| Application Stories |
|
VERTICAL CAROUSELS When a Rockwell Automation's manufacturing facility wanted to improve the availability of Surface Mount Technology (SMT) production equipment, manufacturing engineers looked at a number of improvements, including revamping the reel storage and retrieval operations. The facility manufactures printed circuit board assemblies for Rockwell Automation's industrial control systems, including the Flex I/O flexible, modular I/O system for distributed applications, the Small Logic Controller (SLC) small logic controller and others. The facility manufactures approximately 500-600 printed circuit board assembly numbers for Rockwell Automation systems. The facility occupies about 186,000 sq. ft. and employs some 350 people. In the past, the company used a combination of three-tiered drawer cabinets and metal racks spread throughout the shop area to store reels of SMTcomponents used in circuit board manufacture. The cabinets and shelving occupied about 930 square feet of manufacturing floor space. The reels, some of which hold more than 10,000 individual circuit board components, are placed on high-speed placement machines used in production operations. "When a reel had to replaced on a machine, the operator had to walk to a storage shelf or cabinet, find the correct storage location, bend, stretch and retrieve the part, go back to the machine and load it. It was terribly inefficient," said Steve Poulter, Manufacturing Engineering Supervisor at the facility. "Each SKU had to have a fixed storage location in the system whether we had it in stock or not which dramatically added to the required floor space and wasted time," continued Poulter. Recovering Valuable Floor Space The company replaced the cabinets and racks with two Remstar vertical carousels installed side-by-side on the shop floor. Vertical carousels provide high-density storage with quick access to items via a system of vertically arranged rotating carrier shelves that bring the exact storage position to the operator. With the installation of the vertical carousels, the facility reduced storage floor space by 73%, down to about 260 square feet. "Actually, the recovered area was greater than that," Poulter said, "since the cabinets and racks weren't grouped and required some surrounding open working space to be used. The vertical carousels eliminated the need for most of that space as well." Working with Remstar engineers, the company designed custom, ESD-safe bins. The bins are fitted with slots sized to hold specific size component reels used in the manufacturing operation. Each reel has a bar code for identification. The bar code is scanned into the system software that creates a random storage profile to optimize use of storage space in the vertical carousels. Two vertical carousels installed at the facility have 22 carriers or shelf levels and are 192" tall, 142" wide and 69" deep. "An important consideration in replacing the cabinets and racks was that the vertical carousels allowed us to centralize all of our components and initiate a kitting operation," Poulter said. "This has helped us to significantly streamline our materials retrieval operation, and, consequently, improve the availability of our production machines."
Production Efficiency The key to product efficiency at the facility is to load each high-speed SMT placement machine with as much work as possible. In the manufacturing operation, blocks of orders are scheduled in a machine set up format. The materials management Manufacturing Execution System (MES) portion of their software creates a pick list for the required reels, and sorts the pick list by the location of the components in the vertical carousels. Operators take the list to the appropriate vertical carousel and enter a carrier number. The correct carrier is automatically delivered to the operator at an ergonomically positioned shelf. Operators locate the correct storage bin and slot, pull the reel and check against the pick list. The selected reels are placed in a pick up area where the machine operators retrieve them, load their machines and begin production. "The pick lists represent real time material availability," Poulter said. "Our materials management software also allows us to use First In First out (FIFO) inventory control which was not the case in the past." To determine production efficiency, the facility measures the utilization rate of each high-speed placement machine in the surface mount lines. Because of the time necessary to retrieve components using the cabinet and rack system, machine utilization ran about 40%. With the installation of the vertical carousels and implementation of the kitting operation, machine utilization increased right away. "The vertical carousels, in conjunction with other improvements, have enabled us to further increase machine utilization to 60%," Poulter said. The Remstar vertical carousels are fitted with Rockwell Automation MicroLogix 1500 controllers including a Panel View operator interface. "To meet our current and future business needs, it was determined that Rockwell's controls would allow us greater flexibility. We saw this as an opportunity to develop a control package for vertical carousels, partnering with Remstar," Poulter said. "The resulting combination has worked well. The vertical carousels have been in operation here for nearly three years with no problems." Remstar International
Inc.
MODULAR AUTOMATED TOOLING An increasingly competitive environment in the automotive industry has prompted a demand from top manufacturers to come up with the most cost-efficient engineering processes. As one can imagine, this pressure for innovation has automotive suppliers scrambling to keep up with requests for proposals for new and advanced ways to beat the competition. One supplier who has benefited from the robotic automation trend is SHAFI, Inc., a software solutions supplier specializing in 2D/3D vision guidance and vision inspection systems. Some of SHAFI's most common inquiries for 3D vision guided robotic (VGR) solutions comes from manufacturers seeking to automate material handling applications. A typical request is for the company to design new "AutoRacking" solutions, which involve replacing the manual handling of heavy automotive parts, such as truck beds or hood inners, with the use of robots. "Normally these robotic solutions are justified with savings from reduced labour costs, but there are additional benefits, such as faster production times due to removal of safety hazards," said Adil Shafi, President and Founder, SHAFI, Inc. "Additionally, VGR solutions prevent users from having to retool racks when product geometries change for new product launches because the robots can be reprogrammed at a fraction of the time and cost it takes to build a new production line." A few years ago, SHAFI was tasked with creating a first-of-its -kind AutoRacking solution for a major automotive manufacturer. Time was of the essence and Adil's team needed to design a 3D solution capable of accommodating a variety of car parts with multiple contours, concave surfaces and burred edges. To add to the pressure, the manufacturer had a daily commitment of thousands of parts that needed to be shipped to customer plants. It was crucial that the new solution be implemented in a short window of time without jeopardizing production volumes. After a comprehensive analysis to identify how best to solve the customer's existing engineering bottlenecks, SHAFI put together a design that would be able to detect empty racks or racks of mismatched product models, as well as the depth of each part within the rack. The solution also allowed for compensation of parts hanging at different angles, or, oscillating in the air due to flexible rack design, which does not allow parts to be damaged by touching the rack's floor during transportation. In order to complete the complicated project, SHAFI consulted the expertise of several of the industry's most experienced robotic suppliers. The core of the solution relied on SHAFI's advanced software programming combined with hardware from Cognex, a supplier of machine vision systems. The total solution included a redundant third camera for increased reliability, and easy wizards to calibrate vision of the robots. In addition to the vision-guiding portion of the design, SHAFI needed to come up with the proper end-of-arm tooling (EOAT). Drawing from past experience, Adil understood that EOAT was critical to the productivity of the solution. Often overlooked, this small but crucial element accounts for the "hand" of the robot, which uses vacuum to lift and transport the moving part. "A robot is only as effective as its end-of-arm tooling," said Shafi. "This AutoRacking solution, in particular, needed to rely on flexible tooling because the robot needs to adapt to constant changes in size, which occur each time the vehicle model or car part changes." Shafi knew that if the arm of the robot "missed" its grip on an object it would cause the entire system to shutdown, ceasing production while the tooling is repaired. In an even worse case scenario, the wrong tooling could cause the robot to drop the object, putting employees on the plant floor in imminent physical danger. In order to design the appropriate EOAT portion of his robotic solution, SHAFI turned to Mike Brotz, territory manager at PIAB, a global manufacturer of industrial vacuum products. A major factor in choosing PIAB was the durability of its suction cups. "PIAB's DURAFLEX suction cups are designed to grip uneven or oddly-shaped surfaces, ensuring safe and stable lifting" said Shafi. "They are particularly good for handling non-porous automotive parts." The
new AutoRacking solution used 6 of PIAB's suction cups per robot and
also included a Modular Tooling unit, which was attached to a
multi-stage ejector vacuum pump mounted to a VacTrap check valve.
Part of PIAB's Modular Automation Tooling (PMAT) technology, the
VacTrap is a revolutionary vacuum innovation that "traps" vacuum
pressure for an indefinite period of time, preventing the handled
part from dropping in case of system interruption. Once the EOAT was completed the new AutoRacking system was developed and installed at the manufacturing plant. Since its inception, SHAFI's solution has been running continuously without any problems and new orders have been issued for similar solutions at other automotive plants for just the same manufacturer. "The customer realized a 50% cost savings after just six months," said Shafi. Needless to say, Adil and his team are especially grateful to have PIAB's vacuum technology as a key part of the new AutoRacking solution. "It's quite a challenge coming up with solutions for handling so many shapes and sizes," concludes Shafi. "Having the flexibility of PIAB's modular automated tooling as part of our solutions has made it much easier for us to design and advise systems integrators on AutoRacking solutions that rise to the challenge and handle the toughest applications." "The AutoRacking solution described above has reliably produced 4 million parts. As automotive manufacturers re-think their lines and processes, there are two recurring objectives: to reduce costs and increase flexibility," said Shafi. Thanks to the advanced SHAFI/PIAB solution, companies who currently use robots, and those who are considering using them in the near future, now have an opportunity to accomplish both of these objectives. PIAB Rx
FOR MAINTENANCE-INTENSIVE COOLING TOWERS Metal cooling towers lined with galvanizing or other coatings have been around a long time; in many instances, far too long. Decades-old metal cooling towers frequently become high-maintenance, while performance drops off sharply. Over time, these towers are increasingly thin-skinned, inefficient, and can cause unscheduled process disruptions. Secondary damage can also be caused by chronic "leakers" and outdated fans and motors often consume more energy than necessary. All of this adds up to a classic "money pit" for plant maintenance personnel that rely on cooling towers to support key process equipment. In the past, the prevailing cure for a leaking or corroding cooling tower was simple (although not easy). You either repaired it or replaced it. However, repairs such as re-skinning or coating tower linings often takes weeks and shut down critical processes if maintenance isn't already scheduled. Welding patches on galvanized linings might work, but typically not for long. "We were spending a lot of time and money on cooling tower repairs - patching metal, putting in rubber seals and gasketing. In other words, "band-aid" fixes just to keep the tower from leaking," says Marvin Richer, president of Brock Equipment Company, manufacturer of hydraulic pumps and related tools. On the other hand, replacing towers is time-consuming and expensive, as is the installation of additional towers to increase cooling capacity. "Given our choices, we were most likely going to install a new tower similar to the old one," Richer says. "But first I wanted to look into a new plastic-type of cooling tower that was said to be more reliable and require less maintenance than the old-fashioned metal-lined models." What Richer was looking for has become a new prescription for replacing ailing cooling towers or added capacity: engineered molded plastic cooling towers. Just as advanced plastics have replaced metal in many high-tech and industrial applications, plastics also offer a remarkably comprehensive solution to the chronic deficiencies of metal-skinned cooling towers. When selecting cooling towers, the focus of any plant engineer beyond efficiently meeting duty requirements is on reliability, reduced maintenance and ease of installation. Given these considerations and a choice between metal and plastic towers, many engineers are opting for the latter, which are now high-capacity, lightweight, and often more energy efficient. "As the tower got older not only did we have ongoing leak problems, we started to have a structural problem," Richer explains. "Water is pretty heavy, and the tanks that hold the water on the bottom were getting heavier and heavier as we added more and more materials to fix the leaks. All that weight was beginning to bend the structural members that held the cooling tank together." Metal cooling towers like Brock Equipment's are also subjected to constant changes in pH, requiring chemical treatments that attack the galvanized metal lining, essentially wearing it out in just a year or so. Environmental conditions such as sunlight, pollution, salt air and harsh process chemicals may also contribute to galvanized steel's early demise. On the other hand, engineered molded plastic cooling towers are one-piece so there are no problems with seams, welds, and patches that wear out prematurely. These new towers are also rust and corrosion-proof. Those manufactured by Delta Cooling Towers are rotary-cast with a single or double-wall UV-protected, polyethylene shell that is virtually impervious to weather conditions and harsh environmental elements. Brock Equipment's cooling tower does
not interfere with manufacturing processes, but supports an
absorption-chiller that conditions plant air, a demanding
application that is clearly affected by tower downtime. For this
reason, the reduced maintenance requirements and extended life of
molded plastic cooling towers was very appealing to Marvin Richer.
"In the past, plastic towers were
considered "too small" for many industrial processes. Now,
factory-assembled plastic towers such as Delta's TM Series can be
combined to produce up to 2,000 cooling tons in a single,
modularized unit. Modular cooling towers also facilitate an extra
margin of cooling capacity that can be advantageous in adjusting to
operational heat load or outflow changes, or in upgrading to meet
future cooling requirements. Through the use of plastic cooling towers, utility saving can also be realized. In the case of the engineered plastic towers manufactured by Delta, direct-drive motors are employed to power the cooling fans. With no pulleys, bearings and belts, these motors prove more efficient, and hence, provide substantial savings in energy costs while also delivering more horsepower. "The two motors installed on the old tower were each 40 HP, 3-phase, 480 volts. On the new tower there are 10 HP motors," Richer says. "So we now have only half the power requirement. Plus the new motors are more efficient than the old ones. We have not measured the energy savings, but it's there." The inherent design advantages of the latest plastic cooling towers also include easier installation (especially on rooftops) because a lightweight plastic shell weighs as much as 40% less than a steel tower, while being 5-10 times thicker. For applications that require mounting flexibility, Delta pioneered an induced-draft, counter-flow design that incorporates I-beam "pockets" in the tower basin for reinforcement, so that a plastic tower can be easily mounted on standard I-beams or imperfect concrete pads. "The installation of our new tower took a total of four days," says Richer. "In fact, the installation of the tower was a one-day deal, but some pipes coming into the building had to be reconfigured so that took extra time." Delta Cooling Towers, Inc.
CUSTOM-ENGINEERED SOLUTION MAINTAINS STERILITY AND CLEANABILITY When Regeneron Pharmaceuticals Inc. purchased a new mammalian bioreactor skid, it had the same high expectations that surround any major process improvement. But during initial start-up, it became apparent that the vessel would not maintain sterility reliably, due in large part to the design of the OEM bottom-entry agitator seal. According to Regeneron facilities engineering supervisor Kyle Cherry, the reactor was "problematic." Leaks affect sterilization "The main issue with the OEM seal was that the sterilization requirement hadn't been observed and sealing integrity was compromised," says Cherry. Sterilization of the interior vessel bore was absolutely essential. Once this requirement was met, the bioreactor had to cool to a temperature appropriate for introducing the cell culture medium. The hitch was that the OEM seal faces were not oriented suitably to foster complete sterility. In addition, the port locations were not optimal for total evacuation of air, causing the inner seal to let in vapor. Because clean steam was used for sterilizing the bioreactor, a moderate flow of clean steam-condensate became the barrier fluid to the mechanical seal assembly during certain phases of production. A custom-engineered solution Undisrupted production did not begin until shortly after the OEM agitator shaft seal was replaced with a custom-engineered design from Flowserve Flow Solutions. While both the OEM seal and the Flowserve replacement featured a dual mechanical seal to protect the sterility of the cell culture medium and a secondary sealing device to protect the gearbox, the difference, says Cherry, "is that the OEM seal had cleanability issues making it unable to maintain its sterile environment,"
Installing the Flowserve ST seal as a complete unit provides numerous advantages. The ST seal requires no handling of integral sealing components, has fewer components to stock and maintain, and includes a complete cartridge that can be aerostatically pressure-tested to ensure integrity before installation. Relocating the springs outside the process media and contouring critical sealing components to resist pooling also fostered optimal cleanability and sterility. Adding a flexible stator design compensated for misalignment and mixing anomalies, that can occur under normal operation. The new Flowserve seal maintains absolute containment of the clean steam condensate during each phase of production. By incorporating an internal flow deflector, the primary seal is kept lubricated to eliminate dry run conditions. A Flowserve Bearing Gard II unit was added to eliminate the condensate weepage from penetrating the gearbox.
Because the seal is in contact with the process medium, mammalian
reactors require a high level of reliability. Positive containment
is also critical. Cherry says that with the Flowserve seal and some
small piping modifications and procedural changes, "we are able to
maintain sterility for extended Flowserve Corp.
|
Canadian Industrial Equipment News May 2006 |
"Flowserve
customized a model ST seal to address the repetitive seal problems,"
says Cherry. The new seal was designed as a dual cartridge seal that
mounted directly to the gearbox as well as to the bioreactor's
mounting pad. An additional part of the challenge was that the
European design and the transverse angle of the drive required
detailed field measurement by Flowserve for proper fit and function.
