Injection Molding Cost: Know All Factors and How to Reduce it?

Generally, the injection molding process has no fixed cost for every application. Custom injection molding cost has a varying value that ranges from thousands to hundreds of thousands. Below are common factors that impact the cost of injection molding.

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1. Molding Tooling Cost

It is expensive to machine the mold and mold base for the products, even though the molding equipment is a one-time investment. Besides, the process used to create the molds determines the cost. The standard techniques used in making molds include CNC machining, electric discharge machining, and 3D printing.

CNC Machining

The CNC machining process is well-suited for making metal molds from aluminum or steel materials. For instance, CNC machines use cutting tools to remove materials from an aluminum block to machine an aluminum mold. Besides, this machining method produces aluminum molds with high accuracy.

EDM (Electrical Discharge Machining)

Electrical Discharge Machining (EDM) is an assisted technique for making molds with complex and precise features. It involves using electrical discharge to melt and form the metal workpiece into the desired size and shape. Although EDM offers excellent accuracy, it is compatible with only metal molds.

3D Printing

3D printing is one of the fastest procedures for making molds for plastic injection molding projects. This method uses a 3D printer and doesn’t necessarily require a skilled operator. Hence, it saves labor and mold costs. However, 3D printed components are often limited in dimensions due to the size of the 3D printer’s build platform. Similarly, printed molds are more likely to experience shrinkage.

2. Equipment Cost

The injection molding process requires unique equipment. However, the machine’s size and level of sophistication determine the cost and range from small to large machine. Therefore, it would help to consider the following injection molding machine types and how they influence injection molding costs.

Electric Injection Molding Machines

Electric molding machines utilize an electro-servo motor to direct the machine during injection molding. They utilize less energy, incur low operating and maintenance costs, and are accurate and easy to use. Nevertheless, their initial investment cost is high and requires routine maintenance.

Hydraulic Injection Molding Machines

These hydraulic injection machines perform injection molding operations with a hydraulic pump. They are usually durable, offer highly consistent ejection and injection, and have economical initial purchase costs. However, they can be imprecise and consume excessive energy.

Hybrid Injection Molding Machines

Hybrid injection molding machines combine the characteristics of electric and hydraulic injection molding machines. It uses a servo motor and hydraulic pump to distribute the oil used in producing hydraulic pressure that creates the component in the machine.

These machines provide high precision, repeatability, and energy efficiency. Furthermore, they have high initial investment costs and require heavy maintenance since they use electric motors and hydraulic pumps.

However, it may be ideal to outsource to injection molding service providers instead of buying a machine to avoid the high cost of an injection molding machine.

3. Plastic Resins and Additives Cost

Plastic injection molding is compatible with an extensive range of plastic resins with varying availability, price, applications, and properties. Typical examples of plastic injection materials include PC, ABS, PU, PP, and PE.

The cost of plastic pellets material used in plastic injection molding technique ranges from 1 dollar per kg to 5 dollars per kg. However, the injected material’s final cost depends on the used amount and the required design.

4. Injection Molded Parts Cost

Molded parts’ variables, such as design, size, and volume of injection molding components, often decide injection mold cost. You can optimize the cost of your project significantly when you understand how these variables impact the project’s plastic injection molding cost.

Part Complexity

To make complex parts, you must create a mold with even complexity using manufacturing methods such as 3D printing, CNC machining, or EDM machining. Besides, you need more material to fill the mold to produce complex parts. Consequently, this increases the injection molding material cost. At the same time, complex parts may require extended production time since they may require additional steps in the production process.

Part Size

Creating large molded parts will require more injection molding material, hiking the costs of injection molded components. Similarly, it would be best to use the proper injection molding machine and manufacture the right mold size when handling large parts.

Undercuts

Generally, the undercut injection molding features complicate and in some instances prevent parts injection. Eliminate them if possible. If you find it hard to get rid of them, try sliding shutoffs, pass-through cores, or change the parting line and draft angles to simplify the mold build.

Finishing and Appearances

Unnecessary features that do not add significant value to your final products will increase plastic injection molding costs. Textured surfaces, for instance, may simply not be needed. This holds true for cosmetic add-ons like bead blasting or high mold polish too. Remember that excess features might also require more mold cavities that further drive costs north.

5. Labor and Other Services

Most procedures associated with injection molding are automated and controlled by software systems. However, typical labor costs involved in injection molding include:

• Setup Costs: There are specific molding machine setup requirements and configurations for each stage in the injection molding process. For instance, you must perform some tooling setup when creating the molds, which takes time due to the required technical expertise and accuracy.
• Repair Costs: Plastic injection molding is a mechanical technique requiring various equipment types. Injection mold components are more likely to break down or wear. Hence, you may incur expenses for repairing and maintaining procedures.
• Operator Costs: Even though injection molding machines are automated, you need an operator to monitor the process. As a result, the operator costs are a crucial factor to consider in labor costs.

Different production volumes are also an essential factor in the cost of injection molding. Moreover, the production volume influences the amount of raw material used in injection molding, required machine sophistication, and injection mold properties such as durability, strength, and other properties. Here are the typical types of production volume injection molding:

Low-Volume Injection Molding Production

Low-volume plastic molding includes any production of parts between a hundred to a couple of thousand. Manufacturers often make the molds in-house and perform the molding themselves without necessarily using sophisticated machines. Hence, manufacturers produce molds of 3D-printed polymer resin or fast rapid tooling since it is affordable and doesn’t require a long production cycle.

The complete production run for low-volume molding usually takes precisely three days to create the finished parts. For instance, let’s assume the following parameters for a 100 – 200 part run:

• Number of parts: 100 – 1,000
• Cost of the mold: $100 – $1,000
• Cost of Raw Material per Part: $0.5
• Total Cost of Materials: $50 – $500
• Labor Cost per Part: $3 – $30
• Total Labor Cost: $300 -$3,000
• Total Cost of Injection Molded Process: $450 – $4,500
• Cost per Part: $4.5

Mid-Volume Injection Molding Production

Mid-volume quantities in injection molding often range between five thousand to tens of thousands of molded parts. This production type requires mold made from pre-hardened steel or aluminum. You can outsource the mold production and molding procedures for this production scale.

However, let’s assume the following injection molding cost calculation for a 5,000 – 10,000 unit volume. These are the same parts made using thermoplastic materials such as polypropylene.

• Number of parts: 5,000 – 10,000
• Cost of the mold: $2,500 – $5,000
• Cost of Raw Material per Part: $0.5
• Total Cost of Materials: $2,500 – $5,000
• Labor Cost per Part: $2
• Total Labor Cost: $10,000 – $20,000
• Total Cost of Injection Molded Process: $15,000 – $ 30,000
• Cost per Part: $3

High-Volume Injection Molding Production

High-volume injection mold production involves a few hundreds of thousands of molded parts. This procedure often requires steel molds due to their long life expectancy. Likewise, large-volume projects require a sophisticated machine, which adds to the injection molding cost. However, high-volume production offers higher cost distribution per part, ensuring lower cost per part.

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For instance, let’s assume we are molding 100,000 to 300,000 parts of the same type using ABS.

• Number of parts: 100,000 – 300,000
• Cost of the mold: $25,000 – $75,000
• Cost of Raw Material per Part: $ 0.5
• Total Cost of Materials: $50, 000 – $150,000
• Labor Cost per Part: $ 1
• Total Labor Cost: $100,000 – $300,000
• Total Cost of Injection Molded Process: $175,000 – $525,000
• Cost per Part: $1.75

However, it is evident that the injection molding price per part reduces considerably for high-volume production. Hence, high-volume projects offer the best cost advantage for injection molding costs.

As we mentioned above, the simplest trick to reduce the price per piece is by increasing the parts quantity since the upfront costs while machining and designing the mold can be used over more parts. In addition to that, you can also try the following several ways to reduce injection molding costs and help you get the best results for your project.

Utilizing DfM Analysis

DFM (Design for Manufacturing) in injection molding involves creating a part within a client’s stipulated budget and fulfilling the intended purpose. Analysts often consider different factors for DfM based on technology, art, and science to determine the most efficient design. Hence, it significantly reduces the costs of injection molding.

Simplifying Design Features

It may be compulsory to use complex molds and additional steps during plastic injection molding due to the complex features of your products. Therefore, removing unnecessary features would be best to lower the injection molding price. At the same time, you can save more money by removing any features that only add cosmetic finishes.

Universal Molds instead of Custom Molds

If you do not require a custom mold, consider using the universal mold. These molds are often less expensive than custom molds and can still produce high-quality parts.

Also, If you need a custom mold, always consider having a CAD model in place prior to commencing the manufacturing process. It will help optimize designs and identify potential problems such as steep draft angles, unnecessary wall thicknesses, complex shapes, etc.

Choose the Right Injection Molding Material

The cost of the preferred material for your parts often influences the overall injection molding cost. Where possible, use lower-cost materials such as ABS or polypropylene. It helps to keep a minimal production cost.

Try Insert Molds

Insert injection molding and overmolding are effective technologies that save costs in the long run. For instance, insert molding prevents the need to make threads on the plastic to fasten it to metal parts, thereby making the process economical.

Minimize the Number of Cavities in Mold

The more cavities there are in a mold, the higher the cost will be. Therefore, it is important to minimize the number of cavities in your mold whenever possible.

One way to reduce the number of cavities is to use a moldflow analysis to optimize the design of your part. Moldflow analysis can help you to identify areas where cavities can be eliminated without compromising the function or aesthetics of the part.

Self-Mating Parts

Making self-mating parts is one of the most reliable ways of saving injection molding costs and simplifying design. These parts are those that attach to themselves when turned 180 degrees. These parts are ideal because you can use a single half mold to make the whole part. It reduces mold cost, and the injection mold size is half.

Injection molding is, in many ways, one of the most cost-effective manufacturing processes available — that fact is one of several reasons why it’s so commonly used. Among those other reasons: versatility, relative speed, and access and availability. In this piece, however, we’re going to focus on that cost-efficiency aspect, and how to maximize it by lowering your production costs in targeted areas. The value of injection molding lies in its ability to produce a broad range of part types and designs, at scale, with a relatively fast turnaround time. We’ll look through the lens of that value to help locate areas for even greater efficiency and lower costs.

When assessing areas where you might want to reduce your injection molding costs, there are two big-picture areas to consider: what you can do as a product developer or designer, and what the manufacturer can do as your production partner. While injection molding may seem like a cut-and-dry process with little wiggle room, the opposite is true.

Injection molding, is to be sure, a rigorous process with a number of defined best practices. Though its versatility means that by nature, there are innumerable areas that can be tested and fine-tuned, on both sides: designer and manufacturer. Let’s take a look at a few areas for each.

What Can You Do As a Product Designer?

From small, one-person concepts to larger product development firms, the role of product design is, obviously, all-important in the final product — and has its share of bumps and snags. Difficulties and inefficiencies are not limited to those just starting — even entrenched design teams with longstanding processes are able to locate areas where overall efficiency can be improved. These include:

Design for manufacture: This concept has several names — one you’ll see most commonly is “manufacturability.” What it means, in a nutshell, is taking the practicalities of the manufacturing process into account when settling on a final product design. Note the use of the word “final” here — manufacturability is by no means meant to impede early brainstorming or concepting processes, which often work better with fewer limits placed on them. At some point, however, between the brainstorming process and the delivery of a design to the manufacturer, it’s helpful to take manufacturability into account.

From a cost-savings standpoint, you’ll see several benefits:

• • Fewer additional prototype iterations
• • Less input from the prototyper or manufacturer — more consultation time may mean increased costs
• • A product design that’s easier to implement, with fewer potential production modifications or workarounds
• • Design optimization with the luxury of time, rather than against potential production deadlines (when all potential optimizations may not be explored)
• • You’ll also see a finished product that’s closer to what you designed, which, while not necessarily a direct cost-saver, is a knock-on benefit

Familiarity with production processes: Similar, but not quite identical, to the above point — as a product designer, the more you know about available manufacturing processes, the better off you’ll be working with prototypers and production facilities. Even a baseline knowledge of concepts — such as optimal production runs for different processes, 3D printing and when it can be useful, the existence of different types of injection molding materials, and more — can help you ask the right questions to get the best price possible.

Research potential manufacturing partners: No two injection molding facilities are identical, no matter how much of a commodity it may seem that you’re producing. Price is, clearly, always an important factor in manufacturing, but it shouldn’t necessarily be the final word when sourcing a manufacturer. Try and find companies that, for example, have worked with similar industries and products to yours; that may focus more on production runs more suitable to you (whether 20,000 pieces, or 2 million); or have more experience involving potential cost-saving processes like 3D printing.

What Can a Manufacturing Partner Do to Lower Costs?

On the manufacturing side, there are several ways to offer lower costs to customers without cutting into your bottom line. As a manufacturer, these are worth looking into, and as a customer, they’re always worth exploring.

Make the most of available processes: Injection molding, and design for injection molding, shouldn’t live in an injection molding silo. Processes like 3D printing can lower costs and speed production everywhere from prototyping to mold creation, and can even be a viable solution for injection molded part components via over molding. Don’t ignore the widespread availability and ongoing advances in these areas.

Be a material expert: Understanding the properties and ideal applications of the full range of common materials used in injection molding can not only differentiate you in regards to customer service, it can also help optimize your molding processes — resulting in fewer part defects or rejects and thus higher margins for you. Developing a deep understanding of factors such as viscosity, flow rate, melt temperature and the molecular makeups of types of resins can pay dividends over time.

Take advantage of best practices: In the context of this conversation, communicate them to your customers. Many injection molding best practices are designed to optimize the process and reduce defects and errors: round corners, wall thickness parameters, draft and so on. These are cost-savers through the efficiency they introduce into the process. Other best practices, however, can have a more direct impact on production and material costs, such as using ribs in part design rather than solid walls wherever possible. Not only does this type of best practice reduce production time, it lowers the amount of raw material used overall in a production run, thus reducing material cost.

Keep machinery updated: Just like fuel efficiency in automobiles, energy efficiency with production machinery is continually improving. While it may not be feasible to purchase new machinery every few years, it’s a worthy idea to keep in mind as, at scale, increased energy efficiency can materially lower your overhead costs. If a new machine isn’t on the table right now, look at updating or retrofitting components, or even overhauling your maintenance routine and schedule. Any of these can help you get more out of what you already have.

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