APPLICATION OF RESPONSE SURFACE METHODOLOGY OF EXPERIMENTAL DESIGNS ON WELDING OPERATION SETTINGS TO REDUCE THE DEFECTS OF MINIATURE CIRCUIT BREAKER RATING 2 AMPERE

Abstract

High variability and rework are undesirable for companies which aspire to high efficiency including PT. CZ which manufactures Miniature Circuit Breaker (MCB). High defect number of MCB Rating 2 Ampere that are out of Auto Adjustment’s range of tripping time is due to various Distance B of Welding S1 caused by no standard for Welding S1 machine’s operation settings. Thus, Response Surface Methodology is applied to find the optimum combination to produce Distance B that must be within 27.4  0.4 mm. In 23 Full Factorial Design, three factors with two levels are investigated, upward-downward Distance between Lower Electrode and Jig Table (term A, 3.15 and 3.20 cm), Current (term B, 14 and 16 Ampere) and Welding Time (term C, 15 and 17 seconds). The held-constant factor is 1.0 cm of distance between upper and lower electrodes. First order design including interactions can be built up to second order design of Central Composite Face-Centered Design by adding center points and axial points. The appropriate model includes significant terms A, B, C, AA, AB and AC at significance level 10%. The optimum combination of operation settings’ levels producing 27.4 mm of Distance B is 3.175 cm, 14 Ampere and 16 seconds.