Cleaning prisms in production application

[Viper488]

A relative of mine is involved with a company that has its' production employees use kleenex, toothpicks, and acetone to clean their prisms during the product assembly process. This seems terribly lo-tech, and is a major hold up in the overall production count per shift. The prisms are used in a precision application and have to be perfectly clean of fingerprints, clouding etc. They're about 1.5" long and already epoxied to a metal prism holder by the time they get to the cleaning station along the line. There must be a better way.

 

[Zito]

I would recommend using methanol instead since it's not as harsh as acetone. In order to avoid smears the methanol should be as pure as possible and stored in a glass bottle. Lens tissue should be used instead of kleenex, and the methanol should be applied over the tissue while on the prism face (there's a name for this technique, "drop and wipe" or something like that), and then wiped once across the surface before disposing of the tissue. If the tissue is large it can be folded and used again on the other side. I cannot recommend anything for automating the process.

Zito

 

[IRstuff]

Acetone may be dictated by the prior processing. As a general rule, both acetnoe and methanol may be required, depending on what contaminants need to be removed.

Kleenex is definitely bad, due to the amount of lint that will be shed from the tissues.

The toothpick part sound rather arcane; it suggests that the contaminants are extremely tenacious. This is the crux of the problem, e.g., how can the prior processing be altered to minimize or eliminate the contamination, and hence, the cleaning step.

Ditto on the automation. There are somethings that simply require so light a touch as to make difficult if not impossible to automate. If the prior processing can be altered to change the degree of contamination, there may be some simply automated spray processing and air curtain drying that could be used instead.

TTFN

 

[Viper488]

So sonic cleaning is out then? There's a number of crevices in the small assembly but most of the cleaning is on the many faces of the prism. There is also some sort of orange-ish acid used for stubborn stains.

They're not horribly dirty, just the odd fingerprint or bit of foggy film to be removed.

The largest side of the prism only measures about 3/4" x 1/2" or so. There wouldn't be much room for a drop and wipe technique, but part of the various cleaning methods does call for a one wipe attempt rather than wiping with the same portion of that kleenex more than once.