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What is the best type of prototype for your plastic part?

Benefits of creating a plastic prototype for production molding

3d printer plastic prototype a type of prototype for your plastic part

When you are manufacturing a new plastic part that is to be made of plastic you will save time, money, and stress by testing a mold prior to building the tool. Modifications to a tool can be costly and may degrade its overall performance and longevity. Accurate computer aided design (CAD) software reduces the need for prototyping of some parts. Nonetheless, there are many approaches and benefits to creating a prototype of a product. Determining the best type of prototype for your plastic part is your first step.

Choosing the best type of prototype for your plastic part:


Historically the only approach was to have a model made by a professional model builder.  The prototype may have been constructed of wood, plastic or metal depending on the size and function of the test needed to be performed on the prototype to prove its size and function.  Many parts today still require a fully functioning prototype model to get exact data from which a mold can be built.  It is a small price to pay for a good prototype part to avoid or at least reduce the iterations of design changes often required while designing and developing new parts and new products.

Rapid Prototyping:

Modern technology, such as Plastic Part Printing, also known as 3-D printing has made prototyping quick and inexpensive. With each new product’s life span shortening each year there is much more pressure to create new products and get them out on the shelf as soon as possible.

Pull-Ahead Cavities

Another approach to prototyping is the concept of pulling forward a cavity in a multiple cavity tool.  If the project is for medium to small plastic parts, then it is very common to use a tool in production containing several cavities of the same part.  In this case it is sometimes wise to build one cavity and use that cavity to product prototype parts.  If changes are required, modifications can be made to that cavity only, allowing all subsequent cavities to be constructed to the newly proven geometry; resulting from the testing on the prototype (pull ahead) cavity.  This is also the prototyping choice where many parts are required for testing and the test challenges the strength and toughness characteristics.

SPI Industries used this technique in developing a new plastic collar for Monsanto’s 1 gallon Pump n’ Go “Round-Up” dispenser.  The new tool was to be 4 cavities.  SPI used Mold Flow Software to assist with the tool design.  It was then determined a Pull Ahead Cavity was the right way to go so extensive testing could be done before completion of the other three cavities. We did discover additional changes to be made and thus preserved the strength and durability of the final three cavities.

SPI Offers the Most Current Solutions and Prototypes for your Plastic Part

Do you still have questions on which is the best type of prototype for your plastic part? Please give us a call. SPI’s skilled designers and engineers are experienced in the best practices for plastic part molds and the type of prototype for your plastic part that considers your time, budget and best testing for your specific part.

Bookmark this blog for updates on plastic molding technology and plastics manufacturing. Our next blog will cover more information on rapid prototyping or 3-D printing as it is more frequently known. SPI works closely with a local technical college, Ivy Tech for 3-D printing molds. The Engineering and Design Technology students develop 3-D models for SPI customer review. Read more to determine if a 3-D model will be the best type of prototype for your plastic part.