Page 32 - MetalForming July 2009

Tooling Technology
fasteners. Typical culprits are sub- standard fasteners, tool damage or wear, misalignment of insertion tools and stock strip positioning.
If tool-related problems arise, begin the troubleshooting mission by veri- fying the quality of the fasteners, since fasteners are guided either by their external or internal features, depending on fastener type. If the fas- teners fall within acceptable parame- ters, then best practices call for inspec- tion of the running areas within the tools for excessive wear or damage.
If the die has been running prop- erly in production and the compo- nents have been properly assem- bled, it’s likely that the tool heads
are properly aligned. If, however,
the die is new and alignment has
not yet been verified, improper alignment could be an issue. In
order to verify, metalformers typically place modeling clay or
some similar soft material on
the end of the insertion tool,
close the die, and then examine the impression made by the anvil to con- firm alignment.
Camber in the stock strip also can contribute to positioning problems or low push out/torque out values. Proper alignment of guide rails and piloting in the insertion stations is essential for consistent quality. Operators should check accordingly for worn rails or pilots. In addition, if the station is not properly piloted, additional pilots may be necessary to hold the strip in position for fastener insertion, since some types of fasteners have little tolerance for mis- alignment. Once the fastener is insert- ed in the stock strip, proper insertion can be verified dimensionally and by conducting push-out and torque-out tests.
When using clinch fasteners, con- duct a preliminary visual inspection to, first, confirm that the fastener is prop- erly seated and that the clinch fea- tures are fully embedded into the stock strip. Then verify the alignment of the fastener to its respective hole. It should be centered in the hole; if the strip is
If too many or too few fasteners are staged in the bowl, the feed system may run too quickly or too slowly. The amount of fasteners is controlled by a hopper sensor, which sets the high/low limit for the amount in the bowl.
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misaligned, the fastener will be off- center and, in extreme cases, the shank of the fastener may shear the edge of the hole. Off-center conditions will lead to low performance or damaged fasteners.
The Control System
The control system can be friend or foe. A well-designed and functioning control system will can serve as an ideal asset for troubleshooting a host of metalforming problems, including those centered on the in-die fastening setup. Controls with touch screens have become far superior compared with more rudimentary controls that rely on simple indicator lights as the operator interface. And while a more sophisticated control with a touch- screen operator interface can provide a host of operator and troubleshooting features, such as I/O (input/output) condition screens, the true value in
everyday operation is the ability to provide online help. Properly config- ured and programmed, the technology allows for the display of troubleshoot- ing text and graphics when a fault occurs. Information about the fault, how to correct it, and how to restart the system can be displayed in a variety of ways and even in several different lan- guages. This information can signifi- cantly reduce troubleshooting time and also can minimize the learning curve for new or inexperienced opera- tors. Trial-and-error troubleshooting is avoided, so that the key process vari- ables are isolated.
The most difficult problems to iso- late occur intermittently, without a clear pattern. Often, these types of problems can be traced directly to faulty wiring or poor electrical connections, aggravated by press vibration. Checking the wiring and connections will be a good place to start in these cases. MF