With rapid tooling (RT) technologies emerging and the increasing demands put on toolmakers, the issues of if and when to use RT are becoming critical topics in the manufacturing community. The world of conventional toolmaking is faced with an increasing list of problems, the first being increased competition – local and foreign. Customers also are adding to the tension by increasing the demand to produce tools faster than what was considered good even a few years ago.

Another source of frustration can be the decreasing employment trends in many parts of the world. There is a shrinking pool of skilled labor coupled with fewer people entering the toolmaking field. For these reasons the industry is interested in RT, and curious how and when the many processes work. For the purposes of this article, the term “rapid tooling” does not include tooling generated from CNC or traditional metal removal techniques.

To begin discussing RT, the first thing to have is an open mind. There is a fear that exists with many people in the toolmaking field because these processes are new and different. Many view RT as an unknown, unproven and risky endeavor. This is not to say that all of the methods are fully proven and commercialized, but many of these techniques are fully capable of filling a need if the criteria are a good fit.

Any discussion of RT processes must begin with a realization that each process has its own unique set of advantages and disadvantages. RT is not only a process change, but also a philosophy change. With this in mind, willing toolmakers must realize that some of their basic assumptions about the tool building process must change. As an example, consider a customer who wants to modify the part design soon after the preliminary tool design has been approved. In the traditional tool shop the change is most likely easy to integrate.

The steel has been ordered and may even be in production, but usually the part geometry is not completed. The same example being applied to RT causes a different situation. If the tool cavities are being made through DTM’s RapidSteel, then the first stage is to build the cavities and cores on a Selective Laser Sintering (SLS) machine. In this example the most critical stage of the tool is created first, and any changes could be costly. For this reason the communication and contact with the customer are an integral part to the success of many RT projects. Many details such as shrink rates and engineering changes need to be determined as early in the process as possible. This can be a challenge since many of the best applications are fast turnaround prototype tools.

Early in RT development it became apparent that there was not one single process that would suit all of the company’s goals or the customer’s needs. For this reason RT technology must be a constant search for new processes and the improvement of existing processes. In almost all cases new RT methods must be evaluated. It has been found that some are immature or not fully “dialed in.” Occasionally, a new process is developed that will meet or exceed user needs or show improvement over a similar technique.
*Please note that this article does not cover all of the RT processes currently available, it merely shows how some of the processes have enhanced toolmaking abilities. It also must be stated that just because the representative company does not use a certain RT process, does not mean that it has no benefit or worth. It just means that every RT process has its application.

Following are three types of RT techniques.

1. Development Tooling: The fastest and generally lowest cost tooling solution. Delivery of one to three weeks and a tool life of at least 50 to 200 parts.

2. Mid-Range Tooling: This type of tooling offers a fast turnaround and consistent tool tolerance. Delivery of two to five weeks and a tool life ranging from 200 to 10,000 parts.

3. Low-Volume Production Tooling: This tooling method will serve as a production tool for less demanding applications. Delivery of four to six weeks and a tool life of 10,000 to 100,000 parts.

In order to decide how to match a tooling project with a tooling process, each part must be evaluated and measured by certain general and specific criteria. The general criteria to exact a method are part size, part geometry, part tolerance, plastic material, number of shots required and delivery demands.