Saturday, January 13, 2018

Shop floor in loco manufacturing

Problem of fewer gaps between compressor bracket and compressor legs   analysed.

One should know about stamping schedule .

Stacking of HITACHI armature and 3-phase stator shown here

Problem of shortage of space and shortage of fixtures, should be sorted out.

Stamping work in progress.

Above picture shows the location of transformer mountingplate-central underframe gap. 

This problem can also been reduced by introduction of new quality check points.

Taking the measurement of axle. These axles are bought from RWF Bangalore. All Minus variation are rejected.

Wheel and gear pressing inspection. it may happen that, gear was pressed with 95 Tons, which is less than 100 Tons. 

Friday, October 27, 2017

Some more quality issues in Locomotives

If welding, painting are simultaneously carried out during rainwater testing rain water testing will be compromised.

In the Steel foundry(picture above)   quality issues of cast products, need to be discussed., it was told that use of Zircon sand, prevention of sand erosion and use of special refractory material at places where cross section changes   helps in improving the quality of the castings.

In some locos,  axle guide link post weld failure can occur.  Hence quality welding is required. 

 TM shop should be visited to see that Mica ( of PPCL make ) failure which results in commutator vulnerability to flashing doesnt happen.

Bogie clearances measurement procedure should be inspected in the shop  :

Above shows Gap b/w bump stop and U/F.

Above shows Vertical and  Lateral Gap between STOP and U/F .

Shown above is the Loaded height of secondary spring.
Gap between axle box and bogie frame is measured .
Ensure No loco is dispatched with outstanding NCs on bogie clearances.

Gear and wheel pressing force should be examined
Following is the picture of practical measurement method  :-

Depending upon interference between axle dia and bore dia, this force varies.
It still remains to be studied how we can increase this force .


Tuesday, October 3, 2017

What can go wrong while manufacturing a locomotive?

Material kept in open for months gets rusted and laden with dust. Check this out in  shell shop. Due to lots of corrosion in the bottom, some machining will again be required before fitment.

Rust ridden bottom.

Above is the photograph of one such cab.
Following shortcomings of TM to be looked into:-
  • Less commutator slot depth.
  • Slack insulators in TMs.
 It is to be seen that commutator slot depth in   TMs is not less than standarad.

Problem of slack insulators, need to be watched out.

Rocker rings of TM should be  inspected.

Regarding unsuitable Centre Pivot of Casnub bogies : problem of blow holes may be found.

Problem of Mica getting broken in commutator need to be  inspected in the shop.

It can be seen that due to Mica getting cracked in between slots( while fixing copper bars), the gap between two slots gets reduced which makes commutator unusable.

Commutator Spider is to be inspected as there can be blow holes/ spongy castings/less material while machining.  

Dynamic seasoning plant for commutator should be  inspected. Theres is a standard RPM (say 3050) at which all plants should be working  . Less than that

may result in less seasoning.