Sunday, March 10, 2019

Another day of DSKY decal process fails, with some incremental improvement



After a drive over to CHM I was ready to work on the remaining labeling for the DSKY. I have white dots to apply to the EL side and black text for the indicator side. Having failed a few times with these, I had to change up the process a bit to attempt to get it right.

Images or text printed with laser toner have a colored mylar sheet applied as a sandwich for a pass through a hot laminator. The black toner heats up more than the paper, melting the black mylar at those spots and only at those spots. This leaves the black mylar fused atop the printed images.

Unfortunately, the black mylar itself heats up during the pass through the laminator, partially melting even in the areas where there is no printed toner image. These streaks ruined my prior attempts to produce a decal.

My plan was to add a layer of paper towel around the carrier as the sandwich passes through the laminator, reducing the heat transfer a bit. I hope it still fuses the mylar over the toner images but does not melt or streak at all in the other areas.

Streak free with fused black mylar over toner image
The paper towel trick worked great - nice clean image with no smudges. I proceeded to statically bond the clear mylar over the image and dunk it in the water bath to separate mylar from the paper.
It was here that the process broke down. The images did not cling to the mylar, or they broke off as the paper soaked. Failure, don't know why.

Incomplete static bonding of fused black mylar with top clear sheet
The white dots are produced by fusing a white mylar sheet onto the toner image, much like the black text above. A later step in the process creates a static electric charge between a clear mylar sheet and the paper with its fused colored mylar images. The new sandwich also passes through the laminator and should stick the clear mylar firmly over the fused color images. A water bath separates the paper from under the fused mylar and top clear mylar.

The clear mylar with the fused color images stuck to the underside with static electricity is the decal. A spray adhesive is added to the bottom side, then the decal is placed on the target location and rubbed to transfer the fused color images onto the target.

I had problems getting all nine dots in one large decal, so I changed the images to have three separate decals, each covering an area with three white dots. I can apply these independently to yield the complete EL panel when all is done.

I built the first decal, for the top middle three dots. but it too floated away without extracting all the white dots. I had also cut and processed the left and right sides, so I put another through the water bath. Same miserable results with these. I will need to figure out what process change might be needed to get these to transfer with the clear mylar. No sense continuing to waste supplies until I can work out a solution to the failures at this step.

One dot and part of border transferred, remainder stayed on paper

No comments:

Post a Comment