Understand Injection Molding Cost and How to Estimate It

Injection molding is an ideal process for economically and efficiently mass-producing plastic parts. If you are planning to launch a new plastic injection molding project, understanding the cost structure of injection molding and how to accurately estimate costs becomes crucial. This not only helps ensure the economic viability of the project but also allows you to establish a reasonable market pricing for your product.

This article will delve into the cost components of injection molding and analyze the key factors influencing these costs. By understanding these factors, you will be able to more accurately estimate the costs of your injection molding project and develop a sensible pricing strategy for your product.

Injection molding cost: Overview

Injection molding is also divided into metal injection molding and plastic injection molding, in the manufacturing process of plastic products, it efficiently produces plastic products with complex shapes and precise dimensions, but it also involves higher costs.

For example, when a company needs to produce phone cases using injection molding technology, they may choose PC (polycarbonate) plastic, which is known for its strength, durability, and impact resistance. However, the cost of PC materials is relatively high ($2.3 per pound), resulting in material costs accounting for a significant portion of the total cost. To reduce costs, we would suggest considering using ABS material instead of PC ($1.3 per pound). ABS is a high-strength, general-purpose engineering plastic.

The key factors constituting the cost of injection molding

The cost of injection molding involves multiple aspects, and to maintain competitiveness in the market, businesses need to have a thorough understanding of the cost components of injection molding and implement effective measures for cost control. Here are the key factors you need to pay attention to:

1.Cost of plastic parts

The cost of plastic parts is affected by a number of factors, of which size, design, production and volume are the most critical factors. Understanding how these factors affect injection molding costs helps us better optimize project costs.

Part size

The larger the plastic part to be made, the larger the mold to hold the plastic part, and larger mold designs are usually more expensive than making smaller molds of the same design. Among other things, they require more materials, finer processes, and longer manufacturing times

Part design

Part designs with complex geometries require more complex molds to produce. Mold design usually includes A side and B side. The A-side, also known as the decorative surface, is the surface that the user sees directly and is usually required to be smooth and beautiful. The B side contains the hidden structure used to support the parts, and is usually rougher in finish than the A side. For molds with complex A-side and B-side designs, their manufacturing costs are usually higher. In addition, if the part design includes bottom cut features, additional sliding side action and core may be required, which will also increase the cost of the mold.

Production capacity

When parts are produced using the injection molding process, the cost of the individual part is usually reduced when the volume of production is very large, because the fixed costs (such as mold manufacturing and the rental/purchase of the injection molding machine) are spread more widely. However, for small batch projects, the cost of individual parts can be high because economies of scale cannot be fully exploited.

Part volume

The volume of the part determines the amount of plastic required and the cooling time, which affects energy consumption and production time. Larger parts require more plastic and longer cooling times, which can lead to higher material costs and longer production cycles.

2.Mold tooling cost

The cost of molds depends on the complexity and size of the parts, which are two important factors. If the parts have complex geometric shapes or dense walls, it may be necessary to use more expensive special machines to manufacture molds, which can lead to an increase in mold costs. The specific breakdown of mold costs is as follows:

Material costs

The commonly used mold materials include steel, aluminum alloy, etc., and their prices are influenced by factors such as market supply and demand, production costs, etc. The price of steel is relatively high, but it has high hardness and wear resistance, making it suitable for manufacturing molds for long-term use. The price of aluminum alloy is relatively low, but its hardness is low and it is prone to wear and tear, making it suitable for manufacturing short-term or disposable molds.

Related resources: Aluminum vs. Steel Molds

Gating system

It can be divided into cold runner molds and hot runner molds. Cold runner molds may have injection residue in the runner, resulting in a certain amount of production waste. Hot runner is a method of heating to ensure that the plastic in the runner and gate remains in a molten state. After shutdown, it is generally not necessary to open the runner to remove the condensate. When restarting, only the runner needs to be heated to the desired temperature.

Mold structure

It can be divided into two plate molds and three plate molds. The two plate mold has a large water outlet, while the three plate mold has a small water outlet. Two plate mold opening is directly from the parting surface, and the product is ejected; Relatively speaking, the cost of mold manufacturing is low, but the cost of water outlet recycling is high. When the three board mold is opened, the product and the sprue will be separated, and each template will be separated by a certain distance. The adhesive part will fall from the distance between the two templates on the mold surface, while the cold sprue will fall from another space distance; Relatively speaking, the cost of mold manufacturing is high, but the product automatically separates and falls off, resulting in high efficiency.

Mold type

According to the shape and function of injection molds, mold types can be divided into the following:

• Single cavity mold:The mold cost of a single cavity mold is relatively low, but because only one part can be produced per cycle, production efficiency is low, which may lead to higher production costs. This is particularly evident when mass production is required.
• Multi cavity mold:A multi cavity mold has multiple cavities and can manufacture multiple parts simultaneously. The initial cost of multi cavity molds is usually higher due to the need for more steel and more complex designs. However, due to its high production efficiency, these costs can be quickly recovered. In long-term production, multi cavity molds can significantly reduce the cost of individual parts.

Related resources: Single-Cavity vs Multi Cavity Mold

Common methods and associated costs for creating molds

CNC Machining:

• Method: CNC machines are widely used for crafting molds from materials like aluminum and stainless steel. This process involves precision machining where material is removed using rotating cutting tools.
• Complexity and Cost: CNC machining can handle highly intricate mold designs but may require multiple tool changes, which can increase costs with complexity. Costs typically range based on the intricacy of the mold and the material used.

Electrical Discharge Machining (EDM):

• Method: EDM is preferred for creating complex mold shapes that are difficult to achieve with traditional machining methods. It uses electrical discharges between a tool electrode and the workpiece to shape the mold.
• Accuracy and Cost: EDM is known for high accuracy and does not usually require additional finishing. It is suitable for intricate mold details but tends to be more expensive than CNC machining due to specialized equipment and skill required.

3D Printing:

• Method: 3D printing, particularly using technologies like Stereolithography (SLA), offers a rapid and cost-effective solution for creating injection molds. It involves building layers of resin to form the mold directly from a digital model.
• Advantages: 3D printed molds are beneficial for rapid prototyping and low to mid-volume production. They are cost-effective, especially for designs that require iteration before committing to expensive tooling.
• Cost Range: Simple 3D printed molds can start as low as $100 for low-volume production. Aluminum molds for mid-volume runs typically range from $2,000 to $5,000. Complex molds for high-volume production may range from $5,000 to $100,000, depending on size and complexity.

4.Injection molding machine cost

Here are some common injection molding machine types and their impact on cost:

All-electric injection molding machine

This type of injection molding machine uses electricity instead of hydraulic oil and has the characteristics of high precision, high speed and high efficiency. All-electric injection molding machines are commonly used to produce high-quality, small and precision plastic parts. Although the initial purchase cost is high, its long-term operating costs are relatively low and it is more environmentally friendly.

Hydraulic injection molding machine

Hydraulic injection molding machines use hydraulic oil to drive injection and mold locking mechanisms, and are usually used to produce large, heavy or plastic parts with low precision requirements. The initial purchase cost of a hydraulic injection molding machine is low, but operating costs are high and there may be oil leakage and contamination issues. For example, the use of more expensive engineering plastics can increase manufacturing costs, while the use of less expensive ordinary plastic materials can reduce costs.

Vertical injection molding machine

The injection mechanism and the mold are fixed in the same vertical direction, which is suitable for the production of small, precise or complex plastic parts. Vertical injection molding machines usually have higher production efficiency and accuracy, but the initial purchase cost and operating costs are also higher. For example, large and heavy injection molding machines typically require a higher investment, but they are also more productive and can reduce the cost of individual parts.

Horizontal injection molding machine

The injection mechanism and mold of the horizontal injection molding machine are fixed in the horizontal and vertical directions respectively, which is suitable for the production of large, heavy or plastic parts with low precision requirements. In contrast, small injection molding machines may have a lower initial investment but a higher cost to produce individual parts.

5.Injection molding material cost

The amount of materials used in plastic injection molding directly affects production costs. Due to the different characteristics, applications, availability, and prices of injection molding raw materials, their costs also vary significantly.

Material	Type	Unique Features	Common Applications	Price per Pound (USD)
ABS	Thermoplastic	Durable, lightweight	Electronics, keyboards, phone hardware, LEGO blocks, drainage systems, kitchenware	1.30
Polyethylene	Thermoplastic	Flexible, impact-resistant, water-resistant, moisture-resistant, recyclable	Food packaging, baby bottles, toys	1.20
Polypropylene	Thermoplastic	Water-resistant, flexible	Tupperware, children’s pools, toys, tableware, car batteries	0.90
Polystyrene	Thermoplastic	Warpage-resistant, shrinkage-resistant, impact-resistant	CD/DVD cases, packaging applications, household appliances	1.00
Polycarbonate	Thermoplastic	Impact-resistant, optically transparent, susceptible to chemicals	Auto headlights, bulletproof glass, eyeglasses, greenhouses, DVDs, cell phones	2.30
PVC (Polyvinyl Chloride)	Thermoplastic	Excellent electrical insulation, corrosion-resistant, fire-resistant	Electrical cables, pipes, windows, doors, building materials, clothing, toys etc.	1.00
PMMA (Poly(methyl methacrylate)) (Lucite)	Thermoplastic	High transparency, weather-resistant, UV and chemical resistant	Windows, light fixtures, billboards, vehicle windshields, airplane windows etc.	2.50
PTFE (Polytetrafluoroethylene) (Teflon)	Thermoplastic	Excellent heat resistance, chemical resistance, low friction coefficient	Nonstick coating for cookware, gasket material, piping systems, lining of chemical reactors etc.	10.00
PA (Polyamide) (Nylon)	Thermoplastic	High strength, wear resistance, heat and chemical resistance	Auto parts, machinery parts, electronic components etc.	1.50
PI (Polyimide) (Kapton)	Thermoplastic	High heat resistance, electrical insulation, chemical resistance and radiation resistance	High temperature electrical insulation materials, aerospace materials etc.	5.00

6. Labor and service costs

While injection molding processes heavily rely on automation, labor costs remain significant and encompass various aspects of production:

• Setup/Configuration Costs: Setting up equipment involves configuring machinery according to CAD designs. This process ensures that molds are precisely crafted to meet specified dimensions and requirements. Skilled operators adjust parameters and settings to optimize production efficiency.
• Repair and Maintenance Costs: Maintenance tasks are crucial for keeping injection molding machines in optimal condition. This includes routine inspections, replacing worn-out parts, and addressing any mechanical issues promptly to minimize downtime. Skilled technicians perform these tasks to ensure continuous operation and longevity of equipment.
• Monitoring Costs: Despite automation handling many tasks, operators monitor the injection molding process closely. They oversee equipment performance, inspect finished parts for quality assurance, and make necessary adjustments to maintain product consistency and meet specifications.

In-house production includes these labor costs as part of operational expenses. When outsourcing injection molding, service costs include provider fees and markups. These cover specialized expertise, equipment use, and logistics, offering flexibility without the need for significant capital investment.

Balancing automation with skilled labor ensures precise and efficient injection molding processes, whether managed internally or outsourced. This approach optimizes production costs while maintaining high-quality standards across various manufacturing applications.

Comparing injection molding costs for different production volumes

Low-volume injection molding, medium volume, and high volume production are the three important stages in the injection molding process, each of which faces different challenges and cost factors. From the high cost of small batch production to the economies of scale of medium batch production, and then to the low cost and high efficiency of large batch production, enterprises need to respond flexibly and adopt effective strategies to reduce costs and improve production efficiency

Production scale	Number of parts	Mold cost	Material cost per part	Total material cost	Labor cost per part	Total labor cost	Total injection molding cost	Cost per part (USD)
Low-Volume Manufacturing	100	$100 USD	$0.50 USD	$50 USD	$3 USD	$300 USD	$450 USD	$4.50 USD
Medium Volume production	5,000	$2,500 USD	$0.50 USD	$2,500 USD	$2 USD	$10,000 USD	$15,000 USD	$3.00 USD
High Volume Production	100,000	$25,000 USD	$0.50 USD	$50,000 USD	$1 USD	$100,000 USD	$175,000 USD	$1.75 USD

Strategies to Reduce Injection Molding Costs

Reducing injection molding costs involves strategic planning and optimizing various aspects of the manufacturing process. Here are effective strategies to achieve cost savings while maintaining quality and efficiency:

• Utilize Design for Manufacturing (DfM) Analysis:Designing parts with DfM principles ensures they are optimized for manufacturing processes, minimizing complexities that can drive up costs. By considering factors like material selection, mold design, and production techniques early in the design phase, you can streamline manufacturing and reduce unnecessary expenses.
• Simplify Design Features:Complex features in product designs often necessitate intricate molds and additional processing steps, increasing production costs. Simplifying designs by eliminating unnecessary features or cosmetic finishes helps lower tooling and manufacturing costs without compromising functionality or aesthetics.
• Consider Universal Molds:When feasible, opt for universal molds instead of custom molds. Universal molds are generally less expensive and can still produce high-quality parts. For custom molds, ensure you have a detailed CAD model to optimize designs and identify potential issues upfront, such as steep draft angles or overly complex shapes.
• Choose Cost-Effective Materials:Material selection significantly impacts injection molding costs. Opt for lower-cost materials like ABS or polypropylene where possible, without compromising on part performance or quality. Conducting material cost analysis and considering alternative materials can help minimize overall production expenses.
• Implement Insert Molding and Overmolding:Insert molding and overmolding technologies offer cost-saving benefits by combining multiple parts into a single assembly. This eliminates the need for additional assembly steps and reduces material waste. For example, insert molding allows plastic parts to be directly molded over metal inserts, streamlining production and enhancing product durability.
• Minimize Number of Cavities in the Mold:Reducing the number of cavities in a mold helps lower tooling costs and material waste. Conduct moldflow analysis to optimize part design and cavity layout, identifying opportunities to consolidate cavities while maintaining part integrity. This approach ensures efficient use of mold space and reduces overall production costs.
• Utilize Self-Mating Parts:Designing self-mating parts simplifies mold complexity and reduces tooling costs. These parts feature components that align and connect without additional fasteners or complex assembly processes. By using a single half mold to produce the entire part, you minimize mold size and complexity, resulting in cost savings during injection molding.

Implementing these strategies requires collaboration between design engineers, manufacturers, and suppliers to achieve cost-effective solutions tailored to specific project requirements.

How to estimate the cost of injection molding?

The steps to estimate the cost of injection molding typically include the following:

• Determine material cost: Calculate the cost of the required plastic raw materials based on the type, density and weight of the plastic required. This takes into account the purchase price of raw materials, transportation costs, processing costs and other related expenses.
• Calculation of mold cost: According to the complexity of the mold, the size of the area, the thickness of the material and other factors, determine the design and manufacturing costs of the mold. Mold cost is an important part of injection molding cost, so sufficient attention should be paid to the estimation.
• Analyze production process costs: This includes equipment costs, labor costs, energy costs, overhead costs, etc. Equipment costs include the purchase or lease of injection molding machines, maintenance and maintenance costs, etc.; Labor costs include the wages and benefits of operating workers; Energy costs include the cost of electricity, water and other required resources; Indirect costs include production management, quality control, equipment depreciation and other costs.
• Calculation of other expenses: including the cost of packaging materials, transportation costs, taxes and other related expenses. These expenses may also have an impact on the total cost and should therefore be taken into account when estimating.

Injection molding cost calculator

The injection molding cost calculator can help you quickly estimate the cost of injection molding specific parts. By using an online injection molding cost estimator or consulting with an injection molding service provider, you can obtain benchmark prices and understand relevant cost factors.

The injection molding cost calculator usually provides the following options to help you calculate:

• Step 1: You can choose the desired part type, size, and material, and then calculate the required cost.
• Step 2: You can upload the 3D model to the calculator and obtain an estimated injection molding cost.
• Step 3: You can choose the required services and then calculate the cost.

In addition, injection molding service providers typically use a cost comparison table to provide potential customers with a rough estimate of the process. This comparison table can help you understand the impact of different factors on injection molding costs, such as material type, part size, quantity, mold type, etc.

Obtain high-quality injection molding services

Boyi Company provides a comprehensive injection molding service, from low-cost injection molding to mass production, to a variety of material options, to meet the needs of different customers. By choosing to work with Boyi, you have access to the professional services of a world-class team of engineers and the use of state-of-the-art equipment for manufacturing. This mode of cooperation ensures the high quality of parts and the efficiency of production.

For any injection molding project, no matter its complexity, Boyi Company is able to provide professional services. Whether it is a simple injection molding project or a project overmolding or insert molding, Boyi has the appropriate solutions and experience.

If you are looking for professional injection molding services, partnering with Boyi is a wise choice. Contact Boyi today to get the right injection molding quote for your project, so that your project can get the most professional support and help.

Conclusion

In summary, understanding injection molding costs and estimation methods is of great significance for controlling production costs, improving production efficiency, and product quality. Enterprises can choose appropriate estimation methods and tools based on actual situations to obtain accurate injection molding cost estimation results, and based on this, develop effective cost control measures.

FAQ

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Catalog: Injection Molding Guide