Lathe Machine Operation

LATHE MACHINE OPERATION


Lathe Machine is also called a universal machine because we can do many operation on this single machine. We can perform many operation on lathe machine some are as below

Lathe machine image





1. Plane Turning


 Plane produces a cylinder for the full travel of the tool and diameter of the work throughout is the same. The operation involves removal of the metal for the raw material to bring the work to the required size. Plain turning has two types - Rough and Finish turning.



2.  Taper turning

                             Taper is a gradual increase or decrease in the diameter along the length of the job. The Main methods of taper turning on a lathe are:

1. Forming method
2. Compound slide method
3. Taper turning method
4. Tail stock method


Formula for compound slide method:

By this method both internal and external taper can be produced

Tanα=D-d/2
       D=Big diameter
d=Small diameter
L=Length of taper
α=Included angle in degree



Calculation for Tail stock offset method
                                        
                                  Offset= (D-d) x L /2l
Where
              D= Big diameter of the taper
               l= taper length
               D= Small diameter of the taper
               L= Total length of the job




Comparison of Various types of method for taper turning method


Method
Advantages
Disadvantages
Information
Required
Compound Rest
 Can be used  for internal
External tapers
Only short tapers
Can be produced
Taper angle
Taper Turning
Attachment
Best method for long jobs with small angle
Step tapers can’t be produced
Taper angle or taper per cm
Tail stock set over method
For small angles
Only for external tapers and for jobs which can be held between Centers
Taper per cm.


Form tool
For short tapers
Costlier tool
Taper angle




3.   Facing


                   This is an operation of removal of metal from the work face by feeding the tool at right angles to the axis of the work. It is done to have a face at right angle to the axis of the work. Facing can be rough and finish facing. Rough facing is done to remove excess metal from the job. Finish facing is the operation to have a smooth surface by removing the rough surface produced by the rough facing. Finish facing is done by choosing a cutting speed about twice that of the cutting speed for rough cutting, with a fine feed rate of 0.05mm approximately, and with a depth of cut of not more than0, 1mm.

4. Thread cutting

                              The principle of thread cutting is producing a uniform helical groove on a cylindrical or conical surface by rotating the job at a constant speed, and moving the tool longitudinally at a rate equal to the pitch of the thread per revolution of the job. The cutting tool moves with the lathe carriage by the engagement of a half nut with the lead screw. The shape of the thread profile on the work is the same as that of the form tool. The direction of the lead screw determines the hand of the thread being cut.

5. Drilling

                   Drilling is an operation of drilling a hole on the face of the work using a multi point cutting tool. The drill chuck is mounted in a tail stock spindle and rotating the tail stock hand wheel does the feeding of the drill to work.

6. Chamfering

                             Chamfering is a lathe operation performed by a cutting tool on the edges of the faces of external diameters and bore diameters for a restricted length forming a beveled.

7.     Knurling

                   knurling is the operation of producing straight lined, diamond shaped pattern or cross-lined pattern on a cylindrical external surface by pressing a tool called knurling tool. Knurling is a forming operation. Knurling is done at a slow spindle speed (1/3 the turning speed). Soluble oil is to be used as coolant mostly and, sometimes-straight cutting oil may used to get better finish.

8.  Reaming

                   Reaming is the process to produce an accurately sized and shaped hole with a good surface finish. This operation is performed with a tool called reamer. A reamer is a multi point cutting tool used to increase a drilled or bored hole to accurate dimension.

9.   Shouldering

                             Section joining two diameters on a job or work piece is called shoulder. Different shoulders produced on work piece are square shoulder, filleted shoulder, chamfered or beveled shoulder, under cut shoulder etc.


10.  Parting Off

                             Parting off operation separates the finished part from job or divides the job in two parts. In case of solid bodies, separation is achieved by feeding the tool in up to work piece axis and in case of hollow bodies, by feeding it in up to inner surface of work. The parting off tool point section decreases towards the shank to provide clearance. 

11.  Forming

                      It produces surfaces concave or convex. Forming can be done by using form tools, templates etc. The form tool profile corresponds to the desired shape.


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