Sterlco TG 1200 Series Thermoform Granulators - Manual (Page 20)

T-Series Thermoforming Granulators Maintenance 20 of 37
Bed Knives
We recommend that the same screws and washers be re-used only when the bed knives have
been repositioned or re-ground. When blunt knives are discarded and replaced with new
knives, use new screws and washers. This will reduce the risk of screw failure due to their
overstretching. Screws and washers must be replaced with the type specified in the Spare
Parts List. Use the following procedure to replace or adjust the bed knives:
1. Access the cutting chamber as directed in Section 3-4 on page 14.
2. Remove the downstroke cover screws at the rear of the machine (this includes the
safety switch acutator arm bolt), and carefully slide the covers out of the machine.
(See Figure 4 on page 21.)
3. Remove the bed knife shield screws and lift off the bed knife shield.
4. Remove the screws holding the bed knives, and remove the bed knives.
5. Before installing and adjusting the bed knives, check all rotor knives to make sure
they are properly seated on the rotor and securely fastened.
6. Thoroughly clean the knife seats.
7. Replace the bed knives on the bed knife seat and tighten the screws until they are
finger-tight.
8. Use the adjustment screws (See Figure 4 and Figure 5 on page 21) to set the knife
clearance to 0.15 mm – 0.20 mm (0.006” – 0.008”). The clearance should be
measured with a feeler gauge at the ends of the knife, by rotating the rotor sheave
backwards by hand. The clearance is slightly greater at the center of the knives.
9. Tighten the bed knife screws evenly and torque the 16 mm screws to 271 Nm (200
lbs./ft.).
10. Replace the bed knife shield and adjust the shield using its push and pull screws so
that its front edge is within 1.0 mm (0.040”) of the bed knife edges. If strip material
is to be cut, reduce the knife exposure to less than the strip thickness to prevent
material built-up on the bed knives.
11. Make sure all screws, bolts, and nuts are properly tightened.
12. Reset the downstroke cover in position and tighten in place with the downstroke
cover screws. Make sure the safety switch actuator arm screw sets the arm in the
correct switch operating position.