August 2022 Volume 4

MAINTENANCE

Tonnage Monitoring -- It is impossible to accurately maintain process control without knowing what forces are occurring during the manufacturing process. Understanding how much force or tonnage is being generated during each stroke of the machine is critical to maintaining the usable life of the machine and the tooling. The goal should be to use the least amount of force required to manufacture the product within allowable tolerances. Often, we simply “heat it and beat it” without concern for the press equipment, the only goal being to obtain acceptable parts. We must strive for process control and only use what is necessary for the production of the part, thus enhancing machine life. Temperature at Bushing and Way Surfaces Heat Sensors -- The enemy of all machinery is excessive heat. Simplified, the source of all heat is friction. The normal sources of heat concern within a forging or mechanical press are: • Main Bushings -- Support the crankshaft • Flywheel bearings • Intermediate or driveshaft bearings • Pitman Bushings; Crankshaft, wrist pin and pocket liners/ upsetter linkage • Way Surfaces; Tail and lower ram/heading and grip slides • Clutch and brake assemblies • Counterbalance bearing points, springs on upsetters • Upper and lower knockout assemblies Machine lubrication plays an important role in the bushing/ bearing surface temperatures on a press, forging, trim or stamping. Providing the correct lubricant in the correct amount and frequency each play a major role in the function of the lubrication system. The use of cycle switches on the lubrication distribution blocks is an accurate way to track the proper function of the system as well as temperature probes. Counterbalance System Pressure (Forging Presses and Trim Presses) -- The counterbalance system is critical to maximizing the life of your machine. The system is used for two major purposes. The first is to lift the weight of the crankshaft, bull gear, clutch and brake assemblies and the ram assembly. This gives the motor the chance to recover before the next stroke. The second is to hide the vertical lift clearances as the bearing clearance increases due to excessive wear. The air pressure can be monitored and controlled by using an automatic counterbalance system, such as a Ross system. You may also use a pressure switch to ensure that you have the full adjusted pressure during operation. 9.0 Lubrication andHydraulic SystemManagement: Obviously, the machine must be properly lubricated to achieve its maximum life cycle.The following areas should be monitored to ensure success: • Oil or fluid levels • Lubrication systemmonitoring using cycle switches • Periodic use of fluid testing to monitor contamination level • In hydraulic systems it is wise to use magnetic bars located in the reservoirs to collect metal particles

The first two items above can be monitored electronically. The final two should be included in a regular maintenance program. 10.0 Electrical system issues and maintenance -- When a machine has a control issue, little things like fault lights should be monitored and maintained so that you know right away when there is a problem. One electrical system component that is critical to monitor is the main motor amperage draw. By benchmarking your operational amperage draw you will know when you begin to see an increase. Normally an amperage increase is due to an increase in resistance to rotation in a journal surface within the machine. Any rotational component is subject to this condition. This is an early warning indicator, as you can often see the amperage change before other conditions such as lubrication issues appear.

Forging presses, metal stamping (trim presses) and upsetter equipment are expensive pieces and are critical to your operation. Electronics can and should be used to monitor everything that we have discussed. Due to the adverse conditions experienced during the forging process, care will be needed to protect sensors, probes, and cameras. Even given the difficulty involved in maintaining the electronic and mechanical sensors, the benefits outweigh the problems.

FIA MAGAZINE | AUGUST 2022 9