Why Are Injection Molds So Expensive?

Injection molds are a key part of the manufacturing process. They are used to produce a variety of products, from automotive parts to toys and even kitchen appliances.

The cost of plastic injection mold is an important consideration for many companies, but what factors contribute to their high price tag?

In this article, we’ll explore why injection mold tooling costs are so expensive, including the materials they use, processing time and other factors that affect production costs.

What is an injection mold?

Injection molds are metal tools used to produce a variety of plastic products. They are usually made of steel, aluminum or brass.

What materials can injection molds be made from?

Depending on the number of injection molded parts required, the material of the injection mold can be different.

Quantity less than 100 can be achieved by 3D printing and CNC machining prototyping.

Quantity between 100-200: Silicone material injection mold, also called low-pressure injection process or reaction injection molding.

Quantity between 200-500: Resin material injection mold, also called low-pressure injection process or reaction injection molding.

Quantity between 500-1000: aluminum injection molds, which can use injection moulding or low-pressure injection process or reaction injection molding.

Quantity greater than 1000, Steel mold, injection molding process to achieve.

Types of plastic injection molds

Type of runner: hot runner and cold runner

The type of template: two-plate mold and three-plate mold

The type of the direction of glue feeding: Formal injection mold and Inverted injection mold.

The process of making injection molds

Injection molds are expensive because making them is not what one would call a simple process.

First, many parts must be created before you can begin to manufacture the final product, and these parts may require several molds for their creation.

The next step is to send the designed product drawings to the plastic injection moulding company so that they can begin to study and analyze whether your design can be realized with an injection mold.

Because the design drawings may have structures that cannot be realized with injection molding or structures that are not designed properly will increase the manufacturing costs.

And a professional injection molding company engineer will examine the drawings and make suggestions for design and modification.

This step is very important, and a good job in this step can avoid a lot of trouble caused by unreasonable design in the later stage after the mold is ready.

But this can be a very long process, depending on the number of parts needed for manufacturing and the communication time during the design revision and confirmation process.

Once all parties are satisfied with the design, the factory can then do the mold design based on the final design of the product.

The mold design usually takes about 7 days, during which the DFM report and the mold flow analysis report may be involved.

The DFM report mainly shows the parting line of the product, the location of the glue feed, the location of the ejector pins mark, etc.

The mold flow analysis mainly simulates the flow direction and speed of the plastic during the injection process, as well as the various potential risks that may exist during the injection process.

After the mold design is confirmed to be OK, the next step is to purchase the mold materials, arrange the mold production plan, make 2D processing drawings and accuracy check drawings.

After the mold material is purchased, the mold processing is carried out according to the mold production plan, which involves CNC machining roughing, heat treatment, CNC precision machining, EDM, wire cutting, punching, etc., as well as the final assembly and mold trial after the mold is done.

Factors affecting the cost of injection moulds

From the above mold processing process, we can conclude that the main factors affecting the mold cost are, mold design cost, mold material cost, mold processing cost, assembly cost, labor cost, trial mold cost, etc.

Design cost: Generally a skilled mold design engineer needs to have at least 5 years working experience, the salary is about 2-3 thousand dollars per month, the market price in China.

The cost of material:

There are many kinds of steel for moulds, depending on the material of the molded parts, the output and the surface treatment to choose different mould materials.

In terms of the material cost itself large items of mold than small pieces of mold need more material to make.

If the amount of products is very large, you need heat treatment mold material, so that the life of the mold can be longer, some mold steel heat treatment mold life can reach 1000K die times, of course, the cost of mold material is also higher.

Product volume can also consider the number of mold cavities increase, so that the mold will be larger, mold material costs will also increase.

If the plastic parts are transparent, the mold material needs to high mold polish with better performance, such as NAK80, S136, etc.

If the product material is similar to PVC, POM corrosive plastic materials, the mold material needs to use anti-corrosion materials, such as 4Cr13, S136, etc.

Processing cost:

It depends on the size, shape and complexity of the injection mold.

The more complex the mold is and the more processing, the higher the cost.

The larger the mold, the higher the cost.

The number of cavities of the injection mould also affects the price.

Usually the more cavities and the more processing, the higher the price.

Injection molds usually have moving parts, sliders and slant tops, which also increase their cost.

Labor cost:

The whole mold production cycle is relatively long, generally in 25-40 days, and requires skilled workers to operate each step designed to the processing process.

Mold trial cost:

After the mold processing is completed and assembled, we need to test whether the operation of the mold is smooth and whether the product accuracy can meet the requirements of the drawings.

Generally at least two mold trials are needed.

T0 mainly detects the dimensional accuracy of the molded parts and whether the processing is correct.

T0 confirm that there is no problem, we will do surface treatment on the product, such as polishing, high gloss or textured surfaces, etc.

Then we will do T1 mold trial. Each test mold will involve plastic raw materials cleaning injection molding machine, injection molding engineer adjusting injection molding machines, etc.

What factors will affect the life of the injection mold?

There are many factors affecting the life of injection moulds, mainly mold design, mold material, product structure, product material.

Mold design:

Mold design is the premise to ensure the life of the mold, so you must find a company with strong mold design, so as to ensure the long life of the mold.

Mold material:

Different mold steel, mold hardness is different, some molds through hardening to further enhance the mold hardness.

Mold hardening treatment, in wear resistance and other comprehensive performance greatly improved, help to extend the life of the mold.

Product structure:

Product structure to a certain extent will also affect mold life, the more complex the structure, the more slider structure and slant pin structure, the greater the impact of mold life.

Because these structures in the injection molding process has been in a state of activity, the process of activity will have wear and tear, the life of the mold will be affected.

Product material:

Some manufactured parts need raw material with not good flow ability, the injection molding process needs to increase the temperature of the mold and high pressure.

Some need water temperature to maintain the mold temperature at about 90 degrees, some need oil temperature to maintain the temperature of the mold at more than 100 degrees.

Each part of the mold in the case of higher temperature will be heat expansion, affecting the degree of cooperation. In the high temperature of long-term production, the life of the mold will also have a certain impact.

It is important to find an experienced injection molding company to manufacture injection molds

Finding an experienced and reliable company to work with in the early stages is an important guarantee for the success of the project.

An experienced injection molding company should have a professional English communication team and a technical team.

They can communicate with you smoothly in business and technical communication. Help you to improve the design of your plastic injection molding products with cost effective solution.

A professional plastic injection molding company can optimize the structure of the molding project without changing the appearance and function of the product to save cost during the preliminary communication process.

This can help to avoid potential risk problems and reduce tooling costs. Even some production feasibility assessment problems, which will only appear after the mold is made.

Conversely, if the preliminary ones do not find a professional factory that will not make effective evaluation and modification suggestions for the design, even if the quotation is cheap, the mold will face the mold modification cost after the mold is done later, this will dramatically increase costs.

If the preliminary product structure design or mold design is not reasonable, will affect the mold life, a pair of mold price is cheap, can not produce or lead high injection molding costs are also useless.

So it is very important to find a professional company with good cost performance to make your moulds.

Zetar is a professional one-stop factory for mold design, mold making, and injection production.

We have more than 20 English speakers and 7 experienced engineers (some of them can also speak English), which could make sure fluent communication and offer feasible design solutions before injection mold making.

Our goal is to let you sit back and relax. We take care of all the dirty works, from the scratch drawing to the mass production, post processing and logistics, etc.

Our consultant will keep you informed of the project progress throughout.

Conclusion

Now you have a clear understanding of why injection molds are so expensive, if you have a need for injection molds, first consider the above factors that affect the cost.

And the find a trustworthy injection mold manufacturer. At Zetar, we value your satisfaction and have an excellent team that deals with clients well. Contact us for great offers.