November 2010 Feature Article

Ultra High-Performance Toolpath Engine Delivers 200% Precision Machining Productivity Boost

Aerospace, Medical and Other High-Tech Parts Made Faster at Less Cost with New Volumill Software,7000 RPM at 252 IPM vs 1200RPM at 16 IPM

Advanced Machining Systems, a full-service CNC machining and design shop that specializes in precision-machined components for several industries including firearms, semiconductors, aerospace, and medical, recently embarked on a top-to-bottom analysis of its operations to determine why it was having trouble winning new business.

Formed in 2002, the company’s philosophy is to partner with customers through the design, modeling and prototyping phases of product development, culminating in optimized production. AMS employs 2010 SolidWorks CAD software and Mastercam X4 with solids capability to support its business model. A new, 10,000-square-foot plant was dedicated in 2006 to house the entire operation including CNC machining centers, turning and turn/mill centers, plus extensive quality-control equipment and all business processes.

AMS has streamlined its work flow, moved from single work-holding devices to gang setups to minimize set-up times and has invested in dedicated preset tooling since early 2009. In addition, the company decided to focus machines and areas of the shop for certain types of parts, families of parts and sizes of parts to maximize handling efficiency. The shop specializes in the machining of incubators for medical research companies, aerospace hydraulic systems, interior parts and life support systems for medical transport helicopters, control surfaces for general aviation aircraft, as well as parts for experimental aircraft and firearms.

Big Benefit from New Toolpath Generation

The change that has had the greatest impact, according to AMS Manufacturing Engineer Mark Christiansen, has been the addition of VoluMill™, the high-speed-machining toolpath engine from Celeritive Technologies. Since VoluMill runs as a direct and fully integrated plug-in to Mastercam, AMS was able to incorporate its use without missing a beat. Christiansen says, “I use VoluMill wherever I can now: profiles, slots, pockets, steps. I have been able to save at least 50 percent on my cycle time, even up to 80 percent in many cases, and we’ve slashed programming time, especially on complex parts. As a result, AMS is now more profitable on current work, much more competitive on new business quotes, and more responsive to customers’ needs.”

VoluMill is a CAM-neutral, ultra-high-performance, easy-to-use, plug-in toolpath engine to be used in place of traditional roughing methods when ease of programming, reducing cycle times, extending tool life, and reducing the stress on machine tools is a priority. This single-algorithm software program allows the programmer to determine and utilize the optimum material removal rate for any combination of part geometry, material, machine and cutting tool quickly and easily. VoluMill generates a dynamic toolpath that delivers the most consistent cutting conditions possible and allows the use of the entire flute length of the tool. The use of VoluMill can significantly reduce cycle times and wear on cutting tools and machines.

Christiansen learned about VoluMill from a colleague who told him how much it was reducing his company’s programming and cycle times. “So I went to the VoluMill website, tried it, and discovered it did everything they claimed, plus it reduced my tool inventory by allowing me to use solid end mills versus indexable face-milling cutters,” he reveals. “Well before the end of the 15-day trial, my bosses were saying ‘buy it!’ So I did.”

Firearms Industry

Precision machining is critical in the manufacture of fire arms and their internal components. AMS produces compensators for 9-mm pistols from 7075 aluminum. VoluMill has allowed AMS to realize a huge reduction in cycle time on the compensators by taking a full, 1.6” depth of cut with a .5” five-flute end mill. Taking a full-flute-length-deep cut was not possible before.

“We went from machining this part in 9 minutes doing one at a time before VoluMill to 3 minutes doing three at a time with VoluMill,” Christiansen says. “That’s a 200% productivity improvement, which was achievable not only because VoluMill allows us to use higher feeds and speeds, but in this case, the use of the full length of flute eliminated the need for multiple stepdowns.”

Christiansen reports that he’s also using VoluMill for several other operations when machining the compensators. “I’m not just using it to mill pockets,” he says. “Programming with VoluMill is so easy, it’s saving me tons of time on programming open and complex parts that are so difficult and time consuming to program with Mastercam. On one open part, for instance, VoluMill takes the side profile and allows me to use dashed lines to designate where the stock boundary is to define the area to machine. VoluMill just programs the part after that. It’s so simple. And it knows how to remove the material much more effectively than any Mastercam toolpath. It always starts out of the material, which is a lot better on the cutting tool, and it’s much faster, too. With Dynamic Mill, I have to create dummy geometry, and then do some additional manipulation just to prepare it to generate a toolpath. Before we started using VoluMill, it took me 30 minutes and a lot of frustration to program the part with Mastercam, but it took me only 15 minutes to program it with VoluMill, and then VoluMill roughed the part out better, too.”

Another firearms component on the AMS production schedule is a part made of A6 tool steel that is used for rifle testing. “It used to take 75 minutes to program the part and 35 minutes to rough out the first of two operations. With VoluMill, it took only 45 minutes to program the part and then 9 minutes to rough it out,” Christiansen notes. The smooth and fluid tool motion in the VoluMill toolpath allows AMS to machine the part at 7,000 RPM and 252 IPM with a 6-flute end mill. “I was only able to run the machine at 1,200 RPM and feed it at 16 IPM with a 1/8” step down before, so now I’m getting much higher machine utilization efficiency,” Christiansen explains.

AMS used to wear out two end mills per month on this part that it produces regularly. Now, in the month that AMS has been using VoluMill on this part, the shop has yet to change the end mill. “We have seen hardly any wear on this tool,” Christiansen says. “And it was a used end mill to start with, actually a regrind.”

AMS also produces a 7075 aluminum part used in testing by the semiconductor industry. The part took nearly 11 minutes to machine using a traditional toolpath. Now, using a VoluMill toolpath, the actual run time for the part is “3 minutes flat,” according to Christiansen.

VoluMill Adds Responsiveness

In addition to making it faster, easier, and more cost effective for AMS to produce parts, VoluMill also allows the shop to be more responsive to its customers. For example, an engineer from a local construction company recently walked into the shop needing four different spacers that were to be used in a concrete mold for a building project his company was working on at that time. He told Christiansen he was in a rush so he needed the parts immediately.

“He was a new client; we’ve never done business with his company before,” Christiansen recalls. “He needed the job so fast that we didn’t even go through our usual new product design and order processes. We designed and programmed the four parts from hand sketches and then machined them in less than an hour. We never would have been able to be that responsive before. The programming and machining process would have taken us at least 5 hours before VoluMill,” Christiansen claims.

One of the parts was a 44x2.125” piece machined from 1045 steel bar stock. The run time was 2 minutes using a ½” diameter, 5-flute carbide end mill run at 315 IPM and 10,000 RPM. AMS programmed a 1” axial DOC with a .125” radial DOC. Christiansen indicated that before VoluMill, he probably would have used a three-flute indexable milling cutter at 58 IPM with a .118” depth of cut. He estimates that it would have taken 18 minutes to machine, or about nine times longer.

In addition to the savings of time in programming and machining, Christiansen also reports that the use of VoluMill toolpaths is substantially reducing the wear and tear on his tools and machines, and its use is changing the type and number of end mills AMS keeps in its inventory. “The biggest thing for me is the reduced wear on the end mills, and the ability to run our operation while stocking fewer tools,” says Christiansen.

Before AMS started using VoluMill it kept a large supply of different sizes of end mills in inventory. This was a natural requirement of the practice of starting with large tools to remove as much material as possible from an area, followed by a series of sequentially smaller tools to remove the material where the previous, larger tools could not fit. With VoluMill, AMS has found that removing all of the material with smaller cutting tools that fit everywhere is significantly more efficient than with prior methods. So, with the company’s adoption of VoluMill, AMS purchased just a few, smaller 5-flute end mills. Since then, Christiansen says he “has not had to order any new end mills. With VoluMill, they just don’t wear out, even on A6 tool steel.

“I have been able to push the boundaries on our end mills and even push the conservative speed and feed estimates provided by VoluMill,” he adds. “Moving forward, as we add a new machine – which we do about once a year – we will look for higher spindle speed and feed rate capability. I never thought we’d need more than 8,000 RPM to cut steel, but with VoluMill toolpaths, we can easily use much more than that.”

VoluMill also has had a tremendous impact on AMS’s ability to win new business. According to Christiansen, many of its competitors have slashed their shop rates in an effort to attract new jobs, or even keep existing jobs, but AMS hasn’t needed to follow suit. “With the increased productivity and reduced costs that VoluMill has brought to us, not only have we not lowered our shop rates, but we are able to win bids against shops whose rates are now half of ours, and still attain higher margins than we had before. With VoluMill, our success rate on bids has improved dramatically.”

While AMS made many changes to its operation since early 2009, it’s clear that the addition of VoluMill has had the most impact. By reducing part programming and machining time with VoluMill toolpaths, especially on complex parts, AMS is more profitable, more competitive on new business quotes, and more responsive to customers. Those are results that breed success.

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