Building clear cover for vacuum columns to assist in debugging

HIDDEN TRANSPORT PATH AND VACUUM COLUMNS

The path that the tape takes past the head and into the two vacuum columns is hidden behind an aluminum cover plate, blocking a chance to observe what is working and what is failing during the autoloading. The maintenance manual identifies a service tool that was available - a clear plate to install.

Cover plate hiding tape path and vacuum columns

Since I don't have that plate and there is little chance I would ever find it, the only way I can peek inside is to manufacture my own. The plate has many holes to clear screws and tape heads, as well as holes that apparently help control the airflow to route the tape through the path. It will be a complex piece to design and build, but ultimately worthwhile.

Tape path around left perimeter and two vacuum columns

BUILDING A CLEAR PLEXIGLAS COVER

I took the plate off drive B so that I could carefully measure it out for entry into a CAD program of some sort. I suspect that the number of curves and drilled holes take this beyond the capabilities of TAP Plastics, thus it likely will require laser-cutting.

Cover plate to be replicated in clear acryllic

I will use Ponoko.com to do the cutting. I first have to build the design using Inkscape, an open source and free alternative to Adobe Illustrator. My door fits in a 23 7/8" by 11 1/2" rectangle but the closest common material size offered by Ponoko is P3 which is 31.1" x 15.1".

The shape is complex, even before all the holes and cutouts get added inside the remaining outline. I began by cutting down the outer shape, which took some time and ingenuity in the case of the arcs of unknown radius. After I traced the arc and continued it around a sheet of paper, I could determine the radius and distance from the perimeter to the far edge of the cover.

I then decided I would get better results if I were to take a picture of the cover, import it into Inkscape as a layer and then trace everything on the next higher layer. I had sized the picture so the image dimensions matched quite well, ensuring that my final design will correct. That gave me a good set of circles, paths and other shapes that fit well.

Laser cut file

I then uploaded it to Ponoko.com and selected clear acrylic of the appropriate size as the material. This gave me a set of costs, including premiums for faster production and for speedier shipping. They started at just over $21 not counting shipping, which was a minimum of Priority Mail. I upgraded to 3 day manufacturing which resulted in a total of $40. It should arrive late on the 18th of November.