Maintaining maximum precision whilst working more efficiently is something the Hirschvogel Automotive Group has been able to achieve using the hyperMILL®CAM program from OPEN MIND. The amount of programming required has dropped dramatically and there has been a double-digit percentage reduction in machining times. One important side effect is that there is much less stress on tools and machines.
The Hirschvogel Automotive Group has achieved its success with a wide range of renowned automotive manufacturers and suppliers throughout the world. The business manufactures powertrain, chassis frames, engines, gears as well as diesel and fuel injection parts that are increasing at such a rate that the company will reach €1bn turnover soon.
The main Hirschvogel Umformtechnik GmbH plant in Denklingen in Germany manufactures parts with a total weight of 1,000 tonnes using hot, warm and cold forming processes and rotary swaging operations. Without a high degree of technical expertise in the area of tool making, it would not be possible to ensure the required quality of the products.
Based on the motto ‘To stand still is to regress’, the team that is headed by Robert Haug, Head of Planning and NC Programming at the Hirschvogel tool making have switched over to hyperMILL® CAM from OPEN MIND. Thanks to the introduction of hyperMILL® MAXX Machining performance package, the time required for programming the milling machines for many components has decreased, machining times and the load on the machine and tools have been reduced and new manufacturing options have arisen in the 5-axis machining area. Precision in the single-figure micron range is an absolute must for the 250 tool makers in Denklingen. According to them, this was also a minimum requirement when plans were put in place in 2013 to switch from the previous CAM system to a more powerful solution.
Although 13 programs were considered initially, the company eventually opted for hyperMILL®. It was the significantly reduced programming times that swayed the decision as tool making always involves small batch sizes. Around 200,000 tools are produced each year and the batch size fluctuates between one and 24. The tools weigh between 100 grams and 12 tonnes and are manufactured on 32 machining centres, 17 of these are 5-axis machines.
Five minutes instead of one and a half hours
NC programmer Günter Fasching gives an example of how his work has got faster: “In the past, I developed a 5-axis NC program for a toothing stamp; I had to wait for about one and a half hours for the paths to be calculated. With hyperMILL®, the paths are calculated in about five minutes.”
The CAM team in Denklingen has also been able to reduce programming times by using the 5-axis-optimised rest material roughing function. Based on a preceding operation, this cycle automatically generates high-speed cutting (HSC) that is optimised and collision-checked for rest material machining. A further advantage of indexed 5-axis machining is that shorter tools can be used. This guarantees greater stability and performance. This strategy also allows hard-to-reach areas and cavities to be machined particularly efficiently.
According to NC programmer Thomas Karg, it was previously necessary in the past when programming rest material roughing to work forward manually, tilt angle by tilt angle while watching out for various restrictions. Now, if you choose the ‘Indexing’ function, you can define the tilt angles for the B and C axes easily and quickly using two methods. The ‘Planes’ option allows you generate the tilt angle from the plane normal. In ‘3D mode’, the tilt angles are created automatically within a defined range of angles. All connecting paths between the tilt angles are optimised and fully checked for collisions.
“We were particularly impressed by the extremely short programming and calculation times as well as the machine and tool-friendly machining,” explains Haug.
The outstanding feature and macro technology also helps to greatly accelerate the work carried out by the Hirschvogel programmers. hyperMILL® uses geometrical information from the CAD system, so features such as holes and pockets are processed in the CAM package. The recurring machining strategies that are typical for a feature are combined with tools and technology data, defined as macros and stored in the macro database. This way, machining sequences can be assigned quickly and easily to the appropriate geometries and programming parts can be generated conveniently at the click of a mouse.
The feature and macro technology provided by hyperMILL® offers enormous potential to reduce programming times. The amount of time this saves is huge, reports Fasching. “In the past, I needed more than a day to program a workpiece with 100 drill holes. Now, I only need two hours.”
Spindle load reduced by 70 per cent
Roughing during electrode manufacturing is also drastically accelerated. The Hirschvogel tool makers estimate that an average time saving of between 10 and 20% can be achieved with the high-performance cutting strategies of hyperMILL® MAXX Machining. This is achieved using spiral and trochiodal toolpaths. Dynamic feed rate adjustment according to the actual cutting conditions ensures that milling is always performed with the highest possible feed rate. This results in optimal milling paths with maximum material removal and the shortest possible machining times.
Hirschvogel operates a relatively small machine with a high-speed spindle that machines graphite electrodes. “With our old CAM system, we reached the maximum spindle load. Thanks to the HPC strategies provided by hyperMILL® MAXX Machining, we’re now only at 20 to 30% of the maximum load. This prolongs the machine life and the life of our tools. In the past, we had to replace them after only two or three parts. Now they can easily withstand a complete job consisting of ten parts.”
Haug and his team also appreciate the OPEN MIND support. An important point for Martin Kröner and his colleagues is that: “Whenever we need help and support, the experts from OPEN MIND visit us at our factory and always provide us with quick solutions or we use the call centre. With OPEN MIND, we’ve found a partner that really helps us get ahead,” says Haug.
