Makino is looking at the big picture when it comes to developing machining systems. The Mason, Ohio, company recently added the T1 5-axis horizontal machining center (HMC) to its line, a unit that meets the needs of multiple markets, including titanium parts in aerospace.
“The T1 is designed to appeal to a lot of industries,” David Ward, horizontal line product manager at Makino, told ThomasNet News. The unit is primarily for job shops that want to expand in or enter aerospace supply, but which cannot justify investment in a machine dedicated to titanium fabrication.
As a result, although the T1 is the latest in the line of 5-axis HMC models for titanium production, it is the most versatile of Makino’s models in terms of its ability to machine other metals.
The T1 is a HMC that accommodates relatively large, heavy workpieces. The X, Y, and Z travel axes are, respectively, 59.1 by 51.2 by 78.7 inches (in), and the maximum pallet payload is 6,600 lb. The direct-drive spindle generates 737 ft-lb of torque to machine hard metals at speeds of 20 to 1,000 rpm, and it has a top speed of 12,000 rpm.
The machine has a 45-110 degree (deg) A-axis tilting spindle. Coupled with a deep-chest column, the machine achieves a -90 deg spindle centerline position, to 21.6 in below pallet center. This allows it to machine parts that are 1 square meter (10.76 sq ft) and up to 31.4 in high, in a single five-sided process.
The first model in the HMC line, the T4, is a specialized unit for titanium machining. Ward said that only a handful of aerospace manufacturers are likely to be interested in this machine. It has large X-, Y-, and Z-axis travels (165 by 78 by 39 in), holds workpieces of 11,022 lb, and generates up to 1,100 ft-lb of torque.
Next in the lineup is the T2. Although Makino states that this machine is for midsize titanium aerospace parts, its specifics match those of the T4. The model produces parts up to 74.8 by 78.7 in, accommodates 11,000-lb workpieces, and generates 1,100 ft-lb of torque at peak output. Ward noted that the T2 appeals to “premium aerospace job shops.”
The T1 thus fills an important niche by providing the performance necessary to machine titanium while meeting the production needs in machining other metals.
This flexibility is a prudent benefit for job shops. While the overall aerospace market continues to grow, there are hiccups in some areas — notably defense. Helicopter manufacturer Sikorsky Aircraft, for example, announced on Feb. 21 that 600 employees — half of them union workers — are being laid off, mostly at its Stratford, Conn., headquarters. The company blames cutbacks to the U.S. defense budget that affected production of its iconic Blackhawk helicopter and cast uncertainty on future programs.
The T1 is, nevertheless, equipped with advanced engineering features, some of which resemble those of the T4 and T2. One of these is high rigidity. Makino states that the T1 has thick Z-axis bed castings, wide slideway surfaces, and a deep-chest, monolithic column that supports X- and Y-axis movements.
The B-axis rotary table has a 360-deg rotational speed of 3,600 deg per minute, and generates 10,000 N-m of continuous torque with peak output of 29,000 N-m. The spindle-tilting A-axis produces 6,300 N-m of continuous torque and 20,000 N-m at peak. A 15.7-in pivot distance improves spindle and workpiece accessibility.
Unlike many 5-axis HMCs, a trunnion table is not used for rotary motion on the T1. The machine instead employs an innovative A/B-axis configuration that shifts A-axis motion to the spindle side, which eliminates tilting of the workpiece.
The model is also equipped with Makino’s Active Damping technology, which is designed to eliminate cutting vibration. Ward said the Active Damping feature monitors each axis with servos. When the servos detect vibration, they adjust the guideway load compensation system to intentionally create friction, which dampens vibration.
Ward explained that the dynamic changes in guideway friction are minuscule and difficult to quantify, but added that “there is a night-and-day difference of magnitude” in the force signature that is subsequently created when machining titanium— or other materials. This difference controls vibration, which also increases metal-removal rates by stabilizing roughing operations. Additional benefits include improved machining accuracy, reduction in tool wear, and lower maintenance.
These last two points, in fact, are critical for job shops, Ward said. “People need to look at the big picture and not just the cost of a machining system,” he advised. “If perishable tooling costs decline 15-20 percent when machining titanium with the T1, operators will see significant lifetime savings in tools and maintenance.”