How Much Does A Plastic Injection Mold Cost?

Introduzione

Everyone is concerned about cost when getting parts manufactured. When it comes to cost-effective methods for producing plastic parts in bulk, Injection molding is at the top! When you bulk-produce parts, you reduce the per-part cost.

Typically, injection mold costs range from $ 3,000 to $100,000. The range spans basic to complex molds, depending on the design, complexity, and various other factors. This is the major investment in the entire injection molding project and plays a big role. With that higher upfront injection-mold cost, you can produce thousands of parts at a much more economical per-unit cost.

This guide gives an in-depth overview of the costs associated with injection mold tooling. We’ll break down different factors to assess price fluctuations. Additionally, we’ll suggest ways to reduce costs to improve long-term effectiveness.

How do you calculate injection molding costs?

The injection mold tooling is just one part of the overall process, and the total price extends beyond it. To determine the true injection molding costs of your product, you must analyze how the mold investment affects the unit cost. Since a mold is a one-time fixed expense, its impact diminishes as you scale. At the same time, labor and materials costs per item remain variable. These costs may depend on your location, volume, and the source of your supply.

Calculating the total cost per unit requires allocating the mold cost across the entire production volume. This is a process known as amortization. In high-volume manufacturing, investing in a premium, high-efficiency mold is often more cost-effective. A single high-quality mold can be used to produce hundreds or thousands of parts. This helps lower the per-part cost. So, it’s worth it.

For example, consider producing 1000 parts. $10,000 is the fixed mold cost paid once, while $0.50 is the variable cost per unit for labor and materials.
With the following equation, you can easily calculate the cost per part:

Cost-Per-Part = (Fixed Mold Cost/Total Number Of Parts) + Variable Cost Per Unit

The table below shows the cost per part by production volume, including amortized cost per part.

As shown in the table, the cost per part decreases as more parts are produced.

Key factors affecting injection mold costs

Part design complexity

The complexity of mold design stands at number one, contributing to the cost. Simple, smaller, open-and-shut designs or prototypes may cost you less. They do not involve complex side holes or ribs, while extra machining isn’t needed in these molds. In comparison, larger and more intricate designs require more precise machining and incorporate a range of design features. These include undercuts, internal threads, and others. The tight tolerances require moving parts within the mold, such as slides and lifters, which help in part ejection. All these features significantly increase machining, assembly, and overall costs. So, the simpler the mold design, the lower the cost, and vice versa.

Number of cavities

Cavities are hollow spaces that fill up with molten plastic, taking the shape of the part. It typically determines the number of parts produced in a “single shot.” There are different types of molds, each possessing a certain number of cavities. These include:

• Stampi a cavità singola: Their design is simple, and they produce a single part per cycle. They are low-cost molds.
• Stampi a più cavità: These involve complex designs with multiple cavities, and the size is large. They can produce 2, 8, 16, or even 128 in a single cycle. These are costly; however, they can be offset because the machine’s “cycle time” is shared across multiple units.
• Family Molds: These contain multiple parts (e.g., the top and bottom of a remote control) in a single mold. This saves money on the mold base, but it can be difficult to balance for quality.

Mold material and type

Basically, the mold material is selected based on the expected production volume. Higher-quality materials, such as hardened or pre-hardened steel, are used when the mold needs to be used repeatedly. 100,000 or more parts can be easily produced with high-quality molds, but require heat treatment and specialized grinding. This makes them the most expensive option.

Aluminum is also used for mold making, but it is best for prototypes or low volume, ranging between 1,000 and 5,000 parts.

Surface treatment

For some molds, where aesthetics and precision matter, surface treatment or finish plays a key role. There are different types of finishes that can also be customized according to the client’s business. Major ones used are:

• Utility Finishes: A rough “as-machined” finish or a basic sandblast (matte) is the most affordable.
• Aesthetic Finishes: High-gloss or “Class A” finishes require hours of hand-polishing by skilled technicians using diamond pastes.
• Texturing: If you want a leather grain or a specific pattern (like Mold-Tech), the mold must be chemically etched or laser-engraved, adding a specialized sub-contractor cost to the project.

Production volume

While volume primarily affects your part price through amortization, it also dictates mold quality.

High Volume Justifies expensive “Class 101” molds with hot runner systems (which can add 25% to the cost but eliminate waste).

Production location

Where your mold manufacturer is located can make a big difference in mold manufacturing cost. China is a leading manufacturing market that encompasses hundreds of injection mold manufacturers, and they have high expertise in the industry. They offer lower costs than North American and European molders. So, depending on your business, you can find a trustworthy manufacturer to discuss costs.

How to reduce the cost of injection molds?

There are several ways you can consider to minimize the overall molds cost: the following are some of them:

• Integrating DFM into the Initial Design Phase:

The importance of integrating DFM into the early design phase can not be overstated. DFM involves designing the mold to be simpler and more cost-effective. The experts review the design and simplify it, making it easily manufacturable while maintaining a good look.

• Simplifying mold design:

As discussed before, a simpler mold design is easy to manufacture. So, opting for a simple yet useful design can make a big difference. Try eliminating undercuts, adjusting wall thickness, utilizing standard mold bases, and avoiding unnecessary tight tolerances.

• Optimize the Surface Finish:

When aesthetics are not essential, go for “as machined” or beadblasted finishes. Textured or mirror-like SPI-A1 finishes can be costly as they need hours of manual labor.

• Select the right number of cavities:

Multi-cavity molds, at first, seem like a wise decision for a new product as they reduce the cost per unit. But practically it’s not. Start with a simple single mold cavity and go big after your product’s success.

• Partner with a reliable manufacturer:

An experienced, reliable injection mold manufacturer can help you reduce mold costs. Working closely with the manufacturer, the expert engineering team guides you through all the complexities of design and manufacturing. They ensure the part is designed to meet the requirements while remaining affordable.

Domande frequenti

How much cheaper are Chinese molds compared to those from the US or Europe?

Chinese molds are 30-70% cheaper than the US and European molds. The reason for this is cheap labor and the fast operational efficiency of Chinese injection mold manufacturers. However, it is always important to compare cost and other operational features when selecting molds.

How do aluminum and steel molds differ in cost?

Aluminum molds are ideal for low-volume production and are cost-effective. They are easily manufactured and require less machining time than steel molds. At the same time, steel molds are best for high-volume, repetitive production, producing hundreds of thousands of parts. So, hardened steel is precisely machined for the best results, which in turn increases manufacturing time. These molds are usually higher cost. The cost difference between the two ranges between 30-50%. The primary difference lies in the material’s properties and the machining time required.

How do hot runner and cold runner systems differ? How do they affect costs?

The main difference lies in how the molten material is handled in the runner system:

• Cold Runner: Uses unheated channels where the plastic cools and solidifies along with the part, creating a “runner” that must be trimmed and often recycled.
• Hot Runner: Uses a heated manifold system to keep the plastic molten until it is injected into the cavity, so no runner is formed.

Can I get a free quote or DFM analysis for my mold?

Yes, you can reach out for your free quote and a technical DFM breakdown at no extra charge. Just upload your CAD file, and you’ll get the DFM analysis report from MoldPartner’s expert engineering team in 24 hours.

Are there any hidden costs I should be aware of?

How long does it take to manufacture an injection mold?

The manufacturing time for an injection mold depends on the mold type, complexity, and other factors. However, aluminum molds take 15-20 working days, while steel molds, due to their complex nature, take 3-8 weeks by Chinese molders. The US mold may take longer, up to 8-12 weeks.