Conventional wisdom in crusher maintenance involves two basic approaches: regular replacement investments in new crushers, or overhauls specified for the conditions at hand.
It’s not unlike buying a new car at regular intervals as opposed to making a continuous effort to keep an old car in a good state of repair.
Both approaches, naturally, have their merits and disadvantages. Investing in regular replacements increases capital spending, but helps to minimise maintenance costs. Extended ownership with regular overhauls can be financially more attractive, but the owner may have to accept longer downtimes.
Some suppliers to the industry offer a third way, such as Sandvik’s Reborn rebuild solution, which could be compared to upgrading a used car with a new engine.
Reborn combines a 100 per cent new, factory-built Sandvik crusher with a systematic service package, where usable auxiliaries and surrounding process infrastructures are reutilised.
A part of the Sandvik 365 service concept, the Reborn rebuild solution is combined with a three-year extended warranty that applies to all major components, including on-site service.
‘Born again’
{{image2-a:r-w:300}}Reborn essentially standardises the rebuild process into a systematic, six-stage service product: pre-feasibility assessment, budgetary quotation, crusher auxiliary audit, new crusher installation under Sandvik supervision, on-site training, and regular condition (see boxout).
The exact scope of each Reborn package is defined during the pre-feasibility study, depending on the specific crusher model.
The standard scope in all cases includes a replaced crusher and hopper, a bottom shell liner upgrade with a hard, highly wear-resistant steel grade and a new offline filter. The hydroset cylinder protection is also included as a default for all models.
The most commonly usable auxiliaries and infrastructure surrounding the crusher include the main motor, drive system, lubrication and hydraulic systems, coolers, control, automation and electrical components, foundation, feeders and conveyors.
The pre-feasibility assessment reveals whether the auxiliaries can be reused with normal spare parts exchange and modifications. If so, this results in a quote at a fixed cost and scope.
This can be followed by a Reborn auxiliary audit – a full inspection of all auxiliaries to list the actions to be taken prior to, or in combination with, the Reborn installation.
The installation under Sandvik supervision is followed by on-site training to lay a solid foundation for effective operations and crew safety. Periodic condition inspections verify that the specifications and targets are met and that preconditions for continuous improvement exist.
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Inspections, training Inspection: Three to four inspections are planned and conducted annually by certified engineers. Generally, they coincide with liner changes, to avoid downtime. They take one to two days, and the data gathered helps diagnose maintenance issues. From there, corrective action can be enacted immediately. This is a proactive, predictive and preventative maintenance philosophy, saving the producer time and money in the long term. A three-year extended warranty is included in the offering, which helps maximise equipment uptime and addresses ongoing issues. Training: Sandvik not only supervises installation but provides on-site training to equipment operators. It helps new and veteran workers get to grips with the machinery quickly, ensuring they respond effectively to maintenance challenges. The two and a half days of training consists of theoretical operations, plus maintenance training, equipping operators with the knowledge to keep equipment performing at its peak. It also prepares employees for the tasks they will face when operating the unit in its real-life environment. |
Life cycle aspect
Reborn replaces the complete crusher, to upgrade its performance and restore availability rates close to those of a new unit at a lower operating cost, yet with significantly lower capital expense compared with purchasing an entirely new crusher system.
{{image3-a:r-w:300}}A key feature of the Reborn solution is a pronounced and integrated life cycle aspect, leveraging the expertise advantage of the original equipment manufacturer compared with third-party overhaul firms. The extended three-year warranty covers 85 per cent of the list price of the specified components, typically including top and bottom shell, main shaft and head centre, gear and pinion, hydroset cylinder and cylinder cover, piston, hub, dust collar and eccentric.
On-site training responds to needs arising from matters such as changes in personnel, which can also create maintenance challenges. A two and a half day theoretical operation and maintenance training course gives the operators a comprehensive introduction to maintaining and operating the unit properly in its real life environment, giving them the practical skills to maintain optimal performance.
Three to four annual condition inspections by certified engineers are planned to coincide with liner changes, to avoid extra downtime. Measurements are carried out and reported according to a set protocol designed by Sandvik. The one to two days of inspections provide data to diagnose any progressing maintenance issues and to propose corrective actions as required.
The aim is a proactive, predictive and preventative maintenance philosophy: the owner can draw from accurate data-based predictions and prevent any issues in a controlled manner before they become acute. For example, the status report can include a quote for an imminent bearing change that should advisably be scheduled for the next maintenance stop.
End users most likely to benefit from the Reborn service are mines and aggregate producers processing hard types of rock and thus experiencing greater than average wear and tear.
Downtime solution
Another area where the solution offers high potential includes any operation with low downtime tolerance.
The well defined service concept with clear component interfaces serves to eliminate uncertainties resulting in downtime. It eliminates the risk of omissions in orders of spare parts, typical with regular overhauls.
In essence, the Sandvik Reborn solution keeps the crusher continuously updated with the latest design upgrades. It offers full reliability and performance levels comparable with a new crusher, plus additional value – the extended warranty and service offering – at a very competitive cost compared with a complete overhaul.
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Capital aggregates/delta materials, Marble Falls, Texas, USA The US aggregates producer had a Sandvik CS440 cone crusher installed about 15 years ago for secondary crushing of competent sandstone. The feed material is from a primary jaw crusher, while the crusher itself feeds a tertiary crusher further downstream. After 15 years of operation, the CS440 had started to suffer mechanical issues. However, the ASRi 2.0 setting control system was recently updated. As the lubrication system was also in good repair, only the crusher required refurbishment. The Sandvik Reborn solution offered a cost-effective alternative to a complete overhaul by replacing only the worn-out components, with minimal downtime. Reliability benefits were achieved by solving the mechanical problems, compared with the potential problems after an off-site weld and machining repair. |
Text by Turkka Kulmala. Originally published in Solid Ground magazine, a Sandvik Rock & Technology publication. Visit solidground.sandvik