CNC/DRO/MACHINE CONTROLS

Automated System Controls
Variables, Costs Of
Powder-Coating Process

Process variables include major items such as labor applied to the job, powder transfer efficiency, and conveyor speed, and many less-evident, but still-critical items such as the temperature, pH, and conductivity of the wash system. “What you don’t know about your line can definitely cost you,” says Guy Kinsman, owner of Therm-O-Finishing, Inc. (South El Monte, CA), a prominent southern California contract powder coater.

The company serves a broad mix of clients: manufacturers of vehicles, appliances, and office equipment, as well as suppliers of sheet metal, castings, forgings, and stampings. It also is broad in the work it does: all colors and types of powder are applied; film builds range from 1.5 to 8.0 mils; parts can be 1" in length or up to 86"; and substrates can be ferrous, nonferrous or MDF (medium-density fiberboard). Kinsman believes that agility is what made the company successful, and close control over production is what will keep it that way.

In mid-1995, during its sixth year of operation, Therm-O-Finishing faced a trio of challenges: sales were growing, and a permanent second shift was needed; customer demand for quality documentation was increasing; and, the competitive environment was becoming more crowded and price-sensitive. Kinsman believed that the key to future success was tight control over process variables, an achievement that would only be possible with better, more detailed information. He discussed the problem with Dave Smith, founder and president of IDAC-West, a systems integration company headquartered in Temecula, CA.

Line stoppages were their first target. At the time, there was no way to quantify line downtime precisely, but Kinsman estimated it to be about 17%. Their solution was to attach a sensor to monitor conveyor speed and create a Windows™ 3.1 program to collect data and calculate the ratio of uptime to downtime. The first day that employees realized the line was being tracked, downtime fell by two-thirds. For Kinsman and Smith, it was a good start.

The next step was to bring each stage of the coating process under the same automated management, including the critical parameters of each individual process. Included would be cleaning and pretreatment, dry-off, powder application, cure, and subsequent handling. Most important to Kinsman was the ability to collect and archive this data entirely without manual input.

“There was, and is today,” says Kinsman, “lots of off-the-shelf software for job tracking, estimating, invoicing, and other functions. What’s missing — and we’ve looked at many programs, including five years of Powder Coating shows — is an integrated system: one that links and manages all of the factors affecting line performance, and provides the tools needed to make adjustments before they cost you money.”

The 3.1 system developed by Kinsman and Smith evolved to a Windows 95 platform, then again to a Windows 98/NT-based program. 

The current program achieves all the process management objectives and generates other important information as well, according to Kinsman. “How much labor expense can be directly attributed to a particular job? When should a particular powder be reordered to get the best delivered price? What is the actual powder usage rate at the point of spray? And, why did the line go down repeatedly during the second shift? These were the kinds of questions we wanted to answer, in a ‘just the facts’ way,” he notes. “Call it total accountability.”

What they actually called it, when it was given a name early in 2000, was PowderTrak. The formalization of the product also led to the establishment of a new corporate entity, Powder Management Systems Inc. (South El Monte, CA). “It was a natural step,” suggests Kinsman, “to combine the expert systems experience of IDAC-West with our own everyday, in-the-trenches experience.” Within a few months, three prominent Tier 1 and aftermarket suppliers had implemented the technology or were using it on a production basis.

“Custom coaters have to run a profitable line to stay in business,” says Kinsman. “OEMs (original equipment manufacturers), on the other hand, have their own set of challenges. Costs can be hidden; and, many times, what passes for fact is really just an educated guess. But, phenomenal efficiencies are possible if you really do know what’s costing what. One of the OEMs we work with has gained a solid grasp on costs to the point that they now regard the powder-coating department as a possible stand-alone profit center. They’re considering marketing their surplus capacity to other OEMs.”

Process Tracking, From Start to Finish

PowderTrak operation begins with logging key information regarding a job into the system. The routing ticket that results contains a job number and an “i-button,” a jacketed microchip that identifies the work during processing. The routing ticket identifies the part with the job quantity and the type of powder to be applied. When the job runs, a worker scans the i-button containing all the specifications related to curing temperatures and line speed into the system at a workstation. From this point, information regarding the parts’ journey down the line is recorded and applied to this number.

The system records data for the job being run in real time and archives it afterwards. Information gathered includes names of workers, conveyor speed and uptime percentages, temperatures within the cure and dry-off ovens, pH, temperature and conductivity of the pretreatment, total powder consumed, and the powder use rate at the point of spray. Other functions of the system include scheduling, costing, inventory control, and various process alarms.

Job costing, particularly in a competitive environment, poses the greatest challenge. “P&L is affected by so many factors that arriving at a precise number can be nearly impossible,” says Kinsman. “Yet, that’s what’s absolutely needed if we’re going to identify the jobs that are best suited to our capabilities, with the best potential for profit.

“One of the big factors that confounds job costing goes back to where we started,” says Kinsman “It’s conveyors! If a conveyor were down due to a fault condition, the time seemingly needed to run a given job would skyrocket. And, as a result, you’d think that running that part was less lucrative than is actually the case. The system we engineered tracks the time required to process a job from start to finish and shows uptime/downtime percentages, factoring in stoppages.

“Time and materials are also factored accurately, in part because it’s done automatically,” Kinsman reports. “The only variables that are supplied manually are the number of parts coated and the plant’s overhead factor. From there, job costing is calculated by the system. And, you know, literally the moment the job exits the line, if you were profitable and by precisely how much.” PowderTrak is offered as a phase-able technology that allows powder-coating facilities to implement all its capabilities simultaneously or in stages.

Phase 1 is a monitoring system that is supplied with a dedicated, customized PC, preloaded with software. It includes a suite of sensors and electrical field devices that are supplied ready for mounting and wiring. This phase encompasses all of the technology required for detailed monitoring of process parameters, materials inventory control, averaging functions, conveyor activity, and alarming. The system also includes i-buttons for identification and login at various stations. This feature allows access to various process functions on a selective or temporary basis where desirable.

Phase 2 incorporates monitoring and control. Control in this case is defined as automatic system settings for temperatures, line speed, guns, and other “run” specifications based on recipes and other information. Phase 3 allows IT (information technology) personnel to integrate the data with AIDC, (automatic identification data collection), ERP (enterprise resource planning), and other supply chain programs. It also is an important tool for SPC program management and for companies pursuing QS and ISO certifications. PowderTrak is net-workable, and options for information distribution are extensive.

Whichever route is chosen, customization will always play an important role. “The two current options are both flexible, ‘core’ programs, where, for a very few extra dollars, an endless array of custom capabilities and functions can be added,” says Kinsman. Implementation support for the PowderTrak system, where needed, is provided by PMSI - Powder Management Systems, Inc., which also supplies tools, utilities, and technical training to the finishing industry. PowderTrak developers are currently adapting the technology to meet the needs of platers and liquid finishers. PMSI - Powder Management Systems Inc.

- August 2000