b'ILLUMINATING ALUMINUMAn overview is given for machining aluminum. challenges, especially when pre-sented with high production quan-tities, stringent cycle requirements By Christopher Tate Aluminum is also one of the leastand close tolerances.dense materials commonly usedRolled and extruded alloys are M achinists and toolmakers areformanufacturing,makingtheprone to deformation during the a hardy bunch and fear little.metal easy to handle. Most impor- machining process because inter-Many have conquered the worldtantly, it is a ductile material, whichnal stresses are disrupted. It is com-of manufacturing with little moremakes fabrication and machiningmon for a part to be in tolerance than a set of micrometers and a file.processes uncomplicated. while restrained in a fixture and out Most have survived encounters withPeople sometimes ask, How fastof tolerance when unrestrained. engineers, quality inspectors andcan you machine aluminum? TheCombating distortion might require dreaded safety professionals. answer is as fast as a machine willheat treatment, altered machining The only thing that scares thisrun. Because aluminum is easy totechniques and post-machining op-group of crusty manufacturing pro- machine, there is a broad range oferations. Large parts with thin sec-fessionals is difficult-to-machine ma- effective cutting speeds. Alumi- tions, such as aerospace structures, terials. Being assigned to machinenum is very forgiving and can beare the most problematic.tap-breaking, drill-dulling and gen- machined successfully using a wideIn addition to being ductile, alu-erally aggravating metals like stain- extent of cutting parameters. Theminum conducts heat very well, less steel, Hastelloy and Inconel ismerciful nature of aluminum makesand the combination reduces brit-the main anxiety for these pros. Theyit an ideal material for training stu- tleness in the shear zone during all look forward to aluminum jobs. dents, proving out new CNC pro- chip formation. This means that Aluminum is light, clean and eas- grams and creating cool machinealuminum doesnt like traditional ily machined, which is why machin- tool demonstrations at trade shows. grinding processesfor example, ists enjoy working with it. Alumi- surface grinding and outer diam-num alloys arrive without scale, dirtChallenges eter grinding. Creating close-tol-and oils because aluminum man- Although machining aluminumerance parts without grinding can ufacturing processes are cleanercan be easy, the characteristics thatbe challenging. When I was in the thanthoseforothermaterials.make it simple to machine may poseaerospace industry, we would apply 38JUNE 2021MachiningAluminum.indd 38 5/14/21 3:27 PM'