Improving the Quality of Book Printing Products through Six Sigma Approach that integrated with Experimental Design

Abstract

This research applies the Six Sigma (DMAIC) approach which is integrated with experimental design at 
the process improvement stage. The research was conducted at a book printing company. Three dominant defects were 
found in the book printing process, namely uneven cutting results (44.29%), uneven colors (32.8%) and torn books 
(23.82%). The sigma value measured at initial conditions is 2.172. The research was carried out by following the Six 
Sigma DMAIC stages, and in stage I (improvement) experiments were carried out by changing the cutting speed 
process parameters. The experimental design uses a completely randomized design with the engine speeds to be tested 
in the experiment being 50 RPM, 60 RPM and 70 RPM. The number of replications in the experiment was 10 times 
at each level. The number of levels is 3, so the total number of trials is 30 experiments. The treatment stage selected 
based on the Student Newmann Keuls Test was a level 2 experiment with an independent variable of 60 RPM. The 
sigma value obtained in the post improvement condition was 2.58 σ, an increase in sigma of 0.408 compared to the 
initial condition. The percentage of post-improvement production defects is 4.62%.