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03/08/2023|Schittl GmbH

Vertical Multi-Process Grinding

For over 25 years, Schittl GmbH from Deutsch Kaltenbrunn in Austria has stood for machining based on quality. With many years of experience and professional expertise, the approximately 50 specialists guarantee top-class results even for the most demanding customer projects. Amongst other things, Schittl supplies customers in the fields of automation and energy technology with precision components made of a wide range of materials. 

The team now achieves its good machining results on 15 CNC machines from DMG MORI. Schittl covers a wide range of components – from an automated CMX 70 and DMU monoBLOCK universal machining centers to DMF traveling column machines and a DMU 340 Gantry to CTX beta TC and CTX gamma TC series turn-mill centers. The latest addition in 2022, and a highlight of the machine park, is a TAIYO KOKI CVG 13, also from DMG MORI. The vertical grinding machine enables the company to adopt completely new approaches to the manufacturing process with the highest precision.

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„Vertical grinding is the method of choice, particularly for large and heavy components up to a diameter of 1,350 mm and a length of 700 mm. We have been able to document accuracies of 2 μm on the CVG 13.“
Roman Gradwohl, Managing Director Schittl GmbH

Process integration – accelerate manufacturing and increase quality 

As a traditional manufacturing service provider, Schittl has experienced a change in its history in the direction of increasingly demanding orders. “Particularly after the economic crisis in 2008, it became even more important to remain competitive,” explains Roman Gradwohl. He has been the head of his father-in-law’s company since 2011. The plan to manufacture high-quality and complex components has required extensive investments – in the further training of their specialist staff as well as in modern manufacturing technology. “Investments like this always need to be accompanied by tangible progress.” By this, he is referring to integrated processes such as 5-axis simultaneous machining including high metal removal rates and integrated turn-mill machining. “Our goal is to accelerate the manufacturing process and ideally to continuously increase the quality.” Schittl kick-started the new technology direction with two DMU 85 monoBLOCKs. From then on, the simultaneous 5-axis machining centers enabled the team to manufacture efficient and precise components with diameters of up to ø 1,040 mm and complex geometries. These were followed by a DMF 360 and a DMU 340 Gantry for even larger workpieces. “The cutting performance of the DMF 360 is so high that we were able to almost halve the machining time,” reports Roman Gradwohl. Schittl manufactures high-precision machine beds on a large gantry machine with travel distances of 3,400 × 2,800 × 1,250 mm. “For us, it is the perfect compromise of precision, construction size and cutting performance.”

Automated 5-axis machining for unmanned night shifts 

Schittl was able to achieve automated 5-axis machining on a CMX 70. Roman Gradwohl says about the added value: “In the area of small parts with batch sizes up to 100, the PH 150 pallet handling system provides great support because we can set up several pallets and also operate the machine during unmanned night shifts.” Schittl relies on turn-mill centers from the CTX beta TC and CTX gamma TC series for turning operations. Here we can finish the components in one operation from all 6 sides. Rough turning and milling are followed by grinding to achieve the required precision. A corresponding DMG MORI technology cycle is ideal here for small workpieces. However, the CTX gamma 2000 TC is primarily used to machine components up to 700 mm long and up to ø 700 mm in diameter. “Large and heavy parts like this can be ground better in a vertical position because gravity isn’t influencing the results,” Roman Gradwohl says, referring to the CVG 13.

Ideal combination: 6-sided complete machining and high-precision vertical grinding 

Schittl relies on turn-mill centers from the CTX beta TC and CTX gamma TC series for turning operations. Here we can finish the components in one operation from all 6 sides. Rough turning and milling are followed by grinding to achieve the required precision. A corresponding DMG MORI technology cycle is ideal here for small workpieces. However, the CTX gamma 2000 TC is primarily used to machine components up to 700 mm long and up to ø 700 mm in diameter. “Large and heavy parts like this can be ground better in a vertical position because gravity isn’t influencing the results,” Roman Gradwohl says, referring to the CVG 13.

CVG 13 – vertical grinding to 2 μm 

With a maximum grinding diameter of ø 1,350 mm and a workpiece height of up to 700 mm, Schittl can use the CVG 13 for an extremely broad range of components, such as spindle heads or worm gear components. “We have been able to document accuracies of up to 2 μm for the components with our measuring machine. This is ideal for the workpieces that we produce on the CTX gamma 2000 TC, for example,” comments Roman Gradwohl. The multi-process CNC vertical grinding machine is suitable for cylindrical grinding of internal and external diameters as well as face grinding. “In-process measuring guarantees flawless results.”

Vertical grinding integrated into the manufacturing process 

Overall, the CVG 13 delivers such good results that Schittl has designated complete processes to the grinding machine, as Roman Gradwohl explains: “We use the turn-mill centers for roughing and finishing with grinding tolerance. The same applies to fits. The CVG 13 then delivers the absolute precision.” This allows the multi-process CNC grinding machine to be optimally utilized.

Investments in progress also in the future 

The investment in the CVG 13 achieved precisely the long-term progress that Roman Gradwohl expects from every investment. He also intends to follow this path in the future. “An expansion of our production space is currently in the pipeline. We can then reallocate the technology areas and free up some space.” Discussions about a DMU 340 Gantry are already underway and he can also imagine making another acquisition for grinding: “The CVG 9 enabled us to further expand our grinding capacities in the area of small workpieces.”


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