August 2021 Volume 3

MAINTENANCE

RamWay Surfaces Ajax and National Machines Even though the ram designs differ between Ajax and National Presses, the design principles are much alike. The press ram in a forging press fits into the frame with pre-set clearances. There are two wear plates on the right and two plates on the left. One side is designed to be adjustable and other side is designed to be fixed.There is a direct correlation between the lower ram box and the upper ram box. The relationship between the way surfaces on the lower way surfaces and the upper way surfaces must be parallel. Unparallel loading of the ram during unsupported operations can cause cracks in the ram tail. Normally all dimensions are taken from the centerline of the machine left to right. In the National Maxipres and the Ajax forging presses there is a relationship that must be held between the upper and lower ram boxes. When the ram is placed in the press frame and is forced back against the rear front to rear way surfaces a dimension can be established for the upper box. There are (2) different designs, the Ajax Press Ram has the ram tail stock at the rear of the press and the National Maxipres Press Ram has the ram tail stock at the front of the machine. The following steps should be followed to set the ram clearances.

running clearance for the side and front to rear wear plates will be .0005" x width or depth of the ram. Example: If the ram at the bottom across the front of the machine measures 60" wide then multiply 60" x .0005" = .030" total clearance or .015" per side. 3. Deburr and polish the wear plate surface on the face of the ram. Deburr all vertical wear surfaces, clean and prepare for installation in the press frame. 4. Provide two steel risers that are flat and true of identical height to set on top of the press bed and the face of the ram. Once the ram is in the press, lower the slide on the risers and push the ram toward the rear way surfaces until the ram is flat against the lower way surfaces. Check with feeler gauges. 5. With the ram in the lower box, you can now measure the frame wear plates for the tail front to rear. The front to rear plate should allow for zero clearance. You will set the clearance with the cover. Once you have established the wear plate thickness you can slide the ram back to allow for installation of the wear plates. 6. Next, set all side running clearances on the lower and upper box. 7. Once all clearances are set left to right, install the front gib box covers allowing for the front to rear clearance on the machine. Set the upper box clearances the same as the lower box clearance so that you don't put the ram in bind. 8. Verify lubrication to all ways surfaces. 9. Assemble the remainder of the press and test operate. It is not a difficult job to set the clearances and maintain them, however it is critical to the proper operation of your press. Once the press is assembled, and the counterbalance cylinder pressure is applied to hide the lost motion clearances it is time to place the ram on bottom dead center and perform parallelism checks. The goal is .001" per foot of span, left to right and front to rear. If the press die space is not close enough for running after checking the best method of correction is to lock the lower box down and obtain or hire in a portable machining company. They will then mount a portable mill normally to the face of the slide and reach down to machine the top of the hard plate for minimum clean up flat and true with the ram face. Good luck with your forging press maintenance adventures! ■ Jeff Fredline Sales Engineer MECO Corporation Email: jfredline@meco.net

Figure 3: Slide Liners, Gibs and Wedges 1. The rear wear plates should be ground flat and true and installed with the way surfaces parallel in the same plane. Plates 4 and 5 in Figure 3. 2. Next the wedge and hard plate should be free from wear and surfaced flat and true. Verify that the rear way surfaces are perpendicular with the top of the hard plate on the wedge. The side wear plates should also be surfaced flat and true. Once this has been established it is now time to introduce the ram to the press. Normally the left to right

FIA MAGAZINE | AUGUST 2021 17