Pulling the plug on an old machine

Before the life-or-death decision is made, shops should review these basic criteria for rebuilding or remanufacturing.

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Solar Turbines Inc. chose the OEM as a single-source supplier for remanfacturing this and another VTC. Giddings & Lewis, the OEM, transformed each machine into an independent, automated machining cell.

Rebuilding or remanufacturing can save an ailing machine tool. But are these procedures worth the effort, or is it time to purchase new equipment? Shops can accurately diagnose their situations by knowing when to rebuild or remanufacture a machine tool; which machines are good candidates; and how to evaluate and select a rebuilding/remanufacturing source. In addition, current trends can also influence their final decision.

Whenever shops discuss an investment in a new machine, they should also consider rebuilding or remanufacturing. Usually issues of machine performance and manufacturing processes or output requirements instigate such discussions.

Choosing the right machine to revamp also requires evaluations and decisions concerning such things as mechanical characteristics, facilities, and costs.

Mechanical characteristics.
Does the machine iron provide an acceptable base on which to add new technologies? Can accuracy requirements be met? Can the current machine structure accept required increases in speed and performance capabilities? Will the machine — with its upgrades — meet current as well as future capacity needs? Asking these questions determines if a machine is mechanically fit for a makeover.

Facilities. Will the machine's existing shop-floor foundation adequately support upgraded technologies?

Costs. Will there be significant cost savings due to operator familiarity with the current machine, along with re-use of existing tooling, fixturing, and processing (part programs)? Will reused machine components save enough cost to justify the project? Can the redoing the machine be justified economically? These questions all help determine good machine candidates for rebuilding/remanufacturing.

After qualifying a machine tool as a good candidate, shops can then compare the advantages and disadvantages of revamping against purchasing a new machine.

Once shops make the decision to rebuild/remanufacture, they can begin evaluating potential sources for the job. Shops can start by talking to other people who are using, or have used, a machine rebuilt/remanufactured by any of the companies under consideration. A simple, quick conversation can reveal how satisfied they are.

To further evaluate a rebuilding/remanufacturing source, shops should prepare a spreadsheet or some similar form of supplier checklist. It should include the following supplier requirements, plus any others that might be special for an individual situation.

Technical resources maintained by each supplier
- Experienced, competent staff with good mechanical and electrical engineering capabilities
- In-house software engineering
- Qualified service technicians that can respond within a reasonable time (i.e. 24 hours)
- Project management techniques that ensure conformance to the scope of work, budgets, and schedules
- Complete machine documentation for operators and programmers, plus complete mechanical and electrical maintenance information
Quality system in place
- Inspection results provided by certified and calibrated equipment
- Equipment such as lasers, ballbar checkers, and vibration analysis
- Formal quality procedures and processes used by inspection personnel
Physical facilities capable of handling the job
Clearly defined runoff arrangement, including specifications the supplier will meet at runoff
Warranties included with a rebuilt/remanufactured machine
Likelihood the supplier will remain in business during full life cycle of the rebuilt/remanufactured machine

When it comes to selecting a rebuilding/remanufacturing source, logic dictates that an OEM is usually the most qualified, especially for incorporating its own latest engineering enhancements and technologies.

Likewise, the original machine manufacturer should be most qualified to integrate the latest generation of CNC, automatic toolchanger, pallet shuttle system, in-process probing, and other such technologies into its base machine. But shops should always rely on a thorough spread-sheet comparison when actually choosing a rebuilding/remanufac-turing supplier.

Trends influencing the decision
Trends that may influence whether or not a shop rebuilds/ remanufactures include automated manufacturing, maximum machine utilization, and high speed machining. The move to more automated manufacturing requires a source that can not only rebuild/ remanufacture machines but also incorporate all material-handling equipment, machine CNC, other related automatic machining operations, and computer controls for cell management. The automation trend puts a premium on sources with both the capabilities to rebuild/remanufacture equipment and update a given manufacturing process.

Ever-increasing pressure to maximize machine utilization rates is another trend that calls for the same complete rebuild/re-manufacture capabilities. Hand-in-hand with maximizing machine utilization is high speed machining.

The continuing trend of higher speed machining makes it important to work with a rebuilding/remanufacturing source that is truly up-to-date on the latest designs in machine spindles, bearings, lubrication cooling systems, and all other technologies required for higher speed operations.

Single-source rebuilding/remanufacturing is another trend driven by those already mentioned. Working with an experienced and fully capable single-source supplier provides the least amount of risk and ensures that various new technologies needed to compete profitably are included in the job.

When to consider rebuilding/remanufacturing

Machine performance issues

Maintenance/repair costs are high and continuously increasing.
Lack of machine reliability hurts production.
Age of machine, control, or both make replacement parts scarce and costly.
Technology is so outdated that few people know how to maintain the equipment.
Unscheduled machine downtime causes excessive lost production.
Machine inaccuracies create scrap and rework.

Manufacturing process (output) issues

A need for improved productivity calls for increased production and new products or product variations.
Process changes require improved machine performance for multi-axis contouring, greater machine flexibility, improved accuracies, and increased capacities.
Production flexibility dictates a more automated operation, requiring CNC, cellular manufacturing, and reduced lot sizes/inventories.

Advantages and disadvantages of rebuilding/remanufacturing versus purchasing a new machine

Rebuild/remanufacture advantages

The original machine's design has already proven it can handle the individual chip-cutting requirements.
Rebuilding/remanufacturing provides all the performance capabilities of a new machine at a lower initial investment, typically a savings between 15% to 50%.
Minimum installation costs from using the same machining foundation can generate savings from $10,000 to $200,000. Re-use of main electrical power source lowers costs by about $1,000 to $5,000.
Retention of existing process and tooling can save from $10,000 to $250,000.
Re-use of same basic part programs (software) because of tape compatibility between controls impacts first full-year costs by as much as $100,000.
Operators and maintenance personnel are familiar and comfortable with existing equipment. Because little training in required, companies can save up to $10,000.

Rebuild/remanufacture disadvantages

Existing machine will be out of production for a certain amount of time, and shops may have to outsource work during the process.
The rebuilt/remanufactured machine will have a higher burden rate when it is returned to production.

A single source of savings

When Solar Turbines Inc was in the process of considering whether to buy new machines or remanufacture its two existing vertical turning centers (VTCs), it learned that using the machine carcasses would save about $200,000/machine as compared to the cost of purchasing new machines. So Solar, a subsidiary of Caterpillar Inc., chose the remanufacturing method of machine modernization.

In the process, each original standalone Giddings & Lewis VTC was converted into an independent machining cell consisting of a rotary setup stand and three park stands. With these special stands, Solar can now set up and indicate parts in before shuttling them into each turning center.

Both machines, first installed in 1983, were producing a wide range of turbine parts in nodular iron and cast steel, ranging from 20 in. in diameter and 40 in. high to 48 in. in diameter and 10 in. high. But Solar wanted to upgrade its VTCs in order to improve cost efficiencies, quality, and throughput.

Original machines were 48-in., plain ram-type turning centers with 12-position tool carousels, moveable rails, and G&L 800 controls. Solar Turbines shipped only the base, column, and crossrail of each VTC to G&L.

As a result of remanufacturing, both machines now sport a 54-in.-diameter chuck, pallet shuttle system, additional height under the rail, more ram travel, and a 45-matrix batch toolchanger. G&L's NumeriPath 8000 CNC with a NumeriStation option (a PC integrated into the CNC operator station) runs the machines, while a CM90 cell controller handles the pallet shuttles.

Other new features include a programmable rail, automatic rail leveling, automatic part and tool probing, and an automatic tool-condition sensor system. The lubrication and mist collection systems, along with the coolant chiller, are also all new.