Rapid Prototypes Take The Fast Lane

Developing a new product or modifying an existing one entails more than a few hurdles. One of them is securing management or customer approvals before tooling is cut to optimize part design and minimize rework. And, by the way, you need to ship products out the door yesterday. Want a fast, yet accurate, working model that will be easy for decision makers to evaluate?

Software makers know your answer, so these companies have come up with packages that take your CAD data and translate it into the language needed by an SLS, SLA, or other rapid prototyping system. Service bureaus offer this option as well to help speed up creation of an already rapid model. Both parties displayed their wares at the recent Autofact show, which offered attendees a rapid prototyping "pavilion" for the first time in its history. The upshot? RP technology appears to be shifting into high gear.

Data exchange issues are high on the list for improving speed and utility of RP technologies. Take Delcam's offering, for example. The Birmingham, U.K.-based vendor's Duct5 modeling package features an RP data verification and repair module called Trifix. Along with guaranteeing integrity of RP data, often combined from several sources, Trifix lets users divide CAD models too large to be prototyped in one piece. Duct5 generates RP data accurately, reducing complete CAD models for prototyping, and automatically adding fillets and other details required for the RP model.

Imageware (Ann Arbor, MI) also sees RP users running into problems when data flows between CAD/CAM and RP systems. The company is responding with RPM v5.0, an updated package that reads, writes, verifies, manipulates, and lets designers visualize RP format files (STL, SLC, and others). For gas assist, the new software has enhanced hollowing abilities for thin-shell geometries based on uniform wall thickness the user specifies. A Rapid Tooling module adds the same functions for prototype tooling.

Pinnacle Technologies (Roseville, MI), a rapid prototyping service established by Proper Mold & Engineering, uses CADKey 3D, AutoCAD, and EDS Unigraphics to create SLA stereolithography models, modify product designs before prototyping, and apply surfaces to CAD models for toolpath generation. Pinnacle also offers spray metal tooling (average lead time: 2 to 6 weeks) to mold prototype parts not suitable for RP.

Another service bureau, called Prototype Express, (Schaumburg, IL) specializes in prototyping injection molded parts. The process, according to the largest independent provider of stereolithography-based RP services, consists of three steps: creating an accurate master pattern using SLA or SLS systems; creating the mold using a parting line block and silicone rubber or epoxy; and finally, injecting urethane into the mold under pressure to produce the prototype part. The last step can be done at a rate of three to 12 parts per day. Inserts can be molded into the urethane model as well. Typically, if the company is supplied with CAD files, the first prototypes are ready in one or two weeks.

3D Systems is making the move to desktop prototyping with its Multi-jet Modeler, a CAD peripheral that acts like an inkjet printer in three dimensions to build models. According to 3D sources, even complex models can be handled in minutes with the 96-jet print head and movable platform found in the modeler. Currently being beta tested, the system will be available early in '96.

Not content to simply offer ABS as a modeling material, Stratasys Inc. (Eden Prairie, MN) has added MABS (methacrylate ABS) to the lineup for its FDM 1600 RP system. MABS, says Bill Priedeman, materials manager, is targeted at the medical market because the resin meets all FDA USP Class VI requirements and resists saline, betadine, fatty lipids, and other chemicals commonly in contact with medical devices.