High-Velocity Aluminum Destacking Increases Production Throughput
Technology Case Study
Industry experts thought a leading truck manufacturer took a wrong turn when it announced the shift to more aluminum components in its industry-leading pickup truck. It turns out those experts were wrong; customers were eager for the performance and efficiency benefits of a lighter-weight truck, leaving the manufacturer’s factories unable to keep up with demand.
Automakers continuously search for ways to increase production-line speed to meet customer demand and improve plant profitability. The sudden jump in demand for aluminum components created an intense interest in finding ways to accelerate the related production processes.
Process engineers come up against constraints that limit gains in production speed. Some are hard limitations related to physics that simply can’t be overcome. Most constraints can be reduced through process innovation. One of the constraints in aluminum-forming operations is the speed of destacking blanks. Innovations in destacking technology are reducing that constraint and enabling automakers to increase aluminum stamping throughput.
The Issue of Lighter-weight Blanks
Anyone who has shuffl ed a deck of cards knows they often fail to separate from one another. Stacked, flat objects have a tendency to stick together in the same way due to the suction created as they are pulled apart. This effect has long limited how fast aluminum sheets can be destacked.
The challenge is magnified by the oil or dry lube applied to the blanks to aid in the stamping process. As in many systems, what solves one problem often creates another problem. The fluids applied to the blanks create a light bond between stacked blanks, adding to the difficulty of destacking them. The speed of destacking, therefore, has been a major constraint in aluminum stamping operations. Increasing the destacking speed often resulted in picking up several blanks at once, something that can have disastrous consequences at the stamping or forming operation.
Drawing on their extensive experience in handling aluminum blanks, Güdel Press Automation has improved and accelerated the destacking process.
Demand from automakers for stamped and formed aluminum components has never been higher. Many of these automakers are faced with slower cycle times due to the difficulty of quickly destacking aluminum blanks. Güdel offers automation systems that accelerates destacking, enabling automakers to enhance their productivity requirements.
Three Technologies Accelerate Destacking
Güdel relies on a trio of technologies to speed destacking while ensuring consistent selection of a single blank. Two of these technologies have long been in widespread use, while the third is a more-customized approach. The combination of these technologies enables significant increases in destacking speed, reaching 18 parts per minute with no multiple blanks. This is a significant productivity gain compared to the typical 12 parts per minute. Many destacking systems rely on compressed air to separate the blanks. The Güdel system utilizes this technique, but relies on a specialized nozzle directing a high-pressure blast of air from a dedicated compressor. Plant air typically doesn’t provide sufficient pressure to consistently create the required separation. This blast provides the initial separation by “fluttering” the top blanks.
Next, a suction cup makes contact with the blank. Most destackers lift the blanks with suction cups, but the traditional approach lifts the blank symmetrically, straight up from the stack. That approach maximizes the vacuum effect between blanks and increases the chances of picking up multiple blanks. The Güdel approach, referred to as the pre-separator, positions the suction cups at the edge of the blank to lift from the end, then a fixture is quickly inserted under the top blank to keep the separation. The effect is similar to peeling a sticker off its backing paper, reducing the chance of lifting a second blank.
Güdel also utilizes a flexible Urethane rail with wide bristles that knock down the second blank just below the blank being destacked. The top blank and secondary blank can sometimes stick together with the high acceleration of the top blank as it is lifted. These Urethane rails retract to allow the second blank to settle back on top of the stack.
The gantry robot removes the blank from the top of the stack and transports it to the conveyor. The conveyor represents another Güdel speed-improving innovation. Due to the light weight of the aluminum blanks, they often slip out of position on the belt if it accelerates too quickly. The Güdel automation system includes suction on the belt, holding the aluminum blank in the desired location as it quickly accelerates toward the stamping or forming operation.
The ability to quickly changeover from one part to another is critical to maximizing productivity. The Güdel destacking system changeover is automatic and is almost instantaneous from aluminum to steel sheets. All of the other tooling and destacking devices work with both steel and aluminum. The various destacking devices are servo-controlled, enabling fast, automated transitions between different metals or blank sizes.
Achieving Higher Productivity
As automakers try to lighten vehicles a nd incorporate more aluminum components, these automakers and their automation suppliers – must provide systems capable of meeting their production requirements.When shifting from steel to aluminum blanks, suppliers today often reduce stamping line cycle time for aluminum blanks compared to steel blanks due to issues with destacking aluminum.
Güdel’s extensive aluminum-handling expertise provides a solution that enables dramatically higher speeds, comparable to steel blanks, with increased productivity. This destacking technology can be readily retrofitted on most existing steel destacking systems, minimizing capital costs. Conversions have been completed in as little as four months.
Automakers and suppliers interested in meeting the increased demand for aluminum components should consider the increased productivity possible via Güdel automation.
Fig 1. Fanner for Both Steel and Aluminum Blanks
click image to enlarge
About Güdel Inc.
Güdel Inc. is the US subsidiary of Güdel Group, a global manufacturer of robotic automation products, systems and services. Güdel supplies linear-motion modules, robot track motion units, gantry robots and components to OEMs, systems integrators and machine builders serving the automotive, aerospace, logistics, heavy industrial and power-generation industries. Güdel Inc. is located in Ann Arbor, Michigan, in a dedicated 45,000-square-foot facility, providing North American customers with engineering, design, production and customer service support.
Güdel Group was founded in 1954. Headquartered in Langenthal, Switzerland, today Güdel operates in more than 30 locations worldwide.