Paint process hasn’t changed very much in the last 40 years. Sure, components have improved. Diagnostics have improved. Automation has taken over and efforts to Lean the process is never ending. Paint delivery, the biggest function of a “paint process”, is still struggling to keep up with the efficiency trends though, at least with the large OEM paint processes.
Tiers have made incremental strides towards the technologies that can improve their processes. Many are adopting newer technologies yet very few have taken advantage of ALL the available improvements.
A traditional OEM paint circulation system consists of a graduated pipe system, graduated in terms of pipe diameter. The piping typically runs from the paint kitchen pumping stations, out to the paint booths, and then all the way back to the paint kitchen. In theory the graduated pipe diameter allowed the operator to “balance” the pressures and flow rates, which are usually highly variable, in order to keep a steady flow of paint supplying the valves, which in turn, supply the robots with whatever color is required. All manner of paint process “black magic” is required to keep these types of systems operational. In the best case scenario a system can be kept operational indefinitely, though that is true typically when one color is used indefinitely, and when the system IS actually running indefinitely ….even when the plant isn’t. Heaven forbid a shut down for any reason.
The main problems with a graduated pipe system are that they are hugely wasteful, they require an exorbitant amount of labor to maintain, and they are plagued by maintenance nightmares and quality control issues.
Because graduated piping translates to “piping of different diameters”, there are always issues with paint dirt that manifests when solids fall out of suspension and collect in the crevices that are present at every pipe joint. There can be hundreds of pipe joints with crevices in a typical OEM graduated pipe system. Paint dirt equates to quality defect, and most OEMs are “Making” paint dirt constantly. This “dirt” is usually misidentified as environmental contamination, compounding the problem. On top of that, if for some reason a color change is required, It can take hours and many barrels of solvent to flush a graduated pipe system, and you’ll probably still have residual color left in your lines, dictating that you must dedicate any given line to a color family, because if you try to go from red to white on a graduated pipe system, you’re always going to end up with pink. Sticking to color families is still a good idea, but it’s an imperative with a traditional system, no ifs, ands or buts.
Changing colors is a very time consuming process with a traditional system. I’ve seen OEMs take a half a day to flush a system, and still have quality issues. I’ve seen OEMs use 100 gallons of solvent to clean a system and still have “tinting” issues. I’ve seen 4-5 technicians perform these “maintenance” exercises. Easily 30-40 man hours expended. All of this before the “drops”, valves and guns are ready for cleaning and maintenance. I’ve also seen OEMs shutter a plant for a shutdown or holiday and leave the system circulating because shutting it down is so wasteful and troublesome. It’s impractical to reclaim any of the expensive paint in a graduated pipe system, and what little can be recovered is often contaminated with “dirt”. 20-30 gallons of paint can often be dumped to waste, per line, in order to shut down.
Multiply all of those numbers by the number of lines or colors that are typically used in an OEM or large Tier facility and you’ll be shocked at the waste, lost time and volumes of paint and solvent that get dumped, and this doesn’t even speak to the lost first pass yield due to quality issues that are directly caused by paint dirt, and or viscosity control issues, both of which are rampant in a graduated pipe system.
What’s the solution? Well, in terms of paint process efficiency, the most important technologies are in order, viscosity control, and pig-able paint delivery systems. Each has high value in terms of new construction or ROI on retro-fit. Viscosity control is a whole different subject that, suffice it to say, is a game changer for any paint system. Pig-able paint circulation systems are without a doubt the most efficient way to deliver paint.
Pig-able paint circulation uses a single diameter paint line that runs from the paint kitchen, all the way to the color valve stack, usually in the booth, or even on the robot arm, and then back to the kitchen. Pig-able systems can be steel, ideally stainless, without pipe fittings, but rather welded to form a smooth interior surface, OR they can be constructed with flexible “pig-able” hose, such as that offered by HOSCO.
With little pressure required to circulate paint, the systems require smaller, more efficient pumps. With no “pipe joints”, there’s nowhere for paint dirt to build. When it’s necessary to change colors, virtually all of the paint can be reclaimed back to the paint kitchen tank by pushing a small rubber bullet, or “pig” through the single diameter circ system. Likewise, when cleaning is required, as little as half a liter of solvent can be used to clean the whole circuit, ahead of a pig, which scrubs the pipe clean. One man can perform a color change, or a system clean in as little as 10 minutes.
This is very easy math. Why doesn’t everyone do this? Good question! The answer is a cause for frustration for many people in the paint industry. The answer is “Tradition”. The OEMs rely on the large engineering firms to design systems. Thinking out of the box and throwing away the old playbook isn’t as easy or profitable as referring to an old, accepted specification that may have been developed 40 years ago. Engineering an entirely new process, qualifying it and implementing it is a lot of work, even if you do typically lean on suppliers to provide “free engineering” for the majority of the process, which is what typically happens. Changing the game is a huge uphill battle. All the while vast resources are wasted and inefficiencies plague the industry, an industry that in most other areas is leading the world in lean manufacturing strategies no less.
For some reason the OEM representatives are very placid when it comes to pushing change and as mentioned the engineering firms are happy to avoid change.
A typical pig-able system is far less expensive to build, and the install is quicker and easier. The ROI to retrofit an existing system is typically very fast too.
OEM and Tier Automotives, and anyone that paints anything, take note, paint process CAN be very efficient, and it can be very quantifiable. It just takes a small effort, and perhaps taking a small risk. The more brave souls who step forward, the quicker the industry will be thrust into the 21st century.
Contact Finishing Solutions Inc. for more info. paintROI.com