Understanding Molds: A Comprehensive Guide for Caplugs Customers

Molds are an integral part of the manufacturing process for nearly all the parts made at Caplugs . These devices are used to create precise and customized components consistently and at scale, but different molds are needed for different applications. At Caplugs, we rely on molds every day as part of our manufacturing processes, so let’s take a closer look at the different types and uses of molds in this in-depth guide.

In this article, we'll cover the fundamentals of molds, their types, materials, design considerations and which type of molding to choose. Whether you're new to molds or looking to add to your existing knowledge, this guide will provide helpful insights.

What Are Molds?

In the manufacturing space, molds are precision tools used to shape raw materials, such as plastic and vinyl, into specific forms. Broadly speaking, molds are the rigid form that creates the unique shaping, contouring and features that become the final part. Primarily, we will be looking at injection and dip molds in this article, although Caplugs also offers compression rubber and extrusion molding capabilities.

Types of Molds at Caplugs

To start, let’s take a deeper dive into what defines an injection mold versus a dip mold:

Injection Molds
injected molded part from caplugs

Injection molds receive molten material – in our case, a form of plastic – and force it into pre-designed mold cavities at high pressure. At Caplugs, injection molds (mold cavities) are made of stainless steel and pair with a mold base. We produce insert sets or stacks to meet your exact molding need and have many differently sized mold bases inhouse ranging from single-cavity builds up to 32 cavities for manufacturing optimization.

The part’s size and quantity needed determine the required mold cavitation. For example, because larger injected parts restrict available space, fewer cavities are possible and output is limited. Similarly, for a small quantity needed, less cavities are required. While other companies might point you toward buying a whole injection molding unit, at Caplugs we produce injection mold inserts, allowing us to reuse mold bases and reduce tooling costs for customers.

Vinyl Dip Molds
dip molded part from caplugs

Meanwhile, dip molds are used when dipping a mold into a liquid polymer. At Caplugs, 99% of our dip molds are dipped into some sort of vinyl. The frame for dip molding is made of steel, and then the dip molds – sometimes called tools or stakes – made of lightweight aluminum are attached.

Each frame varies in size, depending on the size of the part to be produced. The frame could include as few as one or as many as 560 stakes. Our engineers work with you to maximize the usable surface area of the dip molding frame so that we can put as many dip molds on the frame as possible, cutting down on cost and production time, while optimizing capacity to meet your quantity output demand.

Materials Used for Injection Molding:

Read on to learn more about the materials used for injection molding at Caplugs:

  • HDPE (High-Density Polyethylene) – HDPE is a thermoplastic used for its high strength, durability and chemical resistance
  • LPDE (Low-Density Polyethylene) – LDPE is a widely used thermoplastic material used for its exceptional flexibility, toughness and resistance to impact
  • Nylon – Nylon is a durable and lightweight synthetic polymer used for its strength and versatility
  • Polypropylene – Polypropylene is a thermoplastic polymer widely used for its toughness, chemical resistance and cost-effectiveness

Materials Used for Dip Molding:

Read on to learn more about the materials used for vinyl dip molding at Caplugs:

  • Polyvinyl chloride (PVC) – PVC is a versatile and resilient synthetic material used for its exceptional durability and chemical resistance
  • Textured PVC vinyl – Increases grip on a vinyl part for safety and ease of use
  • High durometer PVC vinyl – Increases impact protection capability for a vinyl part
  • Standard vs. double dip – Caplugs typically dips parts once (standard dip), but if your need requires a double dip for extra protection we can easily accommodate

Injection and Dip Molding Design Considerations:

There are many aspects of design that must be considered when evaluating injection molds against dip molds. Each molding process offers different benefits, and the right option is a complex balance of form, function and quantity demand. Let’s look at some of the differences and capabilities to keep in mind when evaluating the purpose, quality and production efficiency of each option.

Injection Molding

When considering injection molding, it’s important to first think about the configuration and design of part. For example, if a part requires high material content, it could mean needing to reduce the overall number of cavities on the tool. Additionally, the shot size, or the space and weight the mold will occupy, is a factor. The number of cavities needed to meet the requested production quantity also needs to be considered. For example, a large quantity or a small, light part would work best with a high-cavity tool for effective manufacturing.

Dip Molding

When considering dip molding, it’s important to note that dip molds are more limited in terms of design complexity. That means that dip molding is best suited for simple shapes and coatings. Additionally, for our vinyl tool dip molds, we use a standard wall thickness within a single rack/production run. This means that the shape of the part dictates how many dip molds can fit on the rack. Our expert engineering team ensures that we optimize frame space and therefore each dip.

What type of molding to choose, and why?

At the end of the day, what type of molding to choose and why comes down to three major driving factors – quantity, material and price.


In terms of quantity, injection molding offers high quantity production with rapid cycle times, creating efficiency for large-scale manufacturing. Meanwhile, dip molding is a slower process, particularly if multiple dipping and drying cycles are required, meaning it is often used for smaller production runs or products needing specialized coatings. However, for some smaller and/or simpler parts, racks of dip molds can produce large quantities in a single run.


If your part needs to be a certain material to meet a specific temperature requirement, durability need or other need, that will direct your molding choice immediately. For example, if you needed a HDPE part, you’d go with injection molding, while customers looking for a vinyl dip part will use dip molding.


Finally, cost is always a concern with any manufacturing need. While injection molding is typically more expensive for the tool/mold, it tends to be the most cost-effective option for a part over time. By contrast, dip molding offers reasonable tooling costs, but the per-piece cost for the part itself might be a little more expensive. Since injection molding requires more expensive tooling and molds, it is most suitable for longer-term, higher-quantity production, whereas dip molding’s simpler tooling and molds allows for cost-effective short runs or prototyping. Ultimately, due to the nature of the part or a user's requirements, some parts must be made via one molding process or another with cost-controlled capacity of the mold.


Molds play a pivotal role in manufacturing, enabling the creation of intricate and precise components across a wide range of industries. At Caplugs, we know that both injection molding and vinyl dip molding offer unique advantages and challenges, so it's essential to tailor your design considerations to the specific manufacturing process and material being used. Collaboration between design engineers and manufacturing experts is crucial to achieving successful outcomes in both processes.

We hope this comprehensive guide has provided you with valuable insights into the world of molds. If you have any specific questions or need assistance with injection or vinyl dip molded solutions, don't hesitate to contact our experienced team at Caplugs by using our web chat or by calling 888.CAPLUGS. We're here to support all your manufacturing needs.