Assignment 1 rev1
0 likes70 views
The document details a study on the production process of stadium seats at the University of Southern Queensland, identifying inefficiencies in the current method involving six operators. It outlines the step-by-step operation from cutting steel pipes to painting the finished frames, along with time allocations and labor costs. Suggestions for improving productivity are to be discussed, including potential changes to the workflow, layout, and possibly adding a work cell with justifications based on existing constraints.
Assignment 1 rev1
- 1. MEC3204 Production Engineering S2,2015 1 Faculty of Engineering and Surveying, University of Southern Queensland MEC3204 – Production Engineering, S2, 2015 Assignment 1 – Marks 100/1000 Due: 04th September 2015 INTRODUCTION Work study The initial stage (Figure 1) of manufacturing of cushion seats for stadiums & public seating areas is the preparation of seat frames using hollow steel tubes (Figure 2). There is an increased demand for seats but the factory is not able to meet the present demand with the existing process set up. Due to this reason the management decided that a quick Method Study should be carried out on the initial stage of seat manufacturing for possible improvements of the productivity in that section. Present Method (a) Equipment 1. Pipe Cutter -_Circular saw Cut 4m long pipes to 500 mm long pieces and the ends of 500 mm parts to 450 corners (Fig 2) . 2. Welding – electric Arc Weld four cut 500 mm pipe pieces into a square shape (Fig2). 3. Bench Drill & Cleaning brush wheel Drill two holes of 10 mm dia on each 500 mm pipe part. (8 holes on the square frame) 4. Painting Equipment Clean the surfaces of square pieces and paint the square piece (b) Personnel Six operators are employed on the process. Operator one (Ops1) picks up 10 pipes (12 kg/pipe and 6.5 m long) at a time from the main storage and
- 2. MEC3204 Production Engineering S2,2015 2 transports them in a wheeled trolley to a cutting station. He then helps Operator two (Ops 2) to cut them in to 500m lengths (only 12 pcs from each pipe due to the allowance for cutting tolerance). Operator two cuts all ten pipes in to 500 mm pcs and then cuts two ends of each 500 mm long piece to 45 deg corners (Refer Fig 2). When Operator two finishes cutting the ends of 60 pcs of 500 mm long (cut to 45 deg), Operator one then transfers 60 pcs in a trolley to a welding station bin. Operator one pushes the empty trolley back to cutting station and then returns to storage for next 10 pipes. Ops 1 returns with the next load of 10 pipes and wait for Ops 2 to finish last 60 pcs. Then Ops 1 transports 60 pcs to a welding station bin and returns with the empty bin and helps Ops2 to cut the pipes. Operator 3 (Ops 3) welds the corners of the four pieces of 500mm long pipes (corners cut to 45 deg) in to a square shape and puts them in the out bin (trolley). When Ops 3 finishes 15 pcs (4 X 15pcs =60 pcs) of squares then Ops 3 signals Operator 4 (Ops 4) at the drilling & cleaning bench. Operator 4 pushes an empty trolley to the welding station and takes finished squares in the out trolley to drilling bench. Operator 4 places each square frame in a drilling jig and drills two holes on each leg (total 8 holes) of the square frame and Operator 5 (Ops 5) cleans the frame using the cleaning wheel. When finished 15 pcs, Ops 4 transfers frames to the inspection bench and returns with the empty trolley from the inspection bench. Operator 6 (Ops 6) picks up frames from the inspection bench and paints the frame. Finished frames are hanging on a wheel trolley. Each trolley can have 15 frames. Once finished Operator 6 pushes the trolleys to the drying area.
- 3. MEC3204 Production Engineering S2,2015 3 (c) Method of operation The following flow process charts have been prepared and show the exact methods and element times. (i) Worker type, Operators 1 Chart begins – Operator 1 pickup pipes from the storage Chart ends – Operator 1 returns to storage Pick up ten pipes from the storage O 8.7 min Push the trolley back to cutting station T 5 min Transport finished 60 pcs (previous) to welding & return With empty trolley T 2 mins Help Operator 2 for cutting O 5 min Wait until Operator 2 finish 60 pcs D Transport finished 60 pcs to welding & return With empty trolley T 2 mins Return to storage for next 10 pipes T 3 mins (ii) Worker type Operator 2 Chart begins – Operator 2 start cutting pipe Chart ends – finish last 500 mm piece Cut a 6.5 m long pipe into 12 X 500 mm pieces O 5 min Cut two ends of 120 pcs to 45 deg corner O 32 min Wait for next 10 pipes D ?
- 4. MEC3204 Production Engineering S2,2015 4 (iii) Worker type Operator 3 Chart begins – Receive 60 pcs and Operator 3 start welding 4 pcs Chart ends – finish last 500 mm piece Operator 3 pickup 4 pcs & place in the jig O 0.08 min Weld corners & put in out trolley O 0.5 min Repeat the procedure 15 times O Wait for next lot D (Each hour Operator 3 takes 5 mins break) (iv) Worker type Operator 4 & 5 Chart begins – Receive 15 pcs and Operator 3 starts welding 4 pcs Chart ends – finish last 500 mm piece push empty trolley to welder T 0.03 min pull the trolley with 15 frames T 0.03 min fix one frame in jig and drill 8 holes O 0.7 min Remove from the Jig polish the frame O 0.8 min Put finish frame in out trolley O 0.01 min Repeat procedure for 15 times O Push out trolley to inspection desk & Back with the empty trolley T 0.08 min Wait for next lot D
- 5. MEC3204 Production Engineering S2,2015 5 (v) Worker type Operator 6 Chart begins – Pick up inspected pcs from inspection desk Chart ends –push the trolley to drying area Operator 6 Pick up the frames from Inspection desk T 0.06 min Hang one frame on painting hook O 0.01 min Paint the frame (one at a time) O 0.3 min Remove painted frame hang on the trolley T 0.01 min Repeat the procedure until frames are finished O Push the trolley to drying area T 0.3 min Wait for the next lot D (vi) Material Type Chart begins – From the main storage Chart ends – Drying area waiting for pick up to by assembly Main storage S Pick up 10 pipes and placed in a trolley O 8.7 min Ops 1 Transport to Cutter T 5 min Ops 1 Cutting into 120 pcs (10 pipes) O 5 min Ops 1 & 2 Cutting ends to 45deg corners O 32 m Ops 2 Transport to Welding station T 2 min Ops 1 (1 trips) Weld in to squares O 17.4 min Ops 3 Transport for drilling T 0.06 min Ops 4(2 trips) Drilling 8 holes/frame for 60 frames O (21 min) Ops4 Polishing frames O 24 min Ops5 Transport to Inspection Desk T 0.08 min Ops 4 (2 trips) Inspection #
- 6. MEC3204 Production Engineering S2,2015 6 Transport to painting shop T 0.06 min Ops6 (2 trips) Put on the painting hook (30 Nos) O 0.3 min Ops 6 Painting (30 Nos) O 9 min Ops 6 Put on drying trolley O 0.3 min Ops 6 Transport to drying area T 0.6 min Ops 6 (2 trips) NOTATION: Storage (S) Operation (O) Inspection (#) Transport (T) Temporary storage or delay (D)
- 7. MEC3204 Production Engineering S2,2015 7 General Information: a. The frame manufacturing section operates 7.30 am to 5.00 pm every week day. It closes on Saturday and Sunday. Workers get 30 mins for lunch break and 15 mins per break for the morning tea and the afternoon tea. b. Each worker has been trained in every work type and capable of working in any work cell. c. Management will consider any suggestion i.e. employing an additional worker or adding a work cell but with the same existing type of equipment. However, in this Study they only add an operator and/or a work cell, if the additions can be strongly justified on the basis of significantly increased productivity. No automation or improved material handling equipment will be considered at this stage. d. At the moment Ops 1, 2, 4, 5, are paid at the rate of $16.45/hr and Op3 receiving a higher rate $22.50/hr. No suggestions for increases of wages or other additional payments will be considered by the management at this stage. e. The layout of the work cells may be changed except the painting and drying stations. However, strictly no major constructions or change of factory building layouts will be considered by the Management. f. Management may consider a rotation of workers in operations on logical manner quarterly, if justifiable on the human factors and workers satisfaction (expected). Your Task: Use relevant symbols for your charts, not the abbreviated notations such as O, T, # etc You may estimate missing dimensions in Figure 1 List all the assumptions with a short justification.
- 8. MEC3204 Production Engineering S2,2015 8 (a) Present method: I. Develop a flow process chart for each worker type, material type and equipment type for present method. (10 Marks) II. Develop multiple activity charts for Operators 1 to 6 and materials for the present method. (10 Marks) III. Determine actual time taken per finished frame using the present method and estimate the total labour cost per finished frame. (10 Marks) IV. Estimate present annual output of the frames based on 220 days/year (10 Marks) (b) Critical analysis for improvements and development of a new method: V. Briefly (not more than two A4 pages) discuss your suggestions (preferably in point form) with a valid arguments based on logical and doable within present constraints. Show your changes of factory floor lay out (if any) graphically in neat sketches and calculation in clear steps with detail. You may use additional page for a new floor layout. (20 Marks) VI. Repeat I to III tasks for your proposed method. (24 Marks) VII. Estimate the saved time, annual output and improved productivity. (10 Marks) VIII. In a half A4 paper give an abstract of what you would do to improve the productivity of this factory floor using $50,000 (or less) capital improvement with a hope to recover it within 3 years based on real life situation at present. (6 Marks) Use standard (appropriate) chart types and analysis shown in the “Study Book” Chapters 5,6,7 and 8. Please reference properly if you use other published materials.
- 9. MEC3204 Production Engineering S2,2015 9 15 m 24m 5 m 3m 3m 4m Pipes in Trolley Output/Input trolleys Cut pipe pcs & frames Output/Input trolleys Painted frames 2.8 m Openning 2.8mopenning (Not to a scale) Cutting Bench Welding Bay Drilling & Polishing Bench Inspection Bench Painting Bay Main Storage about 20 m away from this Bldg. 20m Drying Area Drying Area Figure 1. Floor Plan (You are permitted to estimate missing distances)
- 10. MEC3204 Production Engineering S2,2015 10 500 mm 25mmID2.6mmthicksteelpipes 45 deg Figure 2 Cut pcs. and a frame