MIC 6 cast aluminum tooling plate

My opinion? Not great for vise jaws. Being cast, it's quite soft and doesn't machine all that well. It's not really much of a prize if you don't have need for aluminum tooling plate. It's normally used as the name implies---for tooling. Base plates for large fixtures, for example.

Harold

I was thinking soft vise jaws. Looking on the internet, I found the hardness for MIC 6 to be 65 Brinell, which is softer than say 6061 t6.

Dan

Greetings Dan, Cast tooling plate is good for stability. So it won't move like a similar wrought plate made from 6061. Threads pull out easier than

6061 so inserts are comminly used. The "precision machined" surface actually isn't unless someone machined it after buying the plate. The surface looks machined because the aluminum is cast against a machined surface. I used to wonder how the factory got that shiny machined surface when I never could quite match it myself. I figured they maybe used diamond cutters running dry at very high speeds to save time. Then I found out the stuff isn't machined afterall. Eric

I did some looking around on the internet. And found this at

which says they do take off a few thousandth. The piece I have still has the protective film on it and looks as if it was machined with some kind of big rotating cutter.

Dan

Ultimately, it was a process pioneered

by Hunter Engineering that led to today=92s most advanced cast aluminum plate. The

company, a forerunner of Alumax, developed a horizontal, continuous caster to produce individual plate thicknesses. Alumax refined the technology to bring dimensional control and stability to the next level. The original product (named CC-70) has evolved to become the state-of-the-art material known as Mic-6=AE Precision Machined Cast Aluminum Plate. Alcoa, which acquired Alumax in 1998, now produces and markets Mic-6=AE Precision Machined Cast Aluminum Plate at its Mill Products facility in Lancaster, Pennsylvania.

The Mic-6=AE manufacturing technology involves a patented continuous casting technique that allows precise casting to near net thickness - the =93as-cast=94 thickness is only a few thousands of an inch greater than the final plate thickness. Using a continuous flow of molten aluminum, casting speed and the rate of solidification are tightly controlled. A spinning nozzle inert filtration (SNIF) unit provides additional filtration and degassing, virtually eliminating internal defects. Proprietary equipment removes heat from both plate surfaces at a carefully balanced rate so thermal gradients are stabilized. As a result, grain size and distribution are identical on both plate surfaces!

This unique casting process gives Mic-6=AE a granular structure that resembles a honeycomb (see Figure 1). In the solidification process, aluminum (which has a higher melting point than the alloying ingredients) forms the cell core with alloy elements concentrated between the cells. This segregation of low and high melting point compositions imparts characteristics that make Mic-6=AE highly machineable, producing small, uniform chips in a variety of high speed operations.

After casting, the Mic-6=AE plate is subjected to thermal treatment in excess of 700 degrees F for up to 10 hours. The resulting product is fully stress relieved (fully annealed), eliminating stresses that developed during casting as well as any heat-treating effects that may have occurred during or after solidification. The material is =93dead soft=94, comparable to the =93O=94 temper designation in wrought aluminum.

These steps result in a significant design benefit for Mic-6=AE=85there is no decrease in mechanical properties when the plate is exposed to elevated temperatures. This is true for both extended periods of high temperature and cyclical exposure (even an infinite number of thermal cycles). Once the Mic-6=AE plate is returned to room temperature, its tensile properties are the same as they were prior to exposure. There is no over-aging, which occurs in solution heat-treated plate, or the partial annealing that is characteristic of strain-hardened material. Accordingly, Mic-6=AE is recommended for applications where high temperature conditions would be a problem for wrought aluminum tempers.

Machine it to serve as a fixture for some piece which you are machining multiples of, to assure that they all are done the same way.

Small ones could be sized to fit in the vise, ideally with a step on one end to define its location with respect to one side of the fixed vise jaw for repeatability (given zeroing on the fixed jaw before inserting the fixture).

Larger ones would be mounted directly on the table, with a pair of keys to align with the T-slots, and a notch at each end to accept hold-down bolts into T-nuts.

One machinist who I worked with for a while made one (about

1-1/2" thick) on a pair of tall 'I' shaped legs which he planned to bolt down to the outer T-slots on a Bridgeport, but then he changed his mind and put a big projection of similar thickness to clamp in the jaws of the vise while the legs defined the height. On top of that, he put some 3/4" thick tooling plate, and would regularly drill and tap it and machine stops and such to hold a workpiece (this was on a Bridgeport clone which had been converted to CNC). After a while, he would face mill it a bit thinner and continue to use it to make new fixtures. Eventually, it would get too thin, and he would replace that top face only.

The tooling plate is flatter than normal aluminum stock, and is of a precise thickness.

It can also be used as part of something you are building if you get it inexpensively enough, and especially if you can benefit from the greater precision.

A good thing to make with a couple of slabs of that is a gear train, with the plates bored for the bearings.

Enjoy, DoN.

I'm building a prototype 4-stroke gas engine and I used 1/2" MIC6 for the baseplate, sides and cylinder mount. Good stuff, flat enough that I don't have to fly cut it and I was able to find a vender that would cut up a sheet to the rough sizes I need and gave me the drops.

MIC6 is also industry standard for electronics and mechanical assembly and test fixtures.

I have a bench top made from a salvaged 1/2" piece that snapped when a kid tried using it as an ATV snowplow blade. It shattered like glass (or cast iron) and the broken edge shows no deformation.

jsw