Question

IE212-LEAN PROCESS

Suppose that we have a process that produces two types of an item: Blue Item and Orange Item. Both of the items require the same pure sequential operations: O1, O2, O3. O1 and O3 are manual operations. O2 is the main and an automated operation which differentiates the items (e.g. gives different colors). Operation 1 takes 1 minutes per item. It is a manual operation that is common to both types. Operation 2 takes 4 minutes per item. It is an automated operation. Operation 3 takes 2 minute per item. It is a manual operation that is common to both types. Draw the GANTT Chart, calculate the flow time, cycle time, throughput, value added time and waste when the setup time for machine 2 where the Operation 2 occurs is 2 minutes and the batch size is 3 items per batch.

Answer 1

As per the given information:

The process produces two types of an item:

• Blue Item
• Orange Item

Both of the items sequential operations: O1, O2, O3

• O1 and O3 are manual operations
• O2 is the main and an automated operation
• O2 gives different colors)
• Operation 1 takes 1 minutes per item (common to both types)
• Operation 2 takes 4 minutes per item
• Operation 3 takes 2 minute per item. (common to both types)
• Set up time when Operation 2 occurs: 2 minutes

With the given information, the GANTT chart is drawn as below:

		Cycle1 for 1st Item	Cycle2 for 2nd Item	Cycle 3 for 3rd Item
Activities	Minutes	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27
Operation 1	1
Set up Machine 2 for Operation 2	2
Operation 2	4
Operation 3	2

Flow Time = Total time to produce all three products of single batch

      = Total Set Up time + Total Processing/Operational time = 27 minutes

Cycle Time = Average time to produce each items, whereby processes are repeated = 9 minutes

Throughput = Items produced by the process in a given time, it is inverse to cycle time

                   = 60/9 = 6.7 items per hour

Value added time = It is the processing time = 7 minutes per cycle = 21 minutes per batch

Waste Time = The non processing time, which may otherwise should be eliminated to improve process efficiency, i.e. reduce the cycle time and thereby the entire flow time.

Here Waste time is actually the Set up time required each time of Operation 2 by Machine 2.

= 2 minutes per cycle = 6 minutes per batch