Creating Molded Prototypes with Rapid Tooling

When you need to make hundreds of thousands of plastic parts, the process of injection molding often represents the best option. Because although setup costs are high, material and operational costs are not, which makes it easy and affordable to manufacture parts in large volumes.

Manufacturing parts in small volumes is a different story. Metal tooling can be very expensive, so it is rarely economically viable to manufacture a small number of parts using injection molding. When only tens or hundreds of units are required, it may be better to use 3D printing or another process with low setup costs.

With rapid tooling, however, it is possible to reach a compromise. Although molds are always relatively expensive, the use of rapid prototyping techniques such as 3D printing or CNC machining can drastically reduce their cost. It then becomes possible to create plastic prototypes or low-volume production runs without wasting money.

This article explains how rapid tooling works and how its key benefits can be leveraged through China Medical CNC Machining Inc..

What is rapid tooling?

As its name suggests, rapid tooling is a process in which tooling is produced using rapid prototyping techniques such as additive manufacturing or CNC machining. This may involve creating the mold itself — a process known as direct rapid tooling — or fabricating a master pattern around which a mold can be formed. The latter process is known as indirect rapid tooling.

Rapid tooling is incredibly useful because it allows manufacturers to create two kinds of prototypes: a prototype of the mold and, using that prototype mold, multiple prototypes of the injection molded part. It can even be used to create small volumes of end-use parts if quality requirements are minimal.

The ability to prototype injection molded parts can be hugely beneficial to a company’s research and development process since it allows engineers to see how their designs perform in the real world. Unlike 3D printed prototypes, which are not wholly representative of an end-use molded part, molded prototypes are highly similar to the end product.

(Image from Apt-mold)

Advantages of rapid tooling for injection molding

More representative prototypes

Perhaps the biggest advantage of rapid tooling is its ability to produce representative molded prototypes. Since these prototypes are made using the injection molding process, they may be virtually identical or very similar to the end-use part.

This higher level of representation is valuable for several reasons.

Firstly, it allows the manufacturer to determine how well the design can be realized through injection molding. (If defects occur, the design can be reworked to eliminate them.) Secondly, it allows the molded prototypes to be put through physical testing, giving a much clearer picture of the part’s performance levels.

Improved R&D

Creating a prototype of a molded part allows engineers to vastly improve the design of the part during development since the physical prototype can be evaluated, refined and redeveloped if necessary.

Cost savings

Tooling is very expensive, so it is generally only justifiable if used for mass production. Creating a standard mold just for prototyping — and then having to make a second one for actual production purposes — would be a gigantic expense.

Rapid tooling, however, produces cost savings of up to 95 percent on the mold.

This makes it much easier for a company to invest in a run of molded prototypes or even a run of end-use parts. It may not be as cheap as a 3D printed prototypes, but the benefits may outweigh the small financial advantage of 3D printing.

Reduced lead times

As its name suggests, rapid tooling allows for tooling to be fabricated in a very short space of time, since most of the work is carried out by a computer.

This reduces lead times for both the tooling and the molded prototypes, making the process feasible for companies working to tight deadlines.

Bridge production

Once prototype tooling has been fabricated and put through its paces, it becomes much simpler to develop regular tooling for the end-use parts. Moving from prototyping to production is a smoother process when the prototyping stage involves the same processes as the production stage.

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