CNC Lathe Machines, Parts and Working

Background:

Machining process is basically removal of excess material, most often metal and plastic, from job piece, using one or more cutting tools to achieve desired dimensions. There are different machining processes, such as, turning, milling, boring, drilling, etc. In advance manufacturing processes, there are multiple types of CNC machining process. All of them have different

function and purpose of operation; CNC milling uses rotary cutting tool to remove excess material, while CNC turning uses a helix path to cut through the material to give job piece a desired shape and size. All of them require a specific machining tools that enable the job piece to work to the desired work. CNC Lathe is one of the important tool.

Modern precision manufacturing demands extreme dimensional accuracy and surface finish. Such performance is very difficult to achieve manually, if not possible, even with expert operators. Development of Computer Numerically Controlled (CNC) machines has also made possible the automation of the machining processes with flexibility to handle production of small to medium batch of parts. Initially, the CNC technology was applied on lathes, milling machines, etc which could perform a single type of metal cutting operation. CNC machining centers capable of performing multiple operations were developed. CNC machine tools, the modern versions of Numerical Control (NC) machines have an embedded system involving several microprocessors and related electronics as the Modern Control Unit (MCU).

Over the period of time, several additional features were introduced, leading to increased machine utilization and reduced operator intervention. Some of these are:

·        Tool/ work monitoring: for enhanced quality, avoidance of breakdowns,

·        Automated tool magazine and palette management: For increased versatility and reduced operator intervention over long hours of operation,

·        Direct numerical control (DNC): uses a computer interface to upload and download part programs in to the machine automatically.

Introduction:

A lathe machine is typically used for shaping the material into the desired form by removing excess material from a given work piece. Lathe is used to perform simple operations like cutting, facing and complex operations like knurling, deformation, metal spinning, wood turning, thermal spraying, metal working and many more. With the industrial revolution came the modern lathe; advanced, fast, better and automated.

CNC Lathe Axis:

·        X is the back to front motion, with the part X0 being coincident with the Z axis. It determines the diameter,

·        Z is the spindle axis, and the part Z0 is normally the front finished face. Determines location of faces, shoulders and grooves,

·        Home reference position- movement at startup to extreme limits. A zero-return at power/ start-up. This is the machine zero,

·        We use a floating zero referred to as the part zero or part origin,

·        We touch off the face and diameter, and store the offset from the machine zero in X and Z register of the tool offsets page.

Main parts of a CNC lathe Machine:

Following are the primary components of a lathe machine;

1.      Bed

The bed serves as the base of the whole machine where the different components are mounted. The bed of the machine consists of a heavy steel frame that supports linear bearing rods. The beds have a high damping capacity to absorb the vibrations produced when machine operates in high speed.

2.      Carriage

Carriage is used for mounting and moving cutting tools, and it moves the tool horizontally and vertically on the bed for a smooth cutting operation.

3.      Chuck

The main function of chuck is to hold the work piece. This component is attached to the spindle that rotates both the chuck and work piece.

4.      CNC control panel

The storage center of the machine, CNC control panel stores all the CNC programs and instructions. The CNC expert operates the machine by controlling the keys on the panel, instructing the machine to produce the desired results.

5.      Gantry

The gantry runs along the back of the lathe and supports the linear bearing rods. The router spindle moves along the rods on linear bearings. It is moved along the length of the gantry rack and pinion that is controlled by the machine controller.

6.      Router spindle

The router spindle is moved vertically by a precision ball screw system that is controlled by the machine controller.

7.      Caterpillar track

The caterpillar track runs at the back of the lathe and contains all the electrical cables and the motor water pipes.

8.      Tool Turret

The tool turret is used a tool carrier for the machine. The shape and size of the turret are determined by the number of tools that’ll be mounted on them.

Working of CNC Lathe:

Following steps define how CNC Lathe machine works:

·        After checking the machine for the working faults, a cylindrical job piece is inserted into the chuck, which can differ as per requirements,

·        The spindle is set on the desired speed which rotated both chuck and job piece,

·        Cutting tool is located at the desired feed by moving the tool turret and carriage,

·        Excess material from job piece is removed by moving the carriage to get the finished product. High surface finishing tools like diamond tip tool can be used.