injection moulding machine
The first step in the injection industry is to buy a plastic injection machine and a suitable mold. Most molds are made of metal, usually aluminum or steel, and are precisely machined to match the characteristics of the product they are going to produce.
Once the mold is created by the mold maker, the material for the part is fed into a heated barrel and mixed using a helical screw. Heat strips melt the material in the barrel, and then the molten metal or molten plastic material enters the mold cavity, where it cools and hardens to conform to the shape of the mold.
Cooling time can be reduced by using cooling lines that circulate water or oil from an external temperature controller. The injection mold is mounted on the injection plate or plates, which open after the material has solidified so that the ejector pins can eject the part from the mold.
The injection molding process requires careful design, including the shape and characteristics of the part, the materials for the part and the mold, and the characteristics of the molding machine. As a result, there are several considerations that must be taken into account when injection molding.
Tips that you should know before starting injection molding:
Before starting work in the field of injection molding, you should pay attention to several points:
1. The cost of buying a plastic injection machine
The initial cost of producing injection molding can be high – due to the cost of both the injection machinery and the molds themselves.
2. Production amount of plastic injection workshop or factory
One of the most important parameters is determining how many parts you want to make in order to decide whether injection molding is the most cost-effective manufacturing method.
3. Design factors in the purchase of plastic injection machines
Minimizing the number of parts and simplifying the geometry of your items makes injection molding easier. In addition, the design of the mold tool is important to avoid defects during production.
4. Production considerations in purchasing a plastic injection machine
Minimizing cycle time helps production, given that machines with hot runner molds and precision tools are used. Such small changes and the use of hot runner systems can save manufacture your parts. It also saves money by minimizing assembly requirements, especially if you are producing thousands or even millions of parts.
How can we reduce the costs of plastic injection?
Buying an injection molding machine can be an expensive process, but there are several ways you can reduce your injection molding costs, including:
Eliminate the undercut.
Remove unnecessary features.
Use the center hole.
Reduce excess designs.
Design parts that fit together.
Modify and reuse existing templates.
Monitor DFM analysis
Use multi-cavity molds.
Consider the size of your pieces.
When is the plastic injection machine used?
Injection molding machines are used to produce a wide range of widely used products, including common plastic items such as bottle tops as well as remote control housings, syringes and more. It is also commonly used to make larger items such as car body panels.
Injection molding is mainly used in cases where there is a need to make thousands or millions of identical parts from the same mold.
Types of plastic injection processes
There are different types of injection molding processes, including:
Gas-assisted injection molding
Injection molding of liquid silicone rubber
Metal injection molding
Micro injection molding
Reaction injection molding
Thin wall injection molding
Materials used in the injection machine
Injection molding can be done with a variety of materials, including metals, glass, elastomers, a variety of plastics, and usually thermoplastics and thermoplastic polymers.
Materials can also be combined to provide different properties and effects for the final parts.
Advantages of buying a plastic injection machine:
The main advantage of injection molding is that production can be increased for a large number of parts. Once the initial costs of design and molds are covered, the cost of construction is very low. By producing more parts, the production cost is reduced.
Injection molding creates minimal waste compared to traditional manufacturing processes such as CNC machining, which eliminates excess material. However, injection molding produces some waste, mainly from sprues, runners, inlets, and any overflow material that leaks out of the part cavity (also called flash).
The final advantage of injection molding is that it allows the production of many identical parts, which allows for reliability and part consistency in high-volume production.
Disadvantages of the injection machine:
While injection molding has its advantages, there are also a number of disadvantages to the process.
Initial costs can be high for injection molding, especially in the case of injection molding machines. Before you can manufacture any part, a prototype part must be created. Once this is complete, a prototype toolkit should be created and tested. This all takes time and money to complete and can be a costly process.
Injection molding is also not ideal for producing large parts as one piece. This is due to the size limitations of the plastic injection molding machine and mold tools. Items that are too large for the injection molding machine’s capabilities must be made in multiple parts and then joined together.
The final disadvantage is that large undercuts require the design and expertise of experienced people and can add more cost to your project.
The use of buying a plastic injection machine:
Injection molding is used for a wide range of applications where a repeatable manufacturing process is required. This includes manufactured items such as wire spools, packaging, bottle tops, toys, combs, musical instruments (and components), chairs, small tables, storage containers, mechanical parts, and automotive parts and components.
Injection molding and using an injection molding machine is the most common method for making plastic parts, especially in high volumes.
Frequently asked questions about the plastic injection process:
Is injection molding environmentally friendly?
As injection machines become more efficient and materials such as thermosetting polymers are able to withstand extreme temperatures and conditions, injection molding is an environmentally friendly process.
Although there is some material waste in injection molding, it is less than in many other manufacturing processes. Of course, the exact materials used have an impact on the environment in terms of shelf life, whether they can be made from recycled materials, and how they are disposed of. There are also considerations about the carbon impact over the lifetime of the products created, including during manufacturing.
The progress in modern injection devices is such that compared to ten years ago, they now consume between 20 and 50% less energy.
How much is the cost of building an injection workshop and buying a plastic injection machine?
Molding costs are related to the number of holes in a mold. Fewer cavities require less tooling, which lowers manufacturing costs to create an injection mold. The complexity of a part’s design also affects cost, including factors such as surface finish, strength, threads, details, and the number of undercuts. Added details like this increase the cost, as it requires more tools.
The most economical type of injection molding is rubber injection molding, which produces a high yield of durable products. In addition, temperature-controlled continuous vulcanization processes can reduce costs by reducing waste.
How much is the purchase price of the plastic injection machine and its accessories?
Determining the exact cost of injection molding can be done with the following formula:
Mold price = material cost + design + process and profit + VAT + testing cost + packing and shipping cost.
Of these costs, materials and parts are about 15-30% of the total, and process and profit are 30-50%.
With these factors in mind, a small injection mold costs between $1,000 and $5,000. Larger or more complex molds can cost $80,000 or more. However, on average, a typical mold costs about $12,000.
Also, the price of the plastic injection machine can be between 30,000 and 200,000 dollars, depending on whether the machine is automatic or semi-automatic, as well as the production capacity and other parameters.
While injection molding machines and equipment are expensive, actual injection mold manufacturing costs relatively little.
What plastics are used in the plastic injection machine?
With more than 85,000 commercially available plastic material options and 45 polymer families, there is a multitude of different plastics that can be used for injection molding. Among these, polymers can be generally divided into two groups. Thermosets and thermoplastics.
The most common types of plastic used are high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Polyethylene offers several advantages, including high levels of formability, good tensile strength, strong impact resistance, resistance to moisture absorption, and recyclability.
Other common injection molding plastics include:
1. Acrylonitrile Butadiene Styrene (ABS)
This hard and impact-resistant plastic is widely used in industry. ABS offers good resistance to acids and bases, low shrinkage rate and high dimensional stability.
2. Polycarbonate (PC)
This strong and impact-resistant plastic has low shrinkage and good dimensional stability. A transparent plastic that is available in various degrees of optical clarity, PC can have a beautiful appearance and good heat resistance.
3. Aliphatic polyamides (PPA)
There are different types of PPA (or nylon), each with its own advantages. In general, apart from strong acids and bases, nylons have high strength and resistance to temperature and are also chemically resistant. Some nylons are abrasion resistant and provide good stiffness and strength with good impact resistance.
4. Polyoxymethylene (POM)
This plastic, which is commonly known as Stal, has high hardness, stiffness, strength and toughness. It also has good lubrication and is resistant to hydrocarbons and organic solvents. Good elasticity and lubricity also provide advantages for some applications.
5. Polymethyl methacrylate (PMMA)
PMMA, also known as acrylic, offers good optical properties, high gloss and scratch resistance. It also offers low shrinkage and less indentation for geometries with thin sections.
6. Polypropylene (PP)
This inexpensive resin material has high impact resistance to certain degrees but can be brittle at cold temperatures (in the case of propylene homopolymer). Copolymers offer greater impact resistance while PP is also abrasion resistant, flexible and can produce very high elongation and is also resistant to acids and bases.
7. Polybutylene terephthalate (PBT)
Good electrical properties make PBT ideal for electrical components as well as automotive applications. The strength varies from medium to high depending on the glass filling, with unfilled grades being hard and flexible. PBT also repels fuels, oils, greases and many solvents and also does not absorb flavors.
8. Polyphenylsulfone (PPSU)
A dimensionally stable material with high toughness, temperature and heat resistance, PPSU is also resistant to radiation sterilization, alkalis and weak acids.
9. Polyether Ether Ketone (PEEK)
This high-temperature, high-performance resin offers excellent heat and flame resistance, excellent strength and dimensional stability, as well as good chemical resistance.
10. Polytriimide (PEI)
PEI (or Ultem) offers high heat resistance and flame resistance along with excellent strength, dimensional stability and chemical resistance.
The price of plastic injection machine
These devices can have many different functions according to the customer’s needs. Based on this, we recommend that you click on the link to contact us and get in touch with the company’s sales experts to obtain technical advice regarding the purchase of plastic injection machines and price inquiries. Or visit the order registration page and enter the required information so that you will be contacted as soon as possible.
Injection molding has many manufacturing applications, especially for high-volume parts. While the injection molding machine can be expensive, the manufacturing cost is low once it is complete. By offering the ability to produce nearly identical parts, injection molding is used for parts in a variety of materials.
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