Efficiency pays off

Shown is a CAD drawing of a defense industry part made from a 5.00" x 8.00" x 0.75" piece of 6061 aluminum using a VoluMill-optimized toolpath.Diamond Machine Works (DMW) has improved its speeds and feeds, cycle times, and programming time by rough machining complex aluminum, stainless steel, and titanium aerospace and defense parts using toolpaths generated with VoluMill. The software also has given the aerospace-oriented job shop greater flexibility.

Celeritive Technologies’ VoluMill is a plug-in toolpath engine, fully integrated with DMW’s Mastercam system. This technology generates toolpaths with smooth radial motions and controlled force on the spindle and cutting tool. VoluMill toolpaths are based on optimal material removal parameters that dramatically reduce cycle times and significantly extend the life of cutting tools.

DMW is a family-owned business, started in 1959 with manual machines, expanding over time, later embracing CNC machining.

The Seattle, WA–based job shop now has 15 to 20 employees, depending on the workload, and utilizes five CNC mills (two 50-taper and three 40-taper machines) and four CNC lathes – three Kitamura VMC’s – two 40-taper and one 50-taper; one Doosan 50 taper; and one Akira-Seiki 40 taper.

According to David Pruett, the company’s CNC programmer for 15 years, close to 90% of DMW’s work is for nearby aerospace and defense giant Boeing.

“We do a little bit of everything,” Pruett says. “As a job shop, we take a lot of work that other people will not bother taking. We excel with aerospace parts that no one else wants to make, due either to their complexity, low volume, or both.”

DMW prides itself on its ability to handle complex jobs made from steel, and other harder materials, in addition to aluminum.

“Some of the parts we cut are overly complicated,” Pruett says. “At first glance, it may not seem like a very complex component, but when you really look at the drawing, it is a part that you are going to have to work smart to make money. They are often filled with intricate, difficult-to-machine, and tight-tolerance features.”

The complexity of the parts produced at DMW led Pruett to research the latest high-speed toolpath software available. He settled on VoluMill, and accepted the company’s offer to try it free for two weeks.

Prior to VoluMill, DMW was using two separate tools to machine this aluminum part with a cycle time of 3 minutes 53 seconds. Using VoluMill, DMW is now able to use one tool and reduce the cycle time to 1 minute 58 seconds.“During that time, I programmed four or five parts,” Pruett recalls. “At first, I used VoluMill paths on our oldest 50-taper machine, which is nearing the end of its useful life. We experimented with some high-speed, machining-style roughing using solid carbide endmills, versus hogging with larger indexable insert tools. The toolpath itself was noticeably easier on the machine. We are able to run much higher surface footage and much higher feedrates.

In the Beginning
Before VoluMill, DMW was roughing a 5" x 4" x 1.25" 15-5 stainless steel blank into a classified airplane part with a 1.25" diameter, three-flute indexable insert cutter on the 50-taper machine at 400sfm and 22ipm with a 0.4" deep cut. With VoluMill, speed was increased to 800sfm and feed improved to 153ipm, all with a ½" diameter endmill.

“Our 40-taper machines could not even come close to handling a cutter that large,” Pruett says. “It is very hard on the machinery. Once we were able to see how fast and easily the material was being removed using VoluMill, toolpaths and high-speed machining on the 50-taper, we decided to give it a go on the 40-taper. We were pleasantly surprised to find out that the parts machined just as well on the 40-taper as they did on the 50-taper.

“The ability to run this job on the smaller, lower-powered machine, with smaller, less-expensive cutting tools, is a significant advantage for us,” Pruett says. “We benefit from the cost savings on inserts and machine wear and tear, and, most important, from the dependability of the process.”

According to Pruett, when roughing these parts with indexable tools, sometimes the operator had to stop and change inserts, and an operator had to watch the machine 100% of the time.

Other timesavings came when applying VoluMill toolpaths to an important part for the defense industry, machined from 5" x 8" x 0.75" 6061 aluminum.

Prior to VoluMill, DMW was using two separate tools, a 1" indexable insert endmill and a ½" ballnose endmill to machine the part. Cycle time was 3 minutes 53 seconds, using 0.25" step-downs for each pass. With VoluMill, DMW uses one ½" three-flute carbide endmill, at 7,640rpm and 275ipm, triple the previous rate. The new cycle time is 1 minute 58 seconds. DMW machines about 120 of these parts per year and saves approximately two hours of machining time per part using VoluMill.

Even on smaller parts made of harder materials like titanium, DMW has seen improvements in productivity using VoluMill toolpaths.

Pruett cited another difficult component made from 3" x 3.5" x 1.75" heat-treated 6AL4V titanium. “In the past we were roughing it out and sending it out to be heat treated,” Pruett states. “I wanted to eliminate the mid-process heat treating, so I tried the high-speed toolpath on the hardened material. It was a 4-minute roughing time and we got it down to a 1.5 minutes. After the changes, the cycle time is now 25 minutes per part. Where applied, VoluMill toolpaths reduced the roughing cycle time by 62.5%.

“In the short time that I have had VoluMill, I have saved anywhere from just a few minutes to around an hour programming some parts with VoluMill,” Pruett says.

The Benefits
Arguably, the greatest benefit VoluMill’s efficiency has provided for DMW is the flexibility to move work from its 50-taper mill to 40-taper mills.

“One of our 50-taper machines is about to die,” Pruett says. “Since we have certain jobs that require 50-taper machines, we will have to replace the 50-taper. We have some space limitations in our shop so a 50-taper horizontal is out of the question. If we can prove to ourselves that we can machine parts efficiently on the 40-taper machines, that will allow us to replace the 50-taper machine with a 40-taper horizontal. This will not only be beneficial on our current jobs, but will open up a whole new world to us by allowing us to be more competitive on other types of work.”

“For us, the point of buying VoluMill was to see if we could machine parts faster and more efficiently on a smaller machine.”

In the meantime, Pruett continues to find more opportunities for the toolpath engine. “When we first got VoluMill, there were only about four or five jobs that I thought we would want that style of toolpath for,” Pruett states. “Once I started working with it, I discovered that I could use it for a lot more than I originally thought.”

Celeritive Technologies
Cave Creek, AZ
celeritive.com

Diamond Machine Works
Seattle, WA
206.633.3960