Low Volume Injection Molding or Thermoforming for Short Runs - Which is Best

Advanced Plastiform offers guidance on the optimal manufacturing process to maximize efficiency and cost-effectiveness for low run, plastic parts.

Low Volume Injection Molding or Thermoforming: Which is Best for Your Project?

Navigating the realm of manufacturing processes can be a daunting task, especially when considering options like low volume injection molding or thermoforming. At Advanced Plastiform Inc., we understand the critical importance of choosing the right method for your project.

With a commitment to precision, efficiency, and cost-effectiveness, our injection molding company specializes in providing comprehensive solutions tailored to your unique plastic part needs. Whether you're aiming for intricate details with low volume injection molding or seeking the versatility of thermoforming, our expertise ensures that you can make informed decisions to propel your project forward with confidence.

What Is Low Volume Injection Molding?

Low volume injection molding, also known as "short-run manufacturing," serves as the vital bridge between product prototyping and high-volume production, catering to orders typically fewer than 10,000 pieces.

Low Volume Injection Molding Characteristics

Traditional plastic injection molding is renowned for its high-volume manufacture but entails significant upfront costs, primarily due to tooling expenses. Injection molds, usually crafted from steel or copper alloy, endure the intense pressures of the injection process, necessitating intricate and heavyweight designs, thereby escalating fabrication costs and lead times.

In contrast, low volume injection molding often employs aluminum molds, operating at lower pressures to safeguard against mold damage. This strategic choice significantly reduces tooling costs by 5 to 25 percent, with aluminum's malleability facilitating quicker mold creation, thereby expediting the overall injection molding process timeline.

Low volume injection molding finds application across a wide range of industries where precision, flexibility, and cost-effectiveness are paramount. Some of the key industries utilizing low volume injection molding include medicaltelecommunicationsconsumer packaging, and more.

The Low Volume Injection Molding Process

The low volume injection molding process begins with the creation of a custom-designed injection mold. The mold is then mounted onto an injection molding machine, where thermoplastic pellets are fed into a heated barrel within the machine, where they are melted to a liquid state. The molten plastic is then injected under high pressure into the mold cavity, conforming to its shape and intricacies.

After cooling, the mold opens, and the newly formed plastic part is ejected. Depending on the complexity of the part and the requirements of the project, secondary operations such as trimming, machining, or assembly may be performed to achieve the final desired product.

Advantages of Low Volume Injection Molding

Low volume injection molding offers several distinct advantages that make it a preferred choice for small to medium-sized production runs:

  • Facilitates the production of small components with intricate details and variable thicknesses.
  • Provides an opportunity for affordable "test runs," ideal for pilot programs.
  • Reduces upfront investment costs, as the overhead is lower compared to high-volume production.

Disadvantages of Low Volume Injection Molding

Despite its benefits, low volume injection molding also has its limitations and challenges:

  • While faster and less expensive than traditional injection molding, the fabrication process is typically more involved than thermoforming.
  • Larger components may not be cost-effective or time-efficient to manufacture using this method.
  • Design restrictions are imposed to ensure accurate results under lower material injection pressures, including enhanced draft angles and minimal undercuts.

What Is Thermoforming?

Thermoforming is a versatile manufacturing process involving the heating of large plastic sheets until pliable, which are then shaped around a custom-fabricated aluminum tool.

Characteristics of Thermoforming

Thermoforming often utilizes lightweight aluminum molds, minimizing both tooling costs and lead times. Thermoforming molds are typically single-sided and can be fabricated more swiftly due to the material's malleability, making it an efficient and cost-effective alternative to traditional injection molding.

This approach not only reduces initial investment but also enhances the overall flexibility and scalability of the thermoforming process, making it well-suited for low to mid-volume production runs.

The Thermoforming Process

Thermoforming offers three techniques for achieving precise shapes: vacuum forming and pressure forming.

Vacuum forming involves suctioning out the air between the plastic sheet and the tool to ensure a snug fit, ideal for larger pieces with less intricate details. Conversely, pressure forming utilizes highly pressurized air to blast the plastic sheet while simultaneously applying vacuum suction, allowing for sharper angles and finer details, making it a compelling alternative to injection molding.

Twin sheet forming is an advanced technique where two plastic sheets are heated simultaneously and formed together to create a hollow, double-walled structure, offering enhanced strength, insulation, and structural integrity for applications such as automotive componentsfarming equipmentoutdoor furniture, and more.

Advantages of Thermoforming

Thermoforming boasts several advantages that make it an attractive plastic manufacturing method for low- to mid-volume production:

  • Utilizes single-sided molds made from lightweight aluminum, minimizing lead times and reducing costs.
  • Well-suited for fabricating larger pieces, with minimal impact on lead time and cost even as size increases.

Disadvantages of Thermoforming

While thermoforming offers cost and time advantages, it also presents certain limitations and challenges, including:

  • Achieving high levels of detail, especially in smaller parts with variable thicknesses and sharp corners, can be challenging.
  • For parts requiring continued manufacturing cycles or larger production runs, transitioning to injection molding may be more efficient in the long run.

How to Choose Between Low Volume Injection Molding vs Thermoforming Methods?

Choosing between low volume injection molding or thermoforming methods requires careful consideration of various factors to ensure the optimal manufacturing solution for your specific project requirements.

Production Volume

Consider the anticipated production volume for your project. Low volume injection molding is typically suited for production runs of fewer than 10,000 pieces, making it ideal for smaller quantities. Thermoforming, on the other hand, offers flexibility for both low to mid-volume production runs, with the ability to scale up or down as needed.

Complexity of Parts

Evaluate the complexity of the parts you need to manufacture. Low volume injection molding excels in producing parts with intricate details, tight tolerances, and complex geometries, making it suitable for applications requiring high precision. Thermoforming is better suited for larger parts with simpler geometries, although pressure forming techniques can achieve finer details compared to traditional vacuum forming.

Tooling Costs and Lead Times

Compare the tooling costs and lead times associated with each method. Low volume injection molding typically requires the fabrication of aluminum molds, which offer cost savings and shorter lead times compared to steel molds used in traditional injection molding. Thermoforming molds are also cost-effective and can be fabricated more swiftly due to their single-sided design and lightweight materials.

Material Selection

Consider the material requirements for your parts. Both low volume injection molding and thermoforming offer versatility in material selection, with a wide range of thermoplastic resins available. Evaluate factors such as material properties, performance requirements, and cost to determine the most suitable material for your application.

Part Size and Weight

Take into account the size and weight of the parts you need to produce. Thermoforming is well-suited for forming large parts with minimal material thinning, making it ideal for applications requiring lightweight yet durable components. Low volume injection molding can also accommodate a range of part sizes but may be more suitable for smaller, more intricate parts.

Lead Time and Production Speed

Consider your project timeline and production speed requirements. Thermoforming typically offers faster lead times and shorter production cycles compared to low volume injection molding, making it a preferred choice for rapid prototyping and quick-turn projects. However, if precision and tight tolerances are critical, low volume injection molding may be the better option despite longer lead times.

Receive a Free Quote for Custom Plastics Manufacturing

Whether you need 1,000 or 100,000 custom plastic components, the thermoforming experts at Advanced Plastiform Inc. will work with you to determine the best method of manufacturing to provide you with the durable, high-quality plastics you need. This includes prioritizing a low per-unit price with as quick a lead time as possible.

Get started today by receiving a free quote tailored to your project for plastic parts and products. Contact us now by calling us at  919-404-2080 or filling out the online contact form. Don't delay—unlock the potential of custom plastics manufacturing with us today.

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