United Grinding rebuilds new productivity life into 45,000-hour machine

February 04, 2020 - 12:30pm

Article from United Grinding North America Inc.

After 14 years in service, a Studer S40 grinding machine that had over 45,000 hours of run time now produces precision components to tolerances it achieved when brand new. The Studer factory in Switzerland performed the rebuild that involved completely overhauling the machine, and while doing so also provided the machine’s owner LMT Kieninger with a loaner to ensure the customer’s production would continue uninterrupted.

Christoph Jenzer, managing director (head of AVOR), and Edgar Stich, managing director (head of production), in front of one of the many Studer machines at Ingold Tools AG.

A rebuild, or machine overhaul, makes sense not only economically, but also in the fact that operators continue to run a machine that is familiar to them for a seamless transition after the machine has been rebuilt.

In the Studer factory, the rebuild specialists disassemble machines down to all their individual parts. The specialists completely refurbish guideways, overhaul the assemblies and replace all worn electrical cabinet components, as well as all worn hydraulic and lubricating systems and valves. If spare parts are no longer available, Studer provides alternative solutions. For the final stages of the rebuild, the casting and components are sand-blasted and receive a fresh coat of paint. Once reassembled, the machine’s geometry is like that of a new machine.

A Studer grinding headstock before and after the rebuild.

"After our rebuild, we really noticed the difference,” said Heiko Braun, group manager of cylindrical/surface grinding and assembly at LMT Kieninger. “Since the overhaul, we have been grinding with the precision of a new machine. The rebuild process went without a hitch, and the investment has paid off because a 1600-mm grinder is worth its weight in gold for us."

If a customer wishes to expand a machine’s component range, the Studer overhaul process can also include a retrofit during which a machine is modified to a customer’s particular requirements. This opens up new production possibilities on the same machine, which was the case with Ingold Tools AG.

Ingold Tools had been producing high-precision and complex parts for spindle, compressor, hydraulic and general machine manufacturing with 25 employees since 1946. Among its cylindrical grinders, the shop had an 18-year-old Studer S21 with two external spindles and continuous fine adjustment of the turret wheelhead (B-axis fine).

Studer machine overhauls enable a second life for a grinder.  

Studer not only updated the S21 with the latest developments, but also retrofitted it to suit the needs of Ingold Tools AG. The cylindrical grinding machine now has an additional internal grinding spindle for internal cylindrical grinding and the relevant fixture for swiveling the tailstock into the park position. The machine also has a new spindle cooling system with its own circuit, as well as a hydraulically swiveling dressing unit. So that all grinding machines have the same mounting, the universal tool headstock was upgraded from MK4 to MK5.

According to Ingold Tools AG’s two managing directors, Christoph Jenzer and Edgar Stich, the Studer retrofit resulted in them getting a second-hand machine with 50% new hardware. 

Related Glossary Terms

  • cylindrical grinding

    cylindrical grinding

    Grinding operation in which the workpiece is rotated around a fixed axis while the grinding wheel is fed into the outside surface in controlled relation to the axis of rotation. The workpiece is usually cylindrical, but it may be tapered or curvilinear in profile. See centerless grinding; grinding.

  • dressing


    Removal of undesirable materials from “loaded” grinding wheels using a single- or multi-point diamond or other tool. The process also exposes unused, sharp abrasive points. See loading; truing.

  • fixture


    Device, often made in-house, that holds a specific workpiece. See jig; modular fixturing.

  • grinding


    Machining operation in which material is removed from the workpiece by a powered abrasive wheel, stone, belt, paste, sheet, compound, slurry, etc. Takes various forms: surface grinding (creates flat and/or squared surfaces); cylindrical grinding (for external cylindrical and tapered shapes, fillets, undercuts, etc.); centerless grinding; chamfering; thread and form grinding; tool and cutter grinding; offhand grinding; lapping and polishing (grinding with extremely fine grits to create ultrasmooth surfaces); honing; and disc grinding.

  • grinding machine

    grinding machine

    Powers a grinding wheel or other abrasive tool for the purpose of removing metal and finishing workpieces to close tolerances. Provides smooth, square, parallel and accurate workpiece surfaces. When ultrasmooth surfaces and finishes on the order of microns are required, lapping and honing machines (precision grinders that run abrasives with extremely fine, uniform grits) are used. In its “finishing” role, the grinder is perhaps the most widely used machine tool. Various styles are available: bench and pedestal grinders for sharpening lathe bits and drills; surface grinders for producing square, parallel, smooth and accurate parts; cylindrical and centerless grinders; center-hole grinders; form grinders; facemill and endmill grinders; gear-cutting grinders; jig grinders; abrasive belt (backstand, swing-frame, belt-roll) grinders; tool and cutter grinders for sharpening and resharpening cutting tools; carbide grinders; hand-held die grinders; and abrasive cutoff saws.


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