JDS and bowed material

[Scott Shepherd]

Anyone else having issues with Rowmark (or anything else) being bowed really bad, coming from JDS? I've been in discussion with them for over a year now, and it's marked on our account that all material must be checked to make sure it's flat, but everything that comes in has about a 3/16" curl across the 12" dimension on a 12" x 24". I've called, I've sent photos, I've taken samples to the trade shows and left them with JDS, and yesterday, I spoke to my sales rep that told me that they sell 1000's of sheets a week and I'm the only person complaining.

I'm trying very hard to work this out with JDS, but I wanted to come here and ask if it was the case, am I the only person with this issue?

It's almost impossible to sell something that's 12" tall because it's so bowed, you can't hand it to the customer without looking like you sold them junk. You can't use it for engraving a sheet of products because it's bowed so far, it's so far out of focus that it won't work.

I've got my own work arounds for some of it that helps, but I shouldn't have to be "working around" material made for laser engraving.

It's a 1 day ship from them to us, so it's not like it's spending days in humid weather.

Anyone else seeing this problem? Maybe it's a local issue?

The center photo is 1/8" baltic birch under the straight edge. The bow is worse, but the weight of the steel ruler took some of the bow out of the photo. I will add that this material was order around 3 in the afternoon, we got it around 10:00 the next morning, and I pulled it right out of the box and put it on the table, just like this.

rowmark1.JPGrowmark2.JPGrowmark3.JPG

[Wes Mitchell]

I'm sure you've heard most of this before, but this is what Rowmark recommends:

http://www.rowmark.com/MARK/Minimizing%20Warp.pdf


Is that LM942-402? The sheets on our shelf look much flatter than that. If you're having a problem with warping consistently, I would suggest looking at IPI's LaserTuff line. From what I understand it's a pressed material instead of being laminated together. It results in a super flat sheet, but it does take a little more power to get through the slightly thicker cap. It's not normally stocked in 1/8" though, so it would have to be special ordered.

[Scott Shepherd]

It's just 922-402. I'd love to follow Rowmark's advice for storage, but it's bowed when I get it. JDS tell me it's flat when it leaves there, but when it gets here, it's bowed. I can't switch products because we make products for an electronics company and they've actually tested all the materials available to us with meters and this product has the right electrical characteristics for their needs. I would have thought it was all the same, but they assure me it's not.

We have a large rack made to store it all flat, but once it's bowed like this, we can't get it out. I've sat granite tiles on a stack for a month and it didn't change anything. I've heated it, I've soaked it in hot water, I've left it in the sun, I've done just about everything I can think of to try and make it flat, but it just won't budge.

Rowmark sent me pieces and put the silica gel packs in the box, and it got here dead flat.

[Wes Mitchell]

We get complaints like that occasionally as well, knowing that it's perfectly flat when it leaves our shelves (and the 922-402 does look perfectly flat.) I guess you never know what happens to it in the 1 day of shipping, but after seeing some packages that UPS delivers you just never know If you have any interest in having your customer test Lasertuff just let me know and we can get a sample to you, but aside from that I don't know what to tell you as it sounds like you've pretty well covered all the basics in getting rid of your bow, assuming you've tried removing the masking?

[Scott Shepherd]

Yes, several years ago, I was told by Rowmark's tech support that bowing is often caused by uneven hydration of the material, due to the fact that one side was open to humidity and one side was masked from it. They told us to unmask it and let it equalize in a flat space. That didn't help either.

My belief, for some time is that it's actually stress introduced into the material by the shear (or a dull shear).

[Mike Null]

Steve

Warping has been an ongoing problem with Rowmark and IPI for as long as I've been in the business. I don't think they are being honest about what causes warping. It's my opinion that the warping is caused by the manufacturing process when two different materials are bonded together both having different coefficients of expansion. It seems that the thicker the material the worse the problem.

I would suggest trying a heat gun to see if you can flatten them.

[Ron Hartl]

I haven't ordered any for a while, but the stuff I have is still perfectly flat. In your photo's, I would say a "bow" is an understatement. I would call it warped beyond use. Could JDS take some photo's before shipment?

[Scott Shepherd]

Thanks Ron and Mike. We've probably bought 100-130 sheets of that one color this year, so this isn't a "little irritant" for us, it's a major issue at this point.

[John Frazee]

I have the guys name and number that makes it for Rowmark and IPI. His factory is located in NC. I just tried to call him and he is out to lunch. I will try back later and will post back. I will see what his take is on it.

[Scott Challoner]

I agree with Mike that bonding dissimilar materials often creates issues with CTE but I don't think there is a huge temperature change between the JDS facility and yours. When you say Rowmark sent you samples with a desiccant and they were flat, I think it points to moisture as the culprit. I imagine Virginia is pretty humid. (?) Not to mention that the plastic is exposed during transit. Would JDS be willing to pack your sheets in a moisture barrier bag with a desiccant? At least for a test? Can you give them an actual measurement for flatness? Flat to them and flat to you may be two different things. When I worked with PCB's we had an IPC spec dealing with the flatness of the boards which is .0075" per inch over the diagonal of the board. That equates to almost .2" for a 12 x 24 sheet which is a lot for a laser, but like I said, that was for a PCB. Maybe the engraving industry needs to adopt some standards too.

[Randy Digby]

I get my LaserMax material from JDS and the red and yellow are bowed (more on one side than the other) almost always. The other colors, not so bad but are bowed as well on occasion. . It does not hurt my process since I typically cut a sheet up into my standard part size and then engrave the parts as needed.

[Joe Pelonio]

I have never gotten flat IPI, but then I got it by UPS. When I get Rowmark I pick it up locally and have never had it be warped. My money is on the heat/cool of shipping, and the fact that one side is plastic coated. Where I get it they cut to
12x24 from 24x48 when I call them and I pick it up soon after but even the few times I had them ship it came the next day and it was fine (only 20 miles away).

When I had the warped IPI I simply used thin double sided tape to adhere it to a scrap 12x24 1/4" acrylic that I saved with most of the inside cut out from a past job. Keeps the whole thing perfectly flat as long as you have a 1/4" wide or more strip still left in the middle to tape to.

[Rodne Gold]

I think the warpage is due to the composition of the substrate , generally the cap is just a screened colour unless its the thick cappped variants, however the substrate is not ABS like the rotary engraveables , but generally some mix of ABS and acrylic..acrylic expands by 1% or more in the direction its extruded ..most of those substrates are extruded (to maintain thickness tolerance).
1% doesnt sound a lot , but on a 1200mm sheet (4ft) it can actually be almost 1/2 an inch which is substantial. Pretty sure most of the warpage occurs with shipping.
Apart from hold downs , double sided taped on a sacrificial sub boasrd , vacuum , smaller piece sizes and so on..,there is little you can do.
I find that warpage when cutting and engraving a far bigger problem , especially with large area engraving.

[Keith Outten]

I always heard that most plastic is run through rollers during the fabrication phase. It also has a memory so even if it is flat for awhile it will eventually return to a curved state.
I store mine on a rack between two acrylic sheets, just a few sheets of plastic of each color. For the most part it stays flat and when I remove it from the rack I use it right away.
I also machined a custom Corian vector table that is raised off the engraving table with no edge guides so I can place tape over the edge of the plastic onto the Corian table.

I don't know why but the Corian vector table works great for cutting engravers plastic but it doesn't work well for cutting acrylic.
.

[Scott Shepherd]

Hopefully got this resolved. Finally got someone at JDS that wouldn't let the problem go. From what they told me, the problem appears to have been caused by sheets that were cut a little more than 12", and the boxes are made for 12" stock. So they were checking them, they were dead flat when they checked them, then when shoved into the box, it put the bow into it, and that's what I'd get when I opened the box.

I just ordered 15 sheets and they were all right at 12" wide and they are flat FLAT. Flattest material I've gotten from JDS is 2 years.

Hopefully this is resolved. I'm so glad someone took this and ran with solving the problem and apparently did find an issue.