Plastics are synthetically produced non-metallic compounds. It can be molded into various forms and hardened for commercial use. Plastic molding products can be seen everywhere. Examples are jars, protective caps, plastic tubes, grips, toys, bottles, cases, accessories, kitchen utensils and a lot more.
Even the keyboard and the mouse that you use are made through plastic molding. Even the plastic parts of the chair that you are sitting on are created this way.
The basic idea in plastic molding is inserting molten liquid plastic into a ready shaped mold, for example the mold of a bottle. It will be then allowed to cool, then the mold will be removed to reveal the plastic bottle.
Plastic molding can also custom-mold a wide variety of plastic products including: garden pots, cabinets, office trays and boxes, barriers, barricades and traffic signage and displays for product and marketing promotions.
If you are planning to go into plastic molding business, you should first know the different processes. Choose from a plastic molding process that fits your budget, your expertise, and your resources.
What is Plastic Injection Molding?
Plastic injection molding is the process of heating raw material (plastic resin in pellet form, in our case) to its melting point, forcing the viscous material into a mold, and allowing it to cool into a hardened shape. Injection molded parts are used in virtually every product you encounter, from electronics to housewares to automotive to food packaging. At the highest level, it’s a very simple process, but there’s a very complex science that goes into doing it well—from creating the molds to understanding the chemical and physical properties of the materials.
Plastic injection molding owes its existence to pressure die casting processes used for metals in the late 1800s. Plastics were introduced in the 1920s, although the process was still very crude at that time, with simple two-piece molds being manually clamped together. The art and science of plastic injection molding has come a long way since then.
The plastic injection molding process can be summarized into eight steps:
The part is designed, and prototypes are created and tested.
A durable steel or aluminum mold (or tool) is designed and built. This process takes several weeks and includes a lot of complicated systems to control the process.
In production, raw material is loaded into a “feed hopper.”
The material is fed into a heated “barrel” where it becomes viscous—a state somewhere between solid and liquid.
The viscous material is forced by a plunger into a mold, which is held shut by hydraulics to withstand the pressure of the incoming material.
The material cools quickly in the mold and is ejected as a finished part after a predetermined time.
Quality assurance checks are performed on the part.
Meanwhile, the mold is closed again in preparation for the next processing cycle.
Everything from colors and textures, to lettering, logos, and designs, to hinges and other functionality can be incorporated into the creation of a plastic part.
The Many Benefits of Plastic Injection Molding
There are a host of benefits that come from producing parts through plastic injection molding. They include:
Infinite variety. Virtually any shape you can think of can be manufactured as a plastic part.
Intricate details. The force with which plastic is injected into a mold ensures that even the tiniest spaces are properly filled.
Low per-piece cost. While there are upfront costs for creating the mold, highly automated production processes result in a very low cost per part.
High output. Parts can be produced very quickly.
More cost-effective than machining. While the upfront cost of machining may, in some cases, be lower, in the long run, plastic injection molding is much more cost-effective.
Resource-conscious process. The injection process uses only as much material as needed for each part, and any material left at the end of a process can be ground up and recycled.
Injection molding is the largest plastics industry sector, and continues to outperform the overall industrial average. It is a fast process that is used to produce a large number of identical parts, ranging from precision engineering pieces to disposable consumer goods.
The process can make either thermoplastic or thermoset parts. Typically material is fed into a heated barrel, and forced into a mold cavity by a reciprocating screw or a ram injector. The injection molded part cools and hardens to the configuration of the mold.
The segment has seen a number of innovations to help reduce the rate of faulty production. As a result, injection molded technology has gained share in the mass production of complicated plastic shapes.
Parts are generally designed by a designer or engineer. Molds are produced by a mold maker. This process can be done in-house or it can be outsourced.
The process is done under high pressure, which can vary depending on the material being used. Tools generally are made from steel or aluminum. Tool steel can be hardened and plated. Aluminum alloys are used for higher cutting and hand polishing speeds.
The tool can be used to manufacture one consistent part in a repeating process or incorporate multi-cavities, such as molds used for plastic caps and closures. This allows the process to make many parts with a single injection.
There are variations of the injection molding process. These include multi-shot; insert molding; structural foam molding; and assisted molding. There are a number of technologies that are impacting the injection molding segment today, including 3-D printing for prototyping, Internet of Things (also known as Industry 4.0), and automation. These can help molders reduce the time needed to bring a part to market, improve cycle times and productivity.
While plastic injection molding may not be rocket science, it is still a very complex manufacturing process. It involves great attention to detail and there are many factors to take into consideration. First, the part design must be developed and maximized for manufacturability. Then a mold must be built. This involves computerized as well as hand tooling. The mold must then be tested along with resin and color options to determine the best formulation for the project. Press size and configuration are required to begin the manufacturing process. Once all the preliminary phases are complete, fine tuning of the mold and materials may be required before production runs are scheduled.
Plastic Mould is a kind of tool used to produce hundreds of or thousands of plastic parts. Most of our daily used plastic parts are made by plastic injection molding.
While plastic injection molding may not be rocket science, it is still a very complex manufacturing process. It involves great attention to detail and there are many factors to take into consideration. First, the part design must be developed and maximized for manufacturability. Then a mold must be built. This involves computerized as well as hand tooling. The mold must then be tested along with resin and color options to determine the best formulation for the project. Press size and configuration are required to begin the manufacturing process. Once all the preliminary phases are complete, fine tuning of the mold and materials may be required before production runs are scheduled.
Plastic injection molding is the most used method of manufacturing plastic parts with wall thickness between 0.5mm to 5mm. There are some other methods of plastic forming like blow molding for the hollow products, compression molding for the super large parts, extrusion molding for the long and irregular tubes or pipes.
Screw Plasticating
When we come to the step of injection molding, the raw material is poured into the hopper on the top of the injection molding machine. There is a barrel under the hopper with a screw inside. The temperature increases, the screw rotates and the molten raw plastic material slowly moving on the barrel. This process is called plasticalting, the solid raw material is change into flowable liquid. At first, we need to set the proper indexed like the temperature, pressure and speed according to the plastic material and mould structure.
Injection Molding
When the flowable plastic is homogenised inside the barrel, the material is injected into the mold cavity in a short time, maybe less than one second. When the cavity is overpacked, the volume of injected material is more than the part in order to compensate the shrinkage, the pressure is reduced and the cooling system start to work. After the parts are solidified, the back platen of press moves and ejects the parts. Then the process completes.
The key factor is to adjust the press indexes to accommodate with the specific material and mould. Before we start the mass production, the sample shots should be run for several times until the production process is stable. Generally, the period between finish of mould making to official production should be less than 2 weeks. The time of mould trials should be less than 3 days. Or the injection molding supplier is lacking of experience or the mould maker is not professional.
Injection molding is a forming process using molds. Materials such as synthetic resins (plastics) are heated and melted, and then sent to the mold where they are cooled to form the designed shape. Due to the resemblance to the process of injecting fluids using a syringe, this process is called injection molding. The flow of the process is as follows: Materials are melted and poured into the mold, where they harden, and then the products are taken out and finished.
With injection molding, diversely shaped parts, including those with complex shapes, can be continuously and quickly manufactured in large volumes. Therefore, injection molding is used to manufacture commodities and products in a wide range of industries.
The material that you choose to use for injection molded parts has a very large impact on the production cost. Aside from design quality and machining the molds, the material of the parts is one of the most significant factors on overall cost.
Well-known materials can often get the job done. Materials like nylon, polyethylene, and polystyrene are frequently used by product design services because of their price and the range of applications that they are suitable for. Many impressive designer materials have made their way to the market for specific and highly demanding applications. The downside of this is that these cutting-edge options can multiply the material cost of the project. The increase could be as high as ten times or more in some cases when comparing standard materials with new specialty options.
Plastic Mould is a kind of tool used to produce hundreds of or thousands of plastic parts. Most of our daily used plastic parts are made by plastic injection molding.
While plastic injection molding may not be rocket science, it is still a very complex manufacturing process. It involves great attention to detail and there are many factors to take into consideration. First, the part design must be developed and maximized for manufacturability. Then a mold must be built. This involves computerized as well as hand tooling. The mold must then be tested along with resin and color options to determine the best formulation for the project. Press size and configuration are required to begin the manufacturing process. Once all the preliminary phases are complete, fine tuning of the mold and materials may be required before production runs are scheduled.
Plastic injection molding is the most used method of manufacturing plastic parts with wall thickness between 0.5mm to 5mm. There are some other methods of plastic forming like blow molding for the hollow products, compression molding for the super large parts, extrusion molding for the long and unregular tubes or pipes.
Injection molding is considered one of the most common plastic part manufacturing processes. It can be used for producing parts from both thermoplastic and thermoset polymers.
In spite of the relatively expensive tooling cost, injection molding remains the most popular manufacturing process for plastic materials in mass production, thanks to its low operational cost, high throughput, and the flexibility to make parts with complex shapes.
One of the most common methods of converting plastics from the raw material form to an article of use is the process of injection moulding. This process is most typically used for thermoplastic materials which may be successively melted, reshaped and cooled. Injection moulded components are a feature of almost every functional manufactured article in the modern world, from automotive products through to food packaging. This versatile process allows us to produce high quality, simple or complex components on a fully automated basis at high speed with materials that have changed the face of manufacturing technology over the last 50 years or so.
Injection molding is a forming process using molds. Materials such as synthetic resins (plastics) are heated and melted, and then sent to the mold where they are cooled to form the designed shape. Due to the resemblance to the process of injecting fluids using a syringe, this process is called injection molding. The flow of the process is as follows: Materials are melted and poured into the mold, where they harden, and then the products are taken out and finished.
With injection molding, diversely shaped parts, including those with complex shapes, can be continuously and quickly manufactured in large volumes. Therefore, injection molding is used to manufacture commodities and products in a wide range of industries.
The plastic injection molding process can be summarized into eight steps:
1）The part is designed, and prototypes are created and tested.
2）A durable steel or aluminum mold (or tool) is designed and built. This process takes several weeks and includes a lot of complicated systems to control the process.
3）In production, raw material is loaded into a “feed hopper.”
4）The material is fed into a heated “barrel” where it becomes viscous—a state somewhere between solid and liquid.
5) The viscous material is forced by a plunger into a mold, which is held shut by hydraulics to withstand the pressure of the incoming material.
6) The material cools quickly in the mold and is ejected as a finished part after a predetermined time.
7）Quality assurance checks are performed on the part.
8) Meanwhile, the mold is closed again in preparation for the next processing cycle.
Everything from colors and textures, to lettering, logos, and designs, to hinges and other functionality can be incorporated into the creation of a plastic part.
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Plastic injection molding is the process of heating raw material (plastic resin in pellet form, in our case) to its melting point, forcing the viscous material into a mold, and allowing it to cool into a hardened shape. Injection molded parts are used in virtually every product you encounter, from electronics to housewares to automotive to food packaging. At the highest level, it’s a very simple process, but there’s a very complex science that goes into doing it well—from creating the molds to understanding the chemical and physical properties of the materials.
thanks for your introduction