Purpose – The purpose of the study is to explore how productivity can be improved in an assembly line in manufacturing industry. In order to fulfill the purpose, following three research questions have been formulated: 1. How can an assembly line be designed? 2. Which potential improvement areas can be found in an assembly line? 3. How can assembly line balancing be used to improve productivity? Method – A case study was performed in order to answer the research questions. A combination of quantitative and qualitative data have been collected. To build an understanding of existing theories and research within the study area, a literature study was conducted which formed a theoretical framework. Parallel to the literature study, empirical data was collected through a case study. Data collection methods included observations, document studies, time measurements and focus group meetings. The reviewed theories and the collected data were later analyzed and a result was generated. Findings – In order to improve productivity, Theory of Constraints enabled the identification of potential improvement areas. To address the improvement areas, Assembly Line Balancing was found an appropriate method. Through the case study it was found that through Assembly Line Balancing, a reduction of takt time can be achieved which opens up the possibility to increase the production volume. Also, when re-allocating operators between work tasks, a reduction in numbers of operators is possible which results in lower costs. By lowering costs and increasing production volume, improved productivity is achieved. Implications – This study presents an application of the two improvement methods Theory of Constraints and Assembly Line Balancing in a manufacturing industry. Therefore, the thesis can be used as a basis when performing improvement work related to reduction of takt time in other manufacturing industries, to gain a better understanding for the implementation of the studied methods. Limitations – One limitation of the study was the pandemic Covid-19, which enforced restrictions on the case company. This disturbed the conduction of the case study since less focus group meetings were conducted, and suggested improvements could not be tested. Another limitation was the limited study time frame. Consequently, the collected time measurements were relatively few and the study scope was delimited to only packaging activities. To increase reliability, a more extensive time frame is necessary. The analysis has been adopted to the situation at the case company. The conclusions may hence be biased, which could restrict to what extent the study can be generalized.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The conceptual design of a fixtureless reconfigurable automated spot welding system for manufacturing subassemblies for residential circuit breakers was investigated. This research was aimed at developing a possible low cost automation alternative to a South African industrial manufacturer, which is presently heavily dependent on personnel for manual assembly of their core products. System reconfiguration allows for the assembly of a range of subassemblies with geometric component variation on a given system configuration, as well as the potential for the system to be reconfigured to assemble other ranges of circuit breaker subassemblies. The subassembly selected as focus consists of six different components, which vary geometrically from one product variant to another. A fixtureless approach was selected, to minimise reconfiguration down time and the need for reconfigurable fixtures since reconfigurable fixtures have not found significant acceptance in industry. This varies from a fixture-based approach, which was considered in related research. The conceptual assembly system presented here consists of the following modules: a flexible vision based part feeder, twin 6 DOF robotic manipulators each with a multipurpose gripper, and a stationary spot welding station. Critical conceptual design elements were further investigated to refine their selection and confirm feasibility with respect to the target industry application. This process ended with a preliminary cost estimate which served as a basis for comparison between the fixtureless, fixture-based and present manual assembly process. The fixtureless concept was overall more expensive than the fixture-based concept, primarily because of the limits to production throughput. The fixtureless concept was however cheaper than the present manual assembly approach but had a far longer payback period than desired by the industry. The complexity and possible uncertainties of the concept combined with the long payback period indicated that the fixtureless concept is not suitable for the target application. / AFRIKAANSE OPSOMMING: Die konsepsionele ontwerp van 'n setmaatlose herkonfigureerbare outomatiese puntsweisstelsel vir die vervaardiging van subsamestellings van huishoudelike stroombrekers is ondersoek. Hierdie navorsing is gemik op die ontwikkeling van 'n moontlike lae koste outomatiese alternatief vir 'n Suid Afrikaanse industriële vervaardiger, wat tans sterk afhanklik is van werkers wat die montering van hul kern produkte met die handsamestelling doen. Stelsel herkonfigurasie laat die samestelling van 'n reeks subsamestellings, met geometriese komponentvariasies, op 'n gegewe stelsel toe, asook die potensiaal om die stelsel te herkonfigureer om ander reekse van stroombreker-subsamestellings te monteer. Die subsamestelling wat as fokus gekies is, bestaan uit ses verskillende komponente met geometriese verskille van tussen produkvariante. 'n Setmaatlose benadering is gekies ten einde aftyd vir herkonfigurasie en die noodsaaklikheid van herkonfigureerbare setmate te minimeer, omdat laasgenoemde nie noemenswaardig deur die industrie aanvaar word nie. Hierdie benadering verskil van 'n setmaat-gebaseerde benadering wat in verwante navorsing ondersoek is. Die konsepsionele monteringstelsel wat hier aangebied word, bestaan uit die volgende modules: 'n plooibare, visiegebaseerde voerapparaat; dubbele sesvryheidsgraad robotiese manipuleerders, elk met 'n veeldoelige gryper; en 'n statiese puntsweisstasie. Kritiese elemente van die konseptuele ontwerp is verder ondersoek om hul keuses te verfyn en uitvoerbaarheid in die teiken industriële toepassing te bevestig. Hierdie proses is afgesluit deur 'n voorlopige kosteraming wat gedien het as 'n basis vir die vergelyking van setmaatlose, setmaat-gebaseerde en die huidige handsamestellingstelsels. Die setmaatlose konsep was oorhoofs duurder as die setmaat-gebaseerde konsep, hoofsaaklik as gevolg van beperkings op die produksie-deurset. Die setmaatlose konsep was egter goedkoper as die huidige handmonteringsproses, maar het 'n veel langer terugbetalingstydperk as wat deur die industrie verlang word. Die kompleksiteit en moontlike onsekerhede van die konsep, gepaard met die lang terugbetalingstydperk, dui daarop dat die setmaatlose konsep nie vir die teiken toepassing geskik is nie.

published_or_final_version / Industrial and Manufacturing Systems Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Industrial Engineering / Master / Master of Science in Engineering

<p>The purpose of our master thesis was to investigate what motivates assembly line workers performing low-skill jobs in a small industrial laundry business. We wanted to see what fac-tors determine and influence their motivation to work and if and how this motivation can be improved with respect to assembly line systems in general. The method of our investiga-tion was qualitative in nature, where we studied one firm that leases clean bed clothes and textiles to hotels and restaurants around Sweden. We constructed a survey on motivation and handed it out to the assembly line workers who deal with the laundry. Furthermore, we interviewed the shift manager in order to get the company’s view on employee motivation. Our findings indicate that there are several overlapping factors that determine and influ-ence motivation in the long run. From this particular case we saw that a unified working culture and collective efforts both boost the willingness to work and help the process run smoothly. Furthermore, proper communication is motivating, where everyone should be committed to company goals, but the workers should be able to take part in profits, and not just generate them. Also, employees have to be considered as important as customers are. Another factor is to have the right resources to execute company plans, such as proper working techniques that minimise stress, injuries and frustration, and more responsibility that allows employees to see the whole system by learning about the technical aspects, or engaging in customer contacts. When trust builds up between the workers and the man-agement, there will be less need for a controlling boss, and people will be more motivated to work when they are not constantly monitored by their leader. In addition, more CEO visits are encouraged at plant level, because they send the signal that the company cares about all its employees. Finally, a crucial factor is feedback, where the firm should not only criticise, but praise everyone for a job well done. This way, the workers will feel worthy. When long term factors are weak or missing in the company, the only motivation for the people is money. However, money can work as a short term and a long term motivator be-cause it serves as a tool to satisfy needs of both security and self esteem outside work. Con-sidering motivation and assembly lines in general, when the assembly line is at its core, where efficiency is the goal and workers serve as means to get there, the only motivation is money, and possibly working colleagues. Intrinsic motivation can be reached by moving away from the actual system and performing other tasks. Still, the long term factors can improve the situation to a certain extent, but sooner or later everyone will turn into a well oiled machine with no further ways to improve motivation, since boredom and routines will remain. One goes from being a cog in the machinery to an integral part of a successful engine. It is still the same content, but in a different package.</p>

Detta examensarbete har studerat hur produktionsplaneringen av en manuell produktion/montering kan bli produktivare. Genom empiriskt material från fallföretaget och insamlade av relevant teori presenteras idéer om hur detta kan göras. Två viktiga slutsatser från detta arbete är att företag bör planera sin manuella produktion/montering längre tid i förväg och därmed möjliggöra för fler förutbestämda planeringsregler, det vill säga vilka produkter som produceras/monteras när. Dessa slutsatser har dragits utifrån aktuell och relevant teori om produktionsplanering av manuell produktion. Fokus i arbetet har dock legat på att testa om ett införande av ett Walking Workers Assembly Line - system (WWAL) i den manuella produktionen påverkar produktiviteten. För att testa hur införandet av WWAL påverkar produktiviteten har det i arbetet gjorts ett experiment i en manuell produktions-/monteringslinje, experimentet har bedrivits i flertalet veckor för att säkerställa resultaten. Resultaten från experimentet visar att införandet av ett WWAL-system påverkade produktiviteten positivt, totalt sett. Däremot visade experimentet att olika delar av den manuella produktionen påverkades på olika sätt, i en del av linjen påverkades produktiviteten positivt med cirka 40 procent och i en annan del negativt med cirka 9 procent. Dessa skillnader kan bland annat förklaras av att det uppstod ett så kallat rabbit chase i den ena delen, men inte i den andra. Vidare visar experimentets resultat att kostnaderna för att införa WWAL var noll, vilket står i strid med aktuell relevant teori. Teorin antyder också att det kan vara svårt att lyckas med WWAL när det gäller komplexa produkter, detta motsäges av experimentet som har gjort på en relativt komplex medicinteknisk produkt. Arbetet kommer också fram till slutsatsen att det kan vara viktigare att införa WWAL än att jobba med Lean till 100 procent, denna slutsats bygger till stor del på att införandet av WWAL var kostnadsfritt.

<p>U doktorskoj disertaciji obrađen je problem upravljanja montažnim<br />sistemima pomoću bežične senzorske tehnologije u cilju poboljšanja<br />efikasnosti proizvodnje i poboljšanja kvaliteta proizvoda. U okviru<br />ove disertacije je razvijen model bežičnog upravljačkog sistema za<br />upravljanje i nadzor industrijskih procesa. Glavni cilj istraživanja<br />je razvoj integrisanog sistema za praćenje pozicije radnog predmeta i<br />praćenje okolnosti u kojima se radni predmet nalazi u montažnim<br />sistemima. Rezultati istraživanja su potvrđeni eksperimentalnim<br />istraživanjem u laboratorijskoj i u realnoj industrijskoj sredini.</p> / <p>The dissertation deals with the problem of monitoring and controlling<br />industrial assembly lines by wireless sensor technology with the aim of<br />improving the efficiency of production and the quality of the product. A model<br />of a wireless controlling system has been developed for monitoring and<br />controlling industrial processes. The main focus of the study is the<br />development of an integrated system for monitoring the position of the<br />product and the influences on the product in the assembly lines. The results<br />are confirmed by experiments in a laboratory and real industrial environment.</p>

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Microfiche copy available in Archives and Engineering. / Includes bibliographical references. / M.S.

Orientador: Edson Luiz França Senne / Banca: José Roberto Dale Luche / Banca: Luiz Leduino Neto / Resumo: Neste trabalho propõe-se uma abordagem para o Problema de Balanceamento de Linhas de Montagem (do inglês, Assembly Line Balancing Problem - ALBP) para aumentar a eficiência de uma indústria montadora de veículos. O ALBP caracteriza-se como um problema de sequenciamento de tarefas em estações de trabalho classificado como um problema de Otimização Combinatória NP-difícil e, portanto, a solução exata do problema em ambientes reais geralmente implica em elevado custo computacional. Para resolver o ALBP, foram formulados um modelo matemático de otimização inteira mista para obtenção de soluções determinísticas e um modelo estocástico com recurso que considera a incerteza dos tempos de execução das tarefas pelos operadores. A motivação para o desenvolvimento do presente trabalho decorre da observação de interrupções constantes do fluxo de produção nesta indústria, atribuídas às mais diversas naturezas, e que causavam transtornos e elevados níveis de estresse aos trabalhadores. Ambos os modelos, determinístico e estocástico, aumentaram a capacidade de produção de 196 unidades/dia para 245 e 233 unidades/dia, respectivamente. O modelo estocástico aumentou o tempo de ciclo CT em 5,6% quando comparado ao modelo determinístico, embora diminua a capacidade efetiva em 4,8% Porém, não considerar a incerteza no tempo de execução das tarefas pode diminuir a quantidade produzida em até 10,6%. Contrariamente ao entendimento comum em linhas de montagem, este trabalho conclui que reduzir os tem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work proposes solution approaches to the Assembly Line Balancing Problem (ALBP) to increase the efficiency of a vehicle assembler industry. The ALBP is characterized as a task sequencing in workstations which is classified as a NP-hard Combinatorial Optimization problem and, therefore, the exact solution of the problem in real environments usually implies a high computational cost. In order to solve the ALBP, a mathematical model of mixed integer optimization to obtain deterministic solutions and a stochastic model with resource that considers the uncertainty of the execution times of the tasks by the operators were formulated. The motivation for the development of this work stems from the constant interruptions of the production flow in this industry, attributed to the most diverse natures, which cause disorders and high levels of stress to the workers. The deterministic and stochastic models increased the production capacity from 196 units / day to 245 and 233 units / day, respectively. The stochastic model increased the cycle time by 5.6% when compared to the deterministic model, although it reduced the effective capacity by 4.8%, which is equivalent to 12 vehicles / day. However, not considering the uncertainty in task execution times can decrease the amount produced by up to 10.6% or 26 vehicles / day. Contrary to the most acceptable idea, this work concludes that reducing idle times to minimum levels is detrimental to assembly line productivity. This is due to the ... (Complete abstract click electronic access below) / Mestre

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Michael P. Hennessey. / M.S.