Supplier of millable aluminum?

[Marks256]

A friend and i are going to be working on a really cool (and expensive) project.

We need to mill out a LOT of parts, and we need to make it out of aluminum. The chunks need to be about 1 foot x 1 foot (maybe a few inches less)


I was just wondering if anyone knows of any suppliers of millable aluminum (i think the stuff is called bailet, or something like that)

Thanks.

[edit: any thickness should be fine.]

 

[jpanhalt]

Are you very close to McNeilius in Dodge Center? The company is now sold, but used to have a great scrap yard with tons of cut-offs at great prices. When I couldn't find something there, I went to Lynn's scrap (who was McNeilius's dad) and could usually find it. Best part, they were open on Sunday and closed on Saturday. There are also other scrap/cut-off metal places in Dodge Center (Dickie Steel is one).

Second choice is McMaster Carr (much more expensive). As for which alloys to use, pure aluminum (1001) and even half-hard (3003) are hard to machine, as they get gummy. Use lots of cutting fluid with them (kerosene works). A harder aluminum , like 6063, 6061, 2017, 2024, etc. is much easier to machine. McMaster is good, even if you don't buy from it, because it has a convenient table of machinability. John

Edit: I forgot 2011 and MIC6 are also easy to machine. MIC6 is something you will find in large plates.

 

[Marks256]

Hmm... Ok...

Yeah, i am pretty close to McNeilius'. One of my friends is pretty good friends with the people there.

This project is going to take some precision, so i think i will have someone mill them for me...


Maybe Fastenal would do it? I don't want to spend for than a grand ($1000) on this device.

 

[Speakerguy]

Try emachineshop.com.

 

[jpanhalt]

It is hard to say what the cost will be for "a lot." You would need to be specific. I have never used a job shop but suspect you are going to see something like $80 to $100 per hour on the low side. $1000 can be spent pretty quickly making different parts. The expense is all in set-up.

I doubt McNeilius will do custom work. A vo-tech might do it for a low fee or consider adult extension classes. I used to enroll just to get access to machines I didn't have, such as horizontal mills and grinders. John

 

[Marks256]

I know it is going to be spendy. really spendy.

I have heard of emachineshop before... i will check that out.

 

[3v0]

I used to enroll just to get access to machines I didn't have, such as horizontal mills and grinders. John

This is very good advice. Not only do you get the parts made but you learn how to work the tools. If you pay to have it done you can not afford to be wrong. Which is apt to happen. Take the money you do not spend on machining and buy some extra blanks.

 

[Marks256]

yeah. i like this idea, too.

Hmm....


How do you "shine" up the aluminum when you are done machining it? like, getting it really smooth and shiny?

 

[3v0]

yeah. i like this idea, too.

Hmm....
How do you "shine" up the aluminum when you are done machining it? like, getting it really smooth and shiny?

I am not a machinist. But as I understand it you machine to a fine finish and after that a rag and some polish makes it shine.

 

[Marks256]

I am not a machinist. But as I understand it you machine to a fine finish and after that a rag and some polish makes it shine.

That is what i was thinking. My dad is good friends with a very talented machinist. I am sure he would be more than delighted to help me out, just as long as i get the stock.

 

[Pommie]

If you get a good machinist, it will be shiny anyway.

Mike.

 

[Nigel Goodwin]

You've not mentioned what you're trying to do, but isn't milling parts out of a solid block a very expensive way to make components?.

 

[Sceadwian]

What'cha building Marks?

 

[jpanhalt]

yeah. i like this idea, too.

Hmm....


How do you "shine" up the aluminum when you are done machining it? like, getting it really smooth and shiny?

Shine and surface finish are somewhat separable concepts. You can shine aluminum that is quite rough, even an unmachined casting. One common procedure for that is electropolishing. It is done for alloy wheels and such. There is also roll/vat polishing, like is done
with stones.

As for surface finish, machining is part of the answer. The Mic6 and other plate aluminum comes in various surface finishes, from rough mill (rolled), to surface ground. The surface ground plate is not that expensive, gives you a good reference point (the tolerance on aluminum extrusions is pretty big), and is quite attractive. Light bead blasting with glass or walnut shells also gives a nice finish.

Finally, I would suggest you look into home DIY anodizing. This is, after all, an electronics forum. It is really quite easy to do with a battery or battery charger, a little sulfuric acid, and regular old fabric dyes. First, you make the anodic surface, dye it, then fix/seal over steam. There are many step-by-step procedures for the DIY. I have seen some beautiful results too done by a local hobbyist. The best part about anodizing is it gives a protective finish as well.

As for hand polishing, I would avoid it. It is messy, dirty work and does not impart any protection. My first choice is to start with a decent surface, such as the ground material, do decent machining, and finish with anodizing.

John

 

[3v0]

If you get a good machinist, it will be shiny anyway.

Mike.

Hi, I'm 3Vo's significant other.

I studied mechanical and industrial engineering and was trained to be a machinist.

The part when designed will have a specified 'surface finish', that is specified in 'microinches' by the designer. The smaller that number, the smoother the surface will be finished to. The machinist will produce the part to the size, shape, and within the tolerances specified by the designer (engineer) including SURFACE FINISH. The 'smoother' the finish, the more work it takes on the shop floor. So usually only as flat and "shiny" a finish as will suffice will be specified because of the additional work involved to get a flatter smoother finish. Which adds to the cost of manufacturing that part.

Bottom line, the cheaper the part is to make the better.

So a shiny smooth part was specified that way, otherwise that machinist will probably be fired for wasting the time to put that finish on.

Once in awhile for a display or promo rollout, extra work will be taken to smooth, buff, plate, and polish, but that is the exception for the showpiece.
[example, only the very first shuttle sent to orbit had painted white fuel tanks. That added a LOT to the cost PLUS the weight of the paint. All the rest have looked rusty or tan/yellow of the insulating foam....]

Even in our highly automated age, it still costs to do additional work to produce a smoother finish and the bottom line is they will only do what is necessary. Rather than machine from a solid block at a certain point, a part will be cast or pre-formed then the fine machining to tolerance is done after.

A good machinist is economical in work and TIME expended and does hold tolerance as required and specified.

 

[Sceadwian]

Wet sanding and then jewelers rouge work well, if you want real shine get it chrome plated afterwards, we could probably spend the next 50 years discussing methods for machining material for a good shine afterwards but if you tell us what you're building and for what purpose those suggestions might actually benefit you instead of just a general discussion on machining and surface finishing.

 

[Nigel Goodwin]

Hi, I'm 3Vo's significant other.

I studied mechanical and industrial engineering and was trained to be a machinist.

The part when designed will have a specified 'surface finish', that is specified in 'microinches' by the designer. The smaller that number, the smoother the surface will be finished to. The machinist will produce the part to the size, shape, and within the tolerances specified by the designer (engineer) including SURFACE FINISH. The 'smoother' the finish, the more work it takes on the shop floor. So usually only as flat and "shiny" a finish as will suffice will be specified because of the additional work involved to get a flatter smoother finish. Which adds to the cost of manufacturing that part.

Nice to hear from you 'Mrs' 3V0

I know a guy who did CNC machining, manufacturing jet engine parts for Rolls Royce - as you say, surface finish, tolerances etc. are all specified in the contract. As you can imagine, the requirements for Rolls Royce were VERY strict. The guy was called Martin, and they put him on quality control one day - he failed every single component, each of which was between £12,000 and £20,000

I can't remember what metal he used now?, it was a special light and strong alloy containing titanium - but it was expensive.

 

[Sceadwian]

Probably titanium aluminum alloy, a quick google showed they also throw in a pinch of tin molybdenum and even silicon for high strength alloys, I bet it's a ***** to machine. Traditional machining techniques can't keep up with the high stresses and temperatures in modern jet engines, they're moving more to electro chemical machining and other methods for truly high precision work and some nifty new post treatment processes that can make high precision parts so smooth it increases their physical wear properties by 60%
I've seen some processes where the work 'tool' of an electrochemical process is machined to 'standard' tolerances and it's used as the cathode in a electro chemical etching bath to chemically machine the final part to surface finishes the envy of Nasa. At that point though the only inspection tool available is an electron microscope.

 

[Sceadwian]

I still wanna know what Marks is building =)

 

[Marks256]

I will tell you guy's what i am building when i am good and ready.

I would tell now, but i would like to skip the ridicule and whatnot...

But, if it is any help, my friend and i totally changed the designs, and no longer need to mill out ANY complex parts. A few parts may still have to be milled, but nothing that our CNC couldn't handle.

Total cost of the project SHOULD be less than $4000.

Once we get some designs drawn up, i promise i will reveal the identity of the project.