Production & Operations
Management
Session 3-2
More on Processes
1
Outline
Multi-product, multi-flow process analysis
– So far: 1 product, 1 flow
– Differing process times, yield issues, machine breakdown
Big Takeaway:
– Product-mix becomes critical in multiple flows
– Implications in capital investment, scaling business, and risk management Calculating capacity when you have
– Multiple flows
• With the same processing time at each resource
• With different processing times at a single resource
– Yield issues
– Machine Breakdown
2
Measure: Implied Utilization
Implied Utilization captures the mismatch between the capacity requested from a resource by demand and the capacity currently available at
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Processing time: 10 min / unit
10 mins
10 mins
10 mins
10 mins
10 mins
Flow Time (FT) = processing time= 10 mins for all units
Workstation capacity = Flow Rate
= (1/10) units/min*60 mins/hr = 6 units/hr
10
Ex. 2: Capacity with two processing times
Workstation makes two products
– Product 1 processing time 10 min / unit
– Product 2 processing time 12 min / unit
10 mins
10 mins
10 mins
12 mins
Product mix is 3:1, i.e. (3/4)th of the output is Product 1 and
(1/4)th of the output is Product 2
What is the capacity of the workstation?
11
Ex. 2: Capacity with two processing times
PT1=10 mins/unit
PT2=12 mins/unit
Think of a “typical” unit:
– Weighted average of FT1 and FT2
= (3/4)*10+(1/4)12=10.5 mins/unit
– NOTE THIS RELIES ON DEMAND MIX
Capacity of Resource
= (1/10.5)*60min/hr = 5.71 units/hr
Same as capacity of process because only one resource
12
Ex. 2 (Alternate way)
An alternate method is to consider time to make a cycle, i.e. 3 units of product 1 and one unit of product
2
– Total Processing Time for a cycle = 3*10 + 1*12 = 42 mins
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Ques 1: Draw a detailed process flow map of the current process at receiving Plant#1. What is the capacity of each operation in the process?
The following includes, the Drilling Capacity, which has a run time of 2.5 minutes per piece. Therefore, this produces a total of 384 units per machine, giving us a total of 960 minutes. In addition, providing that there are a total of 6 machines, thus giving us a total of 2,304 units. Moving forward, giving that we know that Drilling has a 75-reject rate, and thus providing us with a total of 162 units. Nevertheless, if we subtract the total amount of units produced from all 6 machines of 2,304 units with the 162 units, this will provide us with a new total of 2,142 units.
Determining capacity is a very important of company day to day operations as it considers whether the amount of work that a company is putting out is capable of meeting supply and demand. Management must make correct decisions that consider product mix issues, whether or not processes and capacity can be improved without adding risky staffing or machinery investments, how to avoid bottleneck areas and whether quality is at expected consumer standards (Vonderembse & White, 2013).
Draw the Flowchart 1996 Customer Receiving Status 24 Status 40 Status 41 Status 42 Status 20 Parts Supplier I (unit) 8000 500 1500 1000 500 405 500 2000 R (unit/week) 1000 1000 700 405 405 405 405 1000 T (week) 8 0.5 2.14 2.47 1.23 1 1.23 2 What was The Utilization Achieved by CRU in 1996? Utilization = (Inventoy on Rent)/(Total inventory by CRU) =8,000/14,405= 55.54% For 1996 , Calculate The Average Time Spent by a Unit in Each Buffer.
Q1: A manufacturer’s average work-in-process inventory for a certain part is 1,000 units. The workstation produces this part at the rate of 200 units per day. What is the average time a unit spends at this workstation? Inventory, , Throughput, . Thus, Flow time, . A unit spends an average time of 5 days at this workstation. Q2: The Wilcox Student Health Center has just implemented a new computer system and service process to “improve efficiency.” As pharmacy manager, you are concerned about waiting time and its potential impact on college students who “get no respect.” All prescriptions (Rxs) go through the following process: Drop-off ! Fill Rx ! Pick-up ! Cashier Assume that students arrive to drop-off Rxs at a steady rate of 2 Rxs per
A. 50 pieces per hour X 1/2 (30 mins) / 10 pieces per container = 2.5
To determine how much capacity we needed to add to the production process, we took the standard deviation in demand over the first 50 days (Exhibit 1). This allowed us to do a Newsvendor style calculation, at a two sigma confidence level, where we determined our production process should be set up to be able to successfully cater to an average demand of at least 19.24 . Even though this is actually the maximum expected figure we expect for demand (within a 95% confidence level), we felt that the system should be able to run without ever hitting utilization, and therefore should be able to handle its max demand load as if it were an average amount.
Since we knew the demand would average around 18 kits a day, we wanted to have enough capacity in the machines to handle the demand. We figured to calculate the demand capacity of each machines by looking at the level of utilization of each machines on day 1, when the very first order arrived. Using the percentage of utilization and the actual number of job coming in for the first time, we were able to calculate the capacity of each machine with relative accuracy. It was determined that machine 1 had the capacity of 4.5 jobs per day, machine 2 with capacity of 12.5 jobs per day, and machine 3 with capacity of 12jobs per day. This meant that in order for us to accommodate the expected level of demand, we needed to have five units of Machine 1, two units of Machine 2, and two units of Machine 3. We wanted to have five units of Machine 1 because we did not want to have just 4 and have 100% utilization, causing a bottleneck situation.
5) A process system is used to find an average cost per unit by dividing the cost by the total number of units produced, those units of output being nearly identical. A job-order
volume of production of individual products and level of overhead, activity-based costing allowsfinding individual relationships between volume of production and different overheads. It becomespossible due to combining overheads into cost pools and allocating these cost pools to products inproportion to selected cost drivers that reflect these individual relationships between volume of production and level of overheads.Wilkerson should pool overheads into five groups (cost pools): machine-related expenses, setuplabor cost, receiving and production control, engineering, packaging and shipment. The next step ischoosing most appropriate cost drivers that reflect the relationship between volume of productionof individual products and level of overheads. Machine hours are the most natural cost driver formachine-related expenses. Both setup and receiving, and production control activities are changedin proportion to number of production runs. Engineering cost can be allocated in proportion tohours of engineering work, whereas packaging and shipment activity is driven by the number of shipments
Correct The production manager for the Coory soft drink company is considering the production of 2 kinds of soft drinks: regular and diet. Two of her limited resources are production time (8 hours = 480 minutes per day) and syrup (1 of her ingredients) limited to 675 gallons per day. To produce a regular case requires 2 minutes and 5 gallons of syrup, while a diet case needs 4 minutes and 3 gallons of syrup. Profits for regular soft drink are $3.00 per case and profits for diet soft drink are $2.00 per case. For the production combination of 135 cases of regular and 0 cases of diet soft drink, which resources will not be completely used?
A) Effective scheduling, through lower costs, faster delivery, and more dependable schedules, can provide a competitive advantage.
* supply chain manager: negotiates contracts with vendors and coordinates the flow of material inputs to the production process and the shipping of finished products to customers
There are three initial portions of capacity planning and they are considered to be the productive, nonproductive and the idle. Productive capacity is where products are being produced well; Non-productive capacity is where the products are not being produced at that specific time such as when
The lean systems concept is a current trend in operations management. This involves taking a total system approach to creating an efficient operation. This includes concepts such as just-in-time (JIT), total quality management (TQM), continuous improvement, resource planning, and supply chain management (SCM).