45,000 operating hours. This is how long - or even longer - a 15-year old cylindrical grinding machine is in use. Anything that does this much will wear, and this particularly shows itself in the geometry and precision. High time to give the machine a good overhaul. A machine overhaul at STUDER makes an old machine into one that is as good as new; in other words, a machine that has the same tolerances as when it was first delivered. If the requirements on the machine have also changed, the machine can be configured and retrofitted to the customer’s requirements during the overhaul. 

The S40 was in use at LMT Kieninger for 14 years. The company specializes in highly demanding machining tasks and manufactures special tools for die and mold making. "The S40 was the Rolls Royce of grinding machines. But the machine still wears over time and after intensive use", admits Heiko Braun, Group Manager of Cylindrical/Surface Grinding and Assembly. It was clear to LMT Kieninger that they should send the cylindrical grinding machine to the STUDER factory in Switzerland for an overhaul. STUDER provided them with a loan machine for around three months and took care of everything from A to Z - from collection through to customs formalities. "We were very satisfied with the loan machine. Apart from a few little things, we were able to continue grinding as usual", sums up Braun. The special feature about a machine overhaul at STUDER? It is the only company to refurbish the machines' guideways to the original specifications. After the assemblies have been reinstalled, the machine geometry is equivalent to that of a new machine. Braun's view: "This point in particular really convinced us. We notice the difference. Since the overhaul we have been grinding with the precision of a new machine. I can only recommend a machine overhaul. Everything went without a hitch, the investment has paid off and a 1600 mm machine is worth its weight in gold for us."

Rebuild – new from old
A rebuild, or a machine overhaul, makes sense, and not just economically. The operator gets his familiar machine back and continues where he stopped before the overhaul. But he is full of enthusiasm! Because his old machine is like new. In the STUDER factory the specialists disassemble the machine into all its individual parts. The guideways are completely refurbished, the assemblies overhauled, the wear parts in the electric cabinet replaced, hydraulic and lubricating system as well as all valves replaced. If old spare parts can no longer be obtained, STUDER provides an alternative solution. The casing and components are sand-blasted and then given a fresh coat of paint. After assembly the geometry is like that of a new machine. Commissioning is carried out by STUDER Customer Care, including a functional and geometry inspection, all CE-compliant. "Over 20 people work on machine overhauls at STUDER. This shows the value of rebuild and retrofit at STUDER. The customers are always enthusiastic about the transformation and are delighted to put an as-new machine into operation at an excellent price-performance ratio", says Marcos Cotarelo, Divisional Head and Customer Care Consultant. 

Expanding the component range
If the customer wishes to expand his component range at the same time as the overhaul, he does this with a retrofit. During the machine overhaul the machine can be modified or retrofitted to the customer's requirements. This opens up new production possibilities on the same machine. Ingold Tools AG has taken advantage of this STUDER service. 

Ingold Tools AG has been producing high-precision and complex parts for spindle, compressor, hydraulic and general machine manufacturing with 25 employees since 1946. The machinery includes a variety of CNC-controlled and conventional machines, including robot-automation solutions for turning, milling/drilling, honing, lapping, barrel finishing, sand-blasting, laser marking as well as surface and cylindrical grinding. The cylindrical grinding shop already has several conventional and CNC STUDER machines. A further machine is currently being overhauled in the STUDER production halls. This is an 18-year old S21 with two external spindles and continuous fine adjustment of the turret wheelhead (B-axis fine), which the two managing directors Christoph Jenzer and Edgar Stich recently took on as a second-hand machine. The S21 will not only be updated in line with the latest developments, but will also be retrofitted to suit the needs of Ingold Tools AG. The cylindrical grinding machine will have an additional internal grinding spindle for internal cylindrical grinding and the relevant fixture for swiveling the tailstock into the park position. The S21 will also have 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 will also be upgraded from MK4 to MK5. "This deal is perfect for us. Thanks to the retrofit, we get the second-hand machine with 50 percent new hardware", enthuses Jenzer. 

Trusted quality
The S21 is the second factory-rebuilt STUDER machine at Ingold Tools AG. In 2016 the company took on a second-hand S31 machine, which STUDER overhauled. “We grind to a bearing tolerance and diameter of 1my. STUDER guarantees this accuracy after the overhaul. Either way: An overhauled STUDER will run just as long as a new machine”, attests Stich. Jenzer and Stich see a further advantage of the machine overhaul in the operation: “The employees don’t have to get used to a new machine with a new control system.”

Ingold Tools has relied on STUDER since it was established in 1946. The first external cylindrical grinding machine was a type 01 from the year 1955. This was still in use when Christoph Jenzer joined the company 13 years ago. “We like working with STUDER. The service personnel are quick to respond, and our Customer Care Consultant supports us wherever he can. It’s not without reason that we have so many STUDER machines.” A new machine? Jenzer and Stich say: “We wouldn’t rule it out – a new machine always offers advantages which an old one doesn’t have, such as faster travel in all axes, simpler set-up of the machine, and easy programming with less technical knowledge.” But the employees are looking forward to the overhauled S21, which will soon be on its way to Inkwil in Bern. 

Machine overhaul at a glance

•  Machine base: Completely overhauled, ribbed guideways milled, recast and repainted.
•  Control cabinet: Replacement of wear parts in the electric cabinet.
•  Pneumatics: New valves, hoses and filters. 
•  Hydraulics: New hydraulic and lubricating system, all new valves and hoses.
•  Tool headstock: Completely overhauled.
•  Wheelhead: Completely overhauled.
•  Tailstock: Completely overhauled.
•  Axes: Tables as new, installation of new recirculating ball screw and bearings. 
•  Component casings: Sand-blasting, repainting, color according to STUDER design or customer requirement.
•  Control system: Existing control system is retained.
•  Delivery: Always with precise measurement of new machine tolerance including test certificates. 
•  Loan machine: We can provide a loan machine on request.
•  Renewed original CE certificate