Upgrading to an Automatic Spray System

Question: I work for a company that powder coats scaffold frames and other assorted steel parts.

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I work for a company that powder coats scaffold frames and other assorted steel parts. We currently run a conveyor system and have a spray booth manned by two men. We are considering upgrading to an automatic spray system and would like to analyze the costs vs. the benefits. Is there any information published by an independent source that would assist us in this evaluation? B. D.


There really isn’t an independent, prepackaged, comparative tool that you can use to see if automation makes sense for you. But that doesn’t mean that you can’t do your own investigation and comparison. Some of the things you will need to consider are as follows: Automatic guns are relatively “dumb” devices. When used in their simplest form, they spray an area whether there is a part present or not. So having products densely loaded onto the conveyor is key to getting the maximum benefit from automatic guns and reducing reclaim. On this point, scaffolding products don’t appear to fit this criterion since they have a fair amount of open area (space) that will dramatically reduce transfer efficiency. What can correct this problem is coating your products in their basic form (i.e. rods, tubes, plates, etc.) and assemble them later. This way, you can get maximum product density on the line. Obtaining maximum first pass transfer efficiency is the key when using automatic guns.

Automatic guns can use triggering systems that employ photo eyes or light curtains to “see” a part. The guns are then triggered on/off only when a part is present. This is a very effective way of distinguishing between parts that are short or long and can also turn guns off during line breaks. This system comes with a price tag that can add 10% to 50% to your purchase cost of a system. This will increase transfer efficiency, making automatic guns more practical for your use. There are more sophisticated automatic systems that employ gun motion to follow a part and ignore the empty space. These can be robots or 3-axis gun movers. Now we are really talking some money! The average robot can cost $60,000.00. Add to that the cost of the recognition system (to see the part or recognize a part tag) to initiate the gun motion and now you are looking at almost $100,000.00. However, these devices will also increase transfer efficiency and reduce reclaim. To determine payback for the purchase of your automation follow this calculation:

Payback (years) = capital cost
annual labor savings

However, don’t forget that even automatic systems require someone to provide powder (even if only to change a drum in the automatic feed system), answer alarms, monitor and supervise the equipment. If you currently run your line with two operators and can only go to one-half to one operator, your payback may not be very good for your automation purchase.


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