QUALITY AND RELIABILITY ANALYSIS OF LATHE MACHINE MECHANICAL WORKSHOP STATE POLYTECHNIC OF MEDAN THROUGH STATIC GEOMETRC TEST ACCORDING TO ISO 1708 STANDARD

Abstract

The purpose of this study was to determine the condition and accuracy of the lathe through static geometric tests according to ISO- 1708 standards. The tests include measuring the level of the machine base, sloping straightness towards the horizontal plane, alignment of the motion of the loosehead in the horizontal and vertical planes, accuracy of the main axis, alignment of the supporting shaft launchers to the movement of the nose spindle irregularities, alignment of the nose spindles and alignment of the main axes in horizontal and vertical directions. Tests are carried out by measuring the quality and reliability of the machine to find out how many accuracy deviations that occur in the main part of the lathe. Quality measurements using a precise measuring instrument that is the spirit level, dial indicator, micrometer, and supporting flashlight and mandrel shaft. The results achieved from this study indicate that the condition-, and the quality of the lathe Maximat V13 and the Celtic I4 lathe at the mechanical workshop have decreased. Only 50% of machines can still be operated. The components contained in each engine have been damaged and incomplete. For the number of 7 Maximat V13 lathes, the condition is not optimal, only 3 units of the machine still operate and its reliability has decreased. The results of the inspection of the main parts such as the fixed head, speed control lever, speed control lever, screw movement control lever, machine base, and longitudinal slides are still good but the other parts are damaged and incomplete. For the number of 6 Celtic14 lathe units, 3 machines were still in operation and the engine components were still complete while 3 other machines were damaged and incomplete. This machine condition will affect the quality of the products and the time of machining process practices and for producing precision products.