Setting the Calliper & testing the Couplings/Bearings

Some of our customers experience slight ripping on the leading edge of the sheet as it passes through the slitter shafts or they cannot obtain a deep crease. This is usually caused by incorrect pressure settings on the slitter shaft callipers. The simple answer ito this problem is to CHECK THE COUPLINGS & BEARINGS. This operation can be achieved witin 2 minutes but will give the operator valuable information into why they are having problems.

Regardless of whether you use Tech-ni-Fold products or not, score or crease depth and quality can be affected due to the wear and tear in your folding machine shafts. Although problems of this nature are not common it is usually due to worn out couplings and bearing that are the route cause. The procedure set out below explains how you can easily check the couplings and bearings of the shafts on which you mount your scoring or creasing device, and this takes only a few minutes.

1) Place your finger underneath the top shaft at one side of the shaft and gently apply upwards pressure. If the sheet now becomes slack this is an indication there is wear in the beaings and couplings.

2) The next step is to place 2 sheets inbetween the collars and once again gently raise the top shaft and check to see if the pressure is tight. If after 3 sheets are placed inbetween the collars without any pressure being applied this means the bearings and couplings are too badly worn to give a high quality crease, for every sheet that is not held this is equal to 0.1mm (4 thou). Repeat this procedure on the opposite side of the shaft.

3) Although you have set the callipers correctly, when a sheet of stock runs between the devices the top shaft lifts up as there is insufficient pressure pushing the insert into the paper stock. The operator may think they need to turn Mehr pressure onto the calliper setting but unforunately this may make a deeper crease, it also makes the leading edge rip slightly as the device has been placed closer together.

4) If there is excessive wear the couplings and bearings should be replaced as soon as possible.

This simple and effective procedure can eliminate many problems associated with creasing and micro-perforating. The set-up times will be reduced and the creasing quality increased.

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