The possibilities of a lean powder coating environment
At the core of any discussion about being a lean powder coater is the need to change colors. When the powder coating line is down for a color changeover, parts are not being finished. Meanwhile, the powder coating spray technician is still being paid, and the pretreatment system and curing oven are both running. If a color change takes place, management wants it to happen as quickly as possible.
This can’t be done haphazardly, however. If a shop doesn’t do a good purge of the powder lines, which feed the powder from the feed source to the part, it can’t get a good part. For example, if the shop is applying a finish with a liquid paint, mixing white and red results in a pink coat, which might not meet the original specification but still look OK. If it applied a white powder coat with a line that wasn’t properly purged of the previously applied red powder, the shop could end up with a red part with white specks; the powders don’t blend. That is why equipment makers spend so much time developing systems that purge out the powder quickly and completely. For larger systems, those same companies design equipment so that all areas where powder coating is in process can be easily accessed and cleaned between color changeovers. Cleanliness helps to prevent potential quality problems.
As more metal fabricating companies embrace lean manufacturing principles, they are beginning to look beyond the blanking, bending, and welding departments. No stone is being left unturned in search of waste. That includes the powder coating line. Metal fabricators involved in powder coating are looking for that right balance of system flexibility, maximum uptime, and efficient material consumption. Some might assume that such a balancing act might require a large investment in state-of-the-art application and powder-reclaim technology. They would be wrong. Lean powder coating practices are a real possibility for a shop of any size. It’s just a matter of determining what they want to accomplish.
Reclaiming powder overspray and reusing it seems like the right thing to do, but first impressions can be deceiving. For many shops, it might not make sense. Every metal fabricator with a powder coating line should keep this in mind as it weighs material reuse against powder coating uptime: In many cases, line time is more valuable than the cost of the powder material. That fact has been proven out consistently over the years and across manufacturing settings of all kinds.
The good news for metal fabricators interested in reclaiming and reusing the powder is that color changeover can be done in 10 minutes. The technology is not fast as lightning, but it has advanced to the point where it makes equipment from even 10 years ago seem incredibly slow by comparison. What takes place in that 10 minutes? In the most automated systems, the color-changeover process starts with the line technician initiating the change on the intuitive touchscreen control. The cleaning inside the powder application booth is performed by powerful air pulses, which convey the fallen powder to the central channel extraction area. (Also, because the powder delivery is automated, only a small amount of overspray has to be cleaned up.) The cleaning of the automatic guns inside and outside is done without manual intervention and in seconds.
Automated cleaning of the pumps and key areas, such as the sieve and the collection tank, takes place. (Unusable powder particles are reliably filtered out by means of air turbulence, and the remaining powder, once it has been carefully sieved, is collected for reuse.) The operator selects the next color to be powder coated, and the system is ready to respond. Automated systems without reclaiming requirements can change color in about half of the time. Technology buys efficiency, but that may not be for everyone. Shops that have a more manual approach to powder coating also can be ensured that a steady pace of production can be achieved. Less complex systems have been developed to bring quick color changing to the masses. For instance, with a recently released system to the market, color change occurs in a few quick steps. When the spray technician wants to make a color change, he disconnects from the previous color, connects to the purge station, cleans out the hose, and reconnects to the new powder color. This takes place in about 30 seconds. Such a system has the added benefit of reducing the amount of powder that is purged from the lines. Instead of purging the entire line that feeds back to the material source, the technician is purging only the short length of delivery hose, from the cleaning manifold to the spray gun.
In this article from The Fabricator magazine, Greg Dawson from Nordson discusses why the best equipment and the right training is essential.
About Nordson ICS - Industrial Coating Systems Division
Founded in 1954 to produce and market airless spray equipment, today manufacturers rely on our equipment for the precise application and curing of powder coatings, liquid paint, ambient temperature adhesives and sealants, and food and beverage container production. Our solutions help our customers improve their manufacturing process, produce better products and become even more competitive. We do this by combining in-depth knowledge, world-leading technical expertise and precise, performance enhancing production solutions for some of the world’s most demanding and diverse manufacturing environments.
We offer world leading application and curing equipment for powder coating, liquid spray painting, container coating, automotive applications, battery applications and precision dispensing for various application needs. Visit Nordson ICS on the web at Nordson Website, Twitter Profile, Facebook Profile and LinkedIn Profile.
About Nordson Corporation
Nordson engineers, manufactures, and markets differentiated products and systems used for dispensing and processing adhesives, coatings, polymers, sealants and biomaterials; and for managing fluids, testing and inspecting for quality, treating surfaces and curing. These products are supported with extensive application expertise and direct global sales and service.
We serve a wide variety of consumer non-durable, consumer durable and technology end markets including packaging, nonwovens, electronics, medical, appliances, energy, transportation, building and construction, and general product assembly and finishing. Founded in 1954 and headquartered in Westlake, Ohio, the company has operations and support offices in more than 30 countries. Visit Nordson on the web at Nordson Website, twitter.com/Nordson_Corp or facebook.com/nordson.