Automatic Flat-Line Finishing Systems

Is an automatic flat-line reciprocating high-volume spraying setup practical? February 23, 2008

I operate a 200' hang line at present with twin spray booths and use 1014 Kremlin spray equipment. I have a QuickWood denibber coming in December. For door finishing (and other flat panel products) could you comment on whether (or not) an automatic recip spray machine has been helpful to your production. Are their hidden complex issues when including this type technology in finishing? My hang line supplier suggests that the hang line is still the best way to go because you can spray two sides on the fly... Many in the industry seem to think that flat line is the future for even more modest production levels.

Forum Responses
(Finishing Forum)
From contributor J:
I've seen a flat-line system in action. It's good stuff. Total finish time is measured in minutes instead of hours. The particular one that I saw used UV cured waterborne urethane. It cured practically instantly.

I suspect the big advantage of using a system like this is that it's very labor un-intensive. When the largest cost to wood product manufacturers is health insurance and not wood(!), as in our case, whenever we can eliminate labor, it's a good thing.

From contributor N:
Two issues I have come across are good finished edges and belt cleaning. I don't care what the equipment supplier tells you, your edges will not be as good as the flat surface. You just can't angle the guns enough. If you do, you will leave stripes on the flat side. The only way to ensure edge finish is to manually spray them, which is what you are presently doing.

The other is keeping that belt clean, along with the rest of the equipment. We spray WB UV and have to shut down for hours to keep it clean. Once you figure out the belt and what to use for cleaning, it will be fine.

But as for lowering your labor, I'm not so sure. You will still need a loader or 2, someone to watch the guns so they don't get plugged up and spray rejects, possibly some hand sanding if you have raised panel doors, and of course the line needs to be unloaded. You can automate some of the loading and unloading but you still need human eyes to watch.

From contributor B:
There are different types of recip. Are you talking about using a recip with your current hanging system or a flat line recip configuration? Ultimately it will come down to budgets and level of technology. At this point in time the level of engineering that is going into flat-line machines is growing everyday. When your hang line supplier says the 2 opposing booth system is the best, is that speed-wise, or finish-wise? To me it could potentially be faster than a flat line from start to finish through cures, but the final finish may not be acceptable - spray to spray - cure ir/uv. My concern would be the back side overspray, etc. The flat line I recently saw in the New England market was running in the 30 feet/min mark, which is very fast.

If I were a business owner looking at increasing my production levels, I would look at all avenues. Who are the people in your area using flatlines and overhead automatics? Everything from metal to wood to plastics to medical. Guys pumping serious product are automatic. Certain wood product just lends itself to flatlines.

Reducing labor costs... Potentially it could, or potentially you could increase labor. Some auto/flat line upgrades in technology can be a stumbling block. If you double your production but raise labor hours 20%, is that acceptable? Ideally labor becomes more of a maintenance crew than a finishing crew. The best automatic/flatline guys are proactive in maintenance rather than "wing-it" guys. There will be a learning curve with any system. Golden rule: gotta give a little to give a little. You want speed with coating, you gotta be ready for what it will do to you on the back side... tips cat on you, lines cure - you've got to know what the system is designed for and be ready for it. I would say the learning curve on a flat line is a hell of a lot shorter than the 20+ years your best finisher has put in. If it comes down to a concern about edges or consistent mil build, that will come down to budgets. You want to pay - they will do it.

From contributor Y:
Nicely said. One other point to bring up too. The flat line finish will trigger the guns accurately within the desired distance of the parts always keeping the guns at 90 degrees to the part, meaning your millage will be consistent. The overspray then lands on the belt and a portion of that can be reclaimed. No automatic vertical recip can reclaim material, and no human operator can control the gun/mil thickness as accurately. I have seen the average coating consumption go down 20 to 30 percent on automatic spray vs. manual (both using the same spray gun technology) just because of the triggering and gun position accuracy. How much is 20 or 30 percent of your annual coating bill worth? Also what happens to your business when the finisher you have had leaves, calls in sick, vacations, etc.? It would seem to me to be easier to train operators than finishers.

From contributor R:
Just a little word of caution on automated finishing. The machine doesn't know if it is screwing up, so if someone isn't keeping a close eye out, you can churn out one hell of a lot of mistakes just as fast as you can good production. We are using the Makor system for moldings and a Cefla for our flat line work. Edges can be a problem on the Cefla, especially on thick stock and paper rolls run into big bucks.

From contributor O:
Just another thought… Automated machines can have a fair amount of setup and cleanup times. Even if setup/cleanup is an hour, that is 12 1/2% of an 8 hour shift. Include these times in your overall calculations. Generally you will make the most money off of this equipment if you run it all day. Two shifts is even better.

Another consideration is that as you increase your capacity to spray the doors, the faster you need to be able to make, white wood sand, dry and sealer sand the doors. If the input to and output from the machine cannot keep up, you will have a very expensive piece of equipment sitting idle waiting to be fed. If you think about it, how much time is spent waiving a spray gun over a door versus the time it takes to complete all of the other building, sanding and finishing operations. I have heard numbers like 1000 doors a day is the breakeven point between hang lines and automated.

From contributor T:
Contact two or three potential flat line suppliers and they should be able to give you many favorable references. It is also possible to automate your existing hanging line with either robots or reciprocators. Most suppliers will do free lab testing with your coatings and your parts. As a majority of your big box cabinet manufacturers and all office furniture manufacturers use flat lines, if edge coverage is an issue it does not seem to affect the customer's buying decision. Since you already use Kremlin guns and pumps, you should also use their automatic guns. They are by far the most popular and the best performers for flat line applications.