Documenting Operations
Abstract
This report affirms that using a flow process chart is an effective way to describe work flow. In order to prove this, a multi-activity chart was used to describe parallel activities in a work system. Measurements indicated a decrease in process time through an improved operation workflow. Based on this experiment it is concluded that improved operation work flows increases production levels.
Introduction
The usage of flow process charts and multi activiey charts are important to manufacturers interested in decreasing their cycle time in production areas. This report proves the advantage of utilizing flow process charts by testing the time required to complete a simple sequence of manufacturing operaions and analyzing the process with the charts. The time improves after wasted time and unnecessary processes are identified by charts. For each operation sequence, the time the process required was measured and the conclusions are based upon the improvement in overall process time.
Materials and Methods
The materials necessary to complete this experiment include: a workspace, 3 cylinders, a cylinder altering machine, two bins, two tables and a stopwatch.
This experiment entails the following procedure:
- Measure the time required for one person to transfer one cylinder from the “Raw Materials” table to the workspace, then to assemble the cylinder componants, then to machine the cylinder, then to inspect the cylinder, to repeat this process on two more cylinders then to transfer all three cylinders to the “Inspected” table. This is Process 1.
- Document Process 1 on a Flow Diagram and Process Chart, a Multi-Activity Chart and a Man-Machine Chart.
- Measure the time required for one person to transfer all three cylinders from the “Raw Materials” table to the workspace, then to assemble one cylinder’s components, then to machine the first cylinder, then to assemble the second cylinder’s components, to machine the second cylinder while inspecting the first cylinder, to assemble the third cylinder, to machine the third cylinder while inspecting the second cylinder, to inspect the third cylinder then to transfer all three cylinders to the “Inspected” table. This is Process 2.
- Document Process 2 on a Flow Diagram and Process Chart, a Multi-Activity Chart and a Man-Machine Chart.
- Analyze the data collected and make suggestions for process improvement.
Results
Process 1 required 120 seconds to complete and the worker traveled 74 feet (App. A). During Process 1 the worker was idle for 22 seconds and the machine was idle for 81.2 seconds (App. B). The route traveled by the worker in Process 1 is shown in Appendix C. Process 2 required 90 seconds to complete and the worker traveled 42 feet (App. D). During Process 2 the worker was idle for 15 seconds and the machine was idle for 45 seconds (App. E). The route traveled by the worker in Process 2 is shown in Appendix F. The predicted time to complete the suggested Process is 61 seconds and the predicted distance traveled by the worker is zero feet (App. G).
Discussion
Process 2 was better than Process 1 because it utilized the worker’s idle time during machining for the worker to complete an additional task. The worker also spent less time in transportation by carrying all the cylinders to the workspace in one trip. The Process Chart gave the most information about time spent on each time and summarized the data for easy readability and comprehension. However, it was the multi-activity chart that illustrated the extreme amount of time the worker and machine were idle. This information made it easy to see that the sequence should be altered to minimize idle time. Since the machine is idle during all transportation times, transportation was reduced to one trip to each table. Since the worker is idle for all machining times, the process was changed to allow the worker to inspect the product during machining. In this case the flow diagram was a bit superfluous since the need to minimize travel time was so obvious on the other charts. After testing the second process the Process Chart showed the clear improvement in both time elapsed and distance traveled. The Multi-Activity Chart showed that the machine’s idle time is related to the distance the worker travels. The machine is never on unattended so the further the worker travels the longer the machine sits idle. The Flow Chart became important at this juncture showing the unnecessary distance the worker travels to get materials and drop off inspected products. Therefore, the suggested process recommends moving the “Raw Materials” table and “Inspected” table to either end of the work table. The worker would have all materials at hand and travel time would be non-existent. Once transportation is nonexistent, the worker will spend 100% of his/her time on operations and inspections. Reducing the number of steps in the process reduces delays, so delays in the suggested process (see App. F) are listed as half the delays found in Process 2. This is an approximation used to estimate the total process time, only testing would give an accurate total time. If repeated, this experiment would complete more iterations of each process and test the suggested process.
To me the Multi-Task Chart was the most useful to improving the operation sequence because it showed the amount of time each component of the process was idle. This chart also made it easy to see how processes could be combined to save time. The Process Chart was also important because it provided more information about the operation sequence like the type of action being performed and the distance being traveled to complete each step. The Process Chart also contains a very easy to understand summary that shows the advantages of the suggested improvements.
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