How To Reduce Cost With Injection Molds for Mass Production

Injection molding is a key process in mass production, known for its ability to efficiently produce large quantities of parts with consistent quality. However, the cost associated with this process can significantly impact the overall profitability of a manufacturing operation. 

You will get efficient and thoughtful service from WIT MOLD.

Reducing these costs without compromising product quality is a critical challenge faced by manufacturers. In this blog, we’ll explore effective strategies for minimizing expenses in injection molding, covering aspects from design optimization to material selection and process efficiency. 

Understanding and implementing these strategies can lead to significant savings and improved competitiveness in the market.

What is Injection Molding?

Injection molding is a manufacturing process widely used for producing parts in large volumes. It involves melting plastic material and injecting it into a mold cavity, where it cools and solidifies into the final part’s shape. This process is highly automated, making it ideal for mass production due to its ability to produce parts rapidly and with high consistency.

The benefits of using injection molds in mass production are significant. Firstly, it allows for the production of complex and intricate parts with a high degree of precision. Secondly, once the initial costs of the molds are covered, the cost per unit during manufacturing is relatively low, especially when producing parts in large quantities. This efficiency in scale makes injection molding a preferred method for mass production.

However, several common cost factors need to be considered in injection molding. These include the cost of designing and creating the molds, which can be substantial, especially for complex parts. Material costs also play a significant role, as the choice of plastic and its properties can impact both the performance and cost of the final product. Additionally, energy consumption during the molding process and the maintenance costs for the machinery and molds are ongoing expenses that can influence the overall cost-effectiveness of the process. Understanding these cost factors is crucial for manufacturers looking to optimize their injection molding operations for cost-efficiency.

Design Optimization

The design of the parts being manufactured plays a pivotal role in cost reduction in injection molding. Effective design optimization can lead to significant savings, both in the production process and in the use of materials.

One key strategy for simplifying designs to reduce costs is to minimize the part’s complexity without compromising its functionality. This can involve reducing the number of separate components, integrating functions into fewer parts, or redesigning the geometry of the part to require less material while maintaining structural integrity. Simplified designs often result in shorter cycle times and lower material usage, directly impacting production costs.

Wall thickness is another critical aspect of design optimization. Consistent wall thickness helps in even cooling and reduces the risk of defects, thereby minimizing waste and rework. Additionally, designers can consider incorporating features like ribs or gussets to provide strength without the need for excessive material usage.

Several case studies highlight the impact of effective design optimization in injection molding. For instance, a consumer electronics manufacturer was able to reduce their production costs by 15% through the redesign of a plastic housing for one of their products. The redesign involved integrating multiple components into a single molded part and optimizing the wall thickness for material efficiency. Another example is an automotive parts supplier who achieved a 20% reduction in material costs by redesigning a series of components for more efficient molding, eliminating undercuts and simplifying the ejection from the mold.

These examples underscore the importance of thoughtful part design in not only enhancing the manufacturability of the parts but also in driving down the overall production costs in injection molding.

Material Selection

Selecting the right material for injection molding is crucial for both the quality of the final product and the cost-effectiveness of the production process. Various materials are used in injection molding, including thermoplastics like polyethylene (PE), polypropylene (PP), polycarbonate (PC), and more specialized plastics like polyether ether ketone (PEEK). Each material has its unique properties, cost implications, and suitability for different applications.

Cost comparison among these materials can vary significantly. For instance, standard plastics like PE and PP are generally less expensive and are suitable for a wide range of applications. In contrast, engineering plastics like PC or acrylonitrile butadiene styrene (ABS) offer higher strength and temperature resistance but at a higher cost. Specialty plastics like PEEK provide exceptional properties, such as high-temperature resistance and strength, but are much more expensive and typically reserved for highly specialized applications.

When selecting materials, manufacturers should consider factors such as the mechanical properties required for the part, the environmental conditions it will be exposed to, and the cost implications. Balancing these factors is key to selecting cost-effective materials without compromising the quality and functionality of the final product. For example, using a more expensive material that increases the part’s durability might be more cost-effective in the long run due to reduced failure rates and warranty claims.

Efficient Use of Molds

Maximizing the longevity of injection molds is essential for cost efficiency in mass production. The lifespan of a mold can be significantly extended through proper design, maintenance, and usage techniques.

One key technique for increasing the longevity of molds is ensuring optimal design and material choice for the mold itself. This includes selecting the right steel type for the mold, considering the expected production volume and the plastic material to be molded. Hardened steels, for example, are more expensive but can withstand higher production volumes without significant wear.

Regular maintenance is crucial to prevent wear and tear of the molds. This includes routine checks, cleaning after each production run, and repairing any minor damages or wear before they become major issues. Proper lubrication and storage of molds also play a significant role in extending their life.

Balancing the number of cavities in a mold is another important consideration. While more cavities can increase production speed and efficiency, they also require a larger initial investment and can lead to faster wear if not properly maintained. The decision on the number of cavities should be based on the expected production volume, the complexity of the part, and the capabilities of the injection molding machine being used.

By implementing these strategies, manufacturers can not only extend the life of their molds but also optimize their production process for greater cost efficiency and reliability.

Automation in Injection Molding

The incorporation of automation in injection molding has become a significant factor in reducing labor costs and increasing overall efficiency. Automation in this context refers to the use of robotics and computer-controlled systems to handle various stages of the injection molding process.

Examples of Automation in the Injection Molding Process:

• Robotic Arm Manipulators: These are used for tasks like loading plastic pellets into the injection molding machine, removing finished parts from the mold, and placing them on conveyor belts or in storage containers.
• Automated Quality Control Systems: Employing machine vision and other sensing technologies to inspect the quality of the manufactured parts, reducing the need for manual inspection.
• Automated Material Handling Systems: These systems transport materials efficiently throughout the production facility, from storage to the molding machines.
• Closed-Loop Control Systems: These systems continuously monitor and adjust the injection molding parameters like temperature, pressure, and cycle time, ensuring consistent part quality.
• Automated Mold Changeover Systems: Designed to quickly and efficiently change molds between production runs, reducing downtime.
• Automated Packaging and Labeling Systems: These systems package the finished products and apply labels, readying them for shipment.

Investment vs. Long-Term Savings of Automation:

Investment Considerations Long-Term Savings Initial cost of purchasing and installing robotic systems and software. Reduction in labor costs due to automation of repetitive tasks. Training costs for staff to operate and maintain new automated systems. Consistent product quality leading to lower rejection rates and less waste. Potential downtime during the transition to automated systems. Increased production speed and efficiency, leading to higher output. Regular maintenance and potential upgrades for automated equipment. Savings in energy costs through optimized operation and reduced human error. Cost of integrating automation with existing systems. Improved workplace safety, potentially leading to lower insurance costs.

Energy Efficiency

Energy efficiency is a critical aspect in reducing operational costs in injection molding. The process is energy-intensive, involving the melting of plastic materials and the operation of hydraulic and mechanical systems. By implementing energy-saving practices, manufacturers can significantly reduce their energy consumption, leading to substantial cost savings.

Energy-Saving Practices in Injection Molding:

• Using Energy-Efficient Machines: Modern injection molding machines are designed with energy efficiency in mind. They often include features like variable speed drives and servo-motor systems that consume less energy.
• Optimizing Process Parameters: Fine-tuning parameters such as temperature settings, injection speed, and cooling times can lead to more efficient use of energy.
• Recovering and Reusing Heat: Implementing heat recovery systems to use the excess heat generated during the process for heating in other areas of the facility.
• Regular Maintenance: Keeping equipment well-maintained ensures that it operates at peak efficiency, thereby reducing unnecessary energy consumption.
• Smart Scheduling: Scheduling production runs to maximize machine utilization and minimize idle time can significantly reduce energy waste.

Supplier Negotiation and Bulk Purchasing

Effective management of supplier relationships and strategic purchasing decisions can play a significant role in reducing material costs in injection molding.

Leveraging Supplier Relationships to Reduce Material Costs:

• Establishing long-term relationships with suppliers can lead to more favorable pricing and terms.
• Working closely with suppliers can also lead to joint efforts in finding cost-saving solutions, such as the development of more efficient materials or the identification of logistical efficiencies.

Benefits of Bulk Purchasing:

• Buying materials in bulk often results in lower per-unit costs.
• Bulk purchasing can also reduce shipping and handling costs and minimize the administrative burden of frequent ordering.

Strategies for Effective Negotiation with Suppliers:

• Market Research: Understanding market prices and trends enables more informed negotiations.
• Volume Commitments: Offering to purchase larger volumes can be a strong bargaining chip for better pricing.
• Multiple Supplier Strategy: Engaging with multiple suppliers can provide leverage in negotiations and ensures a backup in case of supply disruptions.
• Value Beyond Price: Negotiations can also focus on value-added services like just-in-time delivery, quality assurance, and flexible payment terms.

Through thoughtful energy management and strategic supplier negotiations, manufacturers can substantially reduce their operational costs, enhancing their competitiveness and profitability in the injection molding industry.

Quality Control and Waste Reduction

Quality control is essential in injection molding, as it directly impacts the amount of waste and rework necessary. Effective quality control measures ensure that products meet specifications and standards from the outset, reducing the likelihood of defects and the need for reprocessing or discarding products. Techniques for quality control in injection molding include real-time monitoring of production parameters, regular inspection of molds and machinery, and rigorous testing of finished products for consistency and durability. Implementing these measures not only maintains product integrity but also reduces material waste and operational costs.

Waste reduction is another critical area. Strategies include recycling scrap material, optimizing runner and gating systems to minimize excess plastic usage, and employing software for precise material usage predictions. These efforts not only contribute to cost savings but also enhance environmental sustainability.

Innovations in Injection Molding

The field of injection molding is continually evolving with new technological advancements. Innovations such as 3D printing for rapid prototyping and the development of smart molds equipped with sensors for real-time data analysis are revolutionizing the industry. These advancements lead to cost savings through reduced development times, improved product quality, and enhanced process efficiency.

Looking towards the future, trends in injection molding include increased automation, the integration of artificial intelligence for predictive maintenance and process optimization, and the continued focus on sustainable materials and practices. These developments promise to further enhance the efficiency, cost-effectiveness, and environmental footprint of injection molding operations.

Conclusion

In summary, reducing costs in injection molding involves a multifaceted approach. Key strategies include optimizing part design for material and production efficiency, selecting cost-effective materials, ensuring efficient use of molds through maintenance and optimal design, embracing automation to reduce labor costs, focusing on energy efficiency, and managing supplier relationships for better material pricing. Quality control and waste reduction further contribute to cost savings by minimizing rework and material waste.

Manufacturers are encouraged to implement these strategies in their processes. Embracing these changes not only leads to immediate cost benefits but also positions companies for long-term success through continuous improvement. The field of injection molding is evolving rapidly, and staying abreast of new technologies and practices is essential for maintaining competitiveness in an increasingly cost-conscious industry.

Introduction:Injection molding costs are a big deal for plastic product manufacturers who use plastic injection molding . This article gets into the nitty-gritty of plastic injection molding costs , explaining all the different things that affect how much it costs.

Is Injection Molding an Expensive Process?

Is injection molding expensive? It’s not a simple answer. While it’s been proven to be cost-effective for mass production of plastic parts, the machines are expensive, so the initial setup costs can be high.

However, as you scale up production, the overall manufacturing costs go down. So, injection molding is widely considered a cost-effective solution for mass production of plastic parts because the price per part goes down as the volumes go up.

So, the more you make, the cheaper it gets.

What are the Key Factors That Influence the Injection Molding Cost?

There are a bunch of things that can make your costs go up or down, and knowing what they are is key to making the money part of your project work out right.

Part Cost

Part Size

Bigger injection molded parts need more stuff, which costs more money. They also need bigger machines that use more energy and take longer to make stuff, which makes it harder to make stuff.

As parts get bigger, it’s harder to make them perfect, so you have to use fancier, more expensive ways to make them. Plus, bigger parts make more trash, especially in runner systems that produce excess material, further increasing plastic injection molding cost.

Part Complexity

Complex designs often require complex molds with finer details, which increases the initial mold expenses. They may also require advanced machinery and tighter tolerances, which leads to higher operating costs and longer production times.

Complex plastic molded parts often result in increased cycle times due to additional cooling and setup requirements, which reduces overall manufacturing efficiency. In addition, the potential for defects increases with complexity, which leads to higher waste and rework rates.

Part Design for Manufacturability

Good parts save money. They use less material, make molds easier to build, and run faster cycles. They do this by having the right wall thickness, being consistent, and not having undercuts.

Bad parts make molds harder to build, run slower cycles, and make more scrap. They do this by having complex shapes and not being designed for manufacturing.

Tooling Costs

The injection mold cost made during the injection molding process depends on the process used to make the mold, the materials used, the complexity of the mold, and the size of the mold cavity.

Choice of Mold Manufacturing Process:

3D Printing: Good for prototyping and complex designs, but may not be strong enough for mass production.

CNC Machining: It’s precise and versatile, but it can take a while and cost more.

Electrical Discharge Machining: It’s good for tiny details, but it might not work as well if the material is hard or complicated.

Mold Complexity

More complex molds, with intricate features, undercuts, or complex geometries, typically have higher mold costs because they’re harder to make. They need special tools and take longer to produce, which means you have to spend more money upfront.

On the other hand, if you have a simpler mold design with fewer complex features, you can reduce the mold cost, making it a more cost-effective option, especially if you don’t need those complex features.

It’s all about balancing your design requirements with your cost considerations to optimize your injection molding costs.

Mold Cavity Size

Bigger molds need to be stronger, which means they cost more. But they can hold more material and make more parts at once.

On the flip side, smaller mold cavities are usually cheaper because they use less material and have a simpler mold design.

You should choose the size of the mold cavity based on your production needs. Getting the right balance between cavity size and part size can help you save on material and mold costs.

Want more information on automotive injection molding? Feel free to contact us.

Choice of Mold Material

The mold material you choose will affect how much you spend upfront and how well your manufacturing process works.

Different mold materials cost different amounts and last for different lengths of time. Aluminum and 3D printed molds are cheaper and work well if you’re making a small number of things.

On the other hand, when you’re making a lot of parts, you need a mold that’s made out of something strong like steel. Steel molds cost more up front, but they last longer and make each part cheaper.

So, picking the right mold material is a big decision. You have to balance the cost of making parts right now with the cost of making parts over time.

Here are the two most common mold material choices in the industry:

Steel: It’s tough and good for making a lot of parts, but it costs more to get started.

Aluminum: It’s light, doesn’t rust, and is cheaper, so it’s good for some things.

Material Costs

When you choose a specific material, like high-performance plastics, it usually costs more. But if you optimize your design and manufacturing process to reduce material waste, you can save a lot of money overall.

And while using recycled materials might cost a little more up front, it’s a step toward sustainability that could pay off in the long run.

Production Volume

Production volume has a big impact on injection molding. It affects how much raw material you need, how fancy your injection molding machine needs to be, and how strong/durable/whatever your injection mold needs to be. There are three big categories of production volume:

Low-Volume Production

This category needs simple molds, usually made of cheap materials like aluminum or 3D printing materials. It also needs less raw materials and less fancy machines, which means lower overall injection molding costs. But the cost per part is usually higher in low-volume production situations.

Medium- and High-Volume Production

You’ll need a tough steel injection mold because it lasts a long time, can handle multiple materials, and, if possible, a fancy machine. This will make injection molding more expensive.

But the high cost is spread out over the parts, so the manufacturing cost per part goes down. It’s important to note that the cost per part is higher in high-volume production than in medium-volume production. So their manufacturing cost per part is lower.

Equipment Expenses

The machines used in the molding process are special. The cost of a machine depends on how big it is and how complicated it is (usually how much of the work it does by itself), and ranges from $10,000 (small) or less for small-volume injection molding to $200,000 (large) for large-volume injection molding.

Medium-sized molding machines ($50,000 or more) can also be customized for medium-volume molding. Also, you need to think about the different kinds of injection molding machines and how they affect cost:

Hydraulic Injection Molding Machines

Hydraulic molding machines use hydraulic pumps to control the machine during the molding process. They have high durability, consistent injection and ejection, and affordable initial purchase costs. However, they consume too much energy and are not precise.

Electric Injection Molding Machines

Electric injection molding machines use electric servo motors to control the machine during the molding process.

They consume less energy, are accurate, have low operating and maintenance costs, and are easy to use. However, they require a high initial investment cost and require routine maintenance.

Hybrid Injection Molding Machines

Hybrid injection molding machines are a combination of these two types of machines. They are characterized by energy saving, high precision, and repeatability.

However, they require a lot of maintenance procedures due to the use of hydraulic pumps and electric motors, and the initial investment cost is very high.

Instead of buying the machines, businesses outsource the project to injection molding service providers. So they no longer have to bear the high cost of purchasing the machines, but instead need to bear the service costs of the service provider.

Labor Costs

Labor costs include a few costs related to human operators:

Setup costs include the cost of configuring and setting up the injection molding machine. It takes a lot of time due to the accuracy and technical expertise required for such processes.

Repair costs include replacing faulty parts, tools, and multiple components during the molding process.

Even though injection molding machines are automated most of the time, operator costs are important.

Surface Finishing

Surface finishing includes processes like annealing, sandblasting, powder coating, etc., where the parts are made to look better or work better. They are not part of the injection molding process itself.

However, many service providers will give you a discount if you use them for injection molding and surface finishing.

There are also extra services, which can be manufacturing processes like machining and drilling, assembly services like sonic welding, and decoration like pad printing, which make the cost of injection molding go up.

Note: Not all parts require surface finishing or other secondary operations. So, make sure you need those services to improve overall production efficiency and reduce material waste.

Part Packaging

The cost of packaging depends on whether it’s consumer packaging (i.e., something you recognize and throw away) or more expensive shipping packaging. Consumer packaging is good for products that are ready to use.

But bigger manufacturers can use automated packaging, which can reduce damage and mistakes.

Part Inspection Requirements

There are two types of part inspection costs: standard and specialized. Standard inspection is an internal process where trained personnel check for part defects (cosmetic defects or critical defects) and the quality verification team determines the possible causes.

Specialized inspection involves inviting professional engineers to inspect the product. Therefore, specialized certification costs more, and sometimes injection service providers charge a fee to provide certification.

What are the Best Practices to Reduce Injection Molding Costs?

There are a few things you can do to save money on plastic injection molds cost without sacrificing quality. By doing these things, you can make your production more cost-effective and efficient.

Simplified Mold Design

Simplified mold design helps shorten the cycle time of the molding process, improve production efficiency, and low cost injection molding . They also minimize material waste by reducing rejection rates and scrap.

Additionally, simpler molds are easier to maintain, which extends their life and reduces the frequency and cost of repairs and replacements.

To make mold design simpler, you need to get rid of stuff you don’t need, make the part shape better, and think about using parts that are already made. You can use computer tools to find and get rid of stuff you don’t need, so you can make a mold that works good and doesn’t make bad parts.

Reducing Unnecessary Part Features

This approach simplifies injection mold tooling design, which reduces manufacturing costs, as complex molds are more expensive to make. Also, reduced part complexity means reduced material usage, which directly saves costs.

Also, simpler designs can reduce molding cycles, increase productivity, and reduce labor and energy costs.

This also means less maintenance for the mold. Importantly, such simplified designs often produce parts with greater structural integrity and consistent quality, which means fewer defects.

To effectively cut the fat, you need to do a deep dive into your design, focusing on optimizing part geometry for functionality and manufacturability.

This might mean rethinking the need for certain aesthetic elements, combining multiple components into a more efficient design, or tweaking part dimensions to get rid of redundant or non-critical features.

The goal is to strike the right balance between what a part needs to do and what it costs to make.

Optimize Material Selection

While high-performance plastics may have specific advantages, they are often more expensive. Analyzing the functional requirements of a part and selecting cost-effective materials that meet those needs can result in significant cost savings without compromising quality.

Eliminate Cosmetic Appearance

In some applications, how a part looks doesn’t matter. Skipping fancy details can make parts faster and easier to make, which can save money. This is especially true for parts that don’t have to look good.

Reuse Molds

Getting the most out of a mold is a smart way to save money in injection molding. By using a mold for multiple production runs, you can spread the cost of the mold over a larger number of parts, which lowers the cost per part.

If you take good care of your mold and do regular maintenance, you can make it last longer, which saves you money in the long run.

Choose Insert Molding

Insert molding is when you put a pre-molded part, or insert, into the mold before you inject. This lets you put multiple parts into one mold, so you don’t have to do extra steps to put them together.

When you do it all in one step, you run the machine for less time and you don’t have to do as many repeats and cycles.

Plus, you don’t have to put different parts together that were designed separately, which saves time. By putting all the steps together, insert molding saves time and money.

Conclusion

Knowing the cost of plastic injection molding process is crucial for optimizing your manufacturing process. By understanding the various factors and components, you can make informed decisions.

For more information, please visit custom plastic molding.