Operations Management Session 4 PDF

PRODUCTION & OPERATIONS MANAGEMENT SESSION 04 MANAGEMENT OF PROCESS  PROCESS ANALYSIS: DEFINITION & SCOPE Process analysis utilizes some analytical mechanism to understand the impact of Process design on output, cost or any other performance met...

PRODUCTION & OPERATIONS MANAGEMENT SESSION 04 MANAGEMENT OF PROCESS  PROCESS ANALYSIS: DEFINITION & SCOPE Process analysis utilizes some analytical mechanism to understand the impact of Process design on output, cost or any other performance metric Alternative process configurations on the chosen performance metric  ISSUES IN PROCESS ANALYSIS Do I have adequate number of resources to meet the demand? If I need to add some extra resources where should I add? What is the utilization of my resources? If I need to increase the capacity of my system how should I modify the process? Should I add some more resources? What will the cost of my operation? One can find answers to the above questions by process analysis  PROCESS ANALYSIS ISSUES FOR MTS From a process and capacity analysis perspective MTS is related to mass production systems. The relevant questions for process and capacity analysis are: What is the productive capacity of my process per shift or per day? Where is the bottleneck for this process? If I need to increase the capacity of the process at which stage of the process should I invest? Can I improve the productive capacity by other means than investing in new resources?  PROCESS ANALYSIS ISSUES FOR MTO The relevant questions for process and capacity analysis are: When will this order be executed?  PROCESS FLOW CHARTING Design & Analysis of process begins with identification of activities that constitute the process time taken for each of the activity nature of flow of materials/information in the process. A pictorial representation of all these information could be developed using process flow charting. Process flow charting employs a set of standard symbols and graphical tools to represent all the information pertaining to the process The symbols used are A step in the Process Transportation (Move) Storage or Inventory  A SIMPLIFIED PROCESS FLOW CHART: CASE OF SHIRT MANUFACTURING Inventory of Cloth & Other WIP materials Inventory Stitching 1 Spreading Cutting Stitching 2 Pressing & Assembly Inspection Inventory of Shirts  PROCESS ANALYSIS: PERFORMANCE METRICS Throughput time Throughput time (TPUT) is the elapsed time from the first stage of the process to the last stage of the process. It is also known as lead time. Cycle Time Cycle time is the elapsed time between two successive output from a process that is continuously operating in a given period of time. Bottleneck That stage of the process that dictates the output of a process is the bottleneck. TPUT is a relevant measure for MTO systems. Measures such as Cycle Time and Bottleneck are relevant in the case of MTS systems.  PROCESS ANALYSIS: TOY MANUFACTURING A toy manufacturer receives crafted toys from local carpenters and performs the final operations before stocking it for sale. The process consists of five steps. The first step is to arrange a set of four toys in a pallet (8 minutes). After this, the pallet moves to the next station where the toys are pre-treated (12 minutes). This is to increase the toys’ life, prevent them from attacks of pests in the future, and also to improve the effectiveness of the painting operation. The next step is to send it to the spray-painting chamber, where it is painted as per specifications (20 minutes). At present, there is one spray painting machine. After painting, it is left in an open area for drying (10 minutes). The painting process and the pre-treatment process are specialised so the paint dries quickly. Finally, the toys are inspected and packed (5 minutes). 1. What is the throughput time for this manufacturing process? 2. Identify the bottleneck for this process. 3. What is the cycle time for this process? 4. What is the productive capacity of the process? PROCESS ANALYSIS: TOY MANUFACTURING Inspect & Prepare Pre-treat Paint Dry Pack 8 minutes 12 minutes 20 minutes 10 minutes 5 minutes The throughput time for the process is 55 minutes The spray painting is the bottleneck in the process Cycle time is 20 minutes. The implication of this is that when the process operates in a continuous manner, a pallet of finished toys come out every 20 minutes. PROCESS ANALYSIS: A GRAPHICAL REPRESENTATION Every batch of four toys come out exactly in an interval of 20 minutes which is the cycle time for the process PROCESS ANALYSIS: PRODUCTION CAPACITY OF THE SYSTEM Inspect & Prepare Pre-treat Paint Dry Pack 7.5 pallets/hr 5 pallets/hr 3 pallets/hr 12 pallets/hr The system can produce at the rate of 3 pallets per hour (12 toys) For a 8 hour operation the daily production is 24 pallets (96 toys) Capacity is unbalanced across different stages of the process  PROCESS ANALYSIS: TOY MANUFACTURING Suppose the preparation process has two parts to it. The first part is the setting up of the pallets, which requires 4 minutes, and the second part is the actual time of loading the pallet with toys. Each pallet consisting of four toys requires 4 minutes to load. Furthermore, the painting booth can hold up to three pallets during spraying operation. There are enough pallets available in the system. Given the additional information, examine the capacity of the system under the following conditions: (a) The revised process will spray two pallets at a time. (b) The revised process will spray three pallets at a time. (c) There are two pre-treatment stations available. What are the main inferences that one can draw from the exercise? PRODUCTION CAPACITY UNDER VARYING BATCH SIZES Existing Scenario: Batch Size of the Process = 1 pallet Inspect & Prepare Pre-treat Paint Pack (8 minutes) (12 minutes) (20 minutes) Dry (5 minutes) 7.5 pallets/hr 5 pallets/hr 3 pallets/hr 12 pallets/hr Scenario 1: Batch Size of the Process = 2 pallets Prepare Inspect & Pre-treat Paint (4+ (2*4) = Pack (12 minutes) (20 minutes) Dry 12 minutes) (5 minutes) 5 pallets/hr 6 pallets/hr 10 pallets/hr 12 pallets/hr Scenario 2: Batch Size of the Process = 3 pallets Prepare Inspect & Pre-treat Paint (4+ (3*4) = Pack (12 minutes) (20 minutes) Dry 16 minutes) (5 minutes) 5 pallets/hr 9 pallets/hr 11.25 pallets/hr 12 pallets/hr PRODUCTION CAPACITY UNDER VARYING RESOURCE AVAILABILITY Existing Scenario: Batch Size of the Process = 1 pallet, 1 painting booth Inspect & Prepare Pre-treat Paint Pack (8 minutes) (12 minutes) (20 minutes) Dry (5 minutes) 7.5 pallets/hr 5 pallets/hr 3 pallets/hr 12 pallets/hr Scenario 1: Batch Size of the Process = 3 pallets, 2 pre-treatment stations Pre-treat (12 minutes) Prepare 5 pallets/hr Inspect & Paint (4+ (3*4) = Pack (20 minutes) Dry 16 minutes) (5 minutes) Pre-treat 9 pallets/hr 11.25 pallets/hr 12 pallets/hr (12 minutes) 5 pallets/hr  PROCESS ANALYSIS: SOME IMPORTANT OBSERVATIONS Batch sizes play a crucial role in determining the bottleneck of a process As several choices are made with respect to the resources and batch size bottleneck shifts from one stage of the process to another. This is referred to as wandering bottleneck. A process analysis exercise often leads to the issue of improving the process