While 3D printing is great for prototyping it is not viable for high-volume production.
Our team can design your component for injection molding and get it produced.
Read more below about what injection molding is and how it can help you.

 

Plastic Injection Molding

Injection molding of plastic components provides an economical, and repeatable method to produce components in the thousands.

3D printing is great for prototypes and very small production runs. 3D printing however, is not a replacement for injection molding. It is not possible to get the refined finishes and strength that injection molding provides with a 3D printer.

Once the component is tested, and market validation is completed, it is time to move on to injection molding for mass production.

What is injection molding?

Injection molding is a process through which a melted material is injected into the mold by heating the material. The material in the mold then cools down and becomes solid. This method is best for large volume production with complicated shapes.

What materials are used in injection molding?

The most important factor in the production of plastic injection molding is choosing the right material. The material directly affects the molding process and also part performance. Thousands of materials are available in the market, but the selection among them is crucial.

To choose a material, you must consider part function and environment. After that, the selection of durability, strength, flexibility, cost, and color comes under consideration.

Let us help you choose the proper material for your application. You can rely on our whole

Here we have described a list of the most common plastic materials with their applications.

  1. Nylon (Polyamide)

Nylon material is used to build strong mechanical parts. Some common automotive products made by nylon are bushings, gear, and bearings. Nylon is a tough material and has a high melting temperature. Nylon also bears good chemical resistance.

  1. Acrylic

Acrylic plastic produces transparent parts like windows, lighting equipment, and transparent walls. It has high tensile strength and weather and scratch resistance, which is why it is used as an alternative to glass. It is also used in containers and refrigerators to store food.

  1. Polycarbonate

It is durable and has excellent optical properties. Polycarbonate is in use when there is a need for stronger material than acrylic. Polycarbonate is not beneficial for food storage because it contains Bisphenol A (BPA).

  1. Polyoxymethylene (POM)

It produces automotive and mechanical parts. It is a kind of acetal resin that is very strong, tough, and rigid. The resin produces ball bearings, fasteners, gears, and knife handles. It has high resistance with solvents like detergents, alcohols, gasoline, and motor oils.

  1. Polystyrene

Two types of polystyrene are commonly used in plastic injection molding, High Impact Polystyrene (HISP) and General Purpose Polystyrene (GPPS). The GPPS is transparent, and HISP is opaque. High impact polystyrene is used to make hard cases for toolboxes and bodies of power tools.

  1. Acrylonitrile Butadiene Styrene

It is an engineering-grade thermoplastic opaque polymer. The plastic is tough, hard, high impact resistance, and has good dimensional stability. It is cheaper and has a low melting temperature. Electronic parts like phone adapters, wall sockets guards, keyboard keys are made with this plastic.

  1. Polypropylene

This material is widely used by the packaging and food industry because this material does not mix with food products. The chemical and moisture resistance high and does not degrade in hot water. The strength, elasticity, and toughness are incredible.

  1. Polyethylene

It is a light-weight thermoplastic material with elasticity, high resistance, and electrical insulating properties.  The material is not very hard and strong, but it is widely used in consumer plastic parts like milk bottles, detergent bottles, medicine bottles, plastic bags, children’s  toys, and trash cans.

How Injection Molding Machine works?

The molding machine has two main units, a clamping unit, and an injection unit.

The function of a clamping unit is to open or close a die and eject out the parts. There are mainly two types of clamping methods, straight hydraulic type or toggle type.

The function of the injection unit is to heat the material and get molten material. This molten material is injected into the mold.  The screw continuously rotates to get uniform heat and melt the material. The molten lava accumulates in front of the screw. When the required amount of material comes in molten form, the injection process starts.

When molten material melts and flows towards the mold, the machine controls the screw moving speed. At the same time, it also controls dwelling pressure to fill the cavities.

What is a mold?

It is a hollow metal block in which molten material is injected to shape the material. There are many holes in the block to control the temperature that is provided by different means like hot water, oil, or heaters.

The molten material flows towards the block and fill the cavities with runners or gates. After depositing material into the mold, let it cools down to become solid. After the cooling process, the ejector rod pushes the plates or product ejection.

Major Advantages of Plastic Injection Molding

Plastic injection molding has multiple benefits because this process is more reliable and simpler than other methods. Here are the major advantages of plastic injection molding.

  1. High Efficiency and fast production

Plastic injection molding is the most common and efficient method of molding. The production rate is incredibly fast, and the high production rate makes it more cost-effective and efficient. The speed of the process depends on the complexity of the design and size of the parts.

It has only 15-120 seconds pass between each cycle, and that is why it produces a large volume in short time. It increases the chances of profit and revenue.

  1. Complex part Design

The injection molding process can produce complex part designs in an efficient way. It can also make millions of identical parts. The design plays an important role in efficiency, quality, and precision of the products. The part design must be carefully developed because a minor mistake can cost you money and time.

The design elements that require focus working are wall thickness, boss design, rib design, gate placement, corner transition, and weld lines.

  1. Improved Strength

The most important factor that must consider while designing a part is its strength. The designer must have experience in designing parts. The designer must know whether the parts need flexibility or rigidness so that he can increase or adjust ribs or gussets.

  1. A wide range of materials and colors

The most crucial factor in injection molding process is the selection of material and colors. Injection molding has a wide range of variety in both material and color, so the choices are endless. While selecting the right material for your project, you must consider following the things.

  • Impact strength
  • Tensile strength
  • Flexural modulus of elasticity
  • Heat deflection
  • Water absorption

You can also color the plastic material by using different coloring systems. Each color has its own unique properties, advantages, and disadvantages.

  1. Less wastage

When you are in search of a high-volume injection molding process partner, consider companies’ green manufacturing initiatives. These initiatives show commitment to safety, quality, and sustainability. This process produces excess waste, so you should search for a company that has a system to recycle the excess waste.

  1. Low labor cost

If we compare the injection molding process with other molding processes, the labor cost is low in plastic injection molding.  It has the ability to manufacture high-quality products at an extremely fast rate and hence reduce labor costs.

  1. Product consistency

Injection molding is a repetitive process. It means when you will manufacture the second part, it will produce an identical part to the first one. It is beneficial for high quality and large volume production because it contains product consistency.

Disadvantages of Plastic Injection Molding process

If something has benefits, it definitely has some disadvantages too, as every coin has two sides. Undoubtedly, the advantages of injection molding process are many in numbers but there are some disadvantages. Let’s have a look at the disadvantages to plastic injection molding.

  1. High tooling cost and long set up lead time

This process costs you more for the design, testing, and tooling required for the process. First, there is initial design and prototyping, then the design of mold tool to produce identical products in large volumes. In the last, after testing in both stages, you can get an injection molded part.

  1. Design restrictions

The plastic parts manufactured by the injection molding process must follow some basic rules that are described below.

  • Avoid undercuts
  • Avoid sharp edges
  • Use uniform wall thickness to prevent the unlikely situation in the cooling process.
  • Encourage draft angles for de-molding

Conclusion

Undoubtedly, injection molding is a great process for large volume production. It provides a wide range of materials and colors. Parts are identical to the first part, and quality remains consistent. The main downside is its tooling. Otherwise, it is a great option for your business.

Injection Molding Diagram