Cutting Tool Engineering
March 2010 / Volume 62 / Issue 3

Sharp focus

By Daniel McCann

ANCA.tif
Courtesy of ANCA

With its diamond superabrasive wheels, an ANCA FastGrind grinder can resharpen a 1 "-dia., 4-flute, corner-radius carbide endmill in less than 4 minutes.

Should you outsource tool sharpening or do it in-house?

Ask Frank Schwenck his criteria for when to bring tool sharpening in-house, and in a blink he’ll answer your question with another: “Does it make sense?” … As in dollars and cents.

Last fall, Schwenck, president of tool manufacturer A&F Engineering Inc., decided to stop outsourcing its router bit sharpening service.

Used in woodworking to make cuts, grooves, notches and hollow out spaces, the solid-carbide router bits are ½ " to 3 " long and ⅛ " to ¾ " in diameter. Manufacturing the tools has been the Clinton Township, Mich.-based company’s primary focus since its founding in 1998. In addition, A&F Engineering also provides its customers with a router bit sharpening service, which it outsourced to local vendors.

But when Schwenck noticed the quality of that sharpening falling off, he started looking for an alternative. His first thought was to use his ANCA TX-7 CNC grinders for the job, but tying up $300,000 manufacturing machines for router sharpening “just didn’t make sense,” he said, adding that the operating cost of $150 per hour would exceed the hourly rate he could charge for resharpening. “You need a low-cost piece of equipment to make it make sense.”

As with Schwenck, economics and quality control are leading other manufacturers and job shops to rethink outsourcing their tool sharpening.

Russell Riddiford, president of CNC grinder manufacturer ANCA Inc., said he’s noticed a trend away from outsourcing since late 2008. “We’re seeing a big push for companies to bring tool resharpening back in-house. Certainly the economy is a major part of it, but there’s also a big desire among companies to be more responsible for the quality.” He added that firms can more confidently plan, schedule and control production runs when they know they can handle tool sharpening in-house vs. the potential time delays involved with outsourcing.

Those market shifts prompted ANCA last September to introduce FastGrind, an entry-level CNC grinding machine for tool resharpening. Priced at about $120,000 and with a double-ended wheel spindle capable of 10,000 rpm, the 5-hp machine is for shops interested in bringing standard and specialized tool resharpening in-house without having to tie up their larger CNC grinders.

Last December, Schwenck installed one of the machines at A&F Engineering. “The operation is relatively simple,” he said. “You reference the machine’s diamond grinding wheel, set up the workholding and make sure the concentricity falls within your specification [for a certain tool]. Then you set up the program so that it will flute out the tool; back off the primary, the secondary and the OD; regash the tool; and hit [start].”

The FastGrind resharpens 30 router bits, at $4 a piece, per hour. That’s an hourly production rate of $120 vs. $60 in operating costs to run the machine. Schwenck figures the FastGrind will pay for itself in about a year.

Rush 1. drill sharpening.tif
Courtesy of Rush Machinery

Point splitting a ½ "-dia. solid-carbide drill on a Rush Model 132C drill grinder equipped with a diamond grinding wheel.

Though Schwenck purchased a CNC to sharpen standard router bits, most shops use manual sharpeners for standard tooling. When it comes to special tooling, such as form tools, manual sharpening machine suppliers and shops alike said CNC sharpening is the best solution. Moreover, use of CNCs for regrinding tools in the U.S. is growing, said Ed Sinkora, marketing manager for CNC grinding machine manufacturer United Grinding Technologies Inc., Fredericksburg, Va., “Like [everywhere] else in the manufacturing world, the computer is king,” he said. “We still sell manual machines, but more so in Asia than in the U.S. market. One issue is skill level—there just aren’t that many people who can grind tools manually in the U.S.”

Yet some shops are using manual sharpeners, and cost savings is one among a number of the machines’ benefits, said Matthew Bernard, director of marketing for Ashland, Ore.-based Darex LLC, which sells drill bit sharpeners to shops. The company’s most popular model is the XT-3000 expandable tool sharpener. Darex also has software tools to help shops determine whether outsourcing or in-house sharpening is the more financially prudent decision.

“A lot of times the toolcrib manager or machine operator will see the value [of bringing sharpening in-house],” Bernard said. “But because they’re not sales people, selling the idea to their bosses can be a challenge. So we help to arm them with [tools] such as an ROI calculator to show decision makers that we can save them some money.”

Darex Machine ROI-Sample.pdf
Courtesy of Darex

Darex provides prospective tool sharpener customers with a ROI work sheet to help evaluate their potential savings after purchasing a drill sharpener.

Bernard has found that shops that bring tool sharpening in-house often realize a variety of benefits. “Aside from the cost savings, they can have sharp drills right when they need them, rather than having to wait while their drills get sent out and returned from a sharpening service. It also allows them to have fewer drills in their inventory and to use their money to buy other things. And then lastly, [with a tool sharpener in-house] they can play with different geometries, try different point angles or relief angles to find exactly what is going to work best in any given application.”

Rush 3.Model 252 Sharpens Drill.tif
Courtesy of Rush Machinery

A Rush Model 252 drill and tool grinder grinds the point on a 1¼ "-dia. HSS twist drill.

Keep on Running

In addition, if they’re running a hot job and a drill breaks, they don’t have to shut down the job until they can get a new tool from the supplier, according to Ted Hildebrant, sales manager for Rush Machinery Inc., Rushville, N.Y., which sells manual, semiautomatic and auto-infeed equipped tool sharpeners.

Hildebrant pointed out that aside from an added emphasis on frugality, more shops are taking on their own sharpening because the struggling economy has forced some tool grinding companies to close. For shops that lost grinding services, the sudden need to move the work in-house has proved challenging. Hildebrant added, though, that with the correct machinery and guidance those obstacles can be surmounted.

Skilled Craftsmen

Ten to 15 years ago, shops often had dedicated tool sharpening areas and skilled craftsmen to do the work. But the pendulum began to swing as shops realized they could outsource a lot of tool sharpening for a lot less money than it took to maintain sharpening equipment and pay craftsmen. Consequently, the skilled tool sharpeners were not replaced when they retired. Today, as more companies take on their own sharpening, making sure their employees are properly trained to sharpen on manual machines is the most common challenge they face, according to Hildebrant. The solution, he added, is to ensure that the tool grinding machine builder provides thorough training.

“A lot of operators of machine tools today run CNC machines,” Hildebrant said. “They’ve gotten away from the feel and look of what a good cutting tool should be. And for them to be able to put a tool on a manual machine, resharpen it and have it come out correctly is the biggest challenge. Once they’re trained, they’ll be more efficient; they’ll be able to grind tools while their [CNC] is making parts.”

The most common pitfall shops make when they bring sharpening in-house is to buy the wrong tool grinding machine, Hildebrant continued. He often fields calls from such companies: “Someone’s bought a machine and didn’t thoroughly go over with the manufacturer what tooling they wanted to sharpen. They’ve got it in-house, and then they realize it doesn’t sharpen the main tool they wanted sharpened; or it does that tool, but it doesn’t sharpen the other six tools they wanted to do. So I recommend making sure that the supplier fully understands the application the shop needs and getting the machine best suited for that application.”

But Hildebrant’s recommendations stop short of advising customers to sharpen specials on manual machines. For those applications, he suggests using CNCs. “Our equipment is for the general-purpose cutting tools,” he said. Specials “are very difficult or impossible to grind manually, and that’s where a [CNC grinding] shop would have a niche.”

CNC Tool Sharpening

Often at about $300,000 or more, CNC grinders are typically out of the price range of all but the largest of manufacturers using hundreds of thousands of dollars worth of special tools annually. Thus, for most shops, outsourcing special resharpening is often the best financial option. “The expense of maintaining, purchasing and upgrading [CNC] equipment is certainly a big hurdle,” said Pat Hjelm, cutting tool specialist at Anoka, Minn.-based Carbide Tool Service Inc. (CTS), which provides CNC tool sharpening and repair services. “A lot of people are having trouble finding skilled employees to do that very specialized work.” Also, because a company specializing in tooling often has more experience in sharpening and repairing a wider range of cutting tools, it can offer a wider range of expertise that a specialized manufacturer does not have, according to Hjelm.

Specialty 1.tif
Courtesy of Specialty Tools

Specialty Tools uses a Walter Power 5-axis CNC tool grinder to sharpen a solid-carbide through-coolant step drill to its original geometries.

For example, he continued, an aircraft component manufacturer was looking for a way to get its damaged tool bodies and dull high-performance drills reconditioned at a single source to simplify the process. CTS developed a program that allowed the customer to consolidate drill resharpening and tool body repair. The solution saved the client more than $100,000 in tool costs annually, and created additional procurement savings by using just one company for the reconditioning.

Quality is another prime concern for high-end tools. “Multistep drills and reamers have critical step lengths and diameters to hold, [and that] requires state-of-the-art grinding machines and checking equipment,” said Eric Lutke, vice president of GKI Cutting Tools, Crystal Lake, Ill., which also provides CNC sharpening. “A good tool grinder can look at a dull tool and determine by the wear if the tool has enough clearance, or if a hone, chamfer or radius, for example, can improve tool performance.”

Despite its advantages for sharpening complex geometries, the cost of CNC equipment has, for the most part, discouraged shops to bring the work in-house.

But that’s not necessarily the case with large manufacturers. When to outsource sharpening, “really boils down to how many tools are in need of [the work],” said Jerry Plummer, president of Specialty Tools Inc., Beloit, Wis., which manufactures carbide cutting tools and provides CNC tool sharpening.

“Let’s say the smaller shop with 10 to 15 machine operators sends out $300 to $500 a month worth of tooling to be sharpened,” he continued. “That probably doesn’t warrant the expense of a CNC machine. Now, if you get into a larger company that has a much larger tooling budget because they are consuming more tools, then it might be more advantageous for them to [purchase a CNC]. And maybe in a few years they will have a return on their investment.”

Training Requirements

As with manual tool sharpeners, among the biggest challenges for companies with CNC equipment is to make sure the operator is adequately trained on all the tool specs. “Everyone is pushing the envelope for higher tolerances and to make parts faster,” Plummer said. “And to do that, more companies are using high-performance tooling with unique geometries. It is important that the grinding operator be knowledgeable about all these tool geometries and with the proper use of the machine to sharpen the tool to the needed specs.”

In fact, companies occasionally purchase CNC equipment without employees prepared to operate it, said United Grinding’s Sinkora, “It’s very difficult to tell somebody over the phone who doesn’t understand a complex machine like a [CNC] tool grinder, how to set it up,” he said.

In addition, complex tools “can be extremely difficult to regrind,” he said. “Often, the helix varies on the flute and the indexing is uneven. The geometries will be unique and sometimes patented, and the only people who can regrind it are those who have an arrangement with the manufacturer.”

Sinkora added that a CNC grinder is “not idiot-proof. If it is not your core competency, think twice before you convince yourself that it is going to pay. If you are going to go with a CNC, get it from a company that has a good training program. It’s too much to expect for an in-house grinder with no training to sharpen tools on a complicated 5-axis piece of machinery, even with good software.” CTE

About the Author: Daniel McCann is senior editor for Cutting Tool Engineering. He can be reached at dmccann@jwr.com or (847) 714-0177.


 

Contributors

A&F Engineering Inc.
(586) 791-0286
www.af-engineering.com

ANCA Inc.
(248) 926-4466
www.anca.com

Carbide Tool Services Inc.
(800) 243-9577
www.carbidetool.com

Darex LLC
(800) 547-0222
www.darex.com

GKI Inc.
(815) 459-2330
www.gkitool.com

Rush Machinery Inc.
(585) 554-3070
www.rushmachinery.com

Specialty Tools Inc.
(608) 313-8730
www.specialtytoolsinc.com

United Grinding Technologies Inc.
(508) 898-3700
www.grinding.com

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