High Volume Injection Molding: An Overview

High Volume Injection Molding: An Overview

High volume injection molding is a specialized plastic manufacturing process that produces large quantities of identical parts efficiently and cost-effectively. It is found in many applications that require large quantities of quality parts. Major markets include automotive, industrial, medical, defense, firearm accessories, and consumer goods among other critical applications. The process represents an evolution of the standard plastic injection molding methods, to accommodate the demands of higher annual quantities. Today, we’ll look at the process and its benefits, how it differs from conventional methods, and some typical parts it produces.

What is High Volume Injection Molding?

High volume injection molding involves quickly injecting molten plastic into a mold cavity, where it cools and solidifies into the desired shapes. The process is highly automated, allowing for rapid production cycles and consistent part quality. You’re probably wondering how big is a high volume run? While it depends on who you ask, for PDI, it generally covers jobs ranging from 100,000 pieces to well over 1 million pieces annually.

Benefits of High Volume Injection Molding

The most obvious benefit is cost-effectiveness, thanks to economies of scale. As volume increases, unit cost decreases. With the help of automation and advanced machinery and processes, turnaround time is also reduced, while quality is strictly maintained. Part design is not compromised, as intricate parts can be repeatedly produced at high speeds in a consistent manner when appropriate tooling and process considerations are made.

How is High Volume Molding Different than Standard Runs?

Above all, the high volume injection molding process requires that parts be produced quickly without sacrificing quality. To facilitate this, many considerations are made throughout the entire process, these include:

• High Volume Tooling – this is crucial to the success of any high volume program. Tooling must be designed to withstand rapid cycles and higher pressures. They are engineered and produced to exacting tolerances, to ensure that every part produced conforms to precise specifications. This level of precision minimizes defects and reduces the need for rework. High-volume multi-cavity injection molds and mold components are often made of higher quality materials such as steel or steel alloys, rather than aluminum.A key feature of a high speed injection molds is higher cavitation, allowing many parts to be molded at once. Rather than producing just a single piece, these molds can produce 4, 8 or 16 in one machine cycle. This significantly increases output and reduces process time. Tooling may include other features like hot runners, balanced mold cavities and runner systems, and optimized cooling channels to achieve optimal processing conditions. But high-speed / high-cavity injection molds also come with higher upfront costs to produce.
• Industrial Strength Machinery (and Process) – Injection molding machines for high volumes are engineered for high-speed operation. With this comes increased stress, and the production process and equipment must be able to handle it. To do so requires a strategic mix of automation and modifications across the production line. Let’s take a closer look.For the pre-injection phase, automated systems transport and feed the resin into the machine. Then high-performance hydraulic or servo-hydraulic systems are used to deliver molten material at high speed and pressure in to the mold. Higher clamping forces are required to withstand the rapid opening and closing of the mold. Servos are used to control clamping force as well as injection speed. The molding press’s injection unit also relies on a high-output screw for quick melting and homogenization of the plastic resin.Cooling the molded part quickly and consistently is equally as important as injection rates. Automated temperature controls systems facilitate this by regulating cooling rates through control of tool steel temperatures.Other components are also integrated into the process including advanced control systems to manage timing and pressure control.Once the parts have cooled, robots swiftly extract the parts, further reducing cycle time while preventing damage to the molded component or injection mold. Machine vision systems typically inspect the parts, rejecting ones that do not meet the required specifications. Robots can then place parts onto conveyors, into bins, or directly into an automated assembly process. This specialized and automated processing and handling equipment can also perform other labor intensive tasks such as trimming and packaging, creating a fully automated production line and ultimately the most economically manufactured molded part.

What Types of Parts or Jobs Qualify for High Volume Injection Molding?

Generally speaking, high volume injection molding is ideal for producing large quantities of identical parts with consistent quality. Common applications include:

• Automotive Components – countless interior and exterior parts and under-the-hood components
• Medical Devices – disposable syringes and other consumables, diagnostic equipment, enclosures and housings
• Industrial Parts – connectors, housings, and enclosures
• Consumer Goods – electronics, household appliances, and packaging

If you require lower quantities but want to reap the benefits of high volume production, many shops including PDI will offer inventory management programs. These allow you to take deliveries, scheduled or as needed, minimizing warehousing demands at your facility. Just be sure to do this for components that aren’t likely to change over time to avoid future waste.

Speed. Efficiency. Quality. Are You Ready?

High-volume injection molding is a powerful process that delivers increased cost-effectiveness, speed, efficiency, and product quality. It is an ideal solution for manufacturers needing to mass-produce their products. From reducing production costs to accelerating time-to-market, the benefits are clear. By leveraging advanced technology and rigorous quality control, high-volume injection molding ensures that your products will perform as designed, and for a long time.

Does your part or assembly qualify for high volume injection molding? Contact our team to find out.