Buying a pre-owned machine may sound like common sense when capital expenditure is under scrutiny, but this strategy is not without its problems.
"Anyone in the industry will tell you that good quality second-hand machines are getting hard to find," says Brian Burn, managing director at Blue Diamond Machine Tools (01388 776052), which provides a refurbishment, rebuild and CNC retrofit service. "As a result, we are seeing an increase in the number of customers seeking our help."
Blue Diamond says it can 'geometrically' refurbish a Colchester Triumph 2000 lathe, service and paint it for a price of around £4,000, excluding any new parts that may be required. Upon completion, the geometrical alignment of the machine will be correct to the manufacturer's specification.
The company will refurbish any machine tool, from a small centre lathe to a 5 m bed machine; or from a Bridgeport turret mill to a 6 m bed Elgamill. It retrofits all popular CNC controls with "Fanuc and Heidenhain being the preferred choices". DRO options are also available.
DRO vendors themselves are also active in the retrofit market, typically through approved system integrators and distributors. A case in point is a special-purpose hybrid turning/grinding centre recently developed and built within eight weeks by an Acu-Rite-approved retrofit distributor, which is playing a key role in the production of special square section polymer seals used in the aerospace industry.
Based on the reground and reconditioned bed of a Hardinge HLV manual centre lathe, the machine was completely re-engineered by Machine Tool Controls Ltd (01495 764345). As well as panel build, the project involved the installation of a new cross-slide and headstock packer to raise the centre height by 65 mm and to carry the Acu-Rite linear encoder and two toolposts.
Image: Machine Tool Controls took care of this Hardinge rebuild
A carbide knife blade in the front toolpost is used to clean-cut the moulded edge of the seals at 45°, while a grinding spindle in the rear toolpost position is used to grind the inside diameter (when the seal runs on a shaft) or produce a step on the outside diameter (if the seal is to be located in a housing). Key for the machine operator to maintain position of the slides and tolerances is the use of an Acu-Rite 200S LCD panel-mounted DRO, supplied by Heidenhain (01444 247711). The MTC-supplied package also included a pair of SENC 5-micron resolution glass linear encoder scales for the machine's X and Z axes. Each scale incorporates roller bearings to reduce any backlash effect when positioning.
"The Acu-Rite 200S DRO has proven very popular in the retrofit market for turning, milling and grinding operations," says MTC's managing director Chris Stinchcombe.
"The large 3D keypad makes data input easy for the operator and ability to hold 16 tool offsets/diameters, preset and zero reset, as well as near-zero warning."
Of course, many suppliers of new machine tools also offer a selection of pre-owned models that have been refurbished to high levels of quality.
"The sheet metal market is presently very strong for good quality used machines, which continue to represent an important and significant part of our business," says Alan Parrott, managing director at sheet metal machine tool specialist Amada (01562 749500).
Post-recession, Mr Parrott says the growing number of start-up businesses is fuelling the demand for good quality, reliable pre-owned machines. Amada occupies a strong position, in that more than 85% of its machines up to five years old will have been supported under its own maintenance contracts.
"While we have a service book and can provide a full service history from our electronic service system, all pre-owned Amada machines are refurbished by our own dedicated engineering team," says Mr Parrott.
Image: Amada is also able to provide refurbished machinery
Among the recent takers of Amada used machines is Castleford-based subcontract fabricator Yorkshire Laser & Fabrications. "I'm really happy with the pre-owned machine I took from Amada. The pre-delivery, installation, training and after-sales support were excellent and no different to what I would expect with a new piece of kit," says the company's managing director Garnett Orford. EDM, milling and laser ablation machine tool specialist Agie Charmilles (024 76 538666) is another supplier promoting its refurbishment and reconditioning service. Following a marketing push last year, Agie Charmilles says enquiry and order levels have risen sharply.
"In most cases, the customer wants to improve their machine's performance via a comprehensive overhaul of its mechanical, hydraulic and electrical components. This entails a 'strip-down' of the machine, the replacement of many wear parts and software upgrades," says Owen Pennington, operations manager at Agie Charmilles.
"Some of the machines we have refurbished recently were up to 10 years old...sometimes older. Even though they had been serviced regularly since initial purchase, their time in service had affected their performance (accuracy, cutting speeds and surface finish capability) and reliability over and above what could be rectified during a normal machine tool service."
Agie Charmilles' refurbishment work is undertaken by the company's own engineers who only use OEM replacement parts, in order to support a 12 month warranty.
"A refurbishment is the right course of action for some companies, but not others," says Mr Pennington. "It really depends on what the customer is looking to achieve and what they expect from a refurbishment – as well as the age of the machine and its condition."
Taking refurbishment to the next level is helping manufacturers to side step the high cost of buying new OEM replacement parts. Fanuc Robotics (02476 639669), for example, has recently introduced a refurbished parts exchange. Only available through the manufacturer, all refurbished Fanuc robot parts are supplied with the same warranty as new parts.
Typical parts available as service exchange include motors, encoders, servos, boards and pendants. In addition, Fanuc Robotics has extended the service to include selected mechanical assemblies, such as wrist joints.
Introducing the service, Tom Bouchier, service manager at Fanuc Robotics, says: "All refurbished parts meet CE approval requirements, having been tested in our own factory.
"Environmentally, this is a good service to offer customers, as it makes our products more sustainable and reduces energy used in new manufacture."
Automotive fixture rebuilds
With just a two-week window during a shutdown period, Inca Geometric (01227 738565) rebuilt four complex fixtures on a special-purpose machine tool, used for producing V8 engine crankshafts. Each fixture had been in continuous three-shift production for over five years, machining two crankshafts per cycle, and each weighed over two tonnes.
"We had general arrangement, circuit and most key part drawings. However, due to in-use wear, modifications and service changes through the life of the units, we were involved in a considerable number of reverse engineering exercises," says Mike Cain, managing director. "We also had to make full use of our machine tool build experience to ensure perfect alignment of the various datums, enabling uninterrupted production to continue immediately following the shutdown."
As part of the rebuild, a complete strip down of each fixture was performed, with all wear parts replaced. Location areas were either coated with ceramic or hard chromed and ground, while all bearings, seals and linear ways were replaced. Each hydraulic cylinder was stripped and either refurbished or replaced, valves checked and all hoses replaced with new.
First published in Machinery, March 2011