Specialty Turbomachinery Shop Gains Vertical Versatility

Barber-Nichols Inc. is not the kind of shop that competes with the average machine shop down the street. The company is quite different in that it produces full assemblies that are so highly complex that there may be only one or two other companies in the world capable of producing them.

Located in Arvada, Colorado, Barber-Nichols designs, engineers, manufactures, and tests specialty high-speed turbomachinery. The company’s products include blowers, compressors, fans, pumps, turbines, and turbopumps for aeronautic, cryogenic, national defense, power generation, and space flight applications.

The company’s turbomachinery and assemblies involve high risk machining due to component shape complexity, tolerances and superalloy difficulties. The cost and time risks of these parts are so great that the shop will usually first produce a prototype from less expensive material to perfect machining setups, cutter paths and part size tolerances.

Barber-Nichols’ high-end components used to be machined on standard horizontal machines and 4 and 4 1/2 -axis vertical machining centers. However, such basic equipment lacked the speed, accuracy and versatility the company needed to improve upon its prototype and low-volume component production. What did improve production was stepping up to 5-axis and 5-axis simultaneous part machining capability provided by vertical machining centers from Mazak Corporation.

The Mazak machines, purchased from Denver-area Mazak distributor Action Machinery Inc., provide Barber-Nichols higher spindle speeds, faster feedrates, tighter tolerance machining, reductions in part setups and the reliability to run parts unattended. With the advantage of complete part machining on a single machine, the Mazaks also eliminated the need for secondary machines for operations such as complex hole drilling or running part deburring programs.

The newest Mazak machines at Barber-Nichols are the VARIAXIS 630 5X and VARIAXIS 630-5X II 5-axis simultaneously controlled vertical machining centers and a VERTICAL CENTER NEXUS 700D/40-II. The two VARIAXIS models feature tilt/rotary tables, through-spindle coolant, and 12,000 rpm, 30 hp spindles.

On the VERTICAL CENTER NEXUS 700D/40-II, the shop uses an aftermarket CNC controlled add-on rotary table attachment, but has also built a special subplate for running smaller 3-axis parts off to one side without disturbing components on the rotary table. The machine provides 1,181 ipm rapid traverse, spindle speeds up to 8,000 rpm (40 hp), high-pressure, through-spindle coolant and a table size of 60.24” x 27.56”.

The shop often runs multiple jobs on the VERTICAL CENTER NEXUS because most jobs involve only two or three parts per order. With the machine’s 60.24” X-axis travel, They can quickly and easily go back and forth between jobs without disturbing part setups.

The machinists are very impressed with the machine’s speed, accuracy and smooth axis motion. They also said that Mazak’s high-pressure, through-spindle coolant system is quite beneficial for hard metal machining. It blasts chips out of the cutting zone, allowing him to feed the machine much faster and produce excellent surface finishes.

As specially requested by Barber-Nichols, its three Mazak machines are all equipped with 40-taper Big Plus spindles, so the same tooling can be run on each machine. In addition, the shop opted for a larger 40-tool carousel – 30-tool is standard – on its VARIAXIS 630-5X II. A special extended Z-axis height on its VERTICAL CENTER NEXUS 700D/40-II adds 10” to the machine’s 25.59” Z-axis travel, allowing the shop to reach much taller parts without worrying if the cutting tool being used is too long.

“Our VERTICAL CENTER NEXUS may be a 40-taper machine, but its spindle is solid, stable and runs concentric,” said one Barber-Nichols machinist. “Actually, all our Mazaks deliver more than enough power for running all our part materials. Whether we are working with aluminum, stainless steels or Inconel, we don’t ever have to pick and choose which machine to run which material. The Mazaks are versatile and handle everything.”

Barber-Nichols produces mostly prototype part volumes and considers 10 or so required parts a big order. However, some jobs might span the course of a year with the total number of pieces amounting to around 100. In the shop’s industry, most consider as few as 10 to 20 parts per year “production.”

Part materials at Barber-Nichols include all types of superalloys, Inconels, Hastalloys, Titanium and all the stainless steels, including 17-4, 304 and 316. Sizes range from 3’ in diameter by 72” long parts weighing up to 3000 lbs to those measuring 0.750” in diameter.

Many of the shop’s parts involve very long machining times. One such example is a small, extremely complex part referred to as a kick stage component. This component took a total of 150 hours of machining time using mostly 0.078” diameter lollypop endmills. First produced as an aluminum prototype, the part was then manufactured from 6AL4V Titanium.

This specially engineered part is quite expensive and was one of the most challenging jobs one of the Barber-Nichols machinists has ever done. He said that the VARIAXIS 630-5X II made the job much easier than if he had to use the shop’s previous standard vertical machining centers.

The machine allowed him to cut all of the part’s features in one set up. Even more notable, he had the confidence to let the machine run unattended for practically all of the part’s 150 hours of machining time.

Another challenging part that the Barber-Nichols machinist said he would not have been able to machine without the capabilities and accuracy of the VARIAXIS was a titanium inducer component. Because it is one of shop’s complex and critical jobs, the part was, as usual, first produced from aluminum.

Using the VARIAXIS 630-5X II, the shop machined multiple blades measuring 0.015” thick and 0.500” deep in the inducer component with an overall size of a little over 1” in diameter. It also had to machine 0-80 (0.060” diameter) threaded holes in the top of the part. This threaded-hole size, according to one of the shop’s machinists, is one of the smallest in the industry.

“We knew that once the Mazak ran the toolpath on the aluminum prototype, which it did, it would definitely run the same exact path for the actual titanium version,” said the Barber-Nichols machinist.

Using the EIA side of the machine’s MAZATROL CNC control allows Barber-Nichols machinist to import solid models directly from the company’s engineering department. The control reads them perfectly and has more than enough memory, so there are never any problems with data starvation.

One Barber-Nichols machinist mentioned the benefit of the control’s inverse times feedrate function, which automatically adjusts machine speeds and feeds to maintain a specified cutting feedrate. The function is not only useful in 5-axis contouring, but it also helps him generate better surface finishes.

For another programmer/machinist at Barber-Nichols, the true positioning accuracies of the VARIAXIS machines are critical when producing components involving what are known as “projected tolerances.” Such tolerances are often required for angled threaded holes to ensure that mating components mounted using those holes are perpendicular. If they are not, there is a risk that the whole finished system assembly could fail.

The angles of such critical threaded holes must perfectly meet projected points that are well above the part datum surface. In some instances, these projected target points are as high as 10” above that surface, as was the case with a large defense component Barber-Nichols recently machined on the shop’s VARIAXIS 630 5X.

The machinist had to make sure that each threaded hole was exactly perpendicular to the part surface. If the perpendicularity had been off by 0.001”, for example, that amount would equate to a 0.010” error at the projected datum point.

The defense part was mounted on the machine’s rotary/tilt table, which provided true angle positioning needed to produce the holes and consistently meet the projected datum points. Without the VARIAXIS 630 5X’s rotary/tilt table, the machinist said the job would have required multiple time-consuming setups and that holding such tight projected tolerances would have been practically impossible.

Gary Frey, vice president of operations at Barber-Nichols, along with the company’s Manufacturing Engineers, all agree that the Mazaks have generated a “cultural” change at the shop – how parts are processed and especially when it comes to unattended operations. As a result of that change, parts with long machining times are now processed much more cost effectively.

“Because our parts are so critical and valuable, we’ve always babysat them from start to finish,” explained Frey. “Now, with the reliable and consistent performance of the Mazak machines, we incorporate much more unattended machining.”

“Basically, we are a prototype/short run production shop, and all our machinists do their own programming and part set ups and run the jobs themselves. We don’t have any ‘operators,’ so with unattended machining, our highly skilled senior-level programmers/machinists can run multiple jobs simultaneously to increase their productivity.” The on-machine inspection probing helps us ensure parts meet print before they come off the set up, further supporting our AS 9100B and ISO 9001 quality systems.

“Having two of one type of machine is also a rare occurrence in our shop. We have two Mazak VARIAXIS machines, so that may give an indication as to how valuable the capabilities of all our Mazak machines are to us,” said Frey.

As a matter of fact, Barber-Nichols is currently working with Mazak for an upcoming military project to manufacture components for the U.S. Navy. The project is of such substantial size that Barber-Nichols is considering setting up a mid-volume production facility dedicated to it, and one that will potentially use Mazak machines.

“For this project, we will focus on reducing setups as much as possible, conducting quick part changeovers and on manufacturing using cells,” explained Frey. “To date, Mazak has been one of the best in supporting this project as far as offering us valuable advice, options and ideas.”

About Barber-Nichols Inc.

In 1966, Bob Barber and Ken Nichols founded Barber-Nichols. The privately owned company now employs 70 people, 24 of which are engineers. Its five-building campus includes an Engineering and design area, a Machine Shop and Manufacturing area, Assembly and test area , ECM and welding areas , and a warehouse. The company’s website is www.barber-nichols.com


About Mazak Corporation

Mazak Corporation is a leader in the design and manufacture of productive machine tool solutions. Committed to being a partner to customers with innovative technology, its world-class facility in Florence, Kentucky, produces over 100 models of turning centers, Multi-Tasking machines and vertical machining centers, including 5- axis models. Continuously investing in manufacturing technology allows the Kentucky Mazak iSMART Factory™ to be the most advanced and efficient in the industry, providing high-quality and reliable products through its “Production-On-Demand” practice. Mazak maintains eight Technology Centers across North America to provide local hands-on applications, service and sales support to customers. For more information on Mazak's products and solutions, visit www.mazakusa.com or follow us on Twitter and Facebook.