Overhaul, Retrofit or Replace Machines?

The productive life cycle of any machine tool is limited. Whether a lathe, milling machine or grinding machine, the accuracy and reliability of any machine deteriorates over time. How long this takes depends on the basic design of the machine, how heavily it is used, how often it runs and how well it is maintained. Companies who carefully monitor their machine utilization typically find that downtimes representing over 20 percent of the available machine time destabilize planning, maintenance and ultimately profitability.

This question is posed by many operation managers when the downtimes begin reaching unacceptable levels. Have there been major technological advances since the procurement of the existing machines, or have the requirements for the machine changed due to additional, new workpieces? In many cases there is no easy answer to the question if a machine overhaul with or without combined conversion or the procurement of a new machine is the better alternative.

A standard overhaul of a machine involves the complete dismantling and inspection of every mechanical, electrical, pneumatic and hydraulic component. In the rebuild departments of the UNITED GRINDING Group, the components are reconditioned or renewed as necessary in accordance with the OEM standards. Guideways are reconditioned or renewed, the machine geometry is restored to its original condition and documented. The parts are professionally stripped of any old paint and re-painted. The machine is then reassembled and run through a functional and geometrical test to ensure that it has been returned to its original state without changing the functionality.

It is also possible to overhaul only part of a machine - an assembly overhaul - following the same procedure but on a smaller scale.

For a complete overhaul of a CNC grinding machine, you have to calculate approximately 75 percent of the costs of a new machine. The typical overhaul cycle can be around 15 years; longer if the machine is used very little and well maintained. However, this time span is quickly reduced if the machine runs daily in three-shift operation with minimal maintenance.

Experience has shown that around 60 percent of the machines overhauled at the UNITED GRINDING Group return to their original location to perform essentially the same machining operations with similar capacity utilization as before. For the remaining machines, further modifications are made to make them suitable for additional or different tasks. The percentage of machines being retrofitted is increasing as the industry moves from long-term contracts for large quantities of identical parts to the modern high-mix low-volume (HMLV) approach in production.

The conversion of a grinding machine usually involves the addition of functions that allow more complex and productive grinding processes or the use of additional systems such as automation for production. The replacement of the complete CNC control system is a typical example because this enables the use of the latest software modules and ensures the future supply of spare parts for the control system.

The most frequently chosen alternative for a worn and unreliable grinding machine is still the replacement by a new machine. Despite the lower price  of the overhaul, appropriate investment strategies and allocations often make the purchase of a new machine more profitable. Depreciation, incentives and other tax aspects can vary depending on the age of a machine - and as technology progresses, many applications can become much more productive, based on the features of the new machine.

UNITED GRINDING machines are designed and built to operate as trouble-free, accurate and profitable as possible for many years. Ongoing maintenance and servicing in accordance with the manufacturer's recommendations increase service life and availability. And when a machine is nearing the end of its life cycle, we help you select options to find the best way to continuous productivity. We call that Customer Care from UNITED GRINDING.