Sterling SXS Series - Manual (Page 50)

BJ5-620 Maintenance 50 of 73
Sharpening Cutters and Bed Knives
Shredder cutters have 4 cutting edges. This means they can be turned 3 times. The
cutters should be replaced after the third use. Bed knives can be turned 2 times and can
be re-sharpened as long as you can fix them with the long hole.
1. Dismount the cutters and bed knives (see “dismounting the cutters”).
2. Sharpen the cutters and bed knives.
NOTE: A specialist in accordance with the sharpening plan using particular care
should uniformly sharpen the cutting knives mechanically. It is important to
make sure that sharpening takes place with small grinding allowance and
sufficient coolant supply. The sharpening process is finished when the cutting
edge is sharply cut. Not all indentations must be ground out; otherwise the
number of possibilities for sharpening is unnecessarily reduced. For the
sharpening process, use soft grinding wheels (Quality 40 H or 46 K). Knives,
which have grinding cracks, are not to be reused due to danger of breakage
during operation.
3. Whet the cutting edges of the cutting knives using a whetstone.
NOTE: The service life of the cutting knives can be increased by taking this
measure.
4. Set the cutters and bed knives (see “setting the cutting knives”).
5. Mount the cutters and bed knives (see “mounting the stator knives”).
NOTE: The cutting knives, in particular the rotor knives, should only be sharpened or
replaced in sets. There is a danger of balance error if a combination of cutters from
different knife sets is used.
WARNING! Danger of cutting caused by sharp knives at all times—even when rotor is at
standstill. Serious Injury especially to the hands and fingers can occur. Wear protective
gloves
!
Setting the Cutting Knives
Cutters for the SXS series shredder do not have to be adjusted. All adjustments have to
be done with the bed knives. To simplify knife setting and shorten standstill periods
when replacing knives, bed knives have 4 adjusting screws, 2 each for pushing and
pulling the knife. Having several knife sets helps to avoid standstill periods. Correct and
careful setting of the gap between the cutters and bed knives (cutting gap) is important
for productive capacity of the shredder. Factors for the size of the knife gap are the size
of the rotor, the design of the rotor, and the material to be ground.