How to Replace Shredder Machine Blades

How to Replace Shredder Machine Blades
The replacement of a new shredding machine knife takes 4 to 6 working days and the number of executors is 6 people.

Make sure before starting work the condition of the power source has been cut off safely.

Remove the infeed hopper (the top of the machine where the material enters) after unscrewing some of the locking bolts. Lift the infeed hopper by a crane or knuckle crane (mobile crane) and have it tied to a chain or steel wire sling.

Document using the camera the position of the shredding blades for each shaft (knife holder) to determine the installation position of the first spacer (separator between the blades in 1 shaft) and determine the order for the installation of the shredding blades for each shaft.

Open the bearing shaft cover for 4 sets. The shafts are marked as upper left shaft, upper right shaft, lower left shaft and lower right shaft.

Open the jack screw, lock ring segment, preload hub, bearing spacer (ring bearing) and finally open the bearing shaft.

Install the hub protector shaft and lock it by tightening the L mounting bolt, so that the hub protector is sturdy when it is hit by a shredding knife or spacer when it is removed from the shaft.

The hub protector functions to protect the end of the shaft so as to prevent scratches by the shredding knife and blade spacer during removal.

Remove the body hopper where the shaft exits. How to release all the locking bolts must be balanced between the right and left and done slowly after the locking pin is released on both sides.

The process of removing the shredding blade and spacer. Executor position is divided:
  • The following shredding blade remover is the spacer
  • Shredding blade receiver with spacer
  • Storage for shredding knives and used spacers.
When removing the shredding blades and spacers, the blades must be removed one at a time. If you encounter difficulties when removing one of the knives, make a vertical tap using a brass hammer so that the residual material from the B3 waste that causes the stickiness can be released. The total number of shredding knives and spacers that must be removed is 72 sets.

Once about 25% of the shredding knife has been released from the shaft, make a footrest for the recipient of the shredding knife along with a spacer, usually a wooden pallet. The more knives removed, the higher the recipient's footrest must be by increasing the number of wooden pallets.

It requires focused attention and physical exertion for this process considering that each shredding knife weighs around 20 kg.

Remove all the screen locking bolts, then remove the screen using a 3.5 ton capacity forklift. Screen cleared.

Clean all shafts using a rag mixed with a little diesel. Smooth the surface of the shaft through the sanding process using fine sandpaper (1000 sandpaper).

It is not recommended to smooth the surface of the shaft using objects other than those mentioned above, including the use of sharp objects because it keeps the surface of the shaft from being damaged.

Drain gearbox head oil. Check the tightness of all gearbox bearing locking bolts at a standard torque of 11 Newton meters. This check aims to ensure that all shaft conditions are not rocking.

Perform a shaft shake test by shaking the end of the shaft with a forklift. If there is wobbling, gently push the shaft by the forklift towards the gearbox while re-tightening all bolts to 11 Nm of torque (after pressing, the bolts usually loosen again). Make sure to check this shaft so that the shaft is not in a loose condition.

The next step is to install a new shredding knife along with a spacer for each shaft.

Open the packing box for the new shredding knife. Shredding machine blades are divided into upper shaft blades and lower shaft blades and have been sorted in sequence 1 to 4 marked with a number on each blade.

Each blade has a marking on the side surface to mark the beginning of the sequence of hexagon blade shafts (regular hexagons). All upper knives have 2 sharp edges except for 1 pcs which has 1 cutting edge which will be installed as the last sequence knife.

The lower blade has a mark called the dimple which will have a different direction for installation on the lower shaft while the lower left shaft dimple faces inward (gearbox direction) and the lower right shaft dimple faces outward.

Each shaft is given the identity number number 1 in the order of the 6 sides of the shaft body, namely in the top surface position. The upper left shaft and lower left shaft are counter clockwise while the upper right shaft and lower right shaft are clockwise.

The number 1 on the shaft is a sign of the sequence number 1 on the knife so that the hexagon number of the shaft and the hexagon number of the shredding knife are aligned.

The shredding knife and spacer have just been cleaned and smoothed on both surfaces, especially the position in the middle because the spacer will touch. This cleaning is done by rubbing with a whetstone and then cleaning it with a cloth mixed with a little diesel fuel.

Install the 2 spacers first on the lower left shaft and upper right shaft. The next sequence of shafts is to attach the shredding knife, lower right shaft, followed by upper right shaft, followed by upper left shaft, followed by lower left shaft, followed by lower right shaft, and so on. After each installation, 1 shredding knife is interspersed with 1 spacer.

When this installation takes place, it must be ensured that the density between the blade and the spacer is standard 0.010 inches measured using a puller guide. If it is not tight, then add pressure using a brass hammer and vice versa.

After the 72 new knife sets are installed, then reinstall the hopper body, bearings and seals. First make sure these bearings are not worn out and can still be used for a prediction period of more than a year. Remove the hub protector from the end of each shaft.

Install screens. Fill gearbox head oil with a record that it has passed 2000 hour meter from the last replacement. Reinstall the infeed hopper. Last test Running. Shredding machine ready to operate with new shredding blades.
Umar A
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