Systematisk kvalitetsförbättring i en tillverkande industri : Förbättringsarbete hos Diplomat dörrar AB med avsikt att förstå problemen som uppstår när ny och gammal industri möts

Sammanfattning: Diplomat Dörrar AB is a company that produces doors for the Swedish market. Presently, there is a quality problem within the paint shop, which also happens to be a bottleneck. The quality problems within the paint shop means that roughly 15% of all painted doors are rejected and are forced to be repainted. To repaint a door comes with a large price tag for the company. The purpose of the work is to identify why doors are being rejected, as well as to propose actions to reduce the amount of rejections, to 7.5% This thesis uses different theories connected to quality development and production control. The main theories used in this report are Lean methodology, variation reduction, maintenance and process breakdown. By exploring these theories, it has been possible to propose actions to take in order to reduce rejections to 7.5%. The information and data that has been collected largely comes from interviews with paint shop employees, as well as preexisting data. However, it has become evident that the preexisting data has been flawed when it comes to raw data, which has not allowed the processed data to provide a clear picture. To combat this, new data collecting has been done, which has given a clear picture of which doors have been affected, which colors as well as where on the door the rejection was found. Presently, the most common forms of rejections are paint flaws, plastering flaws and debris. Paint flaws can be categorized in 4 main flaws, running paint, paint drop, bad coverage and craters. The flaws are caused by faults in the paint booth, where a robot paints the door. Plastering flaws occur because of the plastering staff have missed to plaster a flawed door, and debris flaws are caused because debris has been caught underneath the top layer of paint. All these flaws give the doors a visible defect when undergoing inspection. The faults when organized in size by number of total defects are as follows: Paint flaws – 44%, Debris – 24% and plastering flaws – 18%. This yields a total of 86% of the total rejections at Diplotmat Dörrar AB. An investigation has been done to identify the root causes of the chosen rejections. When it comes to paint flaws a few different root causes have been identified that all flaws share. The root cause for paint flaws is that almost all maintenance work is reactive, which leads to satisfactory doors being rejected because of a lack of maintenance work. The root cause for debris is the lack of instructions or responsibility to remove debris, removal of splinters as well as dirty rails in the paint shop. The reason for plastering flaws is due to the fact that there is no standardized working method when it comes to plastering. The actions that are recommended to Diplomat Dörrar AB are as follows: Create a standardized working method on all different stations as well as to implement a working preventative maintenance scheme in order to reduce rejections. Keywords: LEAN methodology, Standardized working method, Preventative maintenance