Spare Part Reflections

Specialized service providers can offer alternatives that save money and outage time while supporting the local economy.
By Holger Streetz | January 20, 2020

For several groups of components, equipment manufacturers do not offer single parts. Specialized service providers, however, can offer alternatives that save money and outage time while supporting the local economy. In this column, I will share a case solved for a German customer, changing a worn hammermill shaft instead of installing a whole new rotor.

Pelleting equipment must withstand high stress, vibration and wear. Even the best maintenance plan and operating supplies do not prevent fatigue and breakdowns. Therefore, components such as shafts, bearings, gear wheels, pinions and so on will fail at some point. Besides the general inconvenience, failures usually happen on a Friday afternoon, and equipment manufacturers tend to quote component groups rather than single components—especially hammermill equipment from various manufacturers, which is often sold in component groups rather than single parts.

Finding How-to
We were challenged in October with finding an alternative solution to swapping the rotor of a hammermill with a worn shaft. The reasons for finding another option were high component costs and lead times. We decided to locally source a turning shop and pull the shaft, rather than waiting for the rotor. This option offered several advantages. For the comparison, we first took the preparatory work into account. Disassembling the rotor takes at least two days, as it requires stripping the hammers, removing the housing, and clearing the feed chute, conveyors and other surrounding components. In addition, with the rotor weight of 1.5 tons, special lifting equipment is needed. Removing the shaft, on the other hand, requires approximately four hours of jacking and locking the rotor, removing the bearings and pulling the shaft.

Next, we evaluated component and transportation costs. A rotor is priced around $23,000, while a shaft from a nearby turning shop costs about $3,000. In our case, the rotor had a delivery time of 14 to 16 weeks, compared to three days for the locally lathed shaft. Although transportation costs might be included when buying large components from an OEM, the environmental footprint is significantly lower with local sourcing of single parts compared to shipping large components from the manufacturer’s storage or production facility, which is often overseas. The table included shows the simplified cost comparison for swapping the rotor vs. pulling the shaft (not including the call-out fee, which is similar in both scenarios), component transportation and downtime costs.

Lean and Local Sourcing
As a customer-oriented, OEM-independent, full-service provider, we were able to find a solution for less than a quarter of the cost, saving time and money. The concept of lean and local sourcing not only strengthens the local economy and reduces the environmental footprint, but it is also applicable with several components such as sifters and screens, flanges, shafts and pinions, and lately, scrapers and deflectors as well. Often, it takes a third party to overcome organizational blindness, and we are happy to support customers with fresh ideas and field-proven inputs.

Author: Holger Streetz
Director of Business Development, Bathan AG