MemberOctober 30, 2019 at 9:43 am
2 yrs ago we fabricated some dark grey & black ACM trays with push through 10mm acrylic letters.
Lots of the cut edges surrounding the acrylic letters and the tray butt joins now appear to be delaminating/blistering.
Supplier doesn’t have a clue…anyone had the same problems ?
The material is a folding grade .3 branded sheet not a cheap import
MemberOctober 30, 2019 at 12:27 pm
Funny enough…… Actually, not funny…. We have had 3 jobs done in the last 2yrs with this flaw, never had it before, been manufacturing composite trays for a very long time this way and never had it….. one of the signs was installed in May this year and has started……
MemberOctober 30, 2019 at 12:39 pm
Did you get any answers from your supplier why this is happening ?
Same as yourself been using the stuff for years.
It only seems to be happening on the dark grey and blacks…what colour is your problem on ?
What brand did you use ?
MemberOctober 30, 2019 at 1:09 pm
Hi Nick, we have had a few problems in the past – particularly with black. My theory is the black and other dark colours absorb heat quicker and wonder if they are delaminating as the ali face expands quicker than the polyethylene core cracking the glue laminating them together. This could be made worse at the moment if you have a cold night and a south facing sign warms up quickly when the sun comes up (or in the evening but the other way round). Just a theory?
MemberOctober 30, 2019 at 1:53 pm
in theory ?
It looks more like water ingress into the alloy edge …this is then maybe oxidizing and creeping through.. then blowing the face.
Its blowing everywhere along the cut edges and some 100mm into the sheet- ie. the centre of a letter ‘e’ which shouldn’t have much thermal movement or stress.
We bonded the letter middles in with a silicone type adhesive and/or VHB tapes and left a gap around the lettering to allow for movement.
Im told that the aluminium face is heat fused to the core so it cant break its bond !!!, which if it was glued together then maybe it could.
If its a problem with darker colours and thermal mismatch with the core id expect everyone using ACM having issues…sign blanks on walls/road signs etc would suffer and not just stencil cut trays.
MemberOctober 30, 2019 at 4:02 pmquote Nick Johnson:
This is what I’m trying to get to bottom of, its happened on 2 black composite fret cut tray jobs and 1 dark blue composite fret cut tray job, blue one was installed in May, composite is from 2 different suppliers…. 1 of which is trying to investigate, rather not say company but both national large suppliers…
I thought it may be where we are, by the sea with salt air, but I’ve lived here for 22yrs……..
MemberOctober 30, 2019 at 4:39 pm
Our sheet is also from a big name.
we’ve been trying to get answers for months and months…allegedly they have never had this problem with any other sign companies… me thinks a few porkies !!
Have you got any photos of your trays, im trying to find ours.
MemberOctober 30, 2019 at 4:53 pm
Yeah, we have pics. Have also been told have not seen it before :rollseyes: :rollseyes:
MemberOctober 30, 2019 at 4:53 pm
I agree the oxidising effect could also be quite possible. You only have to look up at how some sign companies fit aluminium powder coated trays. Drilling a hole through the painted aluminium and putting a screw in often leads to the powder coat blistering out around the hole as water gets in and oxides the aluminium. So quite possibly the same on where the ACM is cut out.
We had a particularly bad case where we delivered some panels to our customer – panels with returns but no fret cutting. They were left outside, gloss black panels, wrapped in large bubble wrap for protection. The bubble wrap acted like a greenhouse in the summer sun and the panel ended up delaminating all over the place once opened!
MemberOctober 30, 2019 at 5:16 pm
Me thinks that non of the manufacturers are going to admit that ACM has any limitations as to its use.
Imagine the loss in income when sign companies revert to having to use powder coated ali trays.
I have researched most branded ACM’s technical specs and NON of them say not to fret cut as this problem may occur.
How can we carry on using the stuff knowing it may fail !!
MemberOctober 30, 2019 at 5:24 pm
To be honest we try not to make ACM trays any more. As a trade supplier (with metal working facilities) our price for cutting, notching, folding, welding and powder coating aluminium trays comes out cheaper than us setting up the router, programming it, folding and glueing after. But of course if you don’t have that option ACM has it’s uses and I know one company local to us that use stacks of it in the automotive industry – panels up to 7m long in one piece(!) which you would certainly struggle to do in aluminium.
MemberOctober 30, 2019 at 6:34 pm
We’ve had related issues with ACM sheets over the years and from assorted suppliers – mostly black and also brushed silver finish on an odd occasion – blown edges, surface pitting/oxydisation, and accelerated colour fading . We’ve had the reply that they’ve never seen it before but for the most part we’ve had replacement sheets given even long after their original supply (sounds like an acknowledgement to me). OK that doesn’t help if we’ve had to manufacture replacements for our customers but at least we’ve had more sheets. The brands we’ve been using for the last few years do seem to be performing very well without any issues. Some ‘branded’ sheets out there seem to come from a different Chinese mill every time you order them, so a ‘distributor/reseller’ brand isn’t a guarantee of consistent quality and performance, we try to stick to actual manufacturer brands, or single mill brands.
For the most part we avoid using self coloured ACM trays and prefer instead to wrap them with a print as part of the overall design proposal. We find a decent quality laminated print weathers much better than the raw self coloured finish on the ACM, plus we’re creating more value add in the finished design. We’ve never had an issue with a fret cut trays using white sheet with a mounted dark background print but have had with self coloured black sheets?
I know if we don’t set our speeds, feeds and chip rate correctly on the CNC correctly it can still visible seem to give a good cut but compared to the optimum set-up it can generate loads of heat in the cut edge – could this be the cause with excessive heat damaging the laminated bonds in the ACM?
MemberOctober 30, 2019 at 6:38 pm
Making me nervous fellas. We just installed a 9m long fret cut pushed through light box last month… with a matt black face.
That said we did one a year and half ago and I’ve not seen anything.. but then not looked closely.
About to install another 12 over the new few weeks but thankfully all wrapped in various colours.
We are using one of the vink group (am just gunna tip toe into seems everyone else is) is this your big brands?
MemberOctober 31, 2019 at 8:07 am
Im doubtful if its the feed rates etc and heat as my problems are around 50mm and 400mm high lettering and the perimeter cuts so they are all using different machining rates.
So some of you guys are aware of the delamination/paint problems and are now wrapping the ACM in film to help its durability…and taking a chance it holds up…this seems crazy !!
You might as well as put the ACM cutter into a sheet of Ali and fold it back and wrap with vinyl.
What I really cant get my head around is that the white sheets seem fine.
Im new on UKSB and not sure of its rules….am I allowed to name the Brand im using ? cant see why not as it is a real problem with the sheet, im not slandering the company just pointing out a fact.
MemberOctober 31, 2019 at 10:01 am
Do you guys have any images, I’ve not seen this before
MemberOctober 31, 2019 at 1:03 pm
MemberNovember 1, 2019 at 1:33 am
Oh wow. Could it be water getting trapped in the joins?
Does it happen around the edges?
MemberNovember 1, 2019 at 12:14 pm
I have to add that we’ve used 1000’s and 1000’s of sheets of ACM and this problem has only ever happened to us on an extremely small percentage of sheets. Didn’t want to give the impression that its a big problem for us.
MemberNovember 1, 2019 at 12:48 pm
Are we allowed to name the Brands we are all using as it may well be only one Manufacturer.
As I mentioned earlier.. not sure of UKSB rules ?
Ive had it happen on 6 jobs which adds up to some 15 sheets of Grey & Black over the last 2 yrs.
MemberNovember 1, 2019 at 9:13 pmquote Nick Johnson:
There isn’t a problem naming. It is your own view, opinion, experience.
MemberNovember 2, 2019 at 8:05 amquote Robert Lambie:
Ide go even further and say you are expected to name them so everyone else can avoid using them c:
MemberNovember 3, 2019 at 10:07 am
We’ve only seen this on a black panel exposed to the coastal elements (café on the harbourside) and that was after 2 years.
MemberNovember 3, 2019 at 9:42 pm
We have also had problems in the past with Black composite weathering, and the face gets all tarnished.
We bought the material from Righton some years ago. As soon as we contacted them with pictures etc they replaced the material the next day with new sheets.
MemberNovember 4, 2019 at 3:52 amquote Robert Lambie:
Reckon they handled that well.
MemberNovember 6, 2019 at 10:10 amquote Nick Johnson:
Your problem here is the fact you have butt jointed the sheet,
the ACM has nowhere to expand to, so pressure builds up at the edge and causes the aluminium to delam,
All the joints should be folded first and then butt jointed , allowing for expansion in the folded area of the sheet
This is a far neater finish and stops this problem happening.
MemberNovember 6, 2019 at 11:41 am
We’ve butt joined multi-part ACM trays (with a tongue and groove on the back) on 100’s and 100’s of occasions and never had the problem on joins?
I can see the logic but we’ve never had an expansion problem?
MemberNovember 6, 2019 at 12:34 pm
Agree, we never fold the joins, I personally don’t like the way it looks….. We have not had an issue on the joins, its been where we have fret cut the composite…. almost like it is bubbling up from the core out….
We have been told that it is to do with imports being made with a ‘Recycled Core’???
MemberNovember 7, 2019 at 10:56 am
Its not just the butt joins that are the problem, its also all around the push through letters.
ie the middles of an ‘A’ are also going and that cant be down to expansion – we leave a 2mm gap
The sheet we have been having problems with are Alupanel’s .3 folding grade – dark grey & black
MemberNovember 13, 2019 at 8:38 am
what Brand of acm are you all using ….problems or not ?
MemberNovember 13, 2019 at 8:54 am
We’ve only been on the go 3 years and a bit but never seen this. Never seen it when I worked for others using skybond.
I did see the pitting on a matt black sign in our city centre once but no idea who did it or where it came from.
MemberNovember 13, 2019 at 11:01 am
I’ve also had problems with delaminating in the past on a blue aluminium composite, the signs were one piece with no joints.
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