Komori L-640 - Packing moving under blanket

[chvl72]

Haven't seen this one before. The packing under the blanket of one unit (and only one, unit 6) has started to routinely creep forward and bunch up around the gripper edge. Having a hard time understanding how it could be moving in that direction. Each time the blanket shows no sign of being loose (we tourque our blankets to 45).

The only theory I can come up with is that the blanket is stretching ever so slightly while under pressure and then pushing the packing forward as it "snaps back" when it reaches the gap. Possibly a result of the blanket being of inferior construction or material (or both!). Seems though, I should see the effect of that in the work but I haven't yet. Thanks in advance for your input.

[rapid3]

We had this happen on new Heidelbergs. It went
away after we completely cleaned off ALL of the
oil that they coat the cylinders with.

[jbeniston]

Haven't seen this one before. The packing under the blanket of one unit (and only one, unit 6) has started to routinely creep forward and bunch up around the gripper edge. Having a hard time understanding how it could be moving in that direction. Each time the blanket shows no sign of being loose (we tourque our blankets to 45).

The only theory I can come up with is that the blanket is stretching ever so slightly while under pressure and then pushing the packing forward as it "snaps back" when it reaches the gap. Possibly a result of the blanket being of inferior construction or material (or both!). Seems though, I should see the effect of that in the work but I haven't yet. Thanks in advance for your input.

The above is right and it can also be a sign of incorrect packing or tension or both. If you are using all the same type blankets on every unit try increasing the torque a bit. One thing you could do is to make the top packing sheet and only the top sheet long enough that it will overlap the cylinder edge and pass into the gap cavity. When you tension the blanket the long sheet will trap all the other sheets and hold them in position. Normally the packing should not extend over the tail edge of the blanket cylinder

[peter61]

Make sure you have long grain packing and not short.

[abc228]

Make sure pressure is correct. If older press with mechanical gauges, they could need re-setting.