What is custom injection molding?

Table of contents: 

1. Introduction
2. What is custom injection molding?
3. What are the benefits of custom injection molding?
4. What are the challenges of custom injection molding?
5. How do I order custom injection-molded parts?
6. How do I order custom injection-molded parts?
7. Conclusion

1. Introduction

Custom Injection Molding: Everything You Need to Know
Have you ever wondered how plastic products are manufactured? How do they get their shape, color, and texture? How can they be customized to fit your specific needs and preferences? The answer is custom injection molding, one of the most widely used manufacturing processes in the world.

Custom injection molding is a process that involves melting and injecting plastic resin into a mold, where it cools and solidifies into the desired shape. The mold can be designed to produce complex and intricate parts, such as gears, housings, connectors, and more. Custom injection molding can also use different types of plastics, colors, cosmetics, polishes, and surface textures to create unique and high-quality products.

Custom injection molding has many applications and benefits for various industries, such as automotive, medical, consumer electronics, aerospace, and more. Custom injection-molded parts can offer durability, strength, flexibility, resistance, and aesthetics that other manufacturing methods cannot match. Custom injection molding can also reduce waste, save time, and lower costs by producing large quantities of parts in a single cycle.

In this blog, we will explain what custom injection molding is, how it can benefit your business, and what you need to know before ordering custom injection-molded parts. We will cover the main topics of custom plastic injection molding, custom injection molded parts, design for injection molding, injection molding applications, injection molded products, and injection molding techniques. By the end of this blog, you will have a better understanding of custom injection molding and how it can help you create the best products for your customers.

2. What is custom injection molding?

Custom injection molding is a manufacturing process that involves injecting molten plastic into a mold cavity to produce a specific shape and size of a part. The mold cavity is usually made of steel or aluminum and can be customized to fit the design and specifications of the part. Custom injection molding can create complex and precise parts with high quality and efficiency.

The basic steps of custom injection molding are as follows:

Preparing the mold: The mold is cleaned and lubricated to ensure smooth operation and prevent defects. The mold is also heated to a suitable temperature to match the plastic material.

Clamping the mold: The mold is closed and clamped by a hydraulic or mechanical force to withstand the pressure of the injection. The mold consists of two halves: the fixed half (or cavity) and the moving half (or core).

Injecting the plastic resin: The plastic resin is fed into a hopper and then melted by a screw or plunger in a heated barrel. The molten plastic is then injected into the mold cavity through a nozzle at high speed and pressure. The injection time and pressure depend on the size, shape, and material of the part.

Cooling the part: The molten plastic inside the mold cavity cools and solidifies as it contacts the cold surface of the mold. The cooling time and method depend on the thickness, shape, and material of the part. The cooling system can use water, oil, or air to circulate through the mold and remove heat.

Ejecting the part: After the part is fully cooled and solidified, the mold is opened, and the part is ejected by ejector pins, sleeves, or blades. The part is then separated from the runner system, which is the channel that connects the nozzle to the mold cavity.

Inspecting the part: The part is inspected for quality and accuracy, such as dimensions, appearance, and functionality. The part is also checked for defects, such as warping, shrinkage, bubbles, cracks, or flash. The part can be further processed, such as trimming, painting, or assembling, if needed.

The types of plastic materials that can be used for custom injection molding include:

Thermoplastics: These are plastics that can be melted and solidified repeatedly by heating and cooling. Thermoplastics are widely used for injection molding because they are easy to process, recyclable, and versatile. Some examples of thermoplastics are polyethylene, polypropylene, polystyrene, nylon, and acrylic.

Thermosets: These are plastics that can only be melted and solidified once by heating and curing. Thermosets are used for injection molding when high strength, stability, and resistance are required. Some examples of thermosets are epoxy, phenolic, silicone, and urethane.

Elastomers: These are plastics that have rubber-like properties, such as elasticity, flexibility, and resilience. Elastomers are used for injection molding when softness, cushioning, and sealing are required. Some examples of elastomers are natural rubber, synthetic rubber, and silicone rubber.

3. What are the benefits of custom injection molding?

Custom injection molding offers several advantages over other manufacturing processes, such as high accuracy, repeatability, efficiency, scalability, durability, etc. 

Some of the benefits of custom injection molding are:

High accuracy: Custom injection molding can produce parts with very tight tolerances and complex geometries, ensuring that the parts fit and function as intended. The accuracy of custom injection molding depends on the quality of the mold, the material, and the process parameters. According to Pioneer Plastics, custom injection molding can deliver strength that can equal steel.

Repeatability: Custom injection molding can produce thousands or millions of identical parts with consistent quality and performance. The repeatability of custom injection molding depends on the stability of the mold, the material, and the process parameters. Repeatability is important for maintaining quality standards and reducing waste and rework.

Efficiency: Custom injection molding can produce parts in a single cycle, which can take from a few seconds to a few minutes, depending on the size and complexity of the part. The efficiency of custom injection molding depends on the design of the mold, the material, and the process parameters. Efficiency is important for reducing cycle time, energy consumption, and production costs.

Scalability: Custom injection molding can produce parts in large quantities, ranging from hundreds to millions, depending on the demand and the capacity of the machine. The scalability of custom injection molding depends on the availability of the mold, the material, and the machine. Scalability is important for meeting customer needs and market demands.

Durability: Custom injection molding can produce parts with high strength, durability, and resistance to various environmental factors, such as heat, moisture, chemicals, etc. The durability of custom injection molding depends on the choice of the material, the design of the part, and the post-processing of the part. Durability is important for ensuring the longevity and reliability of products.

Custom injection molding can improve the quality, performance, and functionality of your products in various ways, such as:

Reducing defects: Custom injection molding can reduce the occurrence of defects, such as warping, shrinkage, bubbles, cracks, or flash, by optimizing the mold design, the material selection, and the process parameters. Reducing defects can improve the appearance, functionality, and safety of the products.

Enhancing aesthetics: Custom injection molding can enhance the aesthetics of the products by using different types of plastics, colors, cosmetics, polishes, and surface textures to create unique and attractive products. Enhancing aesthetics can improve the appeal, differentiation, and branding of the products.

Increasing strength: Custom injection molding can increase the strength of the products by using thermosets, elastomers, or reinforced plastics, which have high mechanical properties such as tensile strength, flexural strength, impact strength, etc. Increasing strength can improve the performance, durability, and functionality of the products.

Custom injection molding is a cost-effective and profitable manufacturing method, as evidenced by some statistics and facts, such as:

Market size: According to Grand View Research, the global injection molding market was estimated at USD 261.8 billion in 2021 and is anticipated to expand at a compounded annual growth rate (CAGR) of 4.8% from 2022 to 2030. This indicates the high demand and value of custom injection molding in various industries and regions.

Growth rate: According to Mordor Intelligence, the global plastics injection molding market size is expected to grow from 5.66 million tons in 2023 to 6.95 million tons by 2028, at a CAGR of 4.18% during the forecast period (2023–2028). This indicates the high potential and opportunity of custom injection molding in the future.

Demand: According to GlobeNewswire, the increasing usage of injection molding in automotive applications and the growing demand from the packaging industry are the major factors driving the demand for injection molding in the market. This indicates the high relevance and applicability of custom injection molding in various sectors and segments.

4. What are the challenges of custom injection molding?

Custom injection molding, despite its many advantages, also has some drawbacks and difficulties that need to be considered and addressed. 

Some of the challenges of custom injection molding are:

High initial investment: Custom injection molding requires a high upfront cost for designing and manufacturing the mold, which can range from thousands to millions of dollars, depending on the complexity and size of the part. The mold is a critical component of the injection molding process, and it needs to be precise, durable, and compatible with the material and the machine. The initial investment can be a barrier for small businesses or startups that have limited budgets or resources.

Complex design: Custom injection molding can create parts with intricate and detailed features, but it also requires careful design considerations to ensure moldability and quality. The design of the part and the mold need to account for factors such as wall thickness, draft angles, undercuts, shrinkage, warping, cooling, ejection, etc. The design also needs to avoid defects such as sink marks, flash, bubbles, cracks, etc. The design process can be challenging and time-consuming, especially for novice designers or engineers who lack experience or expertise in injection molding.

Limited material selection: Custom injection molding can use a variety of plastic materials, but not all plastics are suitable or compatible for injection molding. Some plastics have high melting points, low flow rates, high viscosity, or high sensitivity to temperature or pressure, which can make them difficult or impossible to inject into the mold. Some plastics also have poor mechanical properties, such as brittleness, low strength, or low resistance, which can affect the performance and durability of the part. Therefore, the material selection for custom injection molding needs to be carefully evaluated and tested to ensure feasibility and functionality.

Environmental impact: Custom injection molding can produce a large amount of plastic waste, such as runners, sprues, gates, flash, etc., which is the excess material that is ejected along with the part. Plastic waste can hurt the environment, as it can take a long time to degrade, release harmful chemicals, or pollute the soil, water, or air. Plastic waste can also increase the production cost, as it reduces material efficiency and requires disposal or recycling. Therefore, the environmental impact of custom injection molding needs to be minimized and mitigated by adopting sustainable practices and technologies.

Custom injection molding can pose some difficulties and risks for your business, such as:

Requiring skilled labor: Custom injection molding requires skilled and trained workers to operate, maintain, and troubleshoot the injection molding machines and equipment. The workers need to have knowledge and experience in handling the plastic materials, setting the process parameters, monitoring the production cycle, inspecting the quality, and resolving any issues or errors. The workers also need to follow safety protocols and regulations to prevent accidents or injuries. Finding, hiring, and retaining skilled labor can be a challenge for many businesses, especially in areas where there is a shortage or high demand for injection molding workers.

Maintaining equipment: Custom injection molding requires regular and proper maintenance of the injection molding machines and equipment to ensure optimal performance and efficiency. The machines and equipment need to be cleaned, lubricated, calibrated, and repaired to prevent wear and tear, breakdowns, or malfunctions. The maintenance also needs to be done by qualified and certified technicians who can diagnose and fix any problems or faults. The maintenance can be costly and time-consuming, and it can also disrupt the production schedule and output.

Complying with regulations: Custom injection molding needs to comply with various regulations and standards that govern the quality, safety, and environmental aspects of the injection molding process and products. The regulations and standards can vary depending on the industry, region, or country where the injection molding is done or where the products are sold or used. The regulations and standards can also change or update over time, requiring constant monitoring and adaptation. Compliance can be challenging and complex, and it can also entail additional costs, documentation, and audits.

Some ways to overcome the challenges of custom injection molding are:

Choosing a reliable and experienced injection molding service provider:

• One of the most effective ways to overcome the challenges of custom injection molding is to outsource the injection molding process to a reputable and professional injection molding service provider. A good injection molding service provider can offer advantages such as lower cost, faster turnaround, higher quality, and greater flexibility. A good injection molding service provider can also provide guidance and assistance in designing, prototyping, testing, and optimizing the injection molding process and products. Choosing a reliable and experienced injection molding service provider can save time, money, and hassle for your business and help you achieve your injection molding goals and objectives.
• Optimizing the design and production process: Another way to overcome the challenges of custom injection molding is to optimize the design and production process to improve efficiency, quality, and functionality. The design and production process can be optimized by using various tools and techniques, such as computer-aided design (CAD), mold flow analysis, design for manufacturability (DFM), finite element analysis (FEA), etc. The optimization can also involve reducing the complexity, size, or number of parts, using the appropriate material and process parameters, minimizing waste and defects, etc. Optimizing the design and production process can enhance the moldability, performance, and durability of the injection molded parts and reduce the cost, time, and risk of the injection molding process.
• Implementing quality control measures: A third way to overcome the challenges of custom injection molding is to implement quality control measures to ensure the consistency, accuracy, and functionality of the injection molded parts. Quality control measures can include inspecting the raw materials, testing the molds, monitoring the production cycle, measuring the dimensions, checking the appearance, verifying the functionality, etc. Quality control measures can also involve using various instruments and devices, such as calipers, micrometers, gauges, cameras, scanners, etc. Implementing quality control measures can prevent or detect any defects, errors, or deviations in the injection molded parts and ensure that they meet the specifications and expectations of the customers.

5. How do I order custom injection-molded parts?

Ordering custom injection-molded parts can be a complex and challenging process, but it can also be rewarding and satisfying if you follow some guidelines and best practices. 

Before ordering custom injection-molded parts, you need to consider some factors, such as:

Specifications: You need to define the specifications of your custom injection-molded parts, such as the dimensions, shape, features, tolerances, material, color, finish, etc. The specifications should be clear, accurate, and complete, and they should match the design and functionality of your product. You can use computer-aided design (CAD) software to create and export your specifications in a suitable format, such as STL, STEP, or IGES.

Requirements: You need to determine the requirements of your custom injection-molded parts, such as quantity, quality, performance, and functionality. The requirements should be realistic, feasible, and measurable, and they should reflect the needs and expectations of your customers. You can use design for manufacturability (DFM) analysis to evaluate and optimize your requirements in terms of moldability, cost, and time.

Budget: You need to estimate the budget of your custom injection-molded parts, which includes the cost of the mold, the material, the production, and the shipping. The budget should be reasonable, affordable, and flexible, and it should account for any potential changes or contingencies. You can use online injection molding services to get an online injection molding quote and compare different options and prices.

Timeline: You need to set the timeline of your custom injection-molded parts, which includes the lead time, the delivery time, and the feedback time. The timeline should be realistic, achievable, and adaptable, and it should align with your product development cycle and market launch. You can use online injection molding services to get an online injection molding quote and check the availability and turnaround time of different injection molding service providers.

After considering these factors, you can follow these steps to order custom injection-molded parts:

Selecting a suitable injection molding service provider: You need to choose a reliable and experienced injection molding service provider that can meet your specifications, requirements, budget, and timeline. You can use online injection molding services to find and compare different injection molding service providers based on their capabilities, quality, reputation, and customer service. You can also check their certifications, portfolios, and reviews to verify their credibility and expertise.

Submitting your design and specifications: You need to submit your design and specifications to your selected injection molding service provider, either through their online platform or by email. You need to make sure that your design and specifications are in a compatible and readable format and that they contain all the necessary and relevant information. You can also request a free design consultation or a mold flow analysis to get feedback and suggestions on how to improve your design and specifications.

Receiving a quote and a prototype: You need to receive a quote and a prototype from your injection molding service provider, either through their online platform or by email. The quote should include a breakdown of the cost, the lead time, the delivery time, and the payment terms. The prototype should be a physical or digital sample of your custom injection-molded part, which you can use to evaluate and test the quality, performance, and functionality of your part. You can also request revisions or modifications if you are not satisfied with the quote or the prototype.

Approving the final product: You need to approve the final product from your injection molding service provider, either through their online platform or by email. The final product should be the production-ready version of your custom injection-molded part that meets your specifications, requirements, budget, and timeline. You need to confirm the order, make the payment, and arrange for the shipping of your final product. You can also request a quality report, such as a first-article inspection (FAI) or a process capability report, to verify the consistency and accuracy of your final product.

To ensure that you get the best quality and value for your custom injection-molded parts, you can follow these tips and best practices:

Communicating clearly: You need to communicate clearly and effectively with your injection molding service provider, either through their online platform, email, phone, or chat. You need to express your needs and expectations, ask questions and get clarifications, provide feedback and suggestions, and resolve any issues or problems. You need to maintain a good relationship and trust with your injection molding service provider and keep them updated on your project status and progress.

Reviewing feedback: You need to review the feedback that you receive from your injection molding service provider, either through their online platform, email, phone, or chat. You need to pay attention to the feedback that they give you on your design and specifications, such as the moldability, the cost, and the time. You need to consider and implement the feedback that can improve your design and specifications, and reject or negotiate the feedback that can compromise your design and specifications.

Testing samples: You need to test the samples that you receive from your injection molding service provider, either physically or digitally. You need to test the samples for their quality, performance, and functionality using various methods and tools, such as measuring, inspecting, comparing, or applying. You need to report any defects, errors, or deviations that you find in the samples and request corrections or improvements from your injection molding service provider.

6. Conclusion

Custom injection molding is a process that allows you to create complex and unique plastic parts for your products. It can benefit your business by reducing costs, increasing quality, enhancing functionality, and improving aesthetics. However, before ordering custom injection-molded parts, you need to know some important factors, such as the design specifications, the material selection, the mold design, the production process, and the quality control.

In this blog, we have explained what custom injection molding is, how it can benefit your business, and what you need to know before ordering custom injection-molded parts. We hope that this information has helped you understand the advantages and challenges of custom injection molding and how you can use it to create better products for your customers.

If you are looking for a reliable and professional injection molding service provider, you can trust us to deliver high-quality custom injection-molded parts at competitive prices. We have the experience, expertise, and equipment to handle any injection molding project, no matter how complex or demanding. We also offer free design consultations, fast turnaround times, and excellent customer service.

If you are interested in ordering custom injection-molded parts, contact us today for a free quote and consultation. We would love to hear from you and discuss your injection molding needs. Thank you for reading our blog.