Shop Tests Super Precision Multitasking Machine

BMT-45 Turret gets an A+

Originally published in Manufacturing Engineering, January 2011
Reprinted with permission of Hardinge Inc.

When Don Miller, Director of Business Development at Magnus Precision (www.magnuscnc.com) received a call from the Hardinge Group (Elmira, NY) asking if his company would test its latest SUPER-PRECISION® T-42 multitasking turning center, he replied, “Yes, how soon can you deliver it?” Magnus had many years of compatible experience with the machine tool builder’s previous T-series generation, the “Conquest”, and wanted to assess the impact that brand new turning technology would have on the company’s work. Magnus Precision is one of the premier contract shops in the Northeast, housed in a world-class 55,000 sq. ft. facility, and known for its meticulousness in producing complex parts in aerospace, medical, optical, and micromachining markets. The company is well-respected among customers and suppliers alike as it embraces a philosophy to apply the latest machining advancements to keep the competition in its rear view mirror.

“We knew that Don and the skilled workforce at Magnus would provide the thoughtful, practical feedback we needed before releasing the machine to the world market at IMTS 2010,” says Paula Ameigh, Director of Corporate Marketing and Customer Services at Hardinge.

The SP T-42 Turning Center was installed in July 2010, and Magnus immediately put it through its paces on two test parts. The first was a 440C stainless steel valve component for an aerospace customer. Miller felt this was an excellent choice as the approximate 4” long x 1.5” diameter part required many turning, milling, and drilling operations which would test the live tooling option on the machine and sub spindle performance. Previously, the valve parts were turned on a CNC lathe and then transferred to a VMC for the milling and secondary drilling operations. With the SP T-42, once the offline programming was accomplished on PartMaker and downloaded to the machine’s 0.000010” resolution Fanuc 31i control, the part’s production went into high gear. Magnus, while familiar with live tooling on other turning centers, did not have experience with the BMT-45 top plate system on the SP T-42.

“The BMT-45 system was new territory for us,” says Miller, “and it’s that aspect of the machine that provided the most surprising results. We took an approximate previous cycle time of 40 minutes down to a total of about 14.5 minutes – part complete, one machine, one set-up. So we’ve almost tripled the productivity. Most manufacturers aren’t as familiar with BMT tooling or BMT top plates as they are with the more common VDI system. We found that it’s significantly more rigid, with a heavier-duty interface, and you can achieve unusually high rpms, up to 32,000, when purchased with the proper gear ratios in the tool holders. We’re looking forward to working with those higher rpms on our micro medical components.”

The BMT-45 turret offers 16 live tooling stations with ½ station index between each station. Both the static and live tool holders are designed to adapt modular add-on tool holder blocks for user flexibility and allow fine tool adjustment in the Y-axis plane. Typically, maximum live tooling rpms are in the 5,000 to 6,000 range. Live tool holders on the Hardinge BMT turret start at 8,000 rpm and are capable of up to 16,000 to 32,000 rpm when purchased with ratios of 2:1 or 4:1 when high speeds are required. They provide run-out within 0.00012”
(3 micron).

In addition to the quantifiable time studies, productivity gains are measured in better accuracies and improved surface finishes, less scrap, and reduced part handling time at Magnus Precision. The second test part, a classified titanium (Ti6AL-4V) aerospace part, featured 0.0003” tolerances on several features.

“We knew that particular proprietary part would relay the precision aspect of the SP T-42 very well. We held the tolerances with no problem, part to part,” says Miller.

“Thermal stability is paramount to accuracy, too, and we are skilled at chasing it here at Magnus,” says Miller. “The SP T-42 has a detached stand which houses the coolant pumps, coolant filter, machine power case, and hydraulic system. By design, the detached stand prevents these heat and vibration generating components to migrate through the machine, resulting in the machine’s ability to achieve higher thermal stability and thus, part accuracy. Further, the spindle is cooled using an oil jacket and chiller for even greater thermal properties.”

Particularly on the company’s optical and medical components, finishes are a significant aspect of the overall accuracy and precision requirement. Part finishes of 0.000006” (.15 micron) Ra are common on the SP T-42. Hardinge’s sub-spindle parts removal system is designed for handling critical parts with delicate surface finishes. The gripper includes nylon, machinable inserts that are gentle on parts. Users can opt for a parts conveyer where they can be offloaded manually or integrated with a robotic device, permitting unattended operation with a barfeed.

During the beta testing phase of the SP T-42, a couple of minor issues surfaced that Magnus relayed to Hardinge. The issues were related to software and implementation of the Fanuc 31i control to the new Hardinge T-series.

“This was the whole idea of beta testing with Magnus,” says Jim Langa, Vice President, Engineering & Global Sourcing at Hardinge, “to learn what we needed to tweak. We resolved those items quickly by working with our software and applications engineers and directly with the Fanuc software engineers.

“As for us,” says Miller, “with the positive results we’ve achieved in such a short time, we are looking forward to putting more of our complex parts on the machine. Continuous improvement can sound like a cliché, a buzzword, but at Magnus, we are very serious about it to not only stay in business, but to thrive in a challenging economy. We keep figuring out better ways of doing things for our customers. They bank on our philosophy. The SP T-42 plays right into those goals.”

The BMT-45 turret on the Hardinge SP T-42 offers 16 live tooling stations with ½ station index between each station. Both the static and live tool holders are designed to adapt modular add-on tool holder blocks for user flexibility and allow fine tool adjustment in the Y-axis plane. Typically, maximum live tooling rpms are in the 5,000 to 6,000 range. Live tool holders on the Hardinge BMT top plate start at 8,000 rpm and are capable of up to 16,000 to 32,000 rpm.

Hardinge’s sub-spindle system, for machining the back end of parts and removing them, is designed for handling critical parts with delicate surface finishes.