Improving the Finishing Process

It was not terribly long ago that quality at most companies was equated with any product that passed quality control inspection. The Total Quality Management (TQM) revolution, however, has changed all that.

Today, quality is defined as excellence in the outcome of an activity and the process used to generate the outcome. It is measured more by customer satisfaction levels than by the approval of internal inspectors. Since customer expectations tend to rise over time, TQM challenges businesses constantly and diligently to raise their standards of excellence, hence the term "continuous improvement."

The TQM focus also recognizes that manufacturers working alone cannot be assured of pleasing their customers, since suppliers and resellers are part of the customer chain. TQM challenges businesses to develop relationships where parties cooperate to improve process and product quality.

That is exactly what The William L. Bonnell Company, one of the world's largest independent aluminum extruders, has done by working closely with its coating partner, The Sherwin-Williams Company.

High capacity. From manufacturing facilities in Carthage, Tennessee, Kentland, Indiana, and Newnan, Georgia, the company produces aluminum extrusions ranging from heavy structural shapes used for casting concrete and requiring little or no finish, to picture frame parts that require sophisticated finishing techniques. Total production capacity for the three plants exceeds 140 million lbs.

Of the three facilities, the Newnan plant has the largest production capacity. Two buildings cover more than 500,000 sq ft and employ 750 people. A complete cast house blends aluminum ingots and scrap into alloys specified by customers for the specialty market. Sales are primarily to fabricators who produce bath and shower enclosures, bicycle rims, air-flow equipment, furniture and automotive trim.

Implementing TQM. Bonnell began implementing a TQM approach across all operations at the Newnan plant in 1992. Since that time, several dozen Process Improvement Teams (PITS) have been formed to develop and implement quality-enhancing ideas. The TQM program has enabled the company to achieve an on-time delivery rate 20 pct above the industry standard. This is one important measure of quality in the aluminum extrusion industry.

The company's continuous improvement strategy did not allow it to stop there. Ongoing scrutiny of processes revealed that the on-time delivery rate could be further improved by increasing finishing line productivity.

Teaming up. Bonnell's finishing department in Newnan operates under the guidance of plant manager Don Moore and paint factory coordinator Don Bowles. The department, however, has been managed since 1994 by an employee-directed work team responsible for scheduling, packaging and ordering materials, including coating colors.

The finishing system, manufactured by Young and Bertke, Cincinnati, Ohio, has the capability to coat extrusions as long as 24 ft. Parts hang every three to 12 inches on a 1,240-ft conveyor that travels 12 to 19 fpm. After processing through the five-stage chrome phosphate pretreatment, parts dry in a 40-ft oven at 250F. Pretreatment chemicals are supplied by Bulk Chemical, Mohrsville, Pennsylvania.

Finishes are applied in two, 30-ft high, eight-ft diameter silo-type Omega loop paint booths using ITW Ransburg turbo reciprocating disks. Coated parts bake at 360F for 10 min before they are packaged and shipped.

Prior to 1995, six suppliers provided coatings to Bonnell's Newnan plant. "If you are buying the same product from six companies, you are probably not a great customer for any supplier," said Andy Massey, Newnan plant purchasing manager. The concept of partnering advocated by the TQM approach encouraged the company to consider a single-source supplier.

"One supplier has the opportunity to learn your business, respond to your needs, and help you improve your processes," Mr. Massey said.

A Bonnell Process Improvement Team (PIT) set about developing a list of criteria for a single source supplier/partner. These quality criteria included:

Provision of a high-quality, high-solids polyester baking enamel that resists drips, runs, sags and blisters. Meets federal and state VOC guidelines. Achieves gloss specifications of plus or minus five units. Is available in a ready-to-use formula.
Technical analysis and support for improving finishing line efficiency.
Customer service programs that provide Bonnell with information on regulatory changes, new equipment developments and updates on coatings technology.
Local warehousing of inventory and next day delivery on stocked items.
Local technical service for immediate response and emergency technical response service within 24 hrs.
Training programs to teach employees application techniques for coatings and equipment.
The ability to process special color orders and sample color chip matches within five days.
The ability to match colors regardless of shape, size, texture or composition of part.
Participation in Bonnell's improvement program.

The selection process was comprised of two parts: on-line testing of various coating systems, and evaluation of supplier programs. Sherwin-Williams was the supplier selected. The company's PermaClad® 2400 high-solids polyester baking enamel met or exceeded the performance requirements as well as other criteria.

"In addition to meeting our coating and service needs, Sherwin-Williams is ISO-9000 certified at all its plants and laboratories," Mr. Moore said. "This was another indication that they would understand and be an active participant in our quality program."

The Bonnell PIT outlined eight measurements for determining the effectiveness of the relationship. "Within the first 60 days we were able to achieve five of our eight objectives," Mr. Bowles said. "Scrap, repaint, and production lead times were reduced. Production run-time increased, while inventories were reduced. We are even receiving quick turnaround on colors. All of these factors have resulted in productivity gains."

Partnering in action. Representatives from the supplier's Design Engineering Group (DEG) visited Bonnell's Newnan plant to evaluate the operation. Closely reviewed were material handling, pretreatment/dry off, application room, delivery system, mixing room, application equipment, and bake oven.

"The result of the visit was a comprehensive report listing 45 suggestions for improving our operation," Mr. Moore said. In the report, both maintenance issues and a need to re-engineer portions of the process were addressed. Recommendations covered topics ranging from parts hanging procedures to paint mix room temperature. For example, one suggestion regarding parts hanging was that the load bar should have inverted teardrop-shaped holes rather than round ones. This reduces rotation of the hanger rod. Another suggestion was more consistent spacing between the load bars. In the paint mix room, it was recommended that pump control panels be moved to the wall closest to the paint application area, and that a trench be installed for circulation tubing. These changes would reduce the quantity of paint in the circulation system and facilitate cleaning the loop during color changes.

"Each change we make will contribute in a small way to improving the overall operation," Mr. Moore said. "Continued effort will keep the system operating properly."

Bonnell also has taken advantage of the services of the supplier's Color and Design Marketing Group. The team of color experts is familiar with trends and technology in a wide variety of markets. It specializes in providing coating users with a fresh and objective approach to their color requirements.

For Bonnell, the group provided an analysis of the standard colors offered by the company and made suggestions for updating and enhancing the color palette so that it would appeal to a broader range of customers. In addition to offering standard colors, Bonnell also works with its supplier to provide custom colors per customer specification.