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View Full Version : Re-anodising erroneously laser marked aluminium (aluminum) sheets.



Dan Kozakewycz
07-11-2014, 5:06 AM
As I'm a complete n00b to the laser engraving game, I've been making a few mistakes with my products and as such I am getting a high wastage rate on my materials through silly mistakes. Each on of my plaques costs me 15 with a finished value of 150, and so far I've managed to scrap about 8 of them. :(

I am wondering if it would be possible to have the anodising chemically stripped from these plates and for them to be re-done, thus completely removing the marking and making it 'as new'.

Is there any reason that the laser marking may make this a non starter?

Henri Sallinen
07-11-2014, 5:32 AM
The best approach would be to minimize the reasons you are making the mistakes. If you are using too little power on a run, you can allways run the same sign again (do this without moving the sign after the first run). If it's a alignment issue, you could try to make a jig out of some scrap material (corrugated cardboard or some spare plastics?) and align your artwork acording to the jig. This should minimize the mistakes you could be making. Also, make sure that there are no hidden layers or wrong colored layers that could give a faulty engraving quality.

No ideas on the re-anodising, sorry!

Dave Sheldrake
07-11-2014, 6:10 AM
Yes you can Dan, they can be stripped with Hydroxide (Sodium) but will cost more to have them re-anodised than they cost you I would think.

Home anodising isn't expensive to set up and can be done for pennies once you have the kit

cheers

Dave

Robert Walters
07-11-2014, 6:21 AM
Anodizing involves electrolysis, battery acid, flammable hydrogen gas, boiling water, and about 90 minutes.

I have no clue on Re-anodizing, but you might get inconsistent coloring batch to batch, and not sure on the lasering would effect it either; may leave artifacts that any "stripping" process may not be able to remove.

Unless you plan on making a LOT of mistakes, probably not worth the time and effort to recover the lost value.
Might be better to just reuse the plates for testing and calibration purposes, then just recycle the aluminum itself.

Dan Kozakewycz
07-11-2014, 6:40 AM
The best approach would be to minimize the reasons you are making the mistakes. If you are using too little power on a run, you can allways run the same sign again (do this without moving the sign after the first run). If it's a alignment issue, you could try to make a jig out of some scrap material (corrugated cardboard or some spare plastics?) and align your artwork acording to the jig. This should minimize the mistakes you could be making. Also, make sure that there are no hidden layers or wrong colored layers that could give a faulty engraving quality.

No ideas on the re-anodising, sorry!

It's mostly errors I've made in the artwork, spelling mistakes, errant lines etc. My product is bespoke replica technical drawings which I draw myself, sometimes I make mistakes on it and don't notice until they've come out of the machine.


Yes you can Dan, they can be stripped with Hydroxide (Sodium) but will cost more to have them re-anodised than they cost you I would think.

Home anodising isn't expensive to set up and can be done for pennies once you have the kit


I got the anodising carried out by a different supplier from who supplied and laser cut the plaques. That company said they'd re-do them (they did some the wrong colour) for the same price but sadly they're out of action following a serious fire recently. Having trouble finding a replacement for the ones in the wrong colour at the moment but when I do I was hoping I could perhaps save a few of the cast offs by re-doing those too. So far I've had one company say it is possible and one say it isn't, so I'm a bit confused.

I do want to check home anodising out eventually, but at the moment I do not have anywhere to do this work safely. Maybe when I get a garage or unit to move in to in future.


Anodizing involves electrolysis, battery acid, flammable hydrogen gas, boiling water, and about 90 minutes.

I have no clue on Re-anodizing, but you might get inconsistent coloring batch to batch, and not sure on the lasering would effect it either; may leave artifacts that any "stripping" process may not be able to remove.

Unless you plan on making a LOT of mistakes, probably not worth the time and effort to recover the lost value.
Might be better to just reuse the plates for testing and calibration purposes, then just recycle the aluminum itself.

Yes this was my initial thought, I can keep errors as demo pieces if the mistakes are minor and as test material as if they're bad. Would just be nice if I end up with a stack of them, to be able to send them off next time I order a new batch for anodising and have them refinished.

Dan Hintz
07-11-2014, 7:24 AM
So far I've had one company say it is possible and one say it isn't, so I'm a bit confused.

Absolutely, it's possible (and done often in the industry). The company that said 'no' simply doesn't want to do it (or isn't set up to do it, which is a real possibility).

Michael Hunter
07-11-2014, 7:53 AM
Any anodiser should strip (at a charge) and re-anodise for you .

Unless you polish or linish the metal after stripping (and before re-anodising), you are likely to see a "shadow" of the previous engraving.
This may not be too much of a problem if the correct engraving goes right over the top of the mistake, but if it is in a different position it will show.

John Coloccia
07-11-2014, 8:00 AM
Sell them for $40 as "scratch and dents". That's what I do with my products. I get enclosures all the time that have imperfections on them...probably 5% to 10% have some sort of issue. Instead of bothering with time consuming QC when they come in, return shipping, etc etc, I simply put them aside when I find them, and then build them up and sell them off as scratch and dent when I have a spare moment. I've still made money, and I have a happy customer that got a steal.

Mike Null
07-11-2014, 8:11 AM
Dan

You've discovered one of the hazards of engraving--carelessness! All of us have made these mistakes and we have learned to proof our work over and over. Even then we make mistakes. Sometimes it's a machine malfunction or faulty material but most of the time it's just human error.

I would put those mistakes in the salvage barrel and not waste any more time or money on them.

Dan Kozakewycz
07-11-2014, 8:27 AM
Sell them for $40 as "scratch and dents". That's what I do with my products. I get enclosures all the time that have imperfections on them...probably 5% to 10% have some sort of issue. Instead of bothering with time consuming QC when they come in, return shipping, etc etc, I simply put them aside when I find them, and then build them up and sell them off as scratch and dent when I have a spare moment. I've still made money, and I have a happy customer that got a steal.

Trouble is everything I do is totally bespoke, so once I've engraved it with all the customers details it's of no real appeal to anyone else unfortunately!


Dan

You've discovered one of the hazards of engraving--carelessness! All of us have made these mistakes and we have learned to proof our work over and over. Even then we make mistakes. Sometimes it's a machine malfunction or faulty material but most of the time it's just human error.

I would put those mistakes in the salvage barrel and not waste any more time or money on them.

A fair comment. I wouldn't bother sending them back normally but under the circumstances (about 25% of the plaques were dyed the wrong colour and need redoing) I thought I might as well get these bits redone at the same time.

Interesting to here that there may be some left over marks on the new surface. I guess I'll just need to test this out with a sample.

Brian R Cain
07-11-2014, 8:36 AM
I can't add much to what has already been said other than to agree with Mike that it's probably not worth the effort and you have to put it down to experience. One thing I will say from my own experiences of having small numbers of items anodised is that the quality can be very variable. I've had parts of batches that were dark blue instead of black, streaks and so on. Never 100% of a batch having the same colour. I'm very impressed though that mass produced items such as pens are anodised so consistently well.

Dan Kozakewycz
07-11-2014, 8:45 AM
I can't add much to what has already been said other than to agree with Mike that it's probably not worth the effort and you have to put it down to experience. One thing I will say from my own experiences of having small numbers of items anodised is that the quality can be very variable. I've had parts of batches that were dark blue instead of black, streaks and so on. Never 100% of a batch having the same colour. I'm very impressed though that mass produced items such as pens are anodised so consistently well.

Yes the anodising on this batch sadly wasn't up to the standard of the material I purchased from Trotec/Suregrave but unfortunately they weren't able to supply the material as I required it for the production work.

Bill George
07-11-2014, 8:54 AM
Rustoleum sells a paint that looks almost chrome like. It comes in chrome and gold colors, looks pretty darn nice. Re purpose your sheets with paint and move on. I use scrap pieces of plywood spray painted for my testing of a concept or design.

matthew knott
07-11-2014, 9:23 AM
Dont even bother trying, the stripping effects the surface finish of the aluminium, on sheet stock it will never be cost effective to get something stripped and re-anodized and get an even half decent finish. At 15 a sheet its better just to bin it and buy new again, we regularly have parts sent into us that have been stripped and re-anodized and you can always tell the difference.

Dan Kozakewycz
07-11-2014, 9:26 AM
Oh that's not good at all Matthew. Ignoring the ones that have been marked on the laser, that doesn't bode particularly well for the 30 odd sheets that were supplied in the wrong colour. :(

David Somers
07-11-2014, 11:08 AM
Dan,

A few more thoughts on Henri's comment about trying to reduce your mistake rate? Obviously proofing on any hand drawn paper copy is the first place to start. Then proof the computer file before doing your output. Sometimes allowing some time between finishing the computer file and proofing it can help you spot problems better.

For myself, there are some things that I see immediately on a computer screen and some I don't. For example, something in my mind prevents me from seeing that Recieve is spelled wrong if I see it on a computer screen, but if it is printed on paper I see it right away. Other words are just the opposite. I see the typo on screen like a bright flashing light, but on paper???? Nope! I can KNOW that I did it wrong and look right at it and not see it. Go figure.

So for important things I have a macro done up that takes all my common typos and misspellings and looks for them and replaces them throughout a file or document. This is in addition to any spell check or grammar check. That has helped me a lot.

And of course, you can always run the final draft by the buyer for a last check of content. It is possible they gave you the wrong details and this is their chance to catch it.

And for a graphic that is bound for the laser....make a check list of things to do on each file to check for duplicate layers, spotting multiple lines that are hidden, etc. Get anal if you will pardon the phrase, and make yourself go through that list each and every file before it heads to the laser.

I will often print a draft on paper and go through it before the final output. In the case of a laser, you might burn it to a cheap material as a test run to be sure of the output, though that doesnt help with the settings you need for the final material.

And since you will still have bad runs, save the material and use small portions of it to run a fast test of the settings you will use on your full run. May as well get some use out of it as a test material to be certain you have covered all your bases.

That seems like a lot to do, but if you find your costs for shot materials is getting unreasonable the cost of doing this level of QC may not be too bad in the long run. And you will get quicker at it if you have a firm process in place to follow.

Dave
he who has so many typos in his forum posts he spends more time in Edit than doing the original post. Sigh. <grin>

Mike Null
07-11-2014, 11:09 AM
I used to have a customer I marked anodized parts for. He would send batches in large tubs. the quality of the anodizing was such that sometimes i'd have to send half back undone. I charged for time on those. He ultimately switched to powder coated material.

The anodizers process seemed to be contaminated and he was putting out some ugly stuff. I buy my anodized sheet stock from Johnson Plastics and have never had an issue.

Kev Williams
07-11-2014, 11:43 AM
You can anodize an already anodized piece, but simply doing that won't 'erase' the engraving. If the metal is thick enough a sheet metal shop MAY be able to run it thru their Timesaver and sand it down and then have it re-anodized, but the downside is the edges can get sanded too much, and whether or not the sanded finish is suitable. If not, then more work is needed to prep the surface...

My suggestion: Keep all your scrap pieces and use them as setup and test engraving parts. Recycle them when they're 'used up'.

Also Have a second set of eyes proof read the job. It's easy to get 'temporary dyslexia' when working with text & graphics on a computer screen all day. If you have several different jobs or layouts, do several of them and job-save them, TAKE A SHORT BREAK to give your eyes a rest, then carerfully proof the layouts. Run a test job first on some scrap to make sure the laser's doing it's job. All okay, then run the saved jobs, start on the next layouts...

My biggest issue is NOT TAKING A BREAK before proofing or running a job. Your eyes and brain do funny things when they're tired! Like typing "Neil" instead of "Niel", or "2014" when it should've been "2013". A tired brain can cause you to type words or numbers the way you're most familiar with them, rather than verbatim. Tired eyes may not catch the mistakes, but a fresh or second set of eyes usually WILL.

Dave Demaree
07-11-2014, 6:51 PM
Hi Dan,

I anodize at home and have to strip parts often. I'm not sure what kind of polish your original plaques had, but the problem with stripping is that it usually removes all polish from the part. You'll end up with a very dull/matte plaque if you strip it and try to re-anodize without first polishing the parts.

Obviously, this will add more time and $$ to the process.

Michael Reilly
07-11-2014, 7:49 PM
I have a client that brought me some parts his company had milled and then had anodized. Due to the confusing nature of the drawings, they got engraved upside down. And although we did a batch of 10 that made it all the way to the client and onto the product assembly line before someone noticed, word didn't get back to us until we'd done the balance of the job. But they were able to bead blast and re-anodize them. Luckily not at our expense... the client acknowledged that he should have spent the time to walk me through the drawings and make sure I understood them. We aren't charging for this job, but because we handled it well, there is plenty more business coming our way. In fact, apparently the same is true for our client. Because he was able to call on his anodizer to get 10 of the parts redone and have Fedex deliver them here same-day and we engraved them at 11pm when they arrived, the client is bringing him more business. Mistakes suck, but sometimes handling them well builds greater trust.