When it comes to the number of application fields, aluminum is the true factotum of the metals. The question is not so much where it is used, but rather where it is not! It has long been indispensable as a structural material for making cars and planes. Aluminum offers low weight and high strength here. Due to its high electrical conductivity, it is valued by electrical engineers as a material for antennas and for conductive cast components. The fact that aluminum is also used, for instance, as a material for making cooking pots or electric irons points to its good thermal conductivity. Against this background, one thing is clear: machining it with cutting tools presents a varying challenge.
The tool experts at LMT Onsrud have for decades been familiar with the difficulties involved in the use of cutting techniques for aluminum machining. One of the company's specializations is the high-speed cutting of this material, and it has therefore learned to master the various conditions that occur. "As is often the case when precision tools are used, it is, of course, important to ensure a high level of machining quality. At the same time, however, fast processing should result in greater profitability. It is particularly when machining aluminum that this combination is not straightforward," explains Leslie Banduch, Senior Vice President, Sales & Marketing at LMT Onsrud.
Improved chip transport – higher yield
A company working in the American defense industry came to LMT Onsrud's experts for help with the production of the American army's Humvee all-terrain vehicle. "The customer was not happy with the performance data for the milling needed on an aluminum component for the Humvee. The tool they were using suffered from poor chip removal. The loading of the machining center's spindle was relatively high, yet the cutting speed was low. In the end, this meant that the total machining time was long", according to Rob Cliff from Onsrud. The wanted increase in performance was provided by the Trough-Coolant rougher from LMT Onsrud – altogether, the machining is now just about 40 percent faster. How can we explain that? Cliff: "The tool incorporates high-performance chip removal. Its whole geometry is designed to achieve that. For the same reason, the spindle loading also fell by 45 percent. At the same time, we were able to increase the cutting speed from 300 m/min to 381 m/min."
Laser and tool machining compared
Onsrud tools were asked to undergo an interesting comparison by one customer from the aircraft industry: Until now, flat aluminum plates had been cut by laser – the yield, however, was relatively low. "The production planners at the site therefore decided that in future the plates would be cut on a CNC router. The aluminum tools 63-606, 63-618 and 63-630 were used", explained Tom Cornwell from LMT Onsrud. In the event, when the American company changed over from a laser to precision tools, the increase in performance was enormous: The tool's feed rate is about six times higher, while the machining quality is noticeably better. And what is more, finishing work is no longer needed on the aluminum plates when the cutting has been done. That had still been necessary when the laser was in use. Cornwell adds that "In this particular field, the laser machining was a real bottleneck for the whole of the company's production flow. That has now been put right. The effect of the changeover is so huge, that it has an effect on the productivity of the whole company including, for example, the manufacture of aircraft doors and windows."