RP-Driven RT - Can it Compete?

Published in the October 1997 issue Prototyping Technology International, UK & International Press Copyright 1998
by Terry T. Wohlers

The idea of rapid tooling (RT) is turning heads. Excitement levels are similar to what the RP industry experienced a few years ago. Indeed, RT has caught the attention of countless organizations that are seeking ways to speed products to market.

RT concepts are so new that a broadly accepted definition has not yet developed to define this new class of tooling. Most would agree, however, that RT is driven from a digital database – the key to making it rapid. One way to do this is to take advantage of CAD solid modeling and RP. RP-driven RT accelerates the tooling process using RP masters that are, in turn, used to produce molds. Examples are epoxy/composite tooling and 3D Keltool from 3D Systems. RapidTool from DTM, metal sintering from EOS, and DirectAIM from 3D Systems are also examples, although these use RP technology to produce core and cavity inserts, directly, on their respective RP systems.

The strong growth and excitement of RP has spawned many ideas and new approaches to tooling. Most of the developments are occurring behind the scenes in closed laboratories around the world. Some companies are developing RT methods for in-house use and do not plan to license the technology or make it commercially available. The hope is to develop an approach that gives them a strategic advantage over their competition.

Meanwhile, several companies are pursuing the development and commercialization of RT because of its potential market size. Last year, the secondary RP market segment, which includes core and cavity inserts created directly from RP processes, grew 62.7 per cent to an estimated US$286.4 million, according to a 1997 industry report from Wohlers Associates, Inc. No one knows for sure how big this market segment will become, although it is a pretty safe bet that someday it will be measured in billions of dollars.

The list of RT developments that have been announced to date is impressive, to say the least. Each of them comes with a unique set of strengths and limitations, and few of them are ready for prime time. Yet because of their possible impact, they are causing a flurry of inquiries from companies in the USA, Europe, Japan, and other developed nations. Manufacturing companies are hard at work trying to determine if now is the time to begin to phase-in one of these new approaches.

Several of the new RT methods use powder metal. An example is MIT’s three-dimensional printing (3DP) technology, an approach that has been licensed to Extrude-Hone, exclusively for metal parts and tooling. Using inkjet printing to deposit a liquid binder material, the system produces ‘green’ metal parts that are then sintered in a furnace and infiltrated with another metal.

Another example is Rapid Dynamics, a company that is preparing to offer a powder metal process for making steel mold inserts. The process takes advantage of an RP pattern and metal powder forging technology. The method produces finished tooling in days rather than weeks, according to inventor Paul Vawter.

Laser Fare affiliate ExpressTool Inc is working towards the commercialization of two new RT technologies. One of them is a powder metal process that produces hard tooling made of chromium carbide, a very hard cermet with hardness levels of 55 to 60 Rockwell C. The second technology, called Hastool, takes advantage of conformal cooling channels.

Proctor & Gamble’s Jim Tobin has developed an RT process called Prototype Hard And Soft Tooling (PHAST), which also involves powder metal. PHAST has been licensed to Plynetics Express, a large service provider in the USA. Beginning with CAD data, the company expects to deliver injection molded parts from the PHAST process in two to three weeks.

Mareco BV (Netherlands) has developed a process called Digital Mould Manufacturing (DMM), which takes advantage of the EOSINT M 250 metal laser sintering machine from EOS (Germany), coupled with conventional finish milling and grinding. Since mid-1995, the company has been perfecting the process, which uses a nickel/bronze alloy powder and resin infiltration. Using DMM, the company has produced many injection molds that have yielded thousands of parts in ABS, polycarbonate and other thermoplastic materials.

CEMCOM is a year or so away from introducing a process called NCC Tooling System, which uses plastic RP models as patterns to produce nickel-ceramic composite tooling. The method involves the plating of nickel over an RP pattern and then reinforcing the thin, hard nickel face with a ceramic material.

Los Alamos National Laboratories, Sandia National Laboratories, and the Fraunhofer-Institute for Production Technology are each developing RT methods using high-power laser sintering technologies that produce metal parts and tooling inserts.

Interestingly, most of these approaches to tooling are not competing as much with one another as they are with decades-old technology – the milling machine, coupled with CNC capabilities. Machining is an established technology that is well understood by thousands of companies. With machining, you do not encounter the material, size and accuracy limitations that are inherent with most RP processes. In addition, companies are finding that machining of molds does not have to take months. Some companies have reduced it to as little as two weeks.

Much of this reduction in time has come from improving the management of the process, as much as the process itself. Years ago, companies were not under as much pressure to develop new products quickly. Consequently, companies ran inefficient operations. Many tool-and-die shops continue to operate this way today, to some extent, although the push for rapid delivery is forcing them to remove bottlenecks and work smarter. Hewlett-Packard is a good example as to why. HP generates more than two-thirds of its revenues from products introduced in the last two years, according to former HP employee Bob Neel, now an independent consultant. The company sells roughly 22,000 products, which translates to a staggering number of new product introductions each year. As time goes on, companies such as HP will face even tighter schedules as the demand increases for new product models.

Compression Inc, another large RP/RT service provider in the USA, has developed methods and company standards that streamline machined tooling. An impressive 100 per cent of its jobs are driven entirely from CAD data. The company maintains that it routinely produces complex machined tooling in P20 steel in about four weeks. Compression can produce simpler, aluminum tooling more quickly. A major manufacturer of cellular phones contracted with Compression to produce 150 polycarbonate parts. The manufacturer supplied a Pro/Engineer file to Compression, and within 10 days it received the 150 parts at a cost of about $80 per part. Needless to say, the cellphone manufacturer was impressed.

Solid Concepts, another established RP/RT service provider, can produce complex machined aluminum tools in 10 working days. While these numbers are impressive, most tool-and-die shops lag far behind. DTM surveyed 300 toolmakers to determine the time it takes to produce machined prototype injection mold tooling. They found that it takes 39 days, on average, which is equivalent to almost eight weeks. Why? Most of these companies have not fine-tuned their workflow, established rigid standards, or made it a goal to become a provider of rapid tooling solutions. A growing number of companies, such as Compression and Solid Concepts, understand the importance of an information-based approach that integrates several methods and technologies and takes full advantage of CAD/CAM.

The Japanese have pinned their hopes on high-speed machining as the solution to rapid tooling. Companies in Japan have developed CNC machining centers that they claim are the fastest in the world. Using air motors and bearings, the machines offer spindle speeds of 150,000 to 200,000rpm. Machining centers at most US tool-and-die shops run at 3,000 to 20,000rpm. Even without high-speed machining, the Japanese can create tooling many times faster than the USA. According to Shinjiro Yamada of INCS, Japanese companies can make production tooling for consumer products in 14 calendar days. In the USA, it takes much longer at most companies. The goal in Japan is four to seven days. CAD solid modeling and high-speed machining, they believe, will help them accomplish this feat.

The question remains: Can RP-driven rapid tooling compete with machined tooling? The answer is yes, if it is competing against 39 days. If it is 10 days, maybe. From a customer’s point of view, the competition between machined tooling and new RP-driven approaches is good news because it is forcing developers to push technologies to their limits. It is also causing user companies to step back and re-evaluate their approach to prototyping and tooling. This in turn is helping companies discover ways of reducing the time to market. The race is on.