A machine-tool rebuild involves complete disassembly and validation of the condition of every part. The machine casting and enclosure go through a deep steam-cleaning, followed by abrasive blasting and fresh coats of long-wearing paint. Everything from windows and lighting to wiring and hoses is fair game for replacement.

The R’s Have It: Rebuild, Retrofit, Repurpose, Replace

Sept. 26, 2019
When an older machine begins to show signs of wear and new technologies make it look out of date, that reliable piece of equipment can start a second life.

Hard work shapes the life cycle of a grinding machine through the impact of day-in, day-out activity shaping electronic and mechanical components. With careful use, regular periodic maintenance and thorough field service, a grinding machine can stay productive for 20 years. Over time, however, accuracy and geometry slip away from their original specifications, and eventually, downtime increases to unproductive levels.

When an older machine begins to show signs of wear and new technologies make it look out of date, that reliable piece of equipment can start a second life — rebuilt to return to its original condition, retrofitted to gain updated capabilities or repurposed to take on new tasks.

Rebuild — A true rebuild proceeds like the frame-off restoration that transforms a rusty vintage automobile into a head-turning showstopper. This thorough process completely disassembles the machine and validates the condition of every part on a nuts-and-bolts level. The machine casting and enclosure go through a deep steam-cleaning, followed by abrasive blasting and fresh coats of long-wearing paint. Everything from windows and lighting to wiring and hoses is fair game for replacement.

Some of these replacements efforts actually qualify as upgrades. Grinding machines often outlast their control technologies by five to 10 years, so reinstalling the same CNC would be impractical, given the limited parts availability for older technology.

Instead, a new control extends machine lifespan, adds features, functions, and convenience – and can make user-friendly conversational programming available on a machine that reached the market before these operator-oriented approaches debuted. The Q&A format of modern human-machine interfaces, or HMIs, allows less-skilled operators to initiate grinding tasks with greater confidence, entering a few data points to start a job rather than taking on full-fledged programming responsibilities to make a part.

Other up-to-date technologies enhance an older machine's precision and help cut cycle times when the grinder returns to service. For example, older motion encoders establish axis positions through a homing process that takes minutes to perform each time the machine powers up. Adding a modern, glass-scale encoder enables the machine to store axis positions, increases resolution by a factor of 100 and adds improved servomotors with much greater accuracy.

Once technicians replace all worn or outdated parts, a machine goes through a full series of geometric workups to compare its rebuilt configuration against OEM worksheets that outline original specifications. Painstaking hand adjustments bring any out-of-spec surfaces back in line with new-machine performance.

Finally, the rebuilt machine gets its certification paperwork, as a quality assurance team member documents the configuration in detail. With all its updates, upgrades, and like-new capabilities, the machine qualifies for new warranty coverage.

United Grinding North America established its Rebuild department to provide these and other services that increase the range of choices manufacturers can make in dealing with their older equipment. In addition to full rebuilds of customer machines, the department also prepares certified rebuilds for sale, and performs other services to retrofit and repurpose other grinders for new or expanded duties.

Retrofit — A gently used machine can qualify for a partial rebuild approach that replaces select elements of its construction to update a single subsystem in an otherwise fully functional grinder. These types of updates qualify as retrofits rather than full rebuilds, with the machine left on the shop floor throughout an on-site procedure that requires a matter of weeks.

A hard-working machine with an unmet need for mechanical maintenance but with an intact electrical system qualifies for a retrofit that overhauls worn or unrepairable mechanical components. Conversely, a machine that needs an electrical overhaul but that passes inspection against OEM mechanical standards can obtain a new electrical cabinet, wiring and servomotors.

Likewise, to take advantage of new technology, a machine with an older CNC unit can receive a new control to ease programming tasks, reduce cycle times and enhance productivity. The same types of updates can benefit other components, including feedback systems and motion encoders.

All of these retrofits extend machine life cycles and forestall or even eliminate the need for a full rebuild. Best of all, because they skip the time involved in shipping a machine to and from a service facility, they reduce a shop's downtime even further. The United Grinding North America Rebuild department uses only OEM parts to perform its services, which assures customers that their equipment will function according to specifications.

Repurpose — Most machine overhauls – nearly 60% of them – add improved functionality to prepare a machine to resume its former duties. Other procedures reconfigure a machine so it can assume a new role through repurposing, which sets up a machine to fulfill a different, increasingly complex part of a production process than it formerly could address.

These additional capabilities take on new meaning at a time when high-mix, low-volume manufacturing places a premium on equipment that can adapt to constantly changing workflows. Long-term contracts for high-volume, low-mix production have become increasingly scarce, and shops that want to thrive in this new era need the nimbleness to transform themselves into a wide range of configurations for equally diverse jobs and parts. In this context, a repurposed machine can make the difference between stagnation and growth.

In a repurposing scenario, an open-enclosure machine might require a new closed configuration to take advantage of new coolant options for use with equally new grinding-wheel technologies. Safety options such as automatic doors could retarget a machine to accept the addition of robot automation. The addition of a rotary dresser could make a machine operate without the need for frequent interruptions to remove grinding wheels, dress and replace them.

Few repurposing strategies result in large-scale reconfiguration. Some of these repurposed upgrades depend on additional engineering to adapt casework, pneumatics or hydraulics, accommodating new subsystems or reconfiguring a machine just enough to add the updates necessary for new features. United Grinding North America's Rebuild department can recommend specific enhancements to broaden the capabilities and expand the working life of a customer's existing equipment, giving customers a full picture of their repurposing options.

Replace — The rebuild versus replacement decision often comes down to cost, time, and expense categorization. On average, grinding machine rebuilds come in at approximately 75% of the cost of a new machine. If a rebuild exceeds that amount, the machine may be a better candidate for replacement than for rebuilding.

Lead times run much shorter for rebuilds than for new equipment. Faced with an urgent new contract or the need to maintain an existing production level, a shop may decide to retrofit an older machine to take on new duties while waiting for new hardware to arrive. This best-of-both-worlds strategy can save money as well as time.

Most corporate accounting systems categorize rebuilding as a maintenance expense, as opposed to the capital expense of new gear. Budgets that constrain funds to one category rather than the other can determine whether a rebuild or a new-equipment purchase makes more sense.

To achieve the best long-term results from a hardware investment, begin with high-quality equipment. Advanced grinding machines from United Grinding North America offer the flexibility and high-quality output to yield years of outstanding production, especially with proper scheduled maintenance.

When a Blohm, Mägerle, Studer, or Walter machine needs more work than regular field service can accomplish, the United Grinding Rebuild department offers factory-trained technicians with a full mastery of brand-specific capabilities and OEM specifications. The department uses only OEM parts for all its rebuild, retrofit and repurpose procedures, backs its work with a full one-year warranty and offers the expert support of an outstanding field service organization.

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