Process Capability Study and Identification of the Causes of Defects and Rejections in Galvanization Line of Corrugated Sheet Production Case on: Adama steel factory (ASF)

Abstract

The process capability measurement is an important aspect in quality management to decide whether a process is capable of meeting the required specifications. The main objective were to study capability of the process and identify the possible source of defects and rejections in galvanized sheet production line and provide recommendations. The study has done through collected and analyzed sample data with the application of Microsoft excel and Minitab software to determine the capability of process, applied statistical quality control tool in order to determine the cause and rate of defects and examine the quality of different products using process capability indices. The result showed that the manufacturing process was incapable and in acceptable in both parameters of coating thickness and weight according to Thumb law and six sigma principle; all the values of indices and ppm were out of standard value. All indices values were less than 1.33 and 1.67 and ppm was much greater than 2700 (cp 1) and 0.545 (cp>1.5). The analyzed data, the mount of defects and rejections 3.23% and the overall profit losses are 74,724,240 birr due to the occurrences of different causes of defects and process variations.

The Process Capability Measurement Is An Important Aspect In Quality Management To Decide Whether A Process Is Capable Of Meeting The Required Specifications. The Main Objective Were To Study Capability Of The Process And Identify The Possible Source Of Defects And Rejections In Galvanized Sheet Production Line And Provide Recommendations. The Study Has Done Through Collected And Analyzed Sample Data With The Application Of Microsoft Excel And Minitab Software To Determine The Capability Of Process, Applied Statistical Quality Control Tool In Order To Determine The Cause And Rate Of Defects And Examine The Quality Of Different Products Using Process Capability Indices. The Result Showed That The Manufacturing Process Was Incapable And In Acceptable In Both Parameters Of Coating Thickness And Weight According To Thumb Law And Six Sigma Principle; All The Values Of Indices And Ppm Were Out Of Standard Value. All Indices Values Were Less Than 1.33 And 1.67 And Ppm Was Much Greater Than 2700 (Cp 1) And 0.545 (Cp>1.5). The Analyzed Data, The Mount Of Defects And Rejections 3.23% And The Overall Profit Losses Are 74,724,240 Birr Due To The Occurrences Of Different Causes Of Defects And Process Variations.