Hang 'Em High

Ask an Expert From: Products Finishing, from Finishing Help, LLC

Posted on: 12/1/2003

Question: What, if any, are the problems with using cables for hanging parts instead of solid metal hooks?

Question:

What, if any, are the problems with using cables for hanging parts instead of solid metal hooks? I have been told that they simply don’t work but have not been given a good reason. Cables would be a lot easier to use when hanging and removing parts due to their flexibility. DS

Answer:

I am assuming from your question that you are processing relatively large and heavy parts. If that is the case, cables and chains can be very useful due to their flexibility (as you pointed out) and keeping hooks in place as parts go up and down conveyor inclines and declines. Adjustable chain slings or “self-balancing” cable units help compensate for changes in the center of gravity as parts float as they enter the e-coat bath.

Possible problems with chains or cables include “carry over” problems in the pretreatment and e-coat systems, since the liquids are carried by surface tension on chain links or between the strands of wire rope cables. This type of dragout can cause “alkaline drip” defects. The other concern with chains (and less so with cables) is the loss of contact because of multiple contact points with e-coat building up on these points until “light-coats” or “no-coats” result.

Lightweight parts with lightweight chains or cables would compound the problems listed above. One unique application of a lightweight cable that I used as a custom coater was to maintain electrical contact or a rack built to pivot parts as they entered and exited the e-coat tank to burp the “air pocket” out of the part without leaving a “puddle.”

As with any unique type of hanging method, be sure you have worked out the bugs before going across the board with the system. Build prototypes and run many samples of different parts before committing a lot of money to any type tooling. In other words “walk before you run.”

 



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