To find the estimate of costs in the injection molding process we have to consider several factors. These factors that influence the costs are tooling expenses, machine costs, material costs and overhead expenses
Various estimation tools are used based on your specific requirement to find the estimated cost of the injection molding process. To optimize your injection molding process for efficiency, accurate cost analysis and considering potential cost saving measures should be utilized.
Injection molding is widely recognized as a cost-effective method for mass-producing plastic parts due to several factors which include, high production efficiency, lower per-unit cost for large production runs, and automation potential. In this article, we will look at the cost drivers in detail and ways of reducing injection molding costs.
Injection Molding Machine (Image Source: Shutterstock)
Types of Costs in Injection Molding
There are various types of costs when it comes to injection. These costs include:
1. Equipment Costs
The equipment cost greatly contributes to the overall expenses in injection molding. Some of the equipment costs involved in injection molding are.
- Injection molding machine: For the injection molding process to be in operation the injection molding machine is the primary piece of equipment needed. These machines are designed in various sizes, configurations, and models. The price of an injection molding machine is influenced by the injection capacity, automation features, and energy efficiency.
- Auxiliary equipment: during the injection molding process auxiliary equipment is needed to support the operation. The equipment are crucial in ensuring an effective and efficient production process. Some of these equipment include granulators, shredders and material handling equipment.
- Quality control equipment: To ensure part quality and consistency inspection and testing equipment are important during production. They ensure quality standards of parts are maintained.
Mold Costs (Tooling Costs)
Another cost that significantly impacts the overall cost of production is the mold costs. Below are several factors that influence the cost of molds.
- Mold design complexity: The dimensional complexity of the part design affects mold cost. Parts with complex intricate features need more elaborate molds which increases the tooling expenses.
- Material selection: The choice of material to be used for the mold affects the upfront cost and the durability. Some mold material are more expensive to produce though they offer superior durability making them preferred for large volume production
- Production volume: The volume of production contributes greatly in estimating the economics of mold cost. The cost per part decreases with increase in production volume due to economies of scale.
Mold-Making Methods and Their Cost Estimation
Some of the commonly used mold making methods are, EDM, 3D printing and CNC machining. Let’s have a closer look at them.
1.CNC Machining
CNC (Computer Numerical Control) machining incorporates the use of computer aided mills in its operation to remove material from parts. This method has a higher upfront cost due to the need for specialized machinery and tooling.
2. EDM
Electrical discharge machining (EDM) is a method that uses electrical discharges to erode material from a workpiece. These machines are expensive to purchase and operate resulting in higher upfront costs compared to CNC machining
3. 3D Printing
3D printing also known as additive manufacturing builds part layer by layer from digital models. Industrial-grade 3D printers are relatively costly. Furthermore, material costs and post-processing equipment may add to the initial investment.
Injected Material Cost
These are the expenses incurred in purchasing the plastic material used in the injection molding process. Some of the common thermoplastics used in injection molding across various industries include.
- Polypropylene(PP): It is economical for high volume production due to its relatively low cost compared to other thermoplastics.
- Polyethylene (PE): It is abundant in supply and has a simple manufacturing process making it cost effective.
- Polystyrene (PS): It is highly durable and brittle
Factors Affecting Material Cost
Material Cost Per Unit Volume
Various thermoplastics have different costs per unit volume. This affects the general material expense.
Performance and Quality
Materials with superior mechanical properties, performance and durability are often more expensive. This minimizes maintenance and replacement costs.
Tooling and Processing Requirements
Some materials may require specialized tooling, processing conditions, or additives adding to production costs. Straightforward processing requirements may result in lower production costs.
Injection Molding Material (Image Source: Shutterstock)
By considering factors such as wall thickness, geometry, complexity, and gate design manufacturers can optimize material usage, minimize waste, and achieve cost-effective outcomes in injection molding.
Labor or Service Costs
Labor costs in injection molding involve a range of expenses associated with human resources including skilled labor and operation support. Skilled technicians are required for the task of setting up the injection molding machine. This involves installing the mold and configuring process parameters.
Skilled operators are needed to monitor injection molding operations to take note of machine performance and process parameters. Through continuous monitoring operation issues are identified rapidly and measures taken accordingly.
To keep injection molding machines in good condition regular preventive maintenance is essential. This includes cleaning,lubrication and inspection to prevent breakdowns. Component failure and unexpected breakdown may need repairs or replacement contributing to overall costs.
Automation
In the injection molding process automation is necessary to reduce operation costs. Automated injection molding machines can perform repetitive tasks without direct human intervention minimizing the need for manual labor.
Processing parameters such as temperature and pressure can be accurately tracked through automated monitoring systems. This ensures proactive measures are taken to optimize processes reducing labor costs associated with manual adjustments.
Automation lowers the overall production cost in the injection molding process through minimizing material waste, reducing labor costs and optimizing process efficiency.
Injection Molding Cost Overview
Injection molding is a highly efficient and cost effective manufacturing process for producing plastic parts. The cost per part is greatly influenced by the production volume. Here is how the production volume affects the cost per part
Tooling Costs
The cost of production per part is relatively high in low volume production as the upfront cost is spread across a small number of parts. This results in a higher cost per part. As production volume increases the cost of tooling per part decreases due to economies of scale.
Material Costs
Material cost per part may be higher in low-volume production due to less efficient use of materials and higher unit costs for smaller quantities of material. With higher production material costs per part decreases due to bulk purchasing discounts and improved material utilization. Economies of scale help manufacturers negotiate for lower prices.
Labor Costs
Labor costs per part tend to be higher in low-volume production as fixed labor expenses are spread across a smaller number of parts. In high-volume production labor cost per part reduces as production efficiency improves and fixed labor expenses are spread across a larger number of parts. Optimization and automation of production processes further reduce labor costs per part.
Variables that Impact the Injection Mold Cost
Several key factors influence the mold costs in injection molding. Manufacturers must carefully consider:
Part Design
The size of the mold is important. Higher material cost and machining time is needed in production of large parts which require larger molds to accommodate their size. More material is required leading to additional material cost. Moreover shipping large parts may require additional transport cost
Design Complexity
Parts with complex geometries and features require more complex molds with intricate core and cavity configurations increasing mold production costs. Complex molds may need high-precision machining which adds to the labor and machining cost.
Production Volume
Higher production volume may need more durable molds which have higher upfront costs but offer longer lifespans and lower per part cost over time. With increasing production volume the cost per part decreases.
Tips for Optimizing Design
- Design simplified part geometry.
- Optimize wall thickness by maintaining uniform wall thickness throughout the part.
- Consider moldability early in the design process avoiding features that require complex tooling.
- Optimize the use of draft angles into part geometry to improve mold longevity.
- Design efficient runner systems and gate locations to minimize material waste and improve part quality.
Injection Molding Cost Calculators
Estimating the cost associated with injection molding projects is essential for budgeting and decision-making. Several tools and resources can be used to achieve injection molding cost estimations/calculations.
Custom Part
This is an online resource for manufacturing cost estimation. The tool is simple to use making users able to rapidly create a new cost estimate from the indepth manufacturing content it possesses. The interactive tool has features like process selection, material selection and manufacturing widget that enable quick manufacturing cost calculations .
ICOMold
This is an online injection molding service provider that offers a wide range of tools and resources for estimating injection molding costs. The system has a quoting system that enables users to estimate costs. Users upload their part design, specify material requirements and other desired details. The quoting system enhances the efficient process of acquiring cost estimates for injection molding projects.
3D Hubs
3D CAD models are uploaded into 3D hubs which provide an instant quoting system that allows users to receive instant cost estimate quotes. Users can specify their quantity, material and lead time requirement to get accurate cost estimates. To cross verify cost projections in injection molding it is important to use multiple cost estimators.
Reducing Injection Molding Costs
To reduce injection molding costs manufacturers can adopt the following practices in their operations. These strategies include:
Design Optimization
Design parts with simple, uniform geometries to minimize mold complexity and machining requirements. This reduces the tooling costs. Maintain uniform wall thickness throughout the part to promote even filling and cooling reducing material usage. Avoid thick sections that increase material costs.
Material Selection
Choose materials that meet performance requirements while offering cost-effective options. Optimize material usage. Select materials with desired properties to maximize material utilization and minimize waste.
Efficient Production Practices
Optimize production volumes to take advantage of economies of scale and lower per-part costs. By implementing optimization techniques, you can minimize cycle times and increase throughput.
Invest in automation to increase productivity and reduce labor costs. Through leveraging technology and expertise manufacturers can achieve cost savings in injection molding operations without compromising quality.
Injection Molding Cost Calculation (Image Source: Boyan)
Conclusion
Accurate estimation of injection molding costs needs careful consideration. You need to understand part complexity and material requirements are essential in cost estimation. Simplifying design, production volume and selecting cost effective materials have a great impact on the overall cost.
Cost calculators in the injection molding process provide valuable insight and ensure accurate cost estimation. To optimize part manufacturing and cost efficiency manufacturers can adopt design for manufacturing principles. Through embracing a holistic approach to cost estimation manufacturers can track the costs throughout the product life cycle.
Manufacturers can make informed decisions and optimize overall costs through considering factors such as upfront tooling costs, operating expenses and potential saving. Through seeking opportunities for improving these factors manufacturers can achieve cost effectiveness and enhance profitability.
