Digger Specialties, has been in the fence, deck and railing systems business for more than 18 years. They are a dynamic company that is vigilantly looking for new and better ways to maintain their high quality products. Digger Specialties is one of the nation’s largest and fastest growing vinyl fence fabricators with four fabrication and distribution facilities serving the Midwest, South Central, Southeastern, and Southwestern United States. They take pride in their ability to solve their customer’s problems with innovative ideas in products and manufacturing.

Tom Hellinga, Digger Specialties Manufacturing Engineer, had been researching different powder coating companies and products to help with a future expansion plan by Digger Specialties. Tom visited with Deimco Finishing Equipment, a Midwest based finishing systems company, at the 2004 Charlotte Powder Show about Digger Specialties plans to construct a new manufacturing facility in Bremen Indiana. Tom was investigating powder-coating methods that would economically and efficiently expand their aluminum fencing production lines to keep up with expected growth and diversification of the products. Digger Specialties was anticipating the completion of the new building in the spring of 2005 and wished to include new powder-coating equipment in the overall plan. Digger Specialties looked to Deimco Finishing Equipment to help them with their production needs.

The problem presented to Deimco was the need to powder coat 10,000 finished parts a day. Digger’s parts would vary from very large products, up to 9ft tall and 12’ long, to the more average parts being about 4-6ft tall and 4" wide. For the most common parts, Deimco figured that they would need a line speed of about 10-12fpm. Digger also wanted to reclaim as much powder as possible for their two most common colors. The objective had been set and Deimco’s sales/engineering department went to work creating a powder-coating system that would meet Digger’s production criteria.

• The powder coating system must have the capability of handling parts 9ft tall by 12ft long.
• The system will be able to handle relatively fast line speeds of 6-8 fpm.
• Color change would need to be done easily and have at least 2 dedicated colors.
• The process will create a quality finish on a continuous or repeatable basis.

Deimco sales and engineering staff went to work creating a powder-coating system to meet the criteria previously established by Digger Specialties. Digger’s extra tall parts would require a fairly large entrance and exit on a booth and require very exact placement of the powder coating guns and equipment to accurately and efficiently coat the parts.

Deimco Finishing Equipment formed an alliance with EXEL Industrial (the parent company of Sames, Kremlin, and Rexson) to be the exclusive provider of Sames automatic electrostatic powder guns and systems to the US general industrial market. Sames developed the first electrostatic powder gun and Sames electrostatic powder guns are a dependable and predictable performer to integrate into Deimco powder systems. It was determined that to efficiently coat the parts, a total of eight SRV-416 automatic powder guns would be necessary. The Sames electrostatic powder guns offer superior charging of the powder whether using the corona tips or the fan tips.

While the parts were not necessarily wide, they were very tall and possess a square profile, which makes wrap around effects of the paint more critical. Sames guns are widely known for their wrap around effects but it was determined that the use of the eight Sames automatic guns, four on each side of the part, would create the coating effects desired and maintain a very repeatable process.

Positioning of the Sames guns on each side of the part would easily take care of coating the square profile; the height of the parts would require additional movement of the guns to minimize the number of guns necessary.

Deimco engineers determined that the addition of two Radial "Y" gun oscillators, moving four automatic guns on each in 22 degree arcs, would give the desired effects of movement required to maximize the efficiency of the powder coating area while minimizing the number of guns to cover that given area.

Deimco’s Radial "Y" can be reconfigured with additional arms or cross members to match any system requirement. The entire unit can be rolled between booths or cantilever mounted from the booth base frame. Together, the guns and gun movers would provide the efficiency and accuracy required to adequately cover Digger’s parts. The last criteria to be met would be the spray booth and recovery of the powder captured powder.

Deimco’s MD booth was a perfect match for containing the powder coating operations. The MD booth is made of high quality stainless steel construction for easy clean up and is designed with a rollaway filter module to make color changing a breeze. The colors can be easily switched by rolling away the filter module dedicated to a certain color and rolling up a new filter module dedicated to another color.

The filter module uses cartridge filters designed to last for 2000 hours of operation. It multiple filter cartridges and can be dedicated to a single color or used in spray to waste operations as well. This module allows the overspray powder, that has collected on the cartridges, to be purged (cleaned) by a reverse air blast. Recovered powder accumulates in the lower hopper section, from where it is transferred to a recycle powder receiver or a disposal container. As the cartridge filters load, the static pressure level increases to a high set point on the photohelic meter. At that point, the cleaning system engages. Cleaning is a sequential reverse air blast of the collector cartridges, causing accumulated powder to be expelled. This cleaning continues until static pressure reduces to the "low" set point. A manual selector allows booth operators to override cleaning functions at their discretion. Once the powder is recovered, it would need to be prepared for reuse, which means sieving of the powder would be necessary.

A rotary sieve on a rollaway cart and two 100 lb., stainless steel, fluidized powder hoppers were included with the system to efficiently reuse the powder. Reclaim and virgin material is transferred from the filter module to the sieve receiver where the air and powder are separated. The powder criteria had all been met and now the Deimco sales and engineering staff could determine the size of the actual booth necessary

handle the part sizes and the airflow requirements.

Deimco’s Modular Design, Direct Drive "MD" powder booth system provides a complete inline spray containment enclosure with primary and secondary air filtration. The booth has self-contained electrical and pneumatic panels, plus a separate filter cartridge module for captured powder containment. These design features are exactly what Digger Specialties needed for a high-production superior finish product.

Parts the size of Digger Specialties’ requires a great deal of air flowing through the booth. This volumetric flow of air through the booth is to maintain a proper velocity of the actual air moving across the part and through the booth. Deimco engineers like to maintain an air velocity throughout a booth of 125 fpm. The new direct drive MD 8200 powder booth provides all of these characteristics and more.

The MD8200 powder booth designed for Digger is 4 ft wide, 11 ft high, and 18 ft long. Deimco engineered and designed above and beyond the criteria set fourth by Digger to allow for future growth of the products. Deimco’s MD8200 booth is capable of moving 9000 cubic feet of air per minute. This allowed for an air velocity of 125 fpm through all openings of the booth and across the part. The last pieces of equipment to be added to the system were additional zones of height sensors for part identification and even greater powder application efficiency. The zones of height will communicate to the gun controls, which guns to fire at one time according part height. The following is a list of items that Deimco Finishing Equipment and Digger Specialties agreed upon as being necessary for the system’s best application results.