molded parts: rubber injection molded parts or plastic injection molded parts.

To add, die casting molding and injection molding also have different mold temperature control.

In injection molding, the mold temperature is basically below 180, and the temperature control requirements can be met by using a water-transporting mold temperature machine.

In die-casting, the temperature of the casting liquid can reach more than 600 degrees, and the mold temperature can reach more than 300 degrees. in the die-casting process.

In the process, the mold temperature needs to be maintained below 300 degrees. It is necessary to configure a special high-temperature mold temperature machine for die casting to conduct heat oil.

As a heat transfer medium, indirect cooling is carried out through a cooler.

Die-casting molding is to inject metal materials into the die-casting mold through the die-casting machine for cooling and forming, and the molding requires the metal materials to be heated from a solid state to a liquid state, and then water is injected into the mold to cool and form like a needle when I was a child. Both the hot and cold chambers of the inlet are larger than those of the injection molding. High processing temperature.

It's fast. Injection molding is to inject polymer materials into plastic molds through injection molding machines for cooling and molding, and molding is only to heat and soften the plastic materials from a solid state into fluids, and then use a screw to rotate the heated and softened plastics into the mold for cooling and molding. The processing temperature is low. Slow it down.

The materials used in the molds are different. The steel used in die casting molds is much more expensive than injection molds.

The mold life is different. The life of die casting molds is usually about 60,000-80,000 molds, while injection molds are much more.

Due to the different materials manufactured, the feeding, runner and slag discharge designs of injection molds and die-casting molds are also different.

First, the nature is different.

1. Injection mold: a tool for the production of plastic products, and also a tool to make the structure of plastic products complete and the size accurate.

2. Compression molding mold: the plastic material is directly added to the open mold cavity, the mold is closed, and the plastic flows to fill the mold cavity under the action of heating and pressure, and then the product is hardened and shaped by chemical cross-linking or physical cooling.

Second, the application is different.

1. Compression molding mold: the application is mainly used for thermosetting plastics (see thermosetting resin), such as phenolic, melamine formaldehyde, urea-formaldehyde and other plastics, as well as the manufacture of glass fiber unsaturated polyester and epoxy resin reinforced plastic products. Thermoplastics (see Thermoplastic Reins) are also made by this process, such as PVC records.

2. Injection mold: an important process equipment for the production of various industrial products. With the rapid development of the plastic industry and the promotion and application of plastic products in aviation, aerospace, electronics, machinery, ships, automobiles and other fields, the requirements for mold products are getting higher and higher, and the traditional mold design methods are becoming less and less.

Compared with traditional mold design, computer-aided engineering (CAE) technology has huge advantages in improving productivity, ensuring product quality, reducing costs and labor intensity.

The injection mold is to inject the molten plastic into the cavity of the mold at a certain speed and pressure, and after the plastic is cooled, the mold is opened to take out the molded injection product; The compression mold is to use a heated mold to heat and press the plastic sheet to form, and then open the mold, take out the molded product, and put it into cold water for shaping and cooling.

Plastic molds are collectively referred to.

Injection mold is one of the plastic molds, or extrusion molds, slush molds and so on.

The classification of molds is also differentiated according to the different processing processes. Extrusion process, injection molding process, slush molding process.

In terms of application, the injection molding process can only make fixed products with a certain shape. For example: injection molding a mobile phone case, bowl, computer case and so on.

Extrusion is the continuous extrusion production within the range of cross-sectional shapes, which can be infinitely long, such as: tubes, profiles, plates, sheets, which are made by the extrusion process.

The slush molding is like a child's toy, the hollow, rubber ball is made of slush molding.

Suzhou Zhenhongxing Precision Mold Hardware Factory is a mold hardware factory integrating mold design, production, sales and service.

1. The composition of the mold is different.

Pressure injection mold: fixed mold, fixed on the fixed mold mounting plate of the die-casting machine, with a sprue connected with the nozzle or pressure chamber; The moving mold is fixed on the die-casting motorized mold mounting plate, and when the mold is moved and clamped with the moving mold mounting plate for opening and closing, the cavity and the casting system are closed, and the liquid metal fills the cavity under high pressure; When the mold is opened, the moving mold is separated from the fixed mold, and the casting is pushed out with the help of the push-out mechanism located on the moving mold.

Injection mold: The moving mold is installed on the moving template of the injection molding machine, and the fixed mold is installed on the fixed template of the injection molding machine. During injection molding, the moving mold and the fixed mold are closed to form a gating system and cavity, and the moving mold and the fixed mold are separated during the mold opening so that the plastic products can be removed.

In order to reduce the heavy mold design and manufacturing workload, most of the injection molds use standard mold bases.

2. The elements of the mold are different.

Injection mold: Die casting mold is one of the three major elements of die casting production, and the correct and reasonable structure of the mold is a prerequisite for the smooth progress of die casting production, and plays an important role in ensuring the quality of castings (pass rate).

Injection molding: Controlling the temperature of the fluid is the most common method, and the control accuracy can meet the requirements of most situations. With this control method, the temperature displayed on the controller and the mold temperature are not consistent; The temperature fluctuations of the mold are quite large because the thermal factors that affect the mold are not directly measured and compensated for these factors, including changes in the injection cycle, injection speed, melting temperature and room temperature.

3. The disadvantages are different.

Pressure injection mold: Although the finish of the fixed mold cavity is very smooth, due to the deep cavity, it still sticks to the fixed mold.

Injection mold: The temperature in the injection mold is uneven at each point.

1. The structure of the die-casting mold and the injection mold are very similar, and the concept is also very similar. The main difference between the two is that the product after die casting mold is metal, and the product after injection molding is plastic. Of course, there will be differences in the specific process.

2. Die-casting mold refers to the precision casting method of filling molten gold into the cavity under high pressure and high speed conditions, and cooling and solidifying under high pressure.

3. Injection mold refers to the mold in which the molten resin material is injected into the metal model under high temperature and high pressure, and the plastic product with a certain shape is obtained after cooling.

The biggest difference between plastic molding pressure injection molds and compression molds is that the former has a separate charging room.

Pressure injection mold: under high pressure and high speed conditions, the molten metal is filled under the mold, and cooled and solidified under high pressure to form a precision casting method.

Compression mold: A mold used to melt and solidify plastic placed directly into the cavity with the help of pressure and heat.

Generally, there are injection molds, blow molds, die-casting molds, sheet metal molds, progressive molds, several common molds, what you say about plastic molding is injection molding, the product is produced by plastic parts, and the general raw materials are zinc and magnesium, and the production is metal parts.

Sheet metal molds are also made of plates as raw materials, and they also belong to hardware molds.

The blow molding mold is generally a plastic as the raw material, and the product is mainly a preform.

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The temperature of plastic mold production is about 200 degrees, and the plastic wears little on the mold, and generally 500,000 times the mold does not wear out. When the casting mold is produced, the temperature is above 600 degrees, and the wear of the metal on the mold is more serious, and the mold has obvious wear after 100,000 times.

The way and principle of feeding are different, and the two are very different.

The others are pretty much the same.