Wear & tear: budget-conscious recyclers have a lot to consider when purchasing wear parts

C&D Recycler, May-June, 2003 by Brian Taylor

As with many things in life, when purchasing wear parts most recyclers are reluctant to go for the lowest-priced products, fearing they may "get what they pay for."

Conducting ongoing cost-benefit formulas for wear parts can be a complicated process for recyclers who operate crushers and grinders, but it can pay off with better purchasing decisions.

Makers of wear parts say it is the only way for recyclers to determine which product is right for their machines.

LONGER LIFE

For several reasons, one of the performance measures used by recyclers when considering wear parts is the life of the product.

The greater number of operating hours a set of blow bars or hammer tips last, the more purchasers are getting for their money. Additionally, if there is a greater time span between replacing wear parts, the less overall downtime there is likely to be on a given project or in a month-long period.

Making cost-effective wear parts decisions--or getting the most for one's money--is unquestionably a critical choice for recyclers of concrete, asphalt, wood and other C&D materials. Along with labor, power and transportation costs, wear parts make up an important fraction of the operating costs pie.

"The percentage of operating costs attributed to wear parts varies from operator to operator, but it is significant," says Jeff Hickey, a product manager with Kennametal, Latrobe, Pa. The company makes hammer tips and other cast parts used in tub grinders and other wood processing equipment.

Operators of concrete and asphalt crushing machines also must tally up wear parts purchases as an ongoing operating cost. Jeff Hillis, parts sales manager of Eagle Crusher Co. Inc., Galion, Ohio, says his company has been reluctant to pin-point a percentage figure to allocate to what the average concrete or asphalt recycler will spend on wearparts. "The problem is, it varies a great deal due to things like the abrasiveness of materials and the operator methods used to feed the machine," says Hillis.

Aggregates recyclers can do little to change their circumstances in terms of regional product differences, notes Hillis. "In Louisiana, if you're crushing concrete with 80 to 90 percent silica, your wear costs could be substantially more than when crushing limestone-based aggregates somewhere like Indiana," he offers.

On the other hand, operators of impact crushers can monitor and change work habits to prolong blow bar life, Hillis contends. As an example, Hillis notes that in its research, Eagle Crusher has found "that if you keep the hopper at a constant fill rate, you reduce your costs not only in fuel savings, but you also lower your wear costs. We think it's because the material flows into a position better where it can be crushed more efficiently."

Operators of both concrete crushers and wood grinding machines can also prolong the life of their wear parts by pre-screening material.

Wood grinder operators can keep their hammer tips out of harm's way by keeping "unshreddables" (such as heavy steel objects) out of the grinder material stream, notes Hickey. "Operators can achieve lower costs by pre-screening their material; they're not tearing up tips and burning up fuel grinding things that shouldn't be ground," he remarks.

Although railroad tracks and anvils may be the types of unshreddables that come to mind, Hickey notes that this can be a broader category that can include "rocks, metal fence posts, wire--it could be anything, and it usually is."

THE RIGHT FIT

Matching wear parts to the task and the machine may seem like an obvious step, but in a fast-paced market with a lot of conflicting claims by manufacturers, this obvious step can get lost.

On the aggregates side, Hillis notes that even though recyclers can't pick up and move away from more abrasive materials that might be found in one geographic region (or on one particular job site), they can prepare to take on these nastier materials. "For example, clean asphalt needs the very hardest blow bar you can find, because it's soft," says Hillis.

Matching metallurgy to the task can be complicated, though. In the case of the asphalt mentioned above, "If it has metal contaminants, you need to move down the metallurgy scale," notes Hillis.

According to Hillis, "With cast wear parts, you're walking a tightrope between the hardest possible material to avoid sliding abrasion, and a material that is forgiving enough to take the impact abrasion." Both types of abrasion work in different ways to wear down the surfaces of blow bars in an impact crusher.

The complicated truth, according to Hillis, is that "there is no one wear alloy that works across the board in terms of both wear and impact resistance."

The result has been the creation of a variety of available products, with Eagle Crusher alone selling a wear parts with a half-dozen different metallurgical alloys, according to Hillis. Other manufacturers offer additional metallurgical innovations, offering crusher operators a variety of choices.

Wood recyclers operating grinding equipment face similar choices, according to Hickey. "Using the right tip for the job, in terms of both geometry and chemistry, is a key consideration," he notes. "Kennametal offers a wide variety of tools for specific applications."