Summary
The Report addresses the layout concerns for New England Foundry Inc, manufacturer of woodstoves and related products. The company has been witnessing a dramatic increase in the sales of their products due to the soaring energy prices coupled to the cost saving features offered by their best selling product, Warmglo III. In order to satisfy this increase in demand, the company does not want to compromise on the quality of the brands it supplies to its customers.
The management at New England Inc, experiencing expanding sales have proposed the option of building a new facility to manufacture their star product warmglo III and related accessories like warming shelves, surface thermometers, and stove pipes etc. which enhance the stove features.
The report analyses the benefit of the proposed layout in terms of time saved per trip, per hour, when compared to the current layout. A cost analysis has also been carried out to find the Net savings that can be achieved with the proposed layout, which would help in better understanding of the new layout’s feasibility.
Introduction
New England foundry Inc has been manufacturing wood stoves and related products, for home use, under different brands specific to the features they are built in with, in terms of heat output delivered and the accompanying accessories. Warmglo III is the most attractive heat efficient stove and includes features like a thermostatically controlled primary intake valve which automatically adjusts itself to produce the correct heat output under varying weather condition.
In order to better understand the layout a brief of the stove manufacturing process has been included.
The Manufacturing Procedure
The Wooden patterns, supplied by Precision patterns Inc are stored in the pattern shop and maintenance room. Specially formulated sand is molded around the wooden pattern in the molding room. Once the wooden patterns are removed the molds are sent to the casting room, where molten iron is poured into the molds. When the iron solidifies the molds are removed into the cleaning, grinding and preparation room. Before being painted the castings are subjected to sandblasting to remove excessive sand and grinding to finish some of the surfaces of the castings. The castings are then assembled into stoves, inspected for defects and then finally moved to storage and shipping to be sent to appropriate locations.
Layout study
Irrespective of the new layout design the casting operations is almost unchanged. The evident changes in the layouts have been included, along with their Queuing models, characteristic nature to find how much time the new layout will save on comparing with the old layout.
Current layout
As seen in the figure below the pattern shop and the maintenance department are located in the same room. One large counter is being used by Peter and Bob to serve people from the pattern shop and the maintenance department respectively. It takes a total travel time of 6 mins for the maintenance personnel, and 2 minutes total for molding personnel to walk to and from their respective departments.
Characteristics of the old layout
1) Arrivals: the size of arrivals is infinite as there is no limit to the number of people that can be served by both Bob and Pete. The arrival rate for both the layouts is 4/hr from maintenance and 3/hr from the molding department, establishing a Poisson distribution given by
P(X)= (e-??x/X!)
The arrival behaviour of the people involves no balking and reneging. This arrival probability distribution is denoted by M (Markowian)
2) Queue: the length of the queue is infinite, as the size is unrestricted. Both Bob and Pete observe the First-in First out (FIFO)queue discipline to serve people in a single line
3) Service: the number of serving channels(S) is two i.e. Pete and bob, through a single phase serving system. Both bob and Pete can serve 10 people/ hr establishing an exponential probability distribution given by
P(t)=e-ut for t =0
The service time probability distribution is denoted by M (Markowian)
Proposed layout
As seen in the figure below the proposed layout has the pattern shop and the maintenance department separated. The waiting lines are converted to single-server, single-line operations i.e. the number of servers is 1. Bob can now service 6 maintenance people per hour, while the arrival rate is 4 per hour. Pete can serve 7 molding people per hour while the arrival rate is 3 per hour. It takes a total travel time of 2 mins for the maintenance personnel, and 2 minutes total for molding personnel to walk to and from their respective departments.
The queuing features for both layouts correspond to the M/M/S queuing model with the following additional assumptions:
- Arrivals are independent and follow a Poisson distribution
- Service times are independent and follow an exponential service time distribution.
- Average service rate exceeds average arrival rate.
- Number of Servers (S) for old layout is 2, while for new layout is 1.
Layout Analysis
Solving the M/M/S queuing model for the old layout (Appendix-1) we observe that the average time that a person spends in the system is W = 0.3922 hours, or 23.5 minutes. As the maintenance personnel take a total travel time of 6 minutes, and 2 minutes total for molding personnel, the total trips take 29.5(23.5+6) minutes for maintenance and 25.5(23.5+2) minutes for molding.
Whereas under the new layout (Appendix-2) the average time spent in Bob’s department is W= 0.50 hour, or 30 minutes. The travel time is 2 minutes, making the total trip time 32(30+2) minutes, an increase of 2.5 minutes per trip for the maintenance personnel. The average time(Appendix-3) in Pete’s department is 0.25 hour, or 15 minutes. The travel time is 2 minutes, making the total trip time 17 minutes. This is a decrease of 8.5 minutes per trip for the molding personnel.
Cost analysis
Assuming the maintenance personnel are paid $9.50/hr and the moulding personnel are paid $11.75/hr the savings at the new facility are calculates as
Maintenance Department
Minutes lost per trip 2.5
Minutes lost per trip2.5 Cost of minutes lost, to the company [(2.5/60)($9.50) = $0.39
Molding department
Minutes saved per trip 8.5
Cost of minutes saved, to the company [(8.5/60)($11.50) = $1.66
The net savings is $1.66 – $0.39 = $1.27 per trip, which is not a major saving.
Conclusions
New England foundry, with its new layout would only be saving $1.27 per trip considering a vast cost that the company would incur in building this layout. Therefore options like modifying current layout, other factors not included in the layout studies like new automated manufacturing machines should be considered and careful analysis should be made before a final decision is made.