Aluminum is one of my favorite materials to work with. It has the best properties of metals, without being so rough on your tools. I personally love how soft it is, and the nice, curly chips it produces when you go through it.
Of course, aluminum has been the testing ground for a variety of techniques and processes intended to enhance workshop performance. High-speed and high-performance machining is constantly evolving, always looking for ways to improve feed rates, minimize tool replacement downtime, push rotation speeds to the limit, or just get a taller parts stack at the end of the workday.
Granted, aluminum is soft enough to accept cheaper steel tools without a problem. Steel tools are manufactured with a sharpness that helps produce a great finish when grinding, chamfering, or beveling. However, this sharpness is often short-lived, and we must watch for high temperatures if we don’t want premature cracks and catastrophic failure to impact our tools.
Moreover, even though tool-grade steel is quite rigid, it still retains the flexibility that characterizes this metal, making it prone to vibrations and wobbling, affecting finish, and increasing the chances of missing the mark due to walk-off and chatter.
In short, steel tools force us to slow work down to a crawl when accuracy is a priority, stop every now and then to let the tools breathe, change them before they break, and cool down the work zone. This flexibility affects performance in more ways than one. Even designing efficient toolpaths becomes a challenge depending on the parts being manufactured. Steel tools are heat tempered, so heating them beyond a certain temperature can severely compromise their strength.
For best all-around results we should use the best end mills for aluminum and that means finding tools made from solid carbide. Carbide is much more rigid and durable than high-speed steel, making it the best candidate for jobs that require a high degree of accuracy, which should include all work done on aluminum in my opinion.
This increased hardness affects production in three distinctive ways.
Firstly, it prevents unwanted vibrations caused by tool wobble. By being so exceptionally rigid, the tool stays in place and gives your machine a significant fighting chance of hitting the piece where it counts and finding purchase with less change of tool deflection. This is the best way to keep your part true to spec and avoid scraping, especially expensive parts.
Secondly, carbide tools retain their sharpness for longer periods. Because the material they are constructed from is so hard, their cutting edges will stay in prime condition for quite a while. This means that your carbide tools will provide consistent results for several times the lifespan of a steel tool while also needing less maintenance.
Finally, carbide´s rigidness prevents the dreaded chatter. Since chatter is produced by vibrations, the very rigid structure of carbide naturally vibrates less than steel would under the same conditions. This allows your machine to produce more aggressive attacks and stay engaged longer, allowing you to greatly increase feed rates and production.
However, not every carbide tool is the same. To make sure you get the best end mills for aluminum, you need to find a trusted carbide tool supplier that can guarantee reliable and predictable bits and mills especially crafted for high-performance machining operations. I only trust Online Carbide as my solid carbide end mill manufacturer. They offer high quality carbide tools at manufacturer direct price, and they always have a straight answer or solution to my inquiries.