August 2022 Volume 4

MAINTENANCE

Electronic Maintenance for Forging Presses and Upsetters By Jeff Fredline

Under current market conditions and looking forward, the manufacturing community must utilize every productive tool at its disposal to improve throughput and profitability. The methods of the past will not be profitable moving forward. The good news is that there are cost effective methods of monitoring your operations. • But what should we monitor? Some items lend themselves easily to electronic monitoring, others to mechanical monitoring. We will begin by first examining the items that require hands-on monitoring and then examine what is available to monitor the presses and their proper operation. There are three functions that each press machine must provide: Perfectly square die space -- This is provided by the machine structure; rigidity and squareness are critical. • Energy -- Energy to drive the forming/holding components of the machine. Mechanical machines generally use a flywheel to store the needed energy to cycle or stroke the machine. • Repeatable force on the workpiece -- Provided by the frame and the drivetrain of the specific machine. Take away any of these three functions and your process will not work. MonitorTheseMechanical Items to Insure theBestPerformance of your Machine Flywheel Function -- The flywheel is normally mounted on anti friction bearings on a shaft and is driven by a main motor. There should not be any end play between the flywheel and the shaft the wheel is mounted on. If there is end play movement while the wheel is idling, the bearing stack up is no longer correct and this condition needs to be corrected as soon as possible. If the flywheel moves end to end when the clutch is engaged the bearing stack up has also been affected and requires immediate attention. These problems can be monitored by the motor amp meter and will result in an increase in amperage draw. Clutch and Brake Function -- The functionality of the brake assembly is checkedby a brakemonitor that senses the brake stopping time function with each stroke of the press. There are issues such as travel and air leakage that are not measured electronically and need manual checks. The clutch air pressure can also be monitored. Clutch travel is also critical to the proper function of the unit. Wear should be monitored on both the clutch and brake linings. This will normally be a manual measurement that needs to be benchmarked. Hydraulic and Pneumatic Leaks -- Both hydraulic and pneumatic systems leak. Oil leaks cause housekeeping issues. Any time there

is a system hydraulic or pneumatic leak on the power side of the circuit there is a reduction in working force that is transferred, such as clutch torque. This can cause excessive slippage, heat generation and premature wear of friction surfaces. Die Space Parallelism -- All tooling is designed to be operated within a perfectly square environment. When you attempt to run tooling and parts in less than such, your manufacturing costs increase, the machinery wears and the parts run will be unable to hold manufacturing tolerances. The only effective method to monitor the die space is a four-channel tonnage monitor that shows the effective force on each of the ram’s four corners. This shows you what is happening with each stroke regarding force. Changes in force on a specific corner of the die space can show potential problems requiring further examination. Understanding Vertical Lift Clearances and their Effect on Throughput -- Vertical lift clearances have a direct effect on die space parallelism, especially if the wear is more to one side of the machine than the other. As you use your machine, it is normal for the working clearances to increase. Counterbalance cylinders are located on your machine to help minimize the effects of the excessive wear. We will further discuss their effectiveness, proper use and adjustment under Counterbalance Cylinders.

Bushing Clearance Points.

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FIA MAGAZINE | AUGUST 2022