Film course "Turning business" Section one (1970)

Alternating frames with parts and mechanisms that have been processed on lathes.

A worker works on a lathe.

Panorama of the plot with lathes.

Turning and screw-cutting machine.

Turning and revolving machine.

Multi-spindle automatic lathes and semi-automatic machines.

Panorama of the workshop.

An old engraving of the 13th century, which depicts the first lathe.

The driving mechanism was a rope with an elastic arc and a foot pedal.

The man was holding a cutting tool in his hands.

An old engraving on which a crank mechanism is already used instead of a rope.

Later, a counter drive appeared.

In the 18th century, a caliper, a mechanical cutter holder, was invented.

The lathe of the 18th century.

Many improvements to the machine were introduced by the Russian mechanic A. Nartov.

Lathe support.

On modern lathes, the outer and inner surfaces of parts having the shape of bodies of rotation are processed.

The ends are cut, the conical outer and inner surfaces are processed, the shaped surfaces are processed, grooves are drilled, parts can be cut.

Drilling and countersinking, countersinking and deployment of holes.

Various threads, both external and internal, can be cut on screw-cutting lathes.

Various cutting tools for lathes.

The gearbox of the lathe.

The feed mechanism of the part in the machine.

The characteristic of each lathe is determined by the largest distance between the centers of the machine, the height of the centers, which determines the largest diameter of the workpiece above the bed and the largest number of spindle revolutions per minute.

Lathes are divided into machines with a height of centers up to 150mm, from 150 to 300mm.

Turning area.

Shop.

A machine for processing large parts.

There are three types of movements in the lathes of the turning group.

The main movement is the movement of the spindle with the workpiece being processed.

Feed movement - movement of the caliper with the cutter and auxiliary movements.

Cartoon explaining the metalworking process on a lathe, chip shrinkage.

Processing of the part.

Large - chip formation during processing of plastic and brittle metals.

The chip shrinkage is greatly influenced by the geometry of the tool.

A cartoon explaining this phenomenon.

The chip shrinkage is influenced by cutting modes.

Large - the process of chip formation.

The cutting speed has the greatest influence on chip shrinkage.

Cartoon explaining the effect of the growth on the cutter on chip shrinkage.

Lubricating and cooling fluid.

Large - the process of cutting the workpiece.

Cartoon explaining the process of deformation of the metal surface.

The phenomenon of riveting.

The work spent during the cutting process on deformation and friction turns into heat.

Excessive heating of the cutting tool leads to softening of its working surfaces and failure of the cutting edge.

Samples of deformed incisors.

As a result, the cleanliness of the treated surface deteriorates and the cutting forces increase, which can lead to machine failure.

During finishing work, the thermal expansion of the tool and the part can have a negative impact on the accuracy of processing.

Heat generation occurs in the zone of plastic deformation along the sliding plane.

A cartoon explaining this process.

The second source of heat is the friction of the chips on the front surface of the cutter.

A cartoon explaining this process.

The third source of heat is the friction of the back surface of the tool on the surface of the workpiece.

A cartoon explaining the heat distribution during cutting.

When the cutting speed increases, most of the heat goes away with the chips.

The role of the coolant in the removal of heat into the environment.

In the process of turning, the cutter has to overcome the forces of resistance of the material to cutting.

All these forces can be brought to a total resultant force located in space and applied to the cutter.

This force is decomposed into three mutually perpendicular components.

The circumferential cutting force is tangent to the cutting surface.

The radial force is directed towards the cutter perpendicular to the axis of the workpiece.

Axial force, the feed force acts parallel to the workpiece axis in the opposite direction to the feed movement.

Simultaneous presence of all cutting forces is not always possible.

So, for example, when working with a cutting cutter, only two forces act, the circumferential cutting force and the radial force from the transverse feed.

When processing a tubular workpiece, two forces also act on the cutter.

Circumferential cutting force and axial force, feed force.

But this is provided that the main angle in the plan is 90 degrees.

Here only the main cutting edge is involved in the work, free cutting takes place.

In all cases, the greatest acting force is the circumferential cutting force.

It acts on the surface of the cutter and carries out the chip formation process.

According to the circumferential cutting force, the main and responsible nodes of the machine are calculated.

According to the circumferential cutting force, the torque to be applied to the machine spindle is calculated, as well as the calculation of the power required for cutting.

When processing long workpieces of small diameter, the radial force causes the workpiece to bend.

The ratio of cutting forces does not remain constant and depends on the cutting conditions.

The physical and mechanical properties of the processed material have a significant influence on the cutting forces.

The change in the cutting force can be observed according to the ammeter readings.

With high strength and hardness of the metal, chip shrinkage decreases, but the stress in the chip formation zone increases.

Depending on the predominance of these phenomena, the cutting forces either decrease or increase accordingly.

When turning cast iron, the predominant effect on the cutting forces is a decrease in chip shrinkage, as a result of which, the cutting forces decrease.

When processing titanium alloys, the predominant influence on the cutting forces is exerted by an increase in the stress in the chip formation zone, here the cutting forces will increase.

The cutting forces are affected by the cross-sectional area of the chip being cut.

A cartoon explaining this process.

Graph of the dependence of the cutting force on the speed for medium-hardness steel.

Explanations of the schedule.

The cutting speed is one of the main parameters that determine the processing performance.

Factors affecting the cutting speed.

Graph of the dependence of the working time of the cutter on the cutting speed when processing hardened steel.

Explanations of the schedule.

Operation of various lathes.