Energy And Resource Reduction For Automated Finishing Systems
Timothy J. Kurcz, Director of Sales
Jessup Engineering, Inc., Rochester Hills, Mich.
OEM and independent job shops can benefit tremendously from investment in new automatic finishing equipment by operating faster, more efficient machines that deliver repeatable quality with reduced labor. Knowledgeable buyers increasingly demand integrated computer controls to manage water and chemistry replenishment, rectifiers, ventilation and air makeup systems, and wastewater treatment to reduce energy and resource consumption and associated ongoing costs.
Jessup Engineering 1, known as a leading manufacturer of programmable hoists and turnkey finishing systems, responded to customer demand for cost-effective, incremental machine improvements. Every customer installation requires careful analysis to fully understand, engineer, and prionttze improvement opportunity. Partnership work teams establish targets, and the customer selects the most cost-effective solution for each machine. Over the past year, the following upgrades achieved specific productivity goals for Jessup customers’ existing plant and equipment.
Before management features can be designed, a new machine should be carefully sized to meet current and future production requirements. The very foundation of energy management begins with proper sizing of the rack, barrel, or basket-collectively known as the work package. Total work package surface area is critical for rectifier sizing; chemistry and rinse water replenishment.
For racks and baskets, the work package is defined as the width, height, length direction of travel(DOT), and load weight, plus liquid if very large or cupping parts are processed. Barrel capacity is definedas the width, diameter, and load weight: A long-established rule of thumb suggests 33% fill for plating and 80% fill for coating (volumes)are typical for barrels.
Figure 1. High-efficiency full machine enclosure. (Photo credit: Photography by Colleen Sadlik, CreationsMadeSimply.com.)
With the work package established, overall dimensions are used to determine tank size and hoist capacity. The objective is to limit tank surface area to the greatest extent possible, thus reducing evaporative losses and floor space required. Maximum load weight, combined with rack or barrel weight, dictates hoist capacity, including lift, transfer, and up-rotation motor sizes.
One more step is needed before machine footprint can be established: It is critical to secure chemistry supplier input when developing a process sequence. They provide technical process details, including baths and temps, immersion time, rectification, number of rinses, dry time, and water supply requirements.
During the machine layout phase, it may be prudent to add space for additional process tanks, rinses, or dryer cells to accommodate future expansion. Alternately, the work package might be expanded to enable increased future capacity should floor space limit DOT additions.
Money is usually better spent increasing the work package of a single machine, compared with the cost and space required for a second future machine. For that reason, multiple processes should be considered at this time. Potential machine builders should willingly provide preliminary layouts, cycle analyses, and resource consumption estimates to assist decision making.
Once agreement is reached between the plating shop, chemistry supplier, and machine builder, application of available resource reduction technology can be applied. Implementation can make a significant difference in long-term profitability. Concepts and features presented are easily implemented in new machines (Figure 1), and can be retrofitted into existing automatic finishing systems with careful engineering.
Energy and Labor Reduction
Simple, rugged, reliable hardware and easy-to-use controls make best use of resources when run round-the-clock. Individual rectification improves process efficiency and part quality when integrated with in-process weighing or other workload measurement systems. For shops running short schedules, end-of-shift or weekend auto-shutdown enables energy reduction. Auto-start-up ensures that an automated finishing system is ready for operation without the need for setup personnel.
Recipe-driven individual cell rectification enables precise, repeatable plating thickness for every load regardless of part count for rack plating, or by weight for barrel plating operations. This feature can calculate surface area on a discreet part number basis. Operator entered load data assures precise ampsquare- foot (ASF) delivery for rack plating systems. Barrel weight is verified by load cells, assuring precise rectification settings.
Hoist improvements reduce energy consumption and enable faster motions, reducing wear and improving operator safety for finishing systems. High-efficiency, VFD-controlled motor/drive combinations provide the smoothest possible motion profiles and reduce electrical energy consumption. Corrosion-proof belt lifts reduce drag and dramatically extend maintenance intervals. Fulllength, non-contact absolute linear encoders allow faster, smoother, more precise hoist positioning and virtually eliminate rack or barrel shake. These features reduce energy consumption, downtime, and maintenance cost for machine operators.
Water and Chemistry Reduction
Given today’s pressure to conserve earthly resources, it’s prudent to make efficient use of water and chemicals. Advances in fluid devices and management can dramatically reduce consumption of both. Naturally, computer controls are at the core of production based rinse water replenishment and chemistry addition functions.
Figure 2. Enclosed ventilation system in action. (Photo credit: Photography by Coleen Sadlik, CreationsMadeSimply.com)
Production-based, load-by-load rinse replenishment can optimize water consumption on a recipedriven basis. This feature enables experimentation with minimum rinse water volume necessary to ensure quality processing. The ultimate goal is to reduce water usage, which also reduces wastewater treatment volume and associated chemistry consumption. The result is less water purchased and treated because there is no rinse water flow between cycles.
Similar to water replenishment techniques, recipe-driven chemistry addition reduces usage and improves bath quality by eliminating saw-tooth fluctuations common with less frequent manual additions. This precision is available only by an integrated PC/HMI, needed to recognize and manage parts, select recipes, and adjust for rack or barrel fill variation. Advanced controls allow local and/or remote adjustment of replenishment at any time during machine operation.
Generation of RO water costs floor space, energy, water, and money. Discussion with your chemistry supplier (water analysis report in hand) will determine if RO water is recommended or needed for a plating or coating process. Use may be recommended because of unsuitable local water quality, or required for a specific chemistry, regardless. Makeup, addition, and replenishment for evaporative losses can sometimes be accomplished with rinse waters, reducing the need for fresh water.
Careful consideration should be given to plating and coating barrel design. Cylindrical plating and coating barrels offer a 17% increase in capacity compared to hex style barrels. Further, more consistent anode-to-work relationship improves efficiency for plating systems. Part-specific tumbling rib and perforation configuration contributes to efficient rollover, quicker drainage, and reduced drag-out.
Recipe-driven, up-barrel rotation drains directly to the process tank, a feature especially important for parts known to cup solution. Up-barrel rotation should be considered mandatory in today’s highly competitive finishing environment.
Wastewater Treatment Basics
Figure 3. Vertical rack oscillation reduces drag-out. (Photo credit: Photography by Colleen Sadlik,CreationsMadeSimply.com.)
Critical to resource reduction strategy is a basic understanding of water consumption drivers. Water use begins with total purchased and ends the total water discharged, a variable expense that directly affects operating cost. Metrics are discussed in terms of loads per hour, parts per hour, gallons per hour, etc.
Consumption is almost purely a function of surface area. A crude rule-of-thumb indicates approximately one gallon of drag-out is generated for every 1,000 square feet of surface area processed, including work, rack, barrel, or basket. The total will vary depending on the shape, size, and orientation of parts in process. It is critical to know the surface area and the number of parts required per hour. Fortunately, most parts are designed in CAD, so area is easily found.
With surface area known, solution drag-out and water consumption is calculated and expressed in gallons per hour. Water treatment experts suggest every gallon of drag-out requires approximately 600 gallons of rinse water to maintain appropriate dilution levels. Total annual water consumption can then be calculated. Be aware rinses may require RO water, a process that is approximately 75% efficient. The 25% loss should be added to total water consumption calculations.
Machines should be designed to reduce solution drag-out by any/ every means possible. Opportunities include efficient rack, barrel, basket, or rotating basket design, long drain dwells, up-barrel rotation (Figure 2), largest possible round or slotted barrel perforations, tipping, tilting, or vertically oscillated racks (Figure 3), re-circulating spray clean and/or multiple cleaners, over tank top sprays, and engineered flow in rinse tanks all contribute to drag-out reduction (Figure 4). Clearly, machine design should be a cooperative effort.
* It is important to note that water treatment is an evolving science. Federal, state, and local environmental regulations regarding water use and treatment-and the methods and cost of treatment and disposal of spent process chemistry and/or sludge-are beyond the scope of this article and should be addressed with a competent water treatment supplier.
Ventilation and Air Makeup Management
While the latest technical advancements are installed on new machines, older systems suffer due the perceived high cost of installation and associated downtime. As a result, air management too often remains a footnote in the energy reduction portfolio. It deserves closer review as improvements can be installed in phases to save finishers energy and cost.
The least invasive improvement is to install VFD controls for the ventilation blower, which is slaved to tank temperatures. This offers the opportunity to slow ventilation output as tanks cool during overnight or weekend shutdowns, or may be shut down completely when temperatures fall to a predetermined level. Further, should your finishing system reside within its own room or a defined air makeup zone, additional savings can be achieved if VFD controls are added to throttle the makeup system, which is, in turn, slaved to the ventilation system.
More complicated to design and install, a full machine enclosure can offer several benefits. They reduce total volume of ventilation air required, and reduce or eliminate disruptive external transient air flows, which can adversely affect push-pull ventilation systems. Furthermore, operator safety is often improved because the transparent ventilation barrier is located between the catwalk and automation.
* It is important to note that industrial ventilation and scrubbing technology is an evolving science. Federal, state, and local regulations regarding emissions-and the methods and cost of air treatment-are beyond the scope of this article and should be addressed with a competent ventilation system supplier.
Control, Monitoring, Recording, Reporting
Figure 4. Up-barrel rotation reduces drag-out.(Photo credit: Photography by Colleen Sadlik, CreationsMadeSimply.com.)
PC/HMI operation of finishing systems should be considered standard for all finishing systems. Errorproof NADCAP & ISO processing is possible if the machine is equipped with appropriate sensor technology. Data such as tank temperatures, immersion times, rectification, pH, conductivity, rotation/ oscillation speed and/or duration, chemistry additions, drain dwells, dryer temps, and water usage, are collected, stored, and exported to the customer database for analysis and report generation.
From an operational standpoint, engineered process cycles offer the most efficient production performance, though mixed processes and variable plate time cycles are available at the cost of some productivity. Most operators prefer fixed production rates so load/ unload operations and external logistics remain unaffected.
Regardless of operational strategy, machine operation must be simple and intuitive. A userfriendly, multi-lingual, touch screen, human machine interface (HMI) is a necessity in today’s finishing environment. A PC with MS Windows-based software offers easy PLC interface and requires no special programming skill.
Recipe upload is typically accomplished with bar code scanner technology. Most important: Individual rectifier, chemical, tank level, tank temperature, ventilation, and wastewater management functions can be easily managed through a security- coded interface. Additional features may include monitoring and control of hoist equipment, process tanks, and accessory equipment.
Performance monitoring may include shift reports for total time and number of cycles run, tracking of automatic vs. manual operation, load/unload delays, and fault data. To speed correction of unexpected stoppages, a well-designed control system will provide automatic system diagnostics. Detailed screens should annunciate and display fault location and actions needed to quickly restore production. Internet based remote monitoring further expedites troubleshooting and repairs.
Conclusion. Reasonably priced, commercially available technology can reduce ongoing energy, water, and chemistry consumption without sacrificing quality, thus improving the profitability of finishing system operations.
About Jessup Engineering
Jessup Engineering is a leading manufacturer of programmable hoist operated turnkey systems for rack, barrel, basket, and rotating basket parts finishing. With more than 650 machines and 1,300 hoists installed in 42 years, Jessup has more finishing equipment operating than any single competing machine builder. To learn how a Jessup automatic finishing system can benefit you, call 248-853-5600 and visit www.jessupengineering.com.
Timothy J. Kurcz, director of sales for Jessup Engineering, Rochester Hills, Mich., is also responsible for market and product development. A member of the surface engineering community for more than 30 years, Kurcz acquired a B.S.B.A. from Lawrence Technological University, and spent 26 years at Loctite Corporation in the Automotive and Industrial groups, later creating the Integrated Equipment Solutions Division. He was awarded U.S. Patent #6292973 for a “Device for Providing Surface Preparation,” and has authored technical papers for the automotive, marine, and aerospace industries. Kurcz also has four years of plating (electro and electroless), polymer coating, and salt bath nitro-carburizing experience with the KC Jones Plating Company. His specialties include application development, assembly process, and machine automation. Kurcz can be reached at 248-853-5600, or via e-mail email@example.com.
Jessup Engineering acknowledges the following companies who provided technical input for this article: J. Mark Systems, Inc. of Grand Rapids, Mich. (wastewater treatment systems supplier); and Duall Division of Met-Pro of Owosso, Mich. (ventilation systems supplier).