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Everything started with a piece of paper, a pencil sketch of four rectangles, the idea of a system with three Grob G751 5-axis machining centers, and a linear memory was born. The general managers of Hetec GmbH – Friedhelm, Günter, and Tom Herhaus – had given intensive thought to the requirements and layout of such a system and were prepared to create the necessary peripheral conditions for it. The aim is maximum flexibility in order processing for just-in-time production.
Modern company with digital processes
Founded in 1998, Hetec specializes in the sophisticated 5-axis milling of components, in particular complex components for tool and mold construction, as well as general machine construction. Hetec almost exclusively machines individual parts and small series and adherence to tight delivery deadlines is key. A modern machine park consisting of 5-axis machining centers guarantees the utmost precision right down to the smallest tolerances in micrometers.
The workflows in the modern production hall have been thought through to the last detail. Every tool is electronically monitored and can be used in every machine, which ensures minimal retooling times. Order management for the individual workpieces is digitalized. Each component receives a material routing slip with a bar code containing all the stored information, which can be updated in real-time if changes are made. An app produced by the machine supplier reduces standstill times by allowing users to check the current status of the system at any time, even outside the factory, and to respond immediately to warnings.
Desire for more flexibility
Given the great diversity of parts, absolutely precise just-in-time manufacturing of complex components is a basic prerequisite for sustainable success and customer satisfaction. This only succeeds with perfect order management and optimal flexibility. The path to automation as a solution to this challenge was developed step by step. First, the company invested in a zero-point clamping system which was later supplemented with a Grob G551 with a pallet changing system to be able to manufacture continually at weekends as well.
However, the general managers continued to think about the idea of further flexibility. The solution of attaching three identical Grob G751 5-axis machining centers to a linear feed system to be able to apply the pallets flexibly in any machine seemed perfect – however, for a small contract manufacturer, this didn’t exist in this form yet except as a pencil sketch. “Hetec approached me with this request and commissioned me to search for suitable project partners”, explains Hans-Hermann Rink, head of Rink Werkzeugmaschinen in Hesse. After a benchmark comparison, the decision was made quickly in favor of the PHS 1500 Allround from Liebherr, and the master computer system Procam was selected soon after that. Decisive factors were the modular concept that enabled machines to be connected successively, and the possibility of adapting the system layout individually to Hetec’s spatial conditions and needs. Rink continues: “The providers understood Hetec’s programming and manufacturing philosophy and were able to implement it with absolute flexibility”.
What impressed me was the great flexibility of our project partners and the way in which they catered to our requests and ideas as a matter of course.
PHS 1500 Allround optimizes machine utilization and part availability
“Many components that we machine are only produced once. The PHS Allround expands part availability and storage capacity, while the linear memory ensures maximum flexibility. We can always decide completely freely, and without a machine standstill during reclamping, on which of the three Grob G751s a part is to be machined. This has significantly improved the utilization of our machines. The operator uses the Procam master computer to link the NC programs with the pallets and organize the workflows. Updates or change requests at short notice are also no problem”, explains general manager Tom Herhaus.
Further plus points for the system are its space-saving, compact layout with two frontal setup stations and the front access with the possibility of decoupling individual machines from the operation. Since the operator performs the component check directly in the work area, machine accessibility is a key point. A well-thought-out integration of the ERP system with the Procam master computer enables continuous digital order management. Hetec has developed its order management system, which is tailored to the company. “We felt that we were in very good hands with Procam and Liebherr”, says Tom Herhaus. “Both of them catered to our wishes one hundred percent. Even with special requests, they said - we can do it.” This included, for example, a setup station with hydraulic clamping and the possibility of weight-optimized machine calibration.
Thought through from start to finish
In spring 2017, the project partners sat around a table together for the first time and began planning. This required a lot of coordination and agreement concerning data security, interfaces, and machine conformity. To create the environmental conditions for maximum precision, Hetec had left nothing to chance and had ensured a temperature-stable environment prior to investment.
In December 2018, everything was ready. The first Grob G751 was connected to the PHS 1500 Allround, and in February 2021, the third Grob G751 completed the system. “The PHS 1500 Allround had only just come onto the market and, because of its weight class, matched our components perfectly”, Tom Herhaus recalls, “What impressed me was the great flexibility of our project partners and the way in which they catered to our requests and ideas as a matter of course.”
Were there any difficulties during the project? Tom Herhaus laughs. “It would be incredible if no difficulties arose in such a complex project. We were impressed by the competent problem-solving and the quick response times. Liebherr was exemplary in this respect. The remote support worked excellently. The service was always manned and responded within a very brief time – which was extremely important to us in order to minimize standstill times.”
Impressive Liebherr quality
Herhaus cited quality, flexibility and the individual addressing of customer requests as the particular strengths of all the companies participating in the project. “The robust, solid workmanship and absolute reliability of the system won us over. Liebherr was even flexible enough to take into account our design wishes with regard to color schemes”, he adds with a wink. “The system is our ‘showcase’.”