Politecnico Di Torino
1 Facolta' di Ingegneria
−−−Preliminary study of an automotive assembly plant for high volume production(1300cars/day with 2 type of cars, 4 doors and 2 doors respectivly, and flexible in volume, 3 shifts of workers)
Prof. COZZARI GIULIANO
1. General infomation from the internship
2.1 high production volume of the assembly plant
2.2 pace calculation
2.3 area calculation and process layout
2.4 flexibility and automization of the system
2.5 “make or buy” decision
2. Review of tutorials and further applications of the tutorial 3.6 General knowledges aquired from the assembly lecture 3.7 Extension of the tutorial
3.8.1 product breakdown structure(PBS) & bill of material(BOM) 3.8.2 work breakdown structure(WBS)
3. Time analysis and relative calculations
3.1 working time analysis(WCT, takt time)
3.2 system length and area calculation
3.3 facility layout
4. Tool and equipment selection
1. General infomation from the internship
1.1 high production volume of the assembly plant
As is define in the internship reoprt, the production volume of the plant that we study is 1300cars/day, with 3 shifts of workers making the planned working time up to 21 hour a day. We developed a rough plan for the entire assembly production process, and then divided our thesis into four parts according to the function of each part. Following the sequence of each part, they are respectively: Stamping process, body in white process, painting process and fianl assembly process. Normally each department is separated with one another, located in different locations inside an assembly plant, and each department has its own building structure, thus we call them stamping shop, body in white shop, painting shop and final assembly shop. Moreover all of these building structures are placed considering the convenience of the entire manufacturing process, to facilitate the flow of materials and parts, to simplify stocks management. For example, stamping shop normally locates near the gate with a stock area to facilitate the incoming of sheet metal. Body in white shop and painting shop lies in between final assembly shop and stamping shop, in order to shorten transfer process. Finally, final assembly shop often locates beside the supplier park, where massive subgroup parts of a car are stocked. 1.2 pace calculation
Since our focus is on the word “high volume”, we must estimate the overall pace of the plant. The required standard time can be calculated considering: 1. 1300 cars/day.
2. 3 shifts of workers with 7 availiable working hours per shift. 3. Overall equipment efficiency=90%
4. Standard time STn is the time needed to assemble a car, starting from pressing shop up to final test at final assembly shop.
AWT(available working time)=3*7*60=1260 min
STn=AWT/1300=0.97min=58sec. It means that each 58 seconds there will be a car coming out from the plant. 1.3 area calculation
The area calculation is decided in the internship report, through the benchmarking result of many plants and we chose the average area of the plants that is most close to our requirements. And here is the decision: Stamping
| Final Assembly
Usually the process layout is like this(I will only focus on the final assembly process): But for the final assembly, I find it more advanced for logistic and warehouse management is I choose the final assembly line like this: In my later discussion, we can see more advantages of this kind of solution according to the three main sub-processes of final assembly. 1.3 flexibility&automization of the system
Equipments are most devoted resource since nowadays factories are normally capital intensive. So we have...
References: 1.COZZARI GIULIANO, Assembly technologies,2010.
2.MARCO GOBETTO, Production Management,2010.
3. Mohammed A. Omar, “THE AUTOMOTIVE BODY MANUFACTURING SYSTEMS AND PROCESSES”, 2011
4. FILIP HELLMAN, BJÖRN LINDAHL, JONAS MALMBERG, thesis of “Mixed-model assembly line at Volvo Construction Equipment”
5. Marshall L. Fisher and Christopher D. Ittner, “THE IMPACT OF PRODUCT VARIETY ON AUTOMOBILE ASSEMBLY OPERA TIONS: ANAL YSIS AND EVIDENCE”
6. technical note five: FACILITY LAYOUT
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