One Manufacturer's Approach - Reducing Costs and Improving Quality Through Orbital Welding

One Manufacturer's Approach - Reducing Costs and Improving Quality Through Orbital Welding

This is the story of one manufacturer’s, one-step-at-a-time approach, to reducing costs and improving quality through welding automation.

Aquafine CorpAquafine Corporation, located in Valencia, California, is one of the largest producers of commercial ultraviolet (UV) treatment systems, both domestically and internationally. Aquafine has been the pioneer in the UV business since 1949 and primarily serves the Semiconductor, Pharmaceutical, Food and Beverage industries. The actual treatment unit consists of a cylinder ranging anywhere from 31/2” to 18” diameter that contains end plates, one or more UV lamps, quartz sleeves, a baffle, and either an internal or external electrical control panel. On these cylinders, there are anywhere from 1 to 36 seam, circumferential or tube-to-tubesheet type of welds. Most units are 316L stainless steel and require electro-polishing after post-weld treatments are complete.

Up until 1990 all of these welds were produced using the manual GTAW process (with filler) and as much as 50% of the manufacturing man-hours were weld-related. In the 1990’s Aquafine began looking for ways to be more competitive both, in quality and technology, and in doing so, Aquafine instituted a long-term program to reduce manufacturing and warranty service costs. One of the first items to be implemented was to mechanize the cylinder seam welds utilizing a semi-automated seamer system.

Due to improved fit-up and mechanization, this weld was switched to an autogenous fusion weld, no longer requiring filler wire. About the same time welding turntables were added to assist the manual welders in circumferential welds on exterior connecting piping, flanges and “S” and “L” type traps. These were fairly simple steps that were relatively easy to implement and only involved a small degree of semi-automation. They also gave management the confidence to move ahead with more complex and automated solutions. The other important thing they accomplished was to switch to dedicated work-cell type of environments for each welding step.

At one end of the cylinders, there is a tubesheet type of end-plate that the UV lamp fitting nipples are welded into. In 1993, these welds were automated using a Tube-to-tubesheet Welding Head and automated Power Supply. This was Aquafine’s first truly automatic system (controlled by the Power Supply) and the process also allowed the switch to fusion welds. This move reduced the welding times of 4 to 5 minutes per nipple to 22 seconds. A typical end-plate weld time went from 1 hour to 6 minutes. This process is still used today and over 40,000 nipple welds are made per year, resulting in a significant cost savings.

In 1996, the inlet and outlet fitting design was changed to allow the use of the T-Drill process. After this change, these were still manually welded; then a search was initiated to find an orbital tube welder that could make these welds. In 1997, Aquafine purchased an Arc Machines, Inc. (AMI) Model 207 Power Supply and a Model 9ER-4500 Weld Head to make these T-Drill welds. This resulted in a significant cost savings to the welding and finishing processes. One of the keys to these savings was the selection of the right Orbital Welding system.

According to Dennis Ziegler, Aquafine Welding Supervisor, some of the significant factors were high usage reliability. “We had used welding equipment in the past that would breakdown in less than 800 welds which was just not acceptable for Aquafine”.

Dennis did a complete investigation of how the heads were designed and the materials and components they were made of. In selecting the Arc Machines equipment, Dennis said “The way it was designed and the materials it was made from convinced me it would stand up to the usage”. Dennis went on to explain “How user friendly the AMI software is and how easy it is to develop the Weld Schedule played an important factor in our decision”. How has this worked out? In recent comments Dennis said “Up to date there has been minimal downtime. Can I put a number to it? Since 1997 it would probably be only a few hours”.

Dennis went on to say “What I think it (orbital welding) has really done – what AMI has helped Aquafine do is build integrity into the unit itself. We now can provide the customers with units that have some of the latest technology in welding”. Another factor is that after a good weld has been made there is no post-weld cleaning or grinding required: it does not need to be touched again. Previous welds using filler needed to be ground and cleaned to prepare for electro-polishing. “Sometimes as much as 50% more man-hours were spent grinding and cleaning. With the orbital systems this has basically gone to zero time”.

Typical assembly inlet / outlet T-drill and flange.

Electro-polished cylinders ready for final assembly.

Another factor in selecting AMI was versatility. Aquafine makes a number of different water treatment Models with various size piping and fitting diameters, lengths and clearances between Models. Having a Weld Head like the M9ER-4500 that can do many sizes of T-Drill, Tube-to-Tube and Tube-to-Fitting welds was also key.

In 2000, AMI, working with a precision lathe manufacturer, produced a fully automated Lathe Welding System for Aquafine that included an AVC and Wire Feed Unit. An AMI Model 227 Power Supply and Torch along with the lathe were used. This unit is used for welding the larger (6” and up) end flanges onto the cylinders. Production at the time of installation did not require wire feed (filler) but R&D on new products showed that this would be a future need. Today some Aquafine Models are requiring the use of filler, but most continue to be fusion welds. For smaller end flanges and sanitary fittings with little axial clearance, Aquafine has recently started using the extremely narrow AMI Model 8-4000 Weld Head to perform those orbital fusion welds.

In addition to the welding man-hour cost savings, there have been other significant savings due to automation. Post-weld treatment labor to prepare the cylinders for electro-polishing has been reduced by 50%. Through use of these systems, Aquafine has been able to increase production while maintaining high quality and low defect rates. Microprocessor-controlled Power Supplies such as the AMI M-207 and M-227 eliminate many of the common errors and mistakes made by welders and the precision fit-ups required for fusion welding insure repeatability. The Power Supplies built-in printers provide a convenient record and weld tracking system. The installation of dedicated welding work cells (stations) has also improved scheduling and improved efficiency. All these changes have contributed to increased manufacturing throughout, from receipt to shipment of order.

When you make expensive, highly polished assemblies such as these, aesthetics are not just important-they are vital to the success of the product. Automated fusion welds not only provide high quality joints; they also look like it as well, especially after they are electro-polished.

All of the cylinder welds are now automated but this only represents about 30% to 40% of a water treatment system’s total weld requirements. There are many structural welds that support the system components that have yet to be automated and, as currently designed, do not lend themselves to automation. Aquafine has also initiated a long-term design-for-manufacturing program to allow more automation of these welds.

Due to sales and production, along with these and other cost-saving efforts, Aquafine has moved from a 40,000 sq. ft. facility to a 100,000 sq. ft. plant and has showed significantly increased sales. Aquafine’s commitment to continuous improvement (CI) is evident in its willingness to invest in technology such as the AMI orbital welding machines. While this technology is just one aspect of the overall CI effort, it continues to pay dividends in improved quality and productivity.