Kärcher, located near Stuttgart, Germany, is part of Alfred Kärcher SE & Co KG group which has over 13,000 employees in over 127 companies across 72 countries. Kärcher is the world's leading cleaning equipment manufacturer, offering a wide range of innovative cleaning solutions including high- and ultra-high-pressure cleaners, vacuum and steam cleaners, sweepers and scrubbing machines, and much more. The Company points to innovation as the most important growth factor. More than 1,000 employees work in research and development. Kärcher currently holds over 630 active patents, and around 90 percent of all products are five years old or younger.
Each new product is initially crafted in the Prototyping Department, which was established in 1988. Prototyping Department Head and certified model maker Achim Sanzenbacher explains what he and his team do there, “We have 12 employees who produce between 600 and 800 prototype parts made of steel, brass, and plastics every week.” CAD/CAM software and other programming systems are used to initiate the work for production on 5-axis machining systems, 3D printers, and sheet metal machining centers.
Beginning in November 2018, Sanzenbacher and his team chose to switch to hyperMILL® software from OPEN MIND Technologies for prototyping due to its very efficient 5-axis machining strategies. In addition, the decision to switch to a new CAD/CAM platform was based on another reason that was just as important. “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 “We cannot afford to work with outdated systems.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.”
When choosing the new CAD/CAM system, the Kärcher machining team of four was looking for an attractive range of services and, of course, state-of-the-art technology. Kärcher initially invited the top four CAD/CAM providers on their list to participate in a benchmark, which comprised of programming and machining a complex 5-axis component with a helical groove under conditions typical in prototyping. This means that the CAD data is made available in the morning and the part is expected to be ready 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 set to work with the hyperMILL® CAM system and completed the benchmark assignment with flying colors. By the 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 highly impressed. He said, “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.”
Another thing had become clear by the end of this day, stressed Sanzenbacher, “We all agreed that we had found a partner in OPEN MIND who would provide us with the service we wanted.”
OPEN MIND maintains close ties with their 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 thirteen 5-axis cycles for surface and cavity machining, as well as uses the roughing and finishing modules in the integrated hyperMILL® MAXX Machining performance package. Wussack said, “We mastered hyperMILL® very quickly because the user interface is highly intuitive and clearly structured. Above all, the general operation is the same in every cycle.” Kärcher also believes it is a benefit that OPEN MIND develops all the software so that its modules will easily integrate together.
For example, hyperCAD®-S is the “CAD for CAM” system that OPEN MIND developed specifically 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.”
Particularly 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 fast and easy-to-use drawing, surface, and solid functions.
Prototyping differs fundamentally from series production with regard to the milling requirements. When making individual parts, it is 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 very quickly. In this respect, 5-axis machining is the ideal technology 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.
hyperMILL® truly stands out in 5-axis milling. There are several tilt strategies available so that a suitable solution is available for every geometry and any machine kinematics. “Programming is simple,” as Michael Wussack points out, “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 5-axis tool positions.”
OPEN MIND software provides numerous automated functions that facilitate 5-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 the individual milling areas. Areas that cannot be machined with a tilted tool are milled simultaneously on five axes.
The automatic 5-axis rest machining function is also very useful. It 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. “This results in enormous time savings,” said Wussack.
Roughing is a machining mode that is frequently used in prototyping. This is 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. Kärcher has also invested in the hyperMILL® MAXX Machining finishing module. Sanzenbacher anticipates using the finishing module when machining the electric motors for hot water high-pressure cleaners. Numerous cooling fins need to be finished to a predefined thickness with great precision to allow for correct heat measurements. "By using a barrel cutter and the corresponding tangential finishing strategy, I hope to reduce the milling times by half,” said Sanzenbacher.
For Sanzenbacher, the next evolution 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.” The foundation for this has 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 very important. hyperMILL® provides efficient options for this, such as simulation solutions that account for the entire machine environment. For 5-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 kinematics.
Achim Sanzenbacher is satisfied, “The OPEN MIND hyperMILL® CAM solution and all other components meet our prototyping needs perfectly. The modular strategy system is very 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.” While he does not have component-related figures to corroborate this, he knows that “the throughput has grown measurably. In my opinion, hyperMILL® is currently at the forefront of prototyping.”