Slotting Machine | Mechanism of Feeding in a Slotter
Slotter is a type of reciprocating machine. The tool is held in the ram reciprocates vertically and the work piece is held on the table. The slotter has a base upon which the column is being integrated. The column houses the driving mechanism for the ram. The top portion of the ram has the guide ways. With the help of this guide ways the ram reciprocates vertically. This reciprocation is achieved by the quick return mechanism. The base has horizontal guide ways which enables the saddle to move perpendicular to the column.
The top face of the saddle has guide ways. These guide ways are perpendicular to the guide ways present in the base over which a cross slide moves. This movement is parallel to the column face.
A circular shaped rotary table is mounted on top of the cross slide. This rotary table can be rotated about a vertical axis parallel to the column. This movement is the circular feed for the table. All the feeding systems are graduated.
T- Slots are being provided on the table for holding the work piece. The longitudinal feed of the saddle, the cross feed of the cross slide and the rotary movement of the table in all these feeding mechanism the feed can either be given by hand or by power.
Quick return mechanism
Metal from the work piece is removed only during the cutting stroke. During the return stroke no metal is being removed. To reduce the idle time of the return stroke quick return mechanisms are being used. The following are the generally used quick return mechanisms in a slotting machine.
· Whitworth quick return mechanism.
· Variable speed reversible electric motor drive.
· Hydraulic drive.
The following are the feed mechanisms generally used in a slotter
· Longitudinal feed: This movement is achieved by moving the saddle either towards or away from the column.
· Cross feed: This is obtained by moving the cross slide parallel to the face of the column.
· Circular feed: This is obtained by rotating the table about a vertical axis.
A groove for the cam is cut on the face of the bull gear of the driving mechanism of the slotter. A roller follower slides in this groove. The roller is fixed at one end of the lever. The lever is pivoted in the middle and the other end of the lever has a slot. In this slot a feed adjustment pin is fitted.
This pin is connected by a connecting rod to the pawl and ratchet mechanism.
The bull gear starts to rotate, the follower follows the groove profile. When the lobe portion of the cam groove passes the follower, the slotted end of the lever moves up and down. This makes the pawl to rotate the ratchet wheel. The ratchet is keyed to the feed shaft. This feed shaft is engaged with the longitudinal, cross or rotary feed screws. This makes to achieve automatic feed.
The amount of feed can adjusted by shifting the location of the feed adjustment pin in the lever slot.