Need a one stop supplier for A1 grade, laser cut 3mm anodised aluminium in the UK...

[Dan Kozakewycz]

I am starting to tear what is left of my hair out about my materials supply and could sure use the advise of the SMC collective on how to improve it!

At the moment I purchase 2.5m x 1.25m sheets of 3mm aluminium from a supplier who laser cuts it down to the 420 x 297mm plates I use for my products, these are then shipped to an anodising firm for finishing in either matte black or dark blue before being shipped to me for laser marking.

The last batch that I purchased was 110 plates, and so far about 40 of them are no use to me because of scratches to the front face! The finish was acceptable, but unfortunately the wastage is simply too high because of these scratches, and with no-one able to say at what point they occurred (quite possibly in the mill prior to the poly wrap being applied) I don't seem to have any comeback on it.

The finish wasn't quite as good as the 1.5mm sheet I previously used from Trotec, but as they were unable to offer a radiused corner on 3mm sheets I wasn't able to use them. It does seem the only way to get that radius on this thickness is to have them laser cut. What I really need is a one stop supplier who can provide me with the finished plates, but I'm not having much luck finding anyone.

My requirements for the finished plates are:
420 x 297mm x 3mm thick plates.
Must have 5mm radiused corners.
Must be 100% scratch free on the front face.
Should ideally be dyed on all faces, leaving minimal clamp marks on the outer edges.

Currently these plates cost me about £18 each but accounting for wasteage it's more like £40 which is far too high. It's possible that I might need to look to China for these but I wouldn't know where to start with that.

Can anyone offer any assistance at all?

[Dave Sheldrake]

Can do all of that other than anodising, what grade Ano are you looking for Dan?

cheers

Dave

[Dan Kozakewycz]

Last batch was 5252 but I'm open to suggestions if there are better grades for anodising.

[Kev Williams]

If your aluminum supplier knows and agrees to your aluminum's finish requirements, and you get them with scratches, they should make good on replacing the scratched parts, or finding out if the plating shop caused the scratches, and getting them to make it right. I have a sheet metal shop make all my anodized aluminum, and every once in awhile I'll run into issues... and regardless if it's a metal or anodizing issue, my shop simply replaces them.

I'm guessing your shop is cutting raw, masked aluminum? You never know what's under the masking unless you remove and inspect the metal first. I have all my aluminum sanded on both sides, so surface issues are rarely a problem.

[Dan Kozakewycz]

It has been suggested that I need to add sanding/polishing as another intermediate stage in the process between laser cutting and anodising to ensure a good finish. I visited a local bead blaster to see if he could assist in recycling the scratched plates and polishing them to the standard I require. He had a go at one of the plates with a typical scratch in it and declared that it would not be cost effective to try and restore them unless I bought the tools and did it myself.

A large part of my issue is that the firm I used for anodising this first batch has been out of action for nearly 4 months following a huge fire that entirely destroyed their plant. As such I've not really had anyone to send anything back to! Once they are back in action I will see if they can offer the sanding/polishing in house. I fear that using a third company for this step would push the cost up too high!

[Scott Shepherd]

They should throw them in a tumbler before sending them to anodizing. It'll smooth all the edges nicely.

[Dan Kozakewycz]

I just found these guys: http://www.supersheen.co.uk/barrel-polishing/

Is that the sort of thing you mean Steve?

[Michael Hunter]

Might be worth a word with Polychromal of Alkmaar, Netherlands.

They specialise in high quality aluminium plates for signs etc. and do everything in-house so the anodising is very consistent.
I had some samples and the quality is superb.

The all speak English and are very happy to deliver to the UK.


PS Barrel polishing will give you lovely smooth edges and completely destroy the flat surfaces. Just DON'T do it (voice of experience).

[Dan Kozakewycz]

Thanks for the recommendation Michael, they look to be the perfect solution!

Noted on the barrel polishing. :)

[Scott Shepherd]

PS Barrel polishing will give you lovely smooth edges and completely destroy the flat surfaces. Just DON'T do it (voice of experience).

That would depend completely on the media used. I engrave things on a weekly basis that were done that way and anodized. They are very smooth and very consistent in color. I ran one of those things many many times, many years ago. We polished brass to a mirror finish in them. It's all in the media used.

[Michael Hunter]

Scott -

I'm surprised!
My experience was with stainless steel sheets which had been delivered with very sharp edges. After we complained the supplier took them back and tumbled them - resulting in smooth edges and scratches all over the previously clean near-polished finish. We had to have them electro-polished after that and the scratching was still visible if you knew to look.

Remember that these are BIG sheets that Dan is talking about - they would certainly crash about in the machine.

[Scott Shepherd]

Scott -

I'm surprised!
My experience was with stainless steel sheets which had been delivered with very sharp edges. After we complained the supplier took them back and tumbled them - resulting in smooth edges and scratches all over the previously clean near-polished finish. We had to have them electro-polished after that and the scratching was still visible if you knew to look.

Remember that these are BIG sheets that Dan is talking about - they would certainly crash about in the machine.

I missed the sheet size, that wouldn't work for that, sorry.

Sounds like your previous experience with it was from someone too lazy to change the media to the right thing. Over the years I've made tiny and not so tiny parts and we just dumped them in, turned it on, came back and fished them out, finished. Some times it was to deburr, some times it was to put a uniform finish on it, someone times it was to give them a highly polished finish. You just had to have the knowledge of the media types to and solutions to put in them to make it all happen.

[Dan Kozakewycz]

Is 'big sheets' in reference to the 2.5m x 1.25m sheets before cutting? I would be looking to get the 420 x 297mm plates polished after cutting. That may still be too big though, I have no idea.

I contacted Polychromal and they are looking rather good value at around £12 per plate. Unfortunately they can't offer me the blue ones I was looking for unless I order 600 plates, but the black ones look to be perfect.

[Kev Williams]

... nearly 17" x 12" sheets would take quite the tumbler!

FWIW, I use the small HB cement mixer for the few things I tumble...

Dan- your reject sheets, have you thought of trying to sell them? I would think there's still a ton of useable material for some jobs--

[Dan Kozakewycz]

I had yes. Can I sell things via this forum? I expect they may be of use to other engravers.

[Michael Hunter]

The reject sheets would probably make good photo mounts - do you have an independent photo/picture frame shop nearby?

[Dan Kozakewycz]

I do actually. How should I approach them about it?

[Dan Kozakewycz]

Got dealt a kick in goolies by Polychromal, turns out I misunderstood their pricing structure and the 1100 euro order I thought I was putting together was actually 7,250.

they seemed rather unwilling to explain the excessive price so I can only assume they didn't want the business.

[Dave Sheldrake]

Dan, try aluminium warehouse, 24 hour and good cut prices on sheet, if you are sulphuric anodising I can give you the run down on how to do that yourself.

cheers

Dave

[Dan Kozakewycz]

Just had a look, they've certainly got some good prices on the raw sheets!

Do you know if they laser cut at all? Although many places can guillotine down to any size, I do need rounded corners on the plates and also have some other smaller components that take up the excess space which makes laser cutting the prime candidate.

I have had a look at home anodising, but unfortunately it's not going to be suitable for me until I get set up in a proper unit to work from. At present I am running this gig from a spare bedroom and I do not want vats of acid in the house with young children.

Trotec have come back and said they can do the 420x297x3mm plates with 5mm rounded corners now for a touch under £15+VAT, however that still leaves me short of the smaller parts (which I have orders for) and means the back faces are not guranteed to be black (not 100% essential, but I do mark the mounting kit locations and personal messages on the back of the pieces.

At the moment, I think that using my original process, but having the parts delivered to me before going to the anodiser so I can inspect and if necessary, polish them before they go off for anodising might be the best solution.

[Dave Sheldrake]

If I can fit it in the laser cutting I can do for you (depends what the Mitsu work load is like though)

AW will get stuff laser cut for you if you order balances of full sheets afaik

cheers

Dave

[Dan Kozakewycz]

I would be looking to make use of every last square inch on the full sheets for sure, but I do not think that buying the raw sheet, getting it cut and then having it anodised is going to give me the kind of guaranteed finish I would like.

At the moment I've had a good price from Polychromal on supplying the uncut 2m x 1m sheets, anodised on both sides which I am confident will be of good quality, just waiting on some samples from them at the moment. If I go this route I will need someone to cut them as per my .dwg layouts.

Can I fire you over a copy of the layout for a quote Dave? Can you advise on what the minimum spacing between each component, and between the components and the edge of the material should be on 3mm metal? I have left 20mm between each component and 10mm to the edges of the material, but if those can be made tighter than I can fit quite a few more of the smaller components on each sheet.

Also, do you know if the laser cutting of pre anodised aluminium will create a noticeable mark on the anodised surface around the cut edges? Wondering if the heat will turn the edges white like the engraver does?

[Dave Sheldrake]

Also, do you know if the laser cutting of pre anodised aluminium will create a noticeable mark on the anodised surface around the cut edges? Wondering if the heat will turn the edges white like the engraver does?

Hiya Dan,

Sure,fire it over and I'll have a look, much of the marking on ally sheet is down to heat dispersion and oxidation. A lot depends on the gas pressure and what gas is used. The type of gas often affects the cost of cutting.

Lasers as such have no speciffic heat (yes a laser beam is stone cold) what they do is cause heat so control of the beam and beam quality makes a huge difference to spread.It's possible to cut clean with anodised sheet with a laser for sure.
The whiting out effect on an engraver (mechanical engraver) is down to stresses in the surface

cheers

Dave

[Dan Kozakewycz]

OK that's good to know.

Any advice on the spacing between components and the edges of the sheet?

[Dave Sheldrake]

If the sheet is good and square (and the guy running the laser knows what he is doing) 1mm to 1.5mm gap between items on a 3mm sheet will work, in general divide thickness of the sheet by 2-3 to get a safe margin for parts. (6mm sheet would need 2-3mm gaps etc etc) that helps with heat distortion or spread. In general don't go below a 1mm gap though specially on alloys as dissipation can cause sagging.

cheers

Dave

ps: 6-8mm edge border will make aligning the sheet easier for the cutter

[Dan Kozakewycz]

OK that's brilliant, means I can fit quite a few more components on that way!