Perfecting the Cutting Edge

Low-power machines getting nearly double the productivity in titanium and stainless steel? It may be hard to believe, however, work being done by two West Coast machining operations is demonstrating that it is not only believable, but it is also profitable.

With the economy grinding its gears in efforts to climb out of the recession, that will be good news to a lot of shops looking for opportunities that do not require new equipment. Better still, there is a lot of work to be had in titanium and stainless, with predictions for more right around the corner.

So, when the two aforementioned machining operations were handed parts to machine in these two hard metals, they did what many perceptive shops are doing: they reached out and took the team approach.

“They are looking for exceptional cutting performance,” says Perry Osburn, president of IMCO Carbide Tool. “But tool life is just as critical. So they are looking at everything – substrates, coatings, tool geometries, and high-efficiency machining techniques. And when they are developed specifically to work together, it can result in some dramatic improvements.”

Based in Perrysburg, OH, the company’s specialty is designing endmills with advanced geometries and coatings for maximum cutting efficiency and precision, even in hard-to-machine metals (superalloys, stainless steel, and titanium).

Less Edge Wear
In fact, IMCO was working on a new line of enDURO endmills designed especially for cutting titanium and stainless steels. IMCO has a long history with exclusively solid carbide tooling designed for high metal removal rates and high-performance coatings, so it was a logical direction. In addition, its recent successes with variably indexed micrograin carbide cutters – POW-R-FEED in particular – IMCO was already well along the tool development learning curve. The company had already found that the same advanced coating used on the POW-R-FEED high-performance endmill was very effective at maintaining the enDURO tools’ ultra-sharp cutting edges in hard metals.

“Most tools fail in titanium and stainless because the cutting edges become chipped or wear unevenly,” Osburn says. “When that happens, you cannot get the exceptional finish quality you need, especially for medical industry parts. In addition, you get shorter tool life. If your cutting edges can resist notching and edge wear, you have a winner.”

Cutting edge wear typically happens because the chips are a bit gummy to begin with. Then, as the chips travel up the flutes, some bond to the cutting edges because of the tremendous heat generated at the cutting surface. As the tool turns, that now-irregular cutting edge strikes the workpiece again, part of it tends to break off.

“To keep these tools cutting, you need a coating with two things: the lubricity to keep those chips moving out of the cutting path, and the heat resistance to keep temperatures at the cutting edge below the bonding point. We found our coating does both with great reliability,” Osburn explains.

When it was time to test and refine the tool geometries, that knowledge would help two machine operations break through barriers to reach their productivity goals. IMCO recently worked with Neumeier Engineering and JAMCO America, two shops based in Washington, with very different project parameters, but the same expectations for superior product quality.

Improving Tool Life
Neumeier Engineering, a family-owned company in Kent, WA, has a long history of working in stainless steel and titanium. In 2009, Neumeier began testing solid carbide tools to produce an aerospace part in heat-treated 15-5 stainless. Years before, they had made it using insertable tools. This time around, their goal was to reduce cycle time and increase tool life.

They were already in production when sales rep Patrick Clewis, with Western Tool & Supply in Lynnwood, WA, saw the tool running. He said he could definitely help them cut faster and increase parts per tool. First, he advised Neumeier on process changes that resulted in better productivity. Then they addressed tools.

That is when Mark Smith, an IMCO rep with Advanced Tooling Co. out of Olympia, WA, entered the picture. Smith knew IMCO was designing its new enDURO endmills to solve exactly the problems Neumeier was having. He also knew enDURO tools were being developed for use with high-efficiency machining techniques, one of the changes Neumeier had already incorporated into the machining process at Clewis’ recommendation.

“Neumeier was using a couple of competitive 3/4" endmills but expressed concern that they were only getting six parts per tool,” Smith says. “The first tool we brought in did about the same or less. So, we talked to Perry and said, ‘We need a tool with this feature and these other features.’ ”

Fine-Tuning Tools
Osburn was ready and willing. IMCO typically works directly with customers to fine-tune its high-performance tools.
Mark Neumeier, vice president and co-owner of Neumeier Engineering, was impressed with IMCO’s eagerness to jump in with solutions. The company had worked with other toolmakers to make tool-design adjustments, he says, but not to this extent.

“Normally it takes our prompting and our suggestions to make tweaks to their existing tools. But, this time IMCO offered to make changes and provided the suggestions for the changes to be made,” Neumeier states.

IMCO’s enDURO M525 had initially performed satisfactorily or better in most categories: heat resistance, substrate strength. The enDURO’s variable indexing performed extremely well, breaking up the harmonics for very smooth and quiet cutting while having no work hardening.

Nevertheless, the problem with every tool tested was cutting edge strength. In the Neumeier tests, Clewis says, the ends wore out too quickly, producing six parts or less per tool. So IMCO focused on refining the cutting edges and corner geometries.

Improved Performance
By August, IMCO had returned with the last iteration. Neumeier’s reaction says it all: “We went through two or three iterations and now we have a tool that is significantly better than what we had before.”

Tool life increased from six parts per tool to a reliable 10½ parts per tool. “And on regrinds, the IMCO enDURO M525 consistently makes 10 parts, compared with five from the other tool we tested.”

Clewis says the best gain was in tool wear. Wear was more even on the enDURO, so the tool ran longer. The enDURO’s metal removal rate was significantly higher as well. Meanwhile, Neumeier is testing a second enDURO tool with IMCO for another program.

“We are able to use M525s on those, too. They bid that new part at a certain rate, and when they see what the M525 will do with it, they will be able to make all kinds of money and lower prices for the customer. They cannot wait to get started,” Smith says.


Higher Speeds, Feeds
A lot of shop owners worry that machining in titanium requires newer or more powerful equipment than they can provide. That is not always the case. Tests at JAMCO America, in Everett, WA, using low-power machining centers have shown that all it takes is the right technique and the right tool.

However, because of titanium’s low modulus of elasticity, it tends to deflect away from the cutting tool. But, when operators are cutting parts that require absolute precision, it is a big problem. With the metals used in the medical and aerospace industries, scrap gets very expensive very quickly – you cannot afford the scrap or wasted time.

“We are in a very time-constrained short-run environment with very fast turns,” says Bill Aldrich, CNC programmer for JAMCO America. “We have to turn faster than our competition. So we have to be on the cutting edge and put out a very good product.”

Therefore, they turned to their tooling rep, Patrick Clewis, and IMCO’s rep, Mark Smith, and followed their advice to test the tool IMCO had been developing with Neumeier. The results surprised him.

The part includes very thin (0.070") walls, so one of his biggest concerns was warpage. Tests showed that enDURO’s special geometries and variable indexing broke up the harmonics, allowing the tool to run very smoothly, and its cutting edges consistently sheared the metal with less wear.

“With titanium’s flex rates, you use the wrong geometry and it will push away from the cutter or it will stress and warp,” Aldrich says. “We experienced neither.” In addition, although he had expected to scrap two to three parts during the test, the first part came through without a hitch – no scrap.

In 2009, when a new project came calling for titanium, Aldrich saw two dilemmas: 1) titanium work was relatively new to the shop, and 2) the shop uses fairly low-power equipment. Therefore, Aldrich called Clewis who recently had helped him solve a different challenge – setup time.

Aldrich showed Clewis and Advanced’s Smith the titanium project and said, “Here, we would like you guys to tell us how you think we should machine it.”

Smith says, “They needed the best tools we had to offer. So we included enDURO M525 endmills” – the same endmills that were proving very effective in heat-treated 15-5 stainless at Neumeier.

Speed in titanium
When Smith sent JAMCO the speeds and feeds for the enDURO M525s, they raised a few eyebrows and more than a few concerns, especially from Art Ostrum, the lead machinist at JAMCO America and Aldrich’s partner in validating new tools. Smith was telling them to test the M525s at the speeds and feeds JAMCO was using to cut aluminum.

They were shocked that the tool machined as fast as it did with improved tool life. Then Smith bumped up the speed to 400sfpm and 80ipm, and the tool still ran smoothly.

“They work as advertised,” Aldrich says. “They will run 60ipm to 70ipm in titanium with a reasonable finish for a rough cut. With their endmills, even finish cuts run at 30ipm. And so far tool life is much better than I expected.”

“You know when you are hearing a good cut. You can tell. When these tools run, they sound better. It promotes a reasonable amount of confidence – you know they are doing the job. The confidence we have in these tools is much higher than usual.

“Someone would have to do a lot of talking to convince me that they could do a better job or had a better product. I am getting what I expected. We could not be happier.”

JAMCO is using enDURO tools in several styles (4-flute to 7-flute) and sizes for its titanium program.

IMCO Carbide Tool Inc.
Perrysburg, OH
imcousa.com