Tri-Tech Precision Products has improved the performance of its five-axis spindle attachment for greater productivity among its customers. The company also is lowering the cost of the core unit by 12% to $39,850.
The spindle attachment converts any three-axis CNC mill to a fully programmable five-axis machining center in 30 min for large parts and multiple part runs. It comes off in about 15 min.
The performance improvements are a result of two significant product enhancements: the installation of an InPro spindle seal and a more robust design of the pivot axle foundation blocks.
“The InPro seal has virtually eliminated spindle contamination for our customers, and we are seeing a 20% improvement in accuracy and rigidity from the beefier foundation blocks, resulting in shorter cycle times and an overall improvement in product reliability,” said Jay Phillips, Director of Sales and Marketing for Tri-Tech.
Tri-Tech is offering a 12% discount on the five-axis head through the end of 2009.
With the motors and adapter, it weighs about 175 lb and measures 12 in from the gauge line of the host machine spindle to the Tri-Tech spindle gauge line. It not only can reach all points in the machine’s native work envelope but also can reach outside the machine’s envelope to cut holes in the inside diameter of a large part. This is due to the fact that, Phillips explained, the tilt capacity is 90°±, and it has a pivot length of about 5 in plus tooling. The rotary axis offers continuous 360° motion in the C-axis without having to unwind.
The head can be attached to any taper—40T, 50T, BT, HSK, or custom. Tri-Tech employs HSK tool holders for improved accuracy and rigidity and to keep the pivot length to a minimum.
“One of the most important applications for our head in aerospace is part size and the economics,” Phillips said. Among the five-axis alternatives available to manufacturers is the tilt/rotary solution. “However," Phillips said, “one of the key limitations of this alternative for aerospace shops is part size and weight.”
Most trunnion-based five-axis machines have size constraints limiting the part to about 24 in, he said. The trunnion table itself (if it is modular) can take up most of the work envelope of the machine and limit the weight of the part to about 400 lb. “Once the part weight gets above the capacity of the tilt/rotary or trunnion table, the manufacturer will begin to see errors as the part moves from side to side,” said Phillips.
Large trunnion tables can weigh as much as 1200 lb and be difficult to install and remove. The latest five-axis machine offerings that integrate the trunnion into the CNC mill permanently limit that machine to smaller parts. They can cost $300,000-$500,000 and do not offer the option to remove the table for bigger parts or hold the tolerances that a three-axis CNC machine can, according to Tri-Tech.
“Relative to the large, dedicated, spindle-based five-axis machines, the point of differentiation that Tri-Tech enjoys is price,” Phillips said. “The entry level spindle-based five-axis mill is probably the Haas VR-8 at about $250,000. It offers approximately 32°± of tilt. That being said, we have seen many customers start their five-axis business with our head, develop the programming skills and customer base, then move on to purchase a dedicated five-axis machine. Those customers still have the option to use the head as needed on their three-axis CNC for holes, pockets, and profiles without taking up the machine time of their new, expensive five-axis mill.”
Although other companies offer five-axis spindle attachments, they are usually about $250,000 and up and are commonly a permanent installation, said Phillips. “Our head with tooling, adaptation costs, and our postprocessor is just under $50,000. To my knowledge, there is not another product available similar to the Tri-Tech head.”
Among the chief benefits of five-axis as a machining category is the ability to reduce fixturing costs for holes, pockets, and profiles that need to be machined on complex surfaces—“something that the aerospace industry has plenty of,” Phillips said. Five-axis machining also allows the operator to get into difficult areas with much shorter cutters, improving accuracy and reducing cycle times, he added. A three-axis machine can create a complex-surface part, he said. “But if that part must be moved to a five-axis machine for holes and pockets, then the opportunity for error increases when unfixturing and refixturing the part.”