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g time is made during the start of the operation and at the end of the operation. Clocking time is used to find out the total time used by each operator to complete his/her task. All the 13 operations in total take an average time of about 70 hours. In due course this time has increased from 70 to 90 hours and the operation has gone out of control. If there is an increase in time it would be very difficult to track the reason for the increase in extra time. It may be very difficult to say in which operation the program has gone out of control.

In order to have a control and an understanding such that which operation could have gone wrong and in what point could help us target the problem very easily. So it is decided to divide the operator clocking time into two. As observed the pocket operation takes a long time, so the clocking time is divided as before the pocket and after the pocket.

By this way even after months of production of a part, we can backdate and could identify the time taken for the pocket operation alone. This could help us to keep the process under control and the improvement is not lost in due course. The update in all the CNC programs and routing would play a commendable role to sustain the change.

4.10 Other Improvements

The improvements in the third operation in the part in the bottleneck machine helped to reduce the confusion and to meet the standards in the cell. The improvements were not stopped when an opportunity was seen in any operation. The second operation in the same bottleneck machine took a lot of time to turn down the OD.

Conventional carbide inserts were used for this operation. The depth of cut for this operation was very high and the process usually takes 7 hours to complete roughing the OD operation. The number of passes as per the program was 2 to complete the operation, but due to insert failure the number of passes required to complete it has been increased from 2 to 4 passes.

To solve this problem and to reduce the time in the operation new ideas were implemented. All new ceramic inserts were ordered for this purpose as the ceramic inserts are capable of running at high speeds thus reducing expensive machining times.

Turning is an almost ideal operation for ceramics. In general, it is a continuous machining process that allows a single insert to be engaged in the cut for relatively long periods of time. This is an excellent vehicle to generate the high temperatures that make ceramic inserts perform optimally.

The time taken to complete one single pass in the turning operation with this new insert takes only 17 minutes, but where as in the old method the time taken to complete it is about 2 hours. Although the new ceramic insert was able to perform extraordinarily well it is recommended to have an insert check in every half pass so that the process is under control and the change could be sustained. The depth of cut used for this operation is 100 thousandths per side and the feed is maintained at 10 thousandths, roughing speed at 500 SFM and the final finish speed is at 600 SFM.

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