Manageable Modeling for Waterjet Machining

How a waterjet OEM added 3D CAD modeling capability

As a user, how do you handle the challenge of upgrading your CAD system from 2D and DXF to a modern 3D modeler with capability to import major types of native CAD models from outside systems?  And how would you handle this challenge if you were installing the new CAD modelers on dozens of waterjet machining systems for outside users?

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Modern waterjet machines can cut plastics, composites, metals, even stone. Titanium and steel parts are commonly produced, as well as aluminum. Courtesy, Flow Corp.

That’s the challenge faced when Flow Corp. realized that their existing software fell short of new needs. Designed years ago, the existing CAD software needed to be upgraded to meet changing user requirements.  The company motto, From Art to Part in One Minute, required that a modern 3D CAD modeler be used, one with the capability of importing native CAD files from outside users.  Here’s how the Kent, Wash. firm did it.

What Flow Corp. needed
”Some time ago, we realized there was a paradigm shift, that the market was evolving from a two-dimensional CAD world into a 3D world,” explained Tim Fabian, marketing manager, Flow Corp. “We realized that manufacturing was going to have to adapt to that, and so our systems were going to have to take advantage of 3D modeling and 3D solids.”

“We invented abrasive waterjet cutting,” Fabian continued, “and Flow has been in business since 1974. When we first started, we were cutting with 30,000 psi, then 40,000 psi by the late 70s.  Today we’re at 94,000 psi and are testing pumps that are significantly higher than that. At 94,000 psi, you cut about twice as fast as at 60,000 psi. Pressure determines the speed the fluid comes out of the nozzle, and a 94,000 psi jet travels at mach IV.”

Food industry represents a small part of Flow’s business, but primary users are metal fabricators and machine shops.  Prime users are firms like Boeing, which uses waterjet machining to cut out carbon fiber or composite parts for the new 787 Dreamliner.  Aluminum is a common material cut by waterjet.  Some users are cutting aluminum up to 18 in. thick.  Others cut titanium, steel, even stone.

When Flow set out to add 3D modeling capabilities, they approached several CAD companies. “We’ve always provided our own CAD solutions for our systems,” Fabian continued, “but realized this was an area we were not expert in, and that we would rather focus our engineering on stream control and other issues more directly a part of the CAM side.  So we approached several CAD vendors and looked at their products, trying to learn which would be easiest to learn for our users.  Our motto is from art to part in one minute, so we must process a CAD file and get a machine cutting that part in one minute or less.  And that was going to be a challenge operating three-dimensionally.  So in looking at potential CAD partners, we were impressed by SpaceClaim because we found their modeling approach very fast and easy to use.  It became apparent that this was going to be a good fit for Flow and for our users.”

What new CAD software offered
”We met Flow about a year ago,” said Rich Moore, VP Business Development at SpaceClaim, “and they had been looking at that time for about two years.  We helped them come up with a total solution for both 2D and 3D.  Every user of a Flow Corp. machine will get FlowMaster controls.  So a typical machine operator can use FlowMaster with SpaceClaim direct modeler, even someone who might not be prepared to use a more complex CAD system.”

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New waterjet machines can cut complex, contoured surfaces like this composite fan blade and this arched piece.

So a user who has relied on FlowMaster for years will now find it is coupled with Direct Modeler, so they can take any CAD file from any environment, make necessary changes to adapt it to waterjet machining, and do it all in the FlowMaster environment.

“We’ve always believed in providing all the software right at the machine,” explained Fabian.  “Everything that is needed to design the part and control the cutting is right on the machine itself, so a user doesn’t have to go in the office and regenerate a CAD file.  He has the ability to adjust the CAD model right there.  So we wanted a CAD solution that could be used right at the machine.”

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Image demonstrates the ability of SpaceClaim Engineer to model complex assemblies, like this lens assembly.

FlowMaster now includes SpaceClaim Engineer and Style software packages.  These are an integral part of FlowMaster and provide the 3D direct modeler.  They can accept DXF files, which some of the Flow customers still use.  But now they have capability to import native CAD files from the five leading CAD systems: Pro-E, Catia, SolidWorks, NX, and Inventor.

“Years ago,” Fabian continued, “our customers used our CAD software to design the parts to be machined.  But more and more, they have access to other CAD equipment, and we encourage them to use what they are comfortable with.  We tell them, ‘don’t retrain yourselves to learn a whole new set of software just for us’.”

SpaceClaim Engineer is promoted by the company as “ the world’s fastest and most innovative 3D direct modeler,” said to enable engineers to easily create concepts and prepare 3D designs for digital prototyping, analysis, and manufacturing.

“Since the mid-90s, we’ve offered our own CAD solutions, as part of our FlowPath software.  Previously, this was 2D, or two-and-a-half-D,” Fabian said. “But we wanted our new software to enable a five-axis machine that would cut 3D parts quickly.  New products soon to launch will bring waterjet machining into a 3D multi-axis world.  We wanted to focus our efforts on cutting parts 3D with compounded angles, and we needed a CAD partner who would be able to feed this new product the part geometry, so we could process and cut out these fancy new shapes.”

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More accurate waterjet cutting process
Dynamic waterjet with Active Tolerance Control uses a new advanced motion system with mathematical cutting models that control a small, articulated wrist attached to the cutting head. The wrist allows the cutting head to tilt in any direction, compensating for the stream lag and taper experienced with conventional waterjet cutting machines.

Stream lag and taper result from cutting with a beam-type cutter such as a waterjet. The faster parts are cut, the greater the stream lag. Stream lag causes part geometry errors. In addition, as cut speed is increased through a given material, the waterjet beam produces ever-increasing taper.

Conventional waterjets must slow down to reduce or eliminate finished-part tolerance errors caused by stream lag and taper. Now these limitations are overcome with new FlowMaster software. The user simply enters the basic cutting parameters, such as material type and thickness, cut speed, and desired edge finish, and FlowMaster dynamically controls the position of the cutting head, determining the amount of tilt and rotation required at numerous incremental points along a cutting path. Claimed benefits include:

• Cut parts 25-400% faster than conventional flat-stock waterjet cutting machines
• Improve cut part tolerances and geometry at significantly higher speeds
• Virtually eliminate taper; taper is < 1 degree in straight-line geometry
• Reduce part cost
• True part stacking ability with consistent tolerance layer to layer
• No secondary finishing required
• Cut a variety of materials, such as metal, stone, glass, and composites
• Cut parts using virtually any CAD file, or scan a drawing directly

Flow Int’l Corp.
www.flowcorp.com

SpaceClaim Corp.
www2.spaceclaim.com