May 2025 Volume 7

MAINTENANCE

HOW TO JUSTIFY THE REPAIR OR REPLACEMENT OF YOUR FORGING PRESSES By Jeff Fredline

Making the decision to repair or replace an existing forging press can be challenging. In this article, we will look at several issues that need to be considered and from what perspective.

If the current press meets the above requirements the next step is to have a complete inspection performed. What does a complete inspection consist of? Please see the steps listed below for further explanation: Die Space Parallelism 1. Place the press on bottom dead center with all tooling removed and with air counterbalance pressure applied. 2. Measure the distance from the face of the ram to the top of the hard plate on centerlines front to rear, and left to right. Now measure the (4) corners and record all readings. Allowable tolerance per industry standards: .001” per foot of span left to right and front to rear of die space. Vertical Lift Clearance Measurement 3. Place a hydraulic jack with 40-50 ton capacity on the centerline of the ram between the face of the ram and the top of the hard plate. Apply maximum pressure with the hydraulic jack and take the same measures of the die space again recording all dimensions. Now you have the reading necessary to evaluate the die space. 4. Next, we need to determine how much wear exists in the vertical stack up. Allowable tolerance for rotational clearances are approximately as follows: For each inch of diameter up to 12”; .001” per inch. For diameters over 12” add .0005” inch of additional inch of diameter. For the larger diameters clearances will vary. Consult manufacturer’s recommendations. 5. Several readings are required to analyze the condition of your machine. We will need to measure the clearance between the main bushings and the crankshaft, the connection to the crankshaft, and the wrist pin pocket. 6. Checking the clearances is easily done. You already have the hydraulic jack in place. Now turn off the counterbalance cylinder(s) and exhaust all the air from the system. 7. Place a die indicator and base next to the jack measuring from the face of the ram to the top of the hard plate. Make sure that you have an indicator with enough travel to measure the total upward movement of the ram assembly and record it. 8. Now it’s time to determine where the wear is. You already have the jack and indicator in the die space, leave them in position. Now you will need one or two additional indicators with magnetic bases. The next measurement we will need to take is from the connection to the ram. Locate the indicator on the connection and measure to the top of the ram. Using the jack and watching the bottom indicator apply pressure

Step One: Evaluate the Condition of Your Press First you need to understand the overall condition of what you currently have. In addition, do the current specifications meet your present and future needs? • Does the press run fast enough to meet your needs now and in the future? • Is the machine able to hold operational tolerances to meet quality standards? • If there are problems with the press/systems, can they be upgraded?

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