SINGLE SPINDLE AUTOMATIC LATHES
A single spindle automatic lathe is a modified form of turret lathe. These machines have an addition to a 6-station turret, a maximum of 4 cross slides. These cross slides are operated by disc cams. The cams are mounted on a shaft which draws the power from the main spindle through a set of gears called cyclic time change gears. Turret operation is also synchronized with the cross slide operation and is driven by another cam called main cam.
The tools used on the cross slides are usually form tools and are plunged into the work piece at the desired feed rate. The tools used in the turret may be turning tool, drilling tools etc. It is general to use more than one tool on a turret station. External threading is usually carried out by a thread chasing attachment. Internal threads are made using taps.
It can be performed in an automatic lathe with the help of special attachments. This is one of the owing features of automatic lathe. The reduction in number of set ups and total machining time enables the parts to be produced at an economical cost in an automatic lathe. For of their application to manufacture screws at low cost, these are called screw cutting machines.
The lathe has a geared headstock. The headstock has one slow speed and one fast speed. The spindle speed is changed with the help of the trip dogs provided on the drum.
At the end of the bed, a square turret is mounted. The travel of the turret slide is achieved by the adjustable cam drum. The turret indexed to the next at the end of each stroke.
Two cross slides are situated between the headstock and the turret. One cross slide is at the front and the other at the rear side. The cross slide have self-governing movements. The movement of the cross slide is independently organized by cam. Overlapping of operations by the tool in the turret and the tools in cross slide can be done. The correct feed for each machining operation can be automatically selected by the feed selector pins on the drum.
The bar stock is held in the rotating spindle by a collet chuck. Headstock slides along the bed ways with the rotating bar stock.
This headstock movement gives longitudinal feed to the work. All the tools in the tool slides take material from the work piece at the same time. Tool in the feed base mounting may also do operations like drilling. The headstock slides back to the original position after the machining process. One revolution of the camshaft manufactures one component.
Most of the turning and forming operations are done by the tools held on the front and rear tool slides. The vertical tool slides are mainly used for undercutting, chamfering, knurling and cutting off.
· It is used to manufacture precision turning of small parts.
· It has many tool slides.
· Wide range of speed is available.
· It is rigid in construction.
· Simple design of can is enough.
· Many working stations are available.
· Micrometer tool setting is possible.