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martin54
10-10-2012, 03:15 PM
Although I am continuing with the MDF book build machine I have already started to look at building a second machine which will be far more sturdy. Been reading all the build logs & trying to figure out which build would best suit my needs so I have a better idea about the design.

In one of the build logs Jonathan mentions using tooling or plate aluminium & not flat bar, so what's the difference between the 3 of them. I know that flat bar is extruded so is tooling cast & then machined rather than an extrusion??

Also whats the differences between the various grades you see for plate, is it something to do with the purity or the way it's manufactured.

jcb121
10-10-2012, 05:06 PM
Aluminium is always an alloy in any use.

different grades have different amounts of silicon, tin or other materials to make it harder.

tooling plate is ground flat on each face, plate aluminium comes in pretty much any size. flat bar is extruded through a die to create the shape.

hope i've helped and my info is correct :)

Robin Hewitt
10-10-2012, 05:42 PM
Aluminium is always an alloy in any use.

AW-1050 is 99.something percent pure and is usually sold as sheet, with or without a plastic facing. Horrible to cut, great big burrrs if you drill it.

Edit: Forgot the link... aluSelect: Applications (http://aluminium.matter.org.uk/aluselect/01_applications.asp)

Jonathan
10-10-2012, 06:07 PM
Flat bar isn't flat, plate is close and tooling plate is flat!
I've had 12"x0.5" flat bar that's been out by 1-2mm across the width, so presumably it warps during as it solidifies. This makes flat bar a bit useless for mounting linear bearings on unless you can first machine the surfaces which the rails will mount to. Although you have to be careful since machining just one side can relieve the internal stresses, causing the material to warp further. Plate is much better, maybe a few tenths of a mm (google it) and tooling plate, as jcb said, is ground on both sides so that they are as close as you'll realistically get to being flat and parallel.

There are various grades of each. One that machines easily and is readily available is 6082-T6

Peter.
10-10-2012, 06:17 PM
AW-1050 is 99.something percent pure and is usually sold as sheet, with or without a plastic facing. Horrible to cut, great big burrrs if you drill it.

Edit: Forgot the link... aluSelect: Applications (http://aluminium.matter.org.uk/aluselect/01_applications.asp)

Yup, my intercooler cores are EN-AW-1050A - 99.5% aluminium.

martin54
10-10-2012, 08:14 PM
Thanks for the replies people least I know now when the time comes to start buying bits.
Jonathan, I did google it but I must be rubbish with google because all I could find were lots of companies wanting to sell it to me lol

martin54
10-10-2012, 08:19 PM
Just a thought, a lot of machines seem to use an extruded profile like Bosch Rexroth so does this give the same problems or is a bit of plate mounted on top of it for the rails to sit on. Sorry if it sounds like a silly question but just trying to make sure I do it right next time.

TonyD
10-10-2012, 09:24 PM
Hello Martin.

I've kept an eye on this site Aluminium Supplier | Aluminium Stock | Aluminium Warehouse (http://www.aluminiumwarehouse.co.uk) for the EcoCast plate, as Jonathan says its premachined on both sides, looks like a good option. No doubt other folks will comment if its not. I costed a 20mm thick plate using the EcoCast of approx 450X200 one off for just under 40 GBP before VAT and Shipping. I havent gone ahead yet so cant confirm shipping. From what I've read here Alu plate is desirable becuase it is easier than steel to machine. So for those with an existing machine that can cut Alu, a good option. I do wonder what a comparable size steel plate would need to be for the same rigidity, I'm assuming 1/3 the thickness due to a comment I read somewhere about material density? As I dont have a machine already I'm not planning to rebate the Z Axis rails etc so I might just go for 7 or 8mm thick steel, but like yourself, I'm still reviewing options.

martin54
10-10-2012, 10:41 PM
Thanks Tony, yes that site has been mentioned before on this forum & I already have an account with them which I use to buy mainly aluminium angle, small box section & the odd bit of channel. Not much in the way of suppliers local to me for that sort of thing, OK for steel but the guy doesn't sell aluminium. Prices have always seemed to be OK as well although they can be a bit slow with processing & delivery at times.
I had just assumed it was flat bar people were using until I read Jonathans comment about using plate. Same position as you in that I don't have access to any equipment to machine it myself. Been reading the build logs & studying peoples designs, it's the z axis that is the biggest problem for me in that it is sometimes difficult to see what people have done the way the pictures are shown on the forum.

Jonathan
11-10-2012, 01:03 AM
Just a thought, a lot of machines seem to use an extruded profile like Bosch Rexroth


Extrusion is pretty good, you can at least mount supported round rails directly to it.


Been reading the build logs & studying peoples designs, it's the z axis that is the biggest problem for me in that it is sometimes difficult to see what people have done the way the pictures are shown on the forum.

If there's anything specific post about it and I'm sure I can help. I took quite a few photos of mine during assembly, see the last post in my build log. If you're using SBR rails it shouldn't be difficult to make it with hand tools, although a pillar drill is well worth it.

m_c
11-10-2012, 02:44 AM
Any alu that's been extruded is generally accurate and consistent.

Plate/flat bar depends on how it's been formed. Larger sizes are generally made via rolling, then sheared/cut to width, and both of those are generally not highly accurate processes.