A GT cell will machine the components for a family of parts. The parts come in several different sizes and the cell will be designed to quickly change over from one size to the next. This will be accomplished using fast change fixtures and downloading the part programs from the plant computer to the CNC machines in the cell. The parts are rotational type, and so the cell must be able to perform turning, boring, facing, drilling, and cylindrical grinding operations. Accordingly, there will be several machine tools in the cell, of types and numbers to be specified by the designer. To transfer parts between machines in the cell, the designer may elect to use a belt or similar conveyor system. Any conveyor equipment of this type will be 0.4 m. wide. The arrangement of the various pieces of equipment in the cell is the principal problem to be considered. The raw work parts will be delivered into the machine cell on a belt conveyor. The finished parts must be deposited onto a conveyor that delivers them to the assembly department. The input and output conveyors are 0.4 m wide, and the designer must specify where they enter and exit the cell. The parts are currently machined by conventional methods in a process type layout. In the current production method, there are seven machines involved but two of the machines are duplicates. "From to" data have been collected for the jobs that are relevant to this problem.

The from to data indicate the number of work parts moved between machines during a typical 40 hour week. The data refer to the parts considered in the case. The two categories "parts in" and parts out" indicate parts entering and exiting the seven machine group. A total of 400 parts on average are processed through the seven machines each week. However, as indicated by the data, not all 400 parts are processed by every machine. Machines 4 and 5 are identical and assignment of parts to these machines is arbitrary. Average production rate capacity on each of the machines for the particular distribution of this parts family is given in the table below. Also given are the floor space dimensions of each machine in meters. Assume that all loading and unloading operations take place in the center of the machine.

Operation 6 is currently a manual inspection operation. It is anticipated that this manual station will be replaced by a coordinate measuring machine (CMM). This automated inspection machine will triple throughput rate to 15 parts per hour from 5 parts per hour for the manual method. The floor space dimensions of the CMM are 2.0 m x 1.6 m. All other machines currently listed are to be candidates for inclusion in the new machine cell.
(a) Analyze the problem and determine the most appropriate sequence of machines in the cell using the data contained in the From To chart.
(b) Construct the network diagram for the cell, showing where and how many parts enter and exit the cell.
(c) Determine the utilization and production capacity of the machines in the cell as you have designed it.
(d) Prepare a layout (top view) drawing of the GT cell, showing the machines, the robot(s), and any other pieces of equipment in the cell.
(e) Write a one page (or less) description of the cell, explaining the basis of your design and why the cell is arranged as it is.

0 45 0 16 14 70 0 8 5 0 0 0| 6-53 20 23 23 0 00 31 0 000 2 2 10.-4-61 0 35 0 0 0 30 5 3-0 0 0 0 0 0 230 2100 82 73 1024 2400072 01 2 3 4 5 6 7 Machine Operation Tum outside diamet Bore inside diameter Face ends Grind outside diameter Grind outside diameter Inspect Drill Production rate 9 pc/hr 15 pchr 10 pchr 12 pc/hr 12 pc/hr 5 pc/hr 9 pchr Machine dimensions 3.5 mx 1.5 m 3.0 m x 1.6 m 2.5 m x 1.5 m 3.0 m x 1.5 m 3.0 m x 1.5 m Bench 1.5 m 1.5 m 1.5 m x 2.5 m er