1)a) Due to wear of the threading insert the effective diameter of the thread got undersized.
b) The operator removed the part from the machine before the completion of threading cycle.|2)a) The life time of the insert used was less than the defined life time of the tool.
b) The machine stopped for a warning raised due to external error for which the operator thought that the part was completed and removed the part. |3)a) According to the insert life monitoring the insert used was supposed to be worn out after 20 parts but this insert got worn before the completion of 20 parts.
b) The machine was stopped for low air pressure because of loss of air in the supply line.