Custom Plastic Molds

custom plastic molds

Producing custom plastic parts requires premium quality molds built to precise specifications. The plastic injection molding experts at our plastic molding company have extensive knowledge, training and experience designing and building custom plastic molds.

We provide custom injection molding services to a wide variety of industries. Our technical knowledge enables us to create quality plastic injection molds for various applications.

Whether you need to produce specialized medical, transportation, industrial or other components, we work with you to design and build molds for manufacturing high-quality molded plastic parts.

What is a Custom Plastic Mold?

An injection mold is a multi-part tool that allows the forming and cooling of molten plastic to create a distinct component shape. If you need to manufacture hundreds or thousands of quality custom parts, acquiring custom molds that meet your exact requirements is essential.

Since the quality of your injection molded parts depends on the quality of your mold, you need a reputable mold maker with experience to create a precision custom plastic mold for your project. MSI has the advanced skills, experience and modern equipment to ensure your project produces high-quality results.

As the first step in your process, a quality-built mold demands effective communication. Our design experts work with you each step of the way. We ensure you receive a top-quality mold that meets the specific conditions unique to the part you are manufacturing.

Custom plastic injection molding utilizes analytical tools, scientific approaches and consistent molding processes to achieve your project’s precise goals. Our injection molding experts communicate and work closely with our customers on advanced quality planning as a blueprint for making sure they get high quality custom plastic parts.

How are Custom Plastic Molds Made?

plastic molded parts manufacturer

A custom mold requires highly trained and experienced mold makers capable of engineering complex mold components that meet strict specifications and tight tolerances. Plastic molded parts used in military, medical or automotive applications necessitate skilled design and manufacturing specialists to satisfy dimensional and testing compliance requirements.

The complexity and cost of your plastic injection mold is determined by the overall size, complexity, and dimensional tolerances required for your plastic part.

Components of Injection Molds

An injection mold consists of a series of metal plates with intricate machined components on both the cavity-side and core-side insert.

Cavity side

The cavity side mounts to the stationary side of the machine platen and houses the following elements:

  • Locating ring
  • Sprue bushing
  • Guide pins
  • Clamp plate
  • Cavity block

Core side

The core side mounts to the moving platen and contains these components:

  • Core block
  • Leader pin bushings
  • Support pillars
  • Ejector pins
  • Return pins
  • Ejector retaining plate
  • Ejector plate
  • Clamp Plate

Construction of Custom Plastic Molds

Creating molds involves two primary methods, EDM and CNC machining.

EDM Machining

This process involves using a copper or graphite electrode to electrically burn the specified mold shape into the mold component. EDM machining is slower and more costly than CNC machining, and it is only used for mold features that are not practical to cut with a CNC machine, such as sharp corners and very thin rib features. The steps of this method include:

  • CNC machining the electrodes in a high speed CNC machine
  • Submerging the mold component and electrode in dielectric fluid
  • Programming an electrical discharge machine to sink the electrode into the workpiece with a precisely controlled pace and amount of electricity

CNC Machining

CNC machining uses advanced computer technology to cut complex and precise surface shapes into molds. Our mold designers define the mechanical dimensions and shapes of the mold details using CAD software, then translate those into manufacturing drawings.

These drawings and 3D CAD models are then used within our CAM software. Our CAM programmers can tell the software how to machine the raw metal into the final mold shape and the software creates the commands to execute in our CNC machines.

Although CNC machining a mold is the most efficient process through the use of powerful computers, the quality of your injection mold will still depend on the experience of personnel and quality of CNC machinery and tooling being used by your injection mold maker.

What are the Costs for Prototype Injection Molds and Custom Plastic Molds?

The cost of custom plastic injection molding for long-term production varies greatly. Simple molds may range anywhere from $3,000 to $10,000. More complex, multi-cavity or high-production molds cost significantly more from tens of thousands to hundreds of thousands of dollars. Calculating injection mold prices involves assessing many details, such as:

  • Mold design costs
  • Part complexity
  • Part size
  • Number of mold cavities required
  • Plastic material used
  • Mold life expectancy
  • Part dimension tolerances

How Does the Quality of the Mold Affect Part Quality?

Building a high quality mold is the first step to receiving high quality custom plastic parts. Although there are a few types of part defects that can be dealt with after the injection molding process is complete, the best way to ensure you receive good parts consistently from your injection molding supplier is to make sure they build a mold that produces good parts without secondary handwork operations.

Considerations for Raw Plastic Material Selection

When choosing the material for your custom molding project, consider the part’s function, application and environment, as well as the following features of the raw plastic:

  • Flexibility for function
  • Impact strength against breakage during use
  • Environmental temperatures
  • Cost and availability
  • Recyclability requirements

Your plastic material’s density is a vital element to consider as raw plastic material ranges from $1 to $25 per pound. In addition, different families of plastic materials can process faster or slower within injection molding applications which directly affects the long term cost of the parts.

Advantages of Molds Made in the USA

Having your custom plastic mold and parts made in the United States can offer consistent quality and lower overall costs. Modern USA plastic injection molding companies use high-tech equipment and offer reliable technical expertise.

In addition, if you source your project to a reputable USA injection molding supplier they will consistently use high-quality materials unlike many offshore suppliers.

When you hire injection molding experts in the USA, you significantly lower the transportation expenses and have readily available access to customer service and communication. Interaction with our molding experts throughout the process ensures the timely production of the best possible molded plastic parts.

Prototype Injection Molding

Creating a prototype is a lower-cost tooling method to evaluate parts before making a plastic injection mold for long-term production. Some reasons you may decide to make injection mold prototypes include:

  • Show customers a finished part before they agree to a purchase.
  • Perform testing to eliminate design risks before releasing your product to consumers.
  • Conduct consumer research before going into full-scale production.
  • Lower volume requirements for introductory production needs.

Do Plastic Injection Molds Wear Out or Have a Limited Production Life?

Plastic injection molds can wear out due to friction or repeated contact between parts over thousands of cycles. Wear primarily affects gates, slides, ejectors and other moving elements within the mold. When components slide or touch against each other, they eventually show signs of wear.

Likewise, if your plastic material has abrasive fillers like glass or mineral to increase part strength or stiffness, these fillers can wear the surfaces of the mold metals over time.

This is a standard expectation of plastic injection molds that require hundreds of thousands of parts or cycles across a projects life expectancy. At MSI, we warranty the production life of the custom plastic molds we build for our clients.

If we build your mold and we run your production you will never see another tooling charge, and our in-house mold makers will perform all required maintenance on your mold for the life of your project.

Our focus on reliability and excellence makes us a clear choice for your custom plastic injection molding needs. We invest time and energy into communicating with our customers, ensuring you get the best, high-quality molded plastic parts possible. Contact us today to discuss how MSI can make your next mold build project a success.