Turning ideas into parts: to get maximum leverage from its manufacturing know-how, this CNC shop draws on all of its software resources—CAD, CAM and shopfloor programming

Modern Machine Shop, Feb, 2005 by Mark Albert

"Shut up and make the part."

These are words that Aaron Krieger uses to describe the attitude of many customers when he started Krieger Machine Company 24 years ago in Stuart, Florida. There wasn't much dialog with design engineers. In those days, customers simply expected a job shop to make parts to print. Of course, part prints and spec sheets were all Mr. Krieger needed to put his manual equipment to work.

Today, the shop relies on CNC milling machines and machining centers to make customers' parts, but capable machines are not the only big attraction, according to Mr. Krieger. "We can start making parts no matter where a design engineer may be in the design process," he explains. That flexibility and responsiveness is what customers look for these days, he says. "They want us to be problem solvers."

That means being able to interact effectively with design engineers, whatever form or format the information about a part is in. Sometimes the information arrives as a fully developed solid model created in a CAD system such as CATIA, Pro E or SolidWorks. In other cases, traditional paper prints are the only source of information about a part that was designed long before data could be captured digitally. Sometimes the parts are merely ideas in the developer's head.

"We have to respond to hand signals like this," says Mr. Krieger, tracing a rectangle in space with his index fingers. "They want us to make a part that is so wide and so tall, with drilled holes here and there," he says, poking the air.

To be this flexible, Mr. Krieger finds that a variety of software resources are needed. The shop has a CAD system to manipulate or create part geometry in a digital format. It also has an off-line CAM system for generating G-code part programs. Finally, the CNC milling machines and machining centers have control systems offering shopfloor conversational programming directly at the machine. These dual-screen control systems also let the shop import geometry generated on a CAD system and run the part programs generated on the CAM system.

Evolution

KMC's flexible, integrated approach evolved naturally out of the shop's first experiences with CNC. For the first 6 or 7 years as a shop owner, Mr. Krieger relied on his skill as a trained machinist to handle incoming jobs. By the mid-1980s, however, he saw that moving into CNC was clearly the only way to survive.

Fortunately, he found an approach that allowed him to think like a machinist yet still successfully program a CNC machine. The answer was a conversational programming system that asked for information about the part in an intuitive, logical pattern. "I knew how the part had to be machined," Mr. Krieger says. "I could see that in my mind. The conversational programming let me get that picture onto the control screen, where it could become the CNC program for machining the part."

Confident that shopfloor programming could make CNC operations successful in his shop, Mr. Krieger acquired a KM3-P milling machine from Hurco (Indianapolis, Indiana) in 1988. This machine came with the Ultimax II conversational programming system, which featured a dual screen format. One screen displays the choices and machining options while the second side-by-side screen displays the part geometry and tool path as defined in response to prompted selections.

This machine was successful. A second machine, almost identical to the first, was installed 1 year later. Three more machines were installed in the last 5 years. All three are Hurco BMC 4020 machining centers with Ultimax III or IV controls. Fully established as a CNC shop, KMC has prospered, with a growing reputation as a reliable producer of preliminary prototype/development units, initial low rate or long-term high quantity production-jobs for the electronics, jet engine and medical imaging industries.

Software Resources

Adding CAD and CAM has helped KMC maintain this momentum.

KMC's main CAD resource is a seat of KeyCreator from Kubotek USA (Marlborough, Massachusetts). This CAD software is an enhanced version of the PC-based CAD system formerly called Cadkey. This CAD system came to KMC when Mr. Krieger brought John Goings on board last year to help him manage the shop. Mr. Goings knew KMC well from his experience as a business unit manager at one of the shop's longtime customers. Mr. Goings also had a strong background in manufacturing and CAD applications. His knowledge of CAD was especially useful.

CAD software allows the shop to work with geometry in almost any format, including 2D or 3D wireframes, surfaces or solid models--the prevalent format for conveying part geometry today. When a customer's part geometry is sent to KMC (usually by e-mail), Mr. Goings opens the file in KeyCreator and translates it into the system's native format. At this point, he and Mr. Krieger analyze the geometry and determine a basic manufacturing strategy. This strategy is the basis for quoting the job.

Any gaps or errors in the geometry are patched at this time, making it usable for machining applications. Likewise, the dimensioning and drafting features of the CAD software make it easy to create 2D drawings for the shop floor at this point.