Slitter shaft health check for your folder – Tip #2…
Still experiencing slight ripping or nicking on the leading edge of the sheet as it passes through the slitter shafts? Or perhaps it is a problem with inconsistent crease and micro-perforation depth across the length of the processed sheet.
If you have conducted the COUPLINGS & BEARINGS check on your folding machine as explained in our last blog, and you are still having these problems, then there is another possible cause.
Over time and with hard use, it is not uncommon to find that the shafts on your folding machine have a slight bow. Especially on machines that have smaller shaft diameters.
Here is a quick health check to see if this might be the cause of your problems:
1. Put one set (pair) of Gripper Boss Support Rollers on the shafts and move to one end (better results will be achieved if both the top and bottom rollers are made of a firmer material other than rubber).
2. Set the callipers to a single sheet.
3. Whilst hand-feeding a sheet, adjust the pressure so you get a slight drag as you rotate the shafts one complete revolution and then move the Gripper Boss Support Rollers to the opposite side and repeat this step.
4. Move the Gripper Boss Support Rollers back to the original side and recheck. If you can’t get consistent pressure at the shaft-ends at this stage, and you are confident that the couplings and bearings are good, then you may have excessively worn Support Rollers.
5. Then move the Support Rollers to the centre position of the shafts and check the pressure. If it is loose or inconsistent as you rotate the shafts through 360 degrees, then there is bow present in the shaft.
Any good machine shop can true up the shafts. Or if the shafts are badly dinged up and in general disrepair, simply replace them.
You will get payback in reduced downtime and improved quality creasing and micro-perforating.
To get more information on this subject, or to book one of our technicians to come and give your machine a free health check and test some of our equipment for you, contact us today.