Some time back I asked about benefits of ATP5 or MIC6 one over the other. I didn't get a lot of response, but some. The biggest differences I found at the time were strength and weldability. ATP5 is stronger, more likely to be weldable, and most times cheaper.
I've since used both based on whomever had the better price for the size I needed. Mostly for making specialty fixture plates to go on the mill. I have a shelf int he front office full of fixture plates I use regularly.
While those are very fast to use I do begrudge the time to remove one, clean everything up, and install another one. Some might say just use a vise or a couple vises, and that's valid, but for actual machining efficiency a fixture plate that allows you to load several bars and remove a multiplier of complete parts outshines a vise (or multiples vises) by so much its not even a comparison. This is really coming home to me right now. I am in the middle (well 3/4 done) of a 50 mold order. This requires 100 blanks. I set up the light weight (8.5x18) mill with a fixture plate that allowed me to cut nine blanks at a time from3 pieces of bar stock (prepping these blanks is more than just sizing), and I made two fixture plates for the small high speed mills to finish out 4 blanks at a time on each one.
I got to thinking about it all. I was thinking I'd like to make some more universal fixture plates. Yeah the old grid of holes (sorta) thing. With purpose built bolt on standoffs for edge clamps and stops. (Stand off so I can drill/tap/threadmill through and edge finish of course.) I think I can make them "good enough" on the larger South Bend manual mill in the back for each of the CNC mills in my machine room.
I think once placed and bolted down they may never come off the table unless they need to be replaced. I may have to replace stop standoffs, edge clamps, etc, but unless I screw up (which I probably will sooner or later the plates will allow me to use MORE THAN 100% of the work envelope of the machine. If I need to make specialty fixtures I can make them so they just drop onto the plate. Zero to the known register on the plate, and lay out the jobs, fixtures, parts, standoffs, stop clamps etc in CAM on an overlay of the fixture plate. I know that sounds ambitious, but I have been thinking it through for a while. Its very similar to what I do with the simpler fixture plates I use now.
To that end I asked my primary aluminum vendor if they stocked any cast aluminum tooling plate, and if the did what alloy. I have bought ATP5 from Midwest in the past, but they have been pretty terrible about order fulfillment. It might take a couple months to get an order from them. I guess I should thank them for that. It lead me to contact Coast which turned out to be a much better fit for my business. They send a truck twice a month with a minimal drop charge and have a better price on most of the 6061 aluminum rectangular bar I use regularly.
So, yesterday I asked my contact at Coast if they stocked any cast aluminum tooling plate and if I could buy cut pieces or if I had to buy a full sheet. They stock MIC6 and K100S and I can order it precut to rough size. That lead me to my next search. What's the difference?
Most source were comparing only two metals and with some bias, but generally agreed. Then I found this chart from Clinton Aluminum:
Basically ATP5 Alca5 and K100S are all a "modified" low porosity 5083 alloy. I think that means they all have the properties of 5083 with each one trying to establish product differentiation through minor tweaking of the mixes. If anybody can tell me they have experienced any real world significant differences that would be appreciated. MIC-6 is a mystery "7000 series."
What stuck me was two things. K100s doesn't have as good of a flatness tolerance as any of the other metals. MIC6 is noted to have greater porosity. The strength was the same as I recalled from before with all the the 5083 plates having greater strength.
I hope some of you find this to be useful.