Wringing Extra Life From Inserts

Throwing away worn carbide inserts? Then you may be interested in a service that not only resharpens those inserts for added use, but also guarantees that the reclaimed inserts will perform at least as well as brand new ones.

“Most companies do throw away their worn inserts,” explains Bob Laflamme, president of R & J Tool Inc. (Laconia, New Hampshire). “That’s a waste, because the insert’s usefulness has not been exhausted. We can resharpen it as many as three or four times before it is no longer usable.”

Insert resharpening is hardly a new idea, but the process has had some definite drawbacks. “The traditional insert-resharpening process has been a downsizing process that retains the original shape of the insert but grinds it to the next smaller standard size,” Mr. Laflamme continues. “The user must then go out of the way to accommodate the smaller size, resorting to such things as shimming the insert, going to a different tool body, and so on.”

R & J Tool has developed an insertresharpening process that overcomes most of the shortcomings of the traditional process. The firm’s process sharpens the worn insert without changing its inscribed circle (IC) size or clamping height. As a result, the resharpened insert can be installed in the tool as if it were a brand new insert; no adjustments are required because the overall size of the insert is unchanged.

Worn inserts are ground using one or more of four grinding patterns that can be used for virtually any carbide insert. Grinding of the worn insert is confined to the cutting edges. “For example, on a square milling insert, we generally just grind the top of the insert on its outer edge; we don’t grind the full thickness of the insert, so the IC size of the insert remains unchanged,” explains R & J Tool sales manager Michael King. “And when grinding the top of the insert, we avoid the area where the insert is clamped, so that the reground insert fits the holder just like a new insert.”

Better Than New

However, grinding is only a part of R & J Tool’s insert-reconditioning process. The process begins with analyzing the user’s particular application to modify cutting edge geometry of the insert for optimum cutting performance, grinding and honing the insert, and then applying a coating (which can be one of several proprietary coatings).

“The worn inserts are the starting point for our analysis, but we also ask for enough information to enable us to engineer a cutting edge for the customer’s particular application,” Mr. King elaborates. “We guarantee that our reconditioned inserts will provide 100 percent of the performance of new inserts, however they typically deliver 125 to 150 percent, and in some cases as much as 300 percent of new insert performance.

“Our analysis also includes the cost to recondition the insert so that the customer can calculate the savings compared to newinsert costs,” Mr. King continues. “New carbide inserts range in price from $2 to $32. We can recondition inserts for about half of the cost of new, so as the price of the insert increases, sharpening becomes an increasingly attractive alternative.”

R & J Tool’s insertrecycling program is geared primarily to users of inserts in large quantities. “Our customers typically spend many thousands of dollars annually for new inserts, and we can offer them significant cost savings,” Mr. Laflamme adds. “Our process also addresses environmental concerns. We can reclaim inserts for only 5 to 10 percent of the energy required to produce them originally. And our automotive and aircraft/aerospace customers are pleased that we can offer them a recycling

process that reduces their waste stream, addressing ISO 14,000 concerns, at the same time that it reduces production costs.”

Smaller firms can also take advantage of the insert-recycling program, however. Mr. King cites as an example a small shop that uses basically one insert type for machining aluminum. The shop placed an order with R & J Tool to recondition 250 inserts, which represented a year’s supply. The shop paid $6 per insert for the reconditioning as opposed to $12 apiece for new inserts. The savings more than justified stocking a year’s supply of reconditioned inserts.