Two of the most common problems faced in machining industry

THREAD CHATTERING.

OVALITY OCCURRENCE ON MACHINING.

  

Thread chattering:-

                Thread chattering is the most common problem faced in manufacturing industry and widely in heavy weight machining process. When a thread is chattered, it is considered as damaged thread. On mating the chattered thread female component to its male component, the most common defects faced are.

      1.        Liquid Leakage will occur through the thread lines (in case of hydraulic components).

      2.        Thread does not answer to the male component.

      3.        Damaging the fine finished male components thread.

Here are two easy methods were u can avoid thread chattering.

Method 1

      While machining the inner thread, the threading bar must be thick enough comparing to its length. This is because, when the thickness increases, the mass and the strength of the bar too increase and it avoids vibration on the process and reduces thread chattering, as shown below.

      

       

Method 2

In case if the threading portion is too long on the inner surface from the top,  

      1.        High quality threading bar can be used in this case of threading process.

      2.        Threading bar can be supported with a long piece of iron bar from the tool holder. as shown below.

      3.        Depth of cut must be decreased from sample to sample.

      4.        Feed & speed ratios must be decrease.

      5.        Thread must be checked for every single cut for any deviations.

      6.        Coolant oil must be flushed heavily into the threading spot.

      

Ovality occurrence on machining process:-

                Ovality most commonly occurs in cylindrical type of components. This happens due to high pressure produced by the chuck. This problem is widely faced in light weight machining process. Here are some problems faced due to cylindrical ovality.

     1.        Over lapping of gears in gear trains.

     2.        Leak occurs through the corners of the body (in oil based industries).

     3.        Explosion of high pressure vessels.

Here are some ways you can avoid ovality.      

              Clamping devices are 75% cause for this defect to occur. In this case the clamping tech must be improved.

       1.        Almost 80% of the component must be covered by the jaws in case of three jaw clamping as shown below 

       2.        Chuck pressure must be altered from component to component after the ovality check.

 3.    Machining must be carried out slowly.