Innovative products call for creative developers equipped with prototyping technology that implements their ideas efficiently. That is true for Kärcher, a global manufacturer of cleaning equipment. Located near Stuttgart, Germany, Kärcher, is part of Alfred Kärcher SE & Co. KG Group, which has more than 13,000 employees in over 127 companies across 72 countries.
Kärcher offers a range of innovative cleaning solutions, including high- and ultra-high pressure cleaners, vacuum and steam cleaners, sweepers and scrubbing machines. The company says innovation is the most important factor in its growth, and it has more than 1,000 employees working in R&D. Kärcher currently holds over 630 active patents, and around 90 percent of its products are five years old or younger.
Each new product is initially crafted in the prototyping department, established in 1988. “We have 12 employees who produce between 600 and 800 prototype parts made of steel, brass and plastics every week,” explained Achim Sanzenbacher, prototyping department head and certified model maker at Kärcher. Software such as CAD/CAM and others are used to program the work for its five-axis machining systems, 3D printers, and sheet metal machining centers.
It is important to Kärcher that prototypes are produced in-house. This shortens the time to market and ensures that know-how is not disseminated prematurely. Prototyping receives special support for investment because it accelerates attaining a functional initial sample.
One of Kärcher’s key technologies for efficient prototyping with comprehensive five-axis machining is its CAD/CAM programming software from Open Mind Technologies. The CAD/CAM package comprises the hyperMILL CAM Software with its integrated CAD module.
Beginning in November 2018, Sanzenbacher and his team decided to switch to Open Mind's hyperMILL CAD/CAM software for prototyping. In addition to the software’s five-axis machining strategies, service provided for hyperMILL was a key factor in the decision to make the switch.
“We were having service problems with our software supplier, which culminated in the failure to deliver software or post-processor updates to us,” said Sanzenbacher. “We cannot afford to work with outdated systems. Our parts are becoming more and more complex, so we want to take advantage of every new development and receive application support from our software vendor, when needed,” he said.
When choosing the new CAD/CAM system, the Kärcher machining team of four was looking for a range of services and technology. Kärcher initially invited the top four CAD/CAM providers on its list to participate in a benchmark challenge, which involved programming and machining a complex five-axis component with a helical groove under conditions typical in prototyping. The CAD data were made available in the morning and the part was expected to be ready in the afternoon, produced by a milling process using a single setup.
Two of the software vendors on Kärcher’s short list opted not to participate in the benchmark challenge. However, Steffen Völker, technical project manager and application specialist for mold construction and prototyping at Open Mind Technologies AG, set to work with the hyperMILL CAM system and completed the benchmark assignment. By afternoon, the benchmark part was milled on a Hermle C400 and ready for inspection.
Michael Wussack, one of the CAM and milling specialists on the Kärcher prototyping team, was impressed. He remarked, “This test allowed us to experience hyperMILL in real-life conditions. After seeing the results, I was certain that this CAD/CAM system was the optimal solution for us. It’s easy to program, fast in terms of machining, and delivers consistently reliable milling results.”
Sanzenbacher added, “We all agreed that we had found a partner in Open Mind that would provide us with the service we wanted.”
Open Mind maintains close ties with its customers. Initially, Völker contacted Kärcher weekly to inquire about any problems relating either to programming or components, and to quickly resolve any issues. However, due to the Kärcher CAM users’ solid prototyping expertise, minimal assistance was needed.
Kärcher has hyperMILL licenses to perform all 13 of its five-axis cycles for surface and cavity machining, and it also uses the roughing and finishing modules in the integrated hyperMILL MAXX Machining performance package. Said Wussack, “We mastered hyperMILL quickly because the user interface is intuitive and clearly structured. Above all, the general operation is the same in every cycle.” Another benefit is that Open Mind develops all its software so that modules will integrate together, according to Kärcher.
For example, hyperCAD-S is the “CAD for CAM” system that Open Mind developed for CAM programmers to speed up NC coding. “It’s fully integrated into hyperMILL,” said Wussack. “This allows users to switch back and forth between CAM and CAD without having to employ an interface. That saves a lot of time and makes the job much less stressful.”
Especially in prototyping, components still need to be adapted for milling because they are often developed for subsequent series production based on injection molding or die casting. When milling parts, a supporting or clamping surface is required, and adjustments such as adapting radii or closing holes must be made. These are precisely the tasks that hyperCAD-S is designed to support by using its drawing, surface and solid functions.
Prototyping differs fundamentally from series production with regard to milling requirements. When making individual parts, it’s not important to shave off tenths of a second from the total machining time. More time is saved if a workable, process-reliable NC program—ideally one that generates the finished component in a single setup—can be created quickly. In this respect, five-axis machining is ideal for prototyping because almost any component can be machined in its entirety from five sides. This also leads to longer continuous processing times, which Wussack and his team leverage to program the next part.
With the hyperMILL CAD/CAM system, there are several tilt milling strategies available so that a suitable solution is available for every geometry and any machine kinematics. “Programming is simple,” said Wussack, “because it is generally based on three-axis 3D milling or milling with the tool set at an angle. In addition to familiar 3D strategies, such as plane finishing or rest machining, only one additional window is needed to supplement the five-axis tool positions.”
Open Mind software provides automated functions that facilitate five-axis programming, such as the automatic indexing feature. It enables programming and milling areas in a single operation even when several tool positions are required. This feature automatically seeks a collision-free, fixed tool angle for individual milling areas. Areas that cannot be machined with a tilted tool are milled simultaneously on five axes.
The automatic five-axis rest machining function detects rest material areas that were processed incompletely during finishing and automatically carries out the required machining operations after the user defines the reference tool and the machining area, resulting in “enormous time savings,” said Wussack.
Roughing is a machining mode frequently used in prototyping because most components are milled from solid stock. At Kärcher, the roughing module of the hyperMILL MAXX Machining performance package performs this job with ease, according to the company. Kärcher has also invested in the hyperMILL MAXX Machining finishing module. Sanzenbacher anticipates using the finishing module when machining electric motors for hot-water, high-pressure cleaners. Numerous cooling fins need to be finished to a predefined thickness with high precision to allow for correct heat measurements. “By using a barrel cutter and the corresponding tangential finishing strategy, I hope to reduce milling times by half,” said Sanzenbacher.
For Sanzenbacher, the next step involves further automation of the milling area. “In prototyping, too, we are concerned with making efficient use of time by utilizing machines with minimal staffing during the night and on weekends,” he said. The foundation for this had already been laid by investing in a Hermle C22 with a six-fold pallet changer.
Since automation requires maximum process reliability, collision checking and avoidance are important; hyperMILL provides efficient options for this, such as simulation solutions that account for the entire machine environment, according to Open Mind. For five-axis simultaneous machining, hyperMILL automatically calculates a collision-free tool angle. The user only has to specify which axis of rotation should be prioritized in collision avoidance, depending on the machine’s kinematics.
Sanzenbacher is satisfied. “The Open Mind hyperMILL CAM solution and all other components meet our prototyping needs perfectly,” he said. “The modular strategy system is versatile, and the user interface is uniform and clearly structured across all cycles. The generated programs ensure safe and reliable processing. And, we’ve also gotten faster.”
For more information from Kärcher North America, Denver, visit www.kaercher.com/us or phone 303-738-2400. For more information from Open Mind Technologies USA Inc., Needham, Mass., visit www.openmind-tech.com or phone 888-516-1232.
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