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Manufacturing

Tool and Die Prototyping

18 Jun, 2004 By: Cadalyst Staff

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VX CAD/CAM helps German company develop and manufacture auto parts and medical devices.

KHP Prototyping, located in Germany's Black Forest, was looking for an edge. A developer and manufacturer of prototypes for the tool and die industry, KHP serves highly competitive markets such as automotive components and medical devices. Quick turnaround times and suitable margins can be challenging to achieve. Customers typically expect KHP to handle the entire product development process or to manufacture components from a customer-supplied CAD model.

"We only make money when a great deal of powder melts during sintering and when lots of chips fly during die making," says CEO Klaus Heinzmann. "We avoid any idle time. Though it sounds simple, it's difficult to achieve on a daily basis."

To maximize efficiency, KHP not only relies on an efficient mixture of laser sintering and high speed machining for rapid prototyping, but also on an integrated CAD/CAM processing sequence. To achieve this level of integration, the company selected VX CAD/CAM.

Injection Molding Tools
It's not unusual for Heinzmann's team to produce a finished prototype within a few days using a customer's CAD data. Prototypes from synthetic materials serve as models to visualize the end product and let the mold designer check part interrelationships in the tool. With the help of a model, an experienced mold designer can see at once how a building block can be constructed most cost efficiently. Testing the prototype can reveal that pushers in the injection mold are to be avoided or can help eliminate problems related to materials and processing, such as indents due to uneven material shrinkage, deformed molds, cutting planes, or probable injection points.

3D Model
KHP began using VX CAD/CAM in October 2002 as its base for digital production development and has expanded its use so that it's now used throughout the entire digital production development, from the first design up to the manufacturing of tools and dies. "The new view display options in VX, for instance, are a great advantage in our daily work. In the new shading mode with edge highlighting, a 3D model can show where a form suddenly disappears under the surface, which helps us easily avoid potential production problems," says Heinzmann.

For quick and efficient development, VX simulates the end product in the early phase of production design. VX's Adaptive Feedrate Control, for example, calculates production speed during milling by considering the material and tool tension volume and tool cutting strength. Smooth movement simulation lets the user plan the finishing process time. With the newly integrated Flow 3D QuickMilling function, the die builder determines how flow lines occur in the form interiors. This is especially useful when creating molds where the plastic flow has to follow specific guidelines.

"It's very important to us at VX that modeling, assembly, and other functions are very user friendly," says Bob Fischer, vice president of sales and marketing at VX Corp. "For example, our hybrid modeling, which combines parametric volume and surface modeling, makes it possible for employees with minimal CAD knowledge to easily produce a 3D layout of a prototype."

Quick Turnaround
After design comes prototyping. To promise quick turnarounds, companies like KHP have to develop NC programs directly from CAD models. The closer CAD and CAM are integrated, the faster the prototype can be produced. "For the preparation of the end product, VX CAM delivers collision and background interface control," says Wolfram Becker, CEO of Varimetrix Deutschland GmbH, the German distributor for VX Corp. "The CAM processing helps minimize expensive idle time that occurs due to programming mistakes."

Laser Sintering
KHP produces prototypes and functional models using SLS (selective laser sintering), which lends itself to complex design geometry. An SLS system uses a laser to melt powders in layers that merge to produce 3D objects. With its laser sintering installation, KHP produces not only prototypes but also synthetic components for small-run production.

"VX is always used when we have to repair customers' CAD models from other systems," says Heinzmann. "VX's STEP data converter lets us remove surfaces and work directly in the model, and this is a great advantage of VX."

High-Speed Milling
In metal machining work, KHP employs high-speed milling techniques to produce prototype tools and electrodes from 3D CAD models as well as ready-to-use components and products such as doorplates in aluminum, brass, and steel. For high-speed milling, VX simulates milling actions to help KHP develop usable NC programs based on the CAD data.

"With the help of appropriate milling strategies, VX CAM software calculates rough and smooth planes, which can then be entered directly into the CNC programs," says Becker. "Since the CAD data has to be more extensively controlled before the NC programming, a highly integrated CAD/CAM system such as VX has the advantage that by using geometric interfaces, inaccuracies due to data conversion can be avoided."

Because the milling machine reproduces the CAD data precisely, high surface quality is essential. Gaps and overlaps must be avoided. VX supplies the CAD/CAM functions for quick and flexible high-quality surfaces as well as their modification and analysis.

"VX doesn't just play a central role in our operations solely because of its many CAD/CAM functionalities," says Heinzmann, "but also because it's important to us as a midsized company that the price-performance ratio of such a system is attractive."