Medical Device Link.

Originally Published January 2000

SOFTWARE FOCUS

Smoothing the Road to Rollout

DFM Concurrent Costing 1.1 Helps Designers Track Costs

Version 1.1 of Design for Manufacture (DFM) Concurrent Costing software allows engineers to quickly generate an initial cost estimate at any stage of the design process. Developed by Boothroyd Dewhurst Inc. (Wakefield, RI), DFM Concurrent Costing isolates the major cost drivers associated with a wide range of processes for part manufacture and finishing. Used as an analysis tool during part design, the DFM software guides engineers as they investigate alternative materials and processes for producing parts and helps them select the most cost-effective design.

Unlike its predecessor, version 1.1 of DFM Concurrent Costing lets users import solid models in order to obtain 3-D part geometry data for cost estimating. Users can open and view solid models of parts created in all the major CAD/CAM software systems. When a CAD file opens, part dimensions, weight, volume, number of surfaces, and other measurements are automatically updated in the DFM software.

As the engineer selects different materials and manufacturing processes for the part, the software uses the imported 3-D part geometry to calculate estimated manufacturing costs.

Another feature of version 1.1 is that it offers twice the amount of information formerly available on material manufacturing processes. The updated software adds five new processes—structural foam molding, plastic extrusion, injection molding, thermoforming, and blow molding—to the original set. In addition, the expanded library of secondary operations now includes information on the plating of plastics and on trimming and hole punching for blow molding. The library's built-in programming capability also features added checkbox and list section variables, which designers can use to improve the accuracy of their cost-estimating practices.

thinkdesign 4.0 Bridges 2-D, 3-D Worlds

A new software application from Think3 (Santa Clara, CA) is designed to help designers bridge the gap between 2-D and 3-D CAD computing. The application provides integration of 2-D design methodology into 3-D, allowing all 2-D legacy data to be carried into the 3-D design process. Conversely, thinkdesign 4.0 makes it "easier than ever to design a sophisticated 3-D model, and to ... document it in industry-standard 2-D format for manufacturing," according to Thomas Jensen, vice president of engineering at the company. This is achieved through its set of 2-D drafting and layout tools that give 3-D users the ability to go back and forth between departments that are still using 2-D designs.

The program offers several features that are designed to facilitate the transition from 2-D to 3-D. A capture and playback feature gives users the ability to record, review, and communicate specific design sessions. This feature is useful for training and internal design team reviews, as well as for reporting technical problems and bugs to thinkcare, Think3's on-line customer service and support center. The part-library management system, thinkparts, allows design teams to create, share, manage, and reuse more than 1000 standard and proprietary components from a central catalog. Existing files and systems can be used, including AutoCad 2-D parts and Catia files. A compatibility mode allows users to call upon a command line interface that elicits an overlay of drawing and editing commands.

Thinkdesign 4.0 also contains traditional design tools, including drafting, conceptual design, wireframe, free-form surfacing, advanced kernel technology, flexible parametrics, feature-based solid modeling, interoperable solids and surfaces, basic surface creation and modification, in-place assembly design, production drafting and detailing, design and document management, and sheet metal features.

ADAMS Builds Virtual Prototypes

Unlike CAD/CAM software, which models the geometries of parts and static part assemblies, virtual prototyping software simulates how parts of a system move with respect to each other. Using virtual prototyping software, engineers model a mechanical system by simulating its 3-D motion behavior under real-world conditions and then refine and optimize the system through iterative design studies.

With ADAMS software from Mechanical Dynamics Inc. (Ann Arbor, MI), engineers can build and test virtual prototypes, realistically simulating on their computers (both visually and mathematically) the full-motion behavior of complex mechanical systems before building a hardware prototype. Users can quickly analyze hundreds of design variations, testing and refining their designs until the system's performance reaches the desired level. This can help reduce the time and cost involved in developing a new product, while also boosting design quality, according to Mechanical Dynamics.

In the medical field, ADAMS software has played a major part in the design of a six-degree-of-freedom articulating knee joint for a total knee replacement (TKR) prosthesis. ADAMS was used to develop a 3-D dynamic model of the TKR (see illustration), which helped engineers determine articulating surface profiles that would suit a patient's gait pattern and physiology.

ADAMS has also been used for orthotic design. Finding the right orthotic insert design for a patient can be a costly, time-consuming process in which inserts are made and tried until one alleviates the patient's pain. With the help of ADAMS, however, an orthotic manufacturer can simulate a patient's walking and running gait based on leg and ankle measurements. Using these simulations, the manufacturer can see the effects of various orthotic insert designs without actually making them and trying them out on a patient.