Page 47 - MetalForming September 2016

The Four Common Causes of Failure
Few industrial processes are as hard on equipment as metal stamping. With the continuous pounding and applica- tions of extreme physical forces along a plant production line, reliability is critical to throughput and uptime. This extends to scrap-clearing and collection systems. They’re subject to the constant drop and bounce of scrap metal, with varying weight loads as scrap is cleared, collected and disposed of.
Based on the experience of design- ing, engineering, installing and serv- icing scrap shaker systems, we have found most failures of these shaker systems have root causes in four key areas: uneven pan loads, jams, insuf- ficient pan support and leveling, and poor pan installation.
Uneven pan loads—Basic physics suggests that uneven pan loads can stress shaker systems designed for more balanced loads. Operators should ensure that an equal number of pans are installed and evenly spaced on each side of a shaker-system’s crossbar. If not, the uneven weight load of scrap metal can cause the top plate of the shaker system to twist with each move- ment. This twisting action can put extra stress on the system’s motor and bear- ings, causing them to fail. For those applications that require uneven pan loads, users should opt for a rack-and- pinion system that utilizes an extrusion at the end to prevent twisting move- ment from the uneven loads.
Jams—Scrap or parts falling through a die can bounce and end up in various places around the press. These pieces can jam between the shaker-system’s pans or drive components. Watch for jams and quickly clear them to prevent excessive wear on the motor and its linear bearings.
Insufficient support and leveling of pans—Be sure to install pans level with the press bed. Inclining or declin- ing pans can add unwanted torque to the motor, creating excess wear. To better support pans and reduce fric- tion from metal-on-metal contact, ultra-high-molecular-weight (UHMW)
polyethylene pads or lining can be used. Poor pan installation—Pans that are crooked, loose or banging against other objects can create additional operating stresses that can lead to pre- mature bearing or motor failures. A solid installation can be achieved sev-
eral ways.
One solution is to use quick-release
pan-mount brackets. These brackets will lock down the pans securely while
also allowing operators quick and flex- ible changes to pan placement. Lastly, the crossbars that the pans mount to should not exceed the manufacturer’s maximum recommended length.
Performance and Cost Advantages of Electric Shaker Systems
When properly installed and main- tained to eliminate the common causes
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