Breaking through the profitability barrier

Titanium and stainless steel are nasty-hard – two of the toughest metals to mill. However, in aerospace machining, those two materials cannot be ignored. Titanium use is already up 30%, and the industry is developing new, more efficient aircraft designs using more of both titanium and stainless.

So, that is where the work is, and savvy aerospace machining firms are working with tool manufacturers and their reps to find the right endmills, as well as the right process, for the job.

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

With solid micrograin carbide the top choice for milling the hardest materials, IMCO is one of the tool makers being approached by aerospace machining firms and their reps. Based in Perrysburg, OH, in the heart of the manufacturing belt, IMCO’s specialty is designing endmills with advanced geometries for maximum cutting efficiency – even in hard-to-machine metals (superalloys, stainless steel, and titanium). Therefore, with its long history of exclusively solid carbide tooling with high metal removal rates and high-performance coatings, IMCO was a logical choice.

During 2010, two shops based in Washington, with very different project parameters but the same needs, have developed highly successful endmill solutions with IMCO: Neumeier Engineering and JAMCO America.

Improving Tool Life
Neumeier Engineering, a family-owned aerospace company in Kent, WA, has a long history of working in stainless steel and titanium. They began testing endmills to machine in heat-treated 15-5 stainless, looking to improve productivity on a job they had – and lost – five years before.

Mark Neumeier, vice president and co-owner of Neumeier Engineering, explains: “When we made the part several years ago, we used insertable tools. Nevertheless, they were less predictable, less reliable. Now that the project was back, we planned to use solid carbide tools. We wanted to reduce cycle time and increase the predictability of tool life.”

They had already started production when Patrick Clewis, a sales rep with Western Tool & Supply in Lynnwood, saw the tool running and said he could definitely help them cut faster and increase their parts per tool.

“We first talked with them about what we could do differently with the process, and with that came increased productivity. Then he agreed to test some tools.” 

Mark Smith, an IMCO rep with Advanced Tooling Company out of Olympia, WA, often consults with sales reps on specific machining challenges.

“Neumeyer 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 (Osburn) and said, ‘We need a tool with this feature and these other features.’ ”

Fine-Tuning Needs
Smith knew IMCO was working on a new series of enDURO endmills geared to solve exactly the problems Neumeier was having. He also knew enDURO tools were being developed for use with the newer high-efficiency machining techniques, one of the changes Neumeier had already incorporated into its process at Clewis’ recommendation.

Osburn was ready and willing, as IMCO typically works directly with customers to fine-tune its high-performance tools, testing and refining and retesting until the customer’s goal is met. In addition, he was particularly pleased about working with Neumeier, whose quality and performance expectations, he knew, would be high.

“Neumeier Engineering is well regarded for being able to produce what others cannot figure out. Their stuff is very good.”

Neumeier was impressed with IMCO’s eagerness to jump in with solutions. The aerospace parts maker had worked with other companies 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.”

The enDURO M525 initially performed satisfactorily or better in most categories: heat-resistance, substrate strength variable indexing for reduced harmonics. and no work hardening. However, 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 next was to focus on refining the cutting edges and corner geometries.

“If your cutting edges can resist notching and edge wear, you have got a winner,” Osburn says. “But that depends on a lot of variables.”

Smoked ’em All
Smith (the IMCO rep from Advanced Tooling) says this was the first real, true test for Neumeier in machining stainless using high-efficiency machining techniques – uninterrupted light cuts, fast. Neumeier says Smith’s experience was very valuable during the project and instrumental in its success.

By August, there was a new, and final, 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. On regrinds, the IMCO enDURO M525 consistently makes 10 parts, compared with five from the other tool we tested.”

The team also ran the enDURO M525 against a few competing tools. “We smoked ’em all,” Smith (the IMCO rep from Advanced Tooling) says. “That was a lot of fun.”

Clewis says the best gain was in tool wear. It was much 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 were 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 states.

Higher Speeds, Feeds
If you have done little or no machining work in titanium, you might think it requires more machining power or newer equipment than you can provide. Not so. Tests at JAMCO America, Everett,  WA, using low-power machining centers have shown that all it takes is the right technique and the right tool.

Titanium is where a growing percentage of machining work can be found; the use of titanium is growing faster than that of all other metals. But, if you have ever worked in titanium, you know it is a nasty-hard material with quirks. The ugliest is its tendency to deflect away from the cutting tool. That can create a lot of very expensive scrap, not to mention time wasted on machining it to that point.

And, when you have warp-speed turn times, like JAMCO America, you cannot afford the scrap or the 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. We have to be on the cutting edge, turn faster and put out a very good product.”

Milling on Low-Power
Aldrich’s career began with Boeing Company in 1967, his first program written on a stack of IBM keypunch cards. JAMCO America has been around awhile, too, manufacturing aerospace interior components, mostly in aluminum. In 2009, a new project came in to produce rails for aircraft seating – in titanium. Aldrich had two dilemmas. First, titanium work was relatively new to JAMCO, second, the shop uses fairly low-power equipment. So, Aldrich called his rep at Western, Patrick Clewis.

Just a few months earlier, Clewis and Advanced’s Mark Smith had helped Aldrich cut set-up time significantly by slowly reducing the number of cutting tools in the machine racks from 16 or more, to as few as six. (See sidebar for details.) So, when the titanium project came in, Aldrich called them.

“They showed us the part 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 endmills are the same ones that proved very effective in heat-treated 15-5 stainless at Neumeier. When Mark 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, lead machinist at JAMCO America and Aldrich’s partner in validating new tools.

Smith tested the M525s at the speeds and feeds JAMCO was using to cut aluminum.

Getting the Speed
“Everybody was leery about using those speeds and feeds – nobody believed you could get this speed in titanium,” Aldrich says.

They were shocked that the tool machined as fast as it did and got good 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. So far, tool life is much better than I expected. ”

Milling parts 96" long with very thin (0.070") walls, one of Aldrich’s biggest concerns was warpage. Tests showed that enDURO’s special geometries and variable indexing broke up the harmonics, allowing the tool to run more 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 fact, Aldrich expected several scrap parts during testing. At 87 lb rough stock for every finished part weighing less than 20 lb, material is already expensive. But the first part came through without a hitch – no scrap.

“You know, a machinist uses his ears. 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.”

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

“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.”

IMCO Carbide Tool Inc.
Perrysburg, OH
imcousa.com