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Die Cushions should always be evenly loaded. When this
does not happen, so called off-center loading takes place. There are several
reasons for this:
* Worn out pins
* Pins of unequal length, sometimes causes by "mushrooming"
* Non-symmetric pin pattern and/or not using compensating pins
* Worn ram guides
* Uncleared slugs
* Double feeds
* Broken grease lines
Such factors cause die cushion cylinder tip to one side causing distortion
to bearing surface and can lead to distroying the die cushion and press'
slide.
Die cushions are designed with generous overlap and in case of high pressure
cushions, they have internal bronze guiding. These features help withstand
conditions as described above. However, it is extremely important to prevent
any uneven die cushion loading to prolong die cushion's operation and
preserve integrity between cylinder and piston surfaces.
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