Video: Five-Axis Milling On Linear-Motor Machining Center
Linear motors take the place of ballscrews on this machine performing high speed cutting of aluminum at a job shop near Atlanta.
Here is video footage of a five-axis machining cycle at GTI, an aerospace-industry job shop near Atlanta. The machine here, a model HSC 105V “Linear” machining center from DMG, features linear motors in place of ballscrews for fast acceleration, particularly during high speed cutting of aluminum. GTI’s version of the machine has a 28,000-rpm spindle. With C-axis travel of 360 degrees, the machine easily reaches all the way around the part, while the A-axis travel of well over 180 degrees allows the machine to perform undercuts. The video shows this.
Hard milling allows mold components to be machined in the hardened state, thus skipping several expensive and time-consuming processes such as electrical discharge machining and hand polishing.
The length by which the tool extends from the toolholder is a variable that can be used to 'tune' the machining process. Contrary to what you may expect, increasing the tool's L:D ratio may reduce chatter and result in more productive milling.
Though it won’t replace high speed machining, Boeing sees “low speed machining” as a viable supplement to higher-rpm machines. Using new tools and techniques, a shop’s lower-rpm machining centers can realize much more of their potential productivity in milling aluminum aircraft parts.