LETS SAY YOU have a modern far sub-micron fab, and you need to move a truck sized tool from one side of the clean room to the other. Standard construction equipment doesn’t work, it is too dirty, so Carpenter Crane Hoist made a line of hoists that are very clean.
The idea is simple enough to explain, take a normally dirty and greasy implement, and clean it up. The problem is that in a fab, you have problems like finishes on the metal flaking off and contaminating wafers, grease vaporizing, and links of the chain rubbing and chipping off. All of this leads to contamination, dead chips, and expensive cleanups.
How to lift in a bunny suit
If you look at the hoists above, they seem fairly normal, but the one on the left is nickel plated. The reason for this is that the normal anodization process will produce too many particles to put into a fab, so for some uses, the hoists have to be nickel plated. Painting is right out for those uses.
The chain itself is covered with a particle free rubberized cloth bellows so anything that flakes off, and bits will, is trapped. The hooks themselves are also specially coated, and the various straps and tie-downs have wrapper to keep flakes contained. If it is not too obvious, all the parts are specially chosen and coated so as not to leave microscopic bits in their wake.
Very expensive hooks
In the end, there isn’t much that Carpenter does that pushes the bounds of technology, just attention to details and a long list of things not to use. You don’t need a team of bunny suited workers to move that machine any more, just a clean hoist.S|A