Optimering av processflöde: Tvätt, montering och provning
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Bosch Rexroth Mellansel is a manufacturer of hydraulic drivesystems for industrial applications. One part of this solution is the hydraulicmotors known as the Hägglunds-engine. Five engine families are manufactured indifferent sizes and for different applications. The purpose of this project wasto investigate four questions regarding three connected steps in themanufacturing of these engines. These steps were washing, assembling andtesting. The desired outcome of the project was to determine the weakest linksin the production steps, increase the understanding of the process and a coupleof improvement suggestion to increase efficiency of the process. The fourquestions were:· What problems and challenges does each part ofthe process have?· Which are the bottlenecks in the process?· What is the reason for any variations in theproduct flow?· What is the capacity for the product flow?Additionally any suggestions for improvements of the productflow were to be investigated.The following paragraphs describe the results derived duringthe project.What problems and challenges doeseach part of the process have?The most common and most serious problem for the washingstep was the internal delivery delay from manufacturing which daily causedinability to follow the planned production schedule. The study that was madeshowed that 75 % of the identified disturbances in the washing step were causedby internal delivery delay.The most common disturbance in the assembly line was issueswith quality which accounted for 50 % of the discovered disturbances. Examplesof the incidents were insufficient quality of bought components, re-assemblingof motors because of leakage and insufficient marking of components.In the testing step the identified issues were machinefaults, problems downstream and other errors. These faults each accounted foraround 30 % of the incidents. The most severe of these were the issues with thetesting equipment and especially the test bench of the CBM-motors. Problemsdownstream were caused by issues in the painting workshop and during periodsthis caused a massive build up of tested motors at the testing site. The othererrors category was almost exclusively CBM-motors missing paint covering capsand therefore couldn’t be painted.The overall biggest problem was the internal delivery delayswhich accounted for 61 % of the serious problems encountered.Which are the bottlenecks inthe process? Discrete eventsimulation with the program Simio was utilized to investigate this question.Two different cases of production were investigated, quarter 4 2014 and quarter4 2011. The result can be seen in Tabell1.What isthe reason for any variations in the product flow?Primarily it was investigated if variation in workload couldbe found in the flow. This was done by doing a day to day comparison of theworkload during quarter 4 2014 and calculate the standard deviation for theperiod. A standard deviation of 15 percentage point was found which indicatedthat issues with variations in workload existed.To investigate if the reason was the internal deliverydelays a comparison was made between the standard deviation of workload in twocases. The first was calculated by using the planned start date of productionand the second by using the actual start date of production. The result showedan increase of the standard deviation by 16.3 % when using the actual startdates. This showed that the reason of the variation in workload was at leastpartially because failure to follow schedule.What is the capacity of the product flow?The capacity of the workflow was measured by using theearlier made model in Simio. The product mix of quarter 4 2014 was utilized andthe production rate was ramped up until the model no longer could keep up. Theaverage capacity of the production line can be seen in Tabell2.
Place, publisher, year, edition, pages
2015. , 30 p.
Teknik, Simio, Bosch Rexroth
IdentifiersURN: urn:nbn:se:ltu:diva-47574Local ID: 519e0621-68f1-4499-97c4-ea54328ccdeeOAI: oai:DiVA.org:ltu-47574DiVA: diva2:1020901
Subject / course
Student thesis, at least 30 credits
Mechanical Engineering, master's level
Validerat; 20150628 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved