Aluminium sheet is not glossy after sublimation

[kman21]

Hello,

Im trying to sublimate thin (0.5mm) aluminium sheets but i get a weird result.

The sheet looks dirty/blurry after sublimation. This happens even if i just use a blank paper with no print.

Any ideas why this is happening? Is it moisture or heat/pressure issue? See the photos below.

Thanks in advance


* Yes i have removed the protective film.
** This happens with any combination of temp/time setting

[Paul]

Heat AND pressure.
Metal need very little, almost no pressure.

[kman21]

Thanks for the reply Paul. Reducing pressure and adding a piece of cloth on top of everything did the trick. However its clear that now i need to increase time and temp to get the print right since it has blotches all over.
Any suggestions? I saw that many use 120 seconds. 185c and 90seconds had this result:

[Andrew]

We print loads of .5 metal and actually use firm pressure. 190c for about 50 seconds with paper side down on press bed so heat platen goes onto back of metal. You can get the odd batch where the coating is not as good and will melt at a lower temp holding onto fibres of the paper when removing. When this happens we drop to around 170c but haven't had a dodgy batch for a while.

[kman21]

Hi Andrew,

I have tested many combinations of heat and temperature settings. Nothing worked. I always get the result that you saw in the first photos. Only if i have the sheet on the rubber pad facing up, then the paper and then a piece of cloth, then and only then the coating remains glossy without these weird stains. Im still not sure what causes this (you say its not pressure). After a few more tests i found out that 190c for 110 seconds produces fine prints. The colors are off but thats a different discussion. I have 10 years of experience with 3d sublimation but im new with heat presses, metal sheets and 2d in general.

[Andrew]

If it works for you that way just keep tweaking until you are happy. We use several different presses and never have to change the way we do it and it is never longer than 60 seconds or 190c. It can work at just under that for us with paper side down on the bed and that is a few thousand sheets a month going through.

The original photos you put up do seem to indicate to much heat getting into the coating. A cloth obviously slows that down and if you aren't rushing to get the work done then that is not a problem. We do often use a cloth or silicone sheet on the base of the presses anyway so perhaps try it that way around and pull the time down. The cloth just stays in place then to save you taking it on and off.

[kman21]

One more question. Do you let the paper dry for a while before pressing?

Is this because of moisture or wrong settings? You can see both the paper and the sheet after pressing.

[Paul]

ALWAYS USE DRY PAPER. AS WET INK WONT HELP YOU. IT WONT BE YOUR FRIEND AT ALL.
i FORGOT TO MENTION THAT YOU DONT USE ANY CLOTH. AND PRESS IT UP SIDE DOWN. sO PAPER AT THE BOTTOM. LOW, VERY LOW PREASURE. !85C for 45sec as starting point.


PS. sory about the caps :rolleyes:

[kman21]

Hi Paul,

Some people say little pressure, some say medium to strong. Some say 90-120 seconds, others 50-60. Its hard to say which settings are right.

Is this because of moisture or wrong settings?

[Paul]

low preasure - up side down. look like you need more heat. also is your meal a quality one?