IPI or Rowmark Plastics?

[John Frazee]

For the most part about all I have ever used was IPI, I think. I have read posts over time about the pros and cons of each. The problems I have may be with both companies but just wondering. The biggest problems I have had are as follows. When lasering, the residue builds up on the nose cone so bad that on some jobs I have to pause the machine to clean the build up off to keep it from scratching the plastic. Another thing is the flatness. I even bought a full case of blue/white that was very wavy so it's not just from buying single sheets. I store it all flat but this will not even out even with added weight. Another, when I peel the plastic protective off, I can see ghosting from the film still on the sheet. Not so bad doing nametags but not so good making larger signage. Anyways, just wondering if it was just me or I need to try a different brand. Thanks for any guidance.

[Mike Null]

John

I have no idea what the nosecone problem is unless you have air assist that is not properly directed. Some IPI material is warped and will not lay flat regardless of what you do. Your supplier or IPI will replace it for you.

I use IPI because I believe it engraves and cuts better than Rowmark. There are many who disagree.

The ghosting cleans easily with dna.

[Scott Shepherd]

Those 2 problems have been well documents on the forum. IPI seem to not care about flat material at all. I've spoken to the distributors and the factory. The factory says it's dead flat when it leaves there and the distributors say they store it flat, so it's not anything they are doing.

I can't use IPI because of it. I'll work around a sheet when it's an emergency, but for the most part, I can't use it. I can't deal with 1/4"-1/2" warp in it. I'd rather not take 15 minutes to try and figure out methods to hold it down that won't interfere with what I'm engraving on it.

I also hate the ghosting. I have instances where it simply won't come off with anything. I've tried DNA, Novus Plastic Polish, and everything in between. I think it's stupid that they put their logo on there. Any light source exposed to it will start burning the image into it.

I hate the fact that they don't seem to care that their product is warped when I get it (don't care who did it, just want it to stop). Shows me a lot about how they do business.

[Joe Pelonio]

I too have had the warped IPI experience and have not used it in a couple of years. Every time I tried, regardless of the vendor, it has been warped. I suppose people with vacuum table machines can use it. The only time I have seen warped Rowmark was my fault, when I stored a sheet with some smaller scraps under it for a long time.

[Mike Null]

I tend to agree but I think it is a process issue that they can't fix without a major change in tooling. I find it to be worse on thicker material and on metallics.

I have not seen a problem with my purchases for the past few months though. About 90% of my purchases are .030" material where the issue is not a problem. But the ghosting is there.

[David James]

I have only used Rowmark plastics, but they too put their logo on the skin which leaves a ghost copy on the plastic. However, I have been able to wipe it off successfully so far. No problems with flatness...I have been pretty satisfied with their plastics. The build up I think is just part of doing the job. Maybe try beefing up the exhaust system and try to take the residue out before it lands on the cone or laser head.

[Scott Shepherd]

I tend to agree but I think it is a process issue that they can't fix without a major change in tooling. I find it to be worse on thicker material and on metallics.



The factory tell me that they have retooled and they promise me that their material is dead flat when it leaves them. They also promised to send me samples to prove it. However, it's been about a year and the samples never showed up, so I can't confirm or deny their material is flat when it leaves them. I have been to my wholesaler and seen the way they store it. They store it dead flat on racks, so it's not a storage issue. Either way, no one wants to own the problem and correct it.

[Scott Challoner]

Just a hunch, but the warping issue sounds very familiar to what I used to go through with printed circuit boards. Muliple layer boards had to have the copper layers properly balanced or they would warp due to different CTE of the various thicknesses of copper layers. Usually, internal layers were the thicker copper with the thinner copper being use on the outer layers. If the layers were stacked from thickest to thinnest, the boards would warp ( usually toward the thin copper since it didn't expand as much as the thick copper). Since engravable plastic is just two layers of plastic, a thick base layer and a thin engravable layer, I think this might be what happens. This seems to go along with Mike's statement that thicker plastics warp more. In this case, I don't think the issue is heat, but moisture. The distributers probably store the plastic in the original packaging from the factory (maybe even with a dessicant?) and when they take it out to ship it to us, the clock starts ticking as to moisture absorption. As it sits on our shelves, it continues to absorb moistue (at different rates since it's two different thicknesses) and warps. This is just a theory and I may be all wet (get it. Wet. Moisture. Is this thing on? ((Forgive me. I had my knee scoped this morning and I'm still groggy from the anesthesia)). Anyway... i think next time i get plastic, I'll get two sheets of the same thing from IPI and store one in a moisture barrier bag with a dessicant and one unprotected on the shelves of my soggy basement.

Honey? Wheres my Vicodin?!

[Mike Null]

There's no question that moisture can have an effect on laminated plastic but I'm quite sure that this material is shipped to distributors in full sheets and then cut by distributors to meet their orders.

To your point about copper I tend to think that there is a different coefficient of expansion between the thicker core and the thin surface layer which causes the warping.

I also suspect process issues as I've received sheets with contamination embedded in the surface.

I have tried numerous methods of flattening the material including heat but nothing works.

[Dan Hintz]

Mike,

Scott's mention of the PCB issue has nothing to do with the core, just the copper (it's something I have to deal with from time to time on larger designs). When the boards are placed in IR reflow ovens during soldering of the surface-mount components, the expansion of the copper sheets is a major issue. In some cases, a poorly-trained or inexperienced designer will try to use an odd number of power/ground planes (the planes tend to be mostly solid copper, rather than individual lines) in the hopes of saving the company money on the board's layup. Then they wonder why the boards fail. As it cools coming out of the oven, the different expansion rates (more copper on one side) warp the board and pop components off.

Probably more than you wanted to know about PCBs :p

As far as the plastics go, I also question water absorption, though wide/fast changes in temp may also permanently warp the boards if the two materials have different expansion rates and one has a low elasticity.

[Scott Shepherd]

I also suspect process issues as I've received sheets with contamination embedded in the surface.



I've had that problem with IPI and Rowmark. I actually cut some vinyl lettering 2 days ago and there was a large patch of flakes of some other colors. Almost like something broke loose and everything fell onto the product.

I also have a lot of problems when I pull off the protective layer on IPI products. They seem to be very prone to actually pulling up small flakes of the cap sheet, leaving me with small holes where the core color shows through.

[Mike Null]

Dan

Thanks for the clarification on the PCB's. It was more than I needed to know but you never know when it'll come in handy.

[Scott Challoner]

Sorry if the PCB comparison was confusing. I was just trying to point out that when you have two layers of different thicknesses bonded together, the two layers will expand and contact at different rates, whether it's due to heat or moisture absorption, and cause warping.