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end of the chapters in the Fourth Edition of Facilities Planning. When a question or problem is open-ended, either no answer is provided or guidance is provided . Request PDF on ResearchGate | On Dec 15, , Ralph Riedel and others published Facilities planning – 4th edition by J.A. Tompkins, J.A. White, Y.A. Bozer. Tompkins/White/Bozer/Tanchoco is the leading facilities planning book on the market, today. Its blending of breadth and depth of coverage are unmatched.
A project to evaluate existing dock area, including receiving and shipping, will allow the determination of those aspects that can potentially prove economically advantageous. A typical layout is depicted below. In direct putaway systems, the staging and inspection activities are eliminated, saving the time, space, and labor associated with those operations. Aisles must be wide enough to accommodate customer traffic in both directions, based on the width of the shopping carts. Finding possible investors in the shopping center 1.
Likewise, the chart submitted for a taco will vary depending on the ingredients included. It is important to verify that the student follows the steps described in Section 2. The assembly chart shows only the operations and inspections associated with the assembly of the product. The operation process chart includes all operations and inspections, fabrication and assembly operations and processing times, and purchased materials.
The scrap values and scrap cost at each step are as follows: Process 3: For simplicity the rework operations are indicated by Rk. All Ik values are rounded to the nearest integer. Given system: Following the derivation method given in Section 2. Using the same derivation, we have the following:. Based solely on the total rework costs of the two systems, the system with reversed scrap rates is preferred, which is consistent with the result of Problem 2.
You should note, however, that the system with reversed scrap rates requires more input to the system to meet the demand. All Ik values rounded to the nearest integer. For machines 1, 2, and 3: Machine 4 operates for half of the amount of time as machines 1, 2, and 3. Running the rework operation on the same shift as the remainder of the cell would cause the machine fraction to reduce to 0. This may allow for the addition of the rework machine to the cell.
All Ik values rounded to nearest integer. Let A1 denote the first step in the production process, and A2 denote the last step. Setup times are identical for machines A, B, and C for a particular product. The setup time for product X, regardless of the machine, is 20 mins; the setup time for product Y is 40 mins.
A critical piece of information needed to determine the number of machines required is the length of production runs between setups. If a single setup is needed to produce the annual requirement of a product on a machine, then the number of machines required is determined as follows:. If setups occur more frequently, then additional machines might be required due to the lost production time consumed by setups.
Using the equations to solve Problem 2. Let represent the new scrap percentage. You could also view the problem statement as indicating that. Part A: This represents a Part B: Part C: The opinion response will depend on the student.
However, the response should look something like the following. Estimation Perspective: For most tasks that a process designer may have to plan for there are likely to be many alternatives. The designer must be able to identify the issues related to each alternative and be able to generate an accurate estimate of the scrap rate. Even in the case where there may be only a single alternative the ability to accurately estimate the scrap rate is of great significance. Continuous Improvement Perspective: Being able to reduce the scrap produced by a process can be shown to significantly reduce the input requirement to a process.
The value of H is up to the student or instructor. Any value will provide sufficient illustration for the follow-up opinion question. For the purposes of this solution, we will assume H is a variable value and solve symbolically. It should be apparent that by reducing the scrap percentage will reduce the number of machines necessary. Assuming one 8 hour shift per day, 5 days per week, reducing the scrap percentage as indicated in Problem 2.
This could be a significant reduction in the floor space required to perform a specific process. For the facilities planner, space is at a premium, so every advantage should be taken to either improve processes or select processes that produce less scrap. Alternatively, you could say that the loss of one hour per shift is a reduction in the reliability.
Thus, the denominator would have the following: In addition, let Mxx represent molding operations for specific components; Pxx represent painting operations for specific components; and INx represent inspection stations in order of occurrence.
To find the number of units of the bottom cover to mold, we'll assume that it only goes through the inspection process once. Shown below is the probability mass function for number of good castings produced x , based on Q castings scheduled for production.
For a given value of Q, multiplying the net income in the column by the probability of its occurrence and summing over all values of x yields the following expected profits for each value of Q. From above, a negative net cash flow occurs if less than 4 good castings are produced. The probability of producing less than 4 good castings equals 0. We could not find a cost that would reduce the optimum production batch to 4 and still have a positive expected profit. For example, if the probability of a good casting is reduced to 0.
Shown below is the probability mass function for number of good high precision formed parts x , based on Q parts scheduled for production. Shown below is the matrix of net income for batch sizes of 10, 11, and Also shown below is the expected profit based on batch sizes of 10, 11, and 12, as well as the probability of losing money.
A batch size of 12 yields the smallest expected profit. Based on the probability of losing money, the least attractive alternative is a batch size of Shown below is the probability mass function for the number of good wafers x resulting from a production batch size of Q. Shown below are the expected profits and probabilities of losing money for various batch sizes.
The optimum batch size is 7, with a 0. Shown below is the probability mass function for the number of good die castings x in a production batch of size Q. Shown below are the expected profits and probabilities of losing money for various values of Q, the batch size. From the results obtained, the optimum batch size is The probability of losing money, which is the probability of less than 25 die cast parts being acceptable, equals 0. Also shown below is a matrix of net profits resulting from the combination of Q and x.
Finally, the expected profit is shown for various values of Q. In Example 2. Without other constraints the optimum number of machines to assign to an operator was shown to equal 2. Hence, two groups of 2 would be less costly, on a cost per part produced basis, than one group of 4 machines. Here, 11 machines are required to meet the production requirements. How should they be assigned?
One of the alternatives being considered is to assign 2 machines to each of 4 operators and then assign 3 machines to one operator; the alternative assignment being considered is to assign 2 machines to each of 5 operators and then assign 1 machine to one operator.
To calculate the cost per unit produced for each scenario, it is useful to evaluate each alternative using a length of time equal to the least common multiple of the cycle times for each machine-operator assignment in the scenario. During a period of 72 mins each 2-machine combination will perform 9 cycles and produce 18 parts; likewise, over the same time period, the 3machine assignment will perform 8 cycles and produce 24 parts.
Hence, over a 72 min. The total cost per unit produced over a 72 min. During an 8 min. The total cost per unit produced over an 8 min. Are there other scenarios that are less costly than the two considered? From Example 2. Hence, any scenario involving multiple assignments of single machines will be more costly than assignments of 2 machines per operator. Likewise, from the analysis performed above, any scenario involving a 3-machine assignment will be more expensive than one with a 2-machine and a 1-machine assignment.
Further, any scenario having a 4machine assignment will be more costly than one that substitutes two 2-machine assignments for the 4-machine assignment. By similar analyses, there are no other scenarios that need to be considered for the assignment of 11 machines.
For the optimum assignment in Example 2. Recall, in Example 2. During 7 hours of work for the operator between 8: In steady state conditions, the repeating cycle is 9 minutes.
Hence, in steady state conditions a total of units are produced. If replacement labor is provided to keep the machines working during the entire 8-hour shift and 3 shifts operate per day, then steady state production will result in units being produced per 8-hour shift.
This situation is illustrated in the following multiple activity charts. The problem statement was overly simplified, assuming sufficient demand exists to keep 5 machines busy and sales prices of the products are such that the calculation of cost per unit produced can be performed by summing the units produced for both products. Also, it is assumed that a machine is dedicated to producing either product 1 or product 2 and cannot be assigned to produce a combination of the two products due to changeover times.
For product 2, the optimum number of machines to assign an operator is obtained as follows for producing product 2: Hence, it appears that 2 machines should be assigned to produce product 1 and 2 machines should be assigned to produce product 2; however, that leaves 1 machine unassigned.
From the solution to Problem 2. The alternatives to be evaluated are as follows: Assign 2 machines producing product 1 to an operator and 3 machines producing product 2 to an operator. The repeating cycle is 3 2. Hence, in 24 minutes, the 2 machines producing product 1 perform 3 repeating cycles and produce 6 parts, and 6 parts are produced by the 3 machines making product 2 while performing 2 repeating cycles.
Assign 2 machines producing product 1 to an operator, 2 machines producing product 2 to an operator, and 1 machine producing product 2 to an operator. The repeating cycle for product 2 is Hence, in minutes there will be 21 repeating cycles for machines producing product 1 and 16 repeating cycles of machines producing product 2.
Assign 2 machines producing product 1 to an operator, 1 machine producing product 1 to an operator, and 2 machines producing product 2 to an operator. As in the previous case, the repeating cycles are 8 and Hence, over a minute time frame, there will be 21 repeating cycles of the 3 machines producing product 1 and 16 repeating cycles of the 2 machines producing product 2. The cost per unit to produce 63 units of. Since this is the least cost option, it would be recommended. As noted, a simplified approach was used to arrive at a preference in the assignment of the 5 machines to the 2 products.
With more information regarding sales prices, demands, changeover times, etc. The underlying objective in presenting the machine-assignment problem was to provide students with experience in using simple mathematical models in making decisions regarding the assignment of machines to operators. No more than 2 mixers can be assigned without idle mixer time. Hence, 2 mixers should be assigned to an operator.
The multiple activity chart is provided on the following page. The length of the repeating cycle is given by the maximum of the following values: The repeating cycle is determined by machine C. As shown, the operator will have 1 minute of idle time during a repeating cycle, machine A will have 3 minutes of idle time, machine B will have 1.
Hence, 4 mixers should be assigned to an operator. Hence, Thus, 3. Hence, 9. Hence, the optimum assignment of 4 machines occurs when 3. In 2, minutes, 1, units will be produced: For the problem, there is no concurrent activity.
Board for part shortages b. Board for back-orders c. Feedback from material handlers when part has low physical inventory d. Feedback from operator handlers when part has low physical inventory. The answers to these questions depend on choices made and course specifics.
See Section 2.
Top Management: Alternative issues and strategies to consider in the analysis such as layout classification, storage-handling strategies, organizational structure, and environmental policy. Product Designer: Process Designer: Schedule Designer: Modern Manufacturing Approaches: A material management system for a bank refers to the flow process into the bank.
The subjects of this system might include, but are not limited to, coin, currency, checks, other monetary instruments, deposit and withdrawal forms, loan documents, customers, suppliers, employees, banking supplies, and equipment required to operate the bank. The material flow system for a bank refers to the movement of materials, supplies, equipment, and personnel within the bank.
The physical distribution system at a bank describes the flow of money and information, including loan and other documents, out of the bank. The impact includes delivery of small lots, the elimination of paperwork due to electronic data interchange EDI , receiving material in decentralized storage areas, by-passing incoming inspection since suppliers have been certified, reduced movement of material, and simpler material handling equipment alternatives.
The overall impact to the logistics systems includes shorter lead times, lower cost, and better quality. Logistics encompasses the arrival and departure of parts and products, including the quantities of each.
Material handling and storage are extremely important for the facilities planner. In fact, some define manufacturing as production processes located strategically in a logistics system. The basic layout of the hospital will depend on who moves and who remains fixed in location.
Actually, all subjects are candidates for movement, except for the most expensive diagnostic equipment; it cannot always be taken to the patient. However, advances in medical technology are such that more and more the technology is being brought to the patient via distance medicine. If it is desired that patients not be transported around the hospital to the various x-ray, cat-scan, and MRI facilities, then either remote sensing methods must be provided or the diagnostic equipment must be duplicated.
Hospitals are often designed using group technology layouts, where the grouping is based on the medical services provided the patients. Backtracking results in excessive flow or travel, longer lead-times, and complications in scheduling. Backtracking may be avoided by duplicating machines, redefining the process plans to complete the machining in consecutive steps, specifying the use of another machine not requiring backtracking, or redesigning the product to eliminate the processing requiring backtracking.
The answer may depend on the region in which the store is located; however, some basic principles will likely apply. The ordering of the answers is up to the student.
Customer perspective: Aisles must be wide enough to accommodate customer traffic in both directions, based on the width of the shopping carts. Like items should be relatively close to each other. Employee perspective: The angle at which the aisles are located relative to the stockroom. The width of the aisles must be sufficient to allow for whatever means of material movement is used. The space requirements in terms of the shape of the department will be different.
The means of material handling will also change. In addition, switching from a straight line flow to a u-shaped flow will change the tasks of the workers on the line. The flow strategy may also change, since a conveyor line is often associated with push or continuous systems and u-shaped cells are most often associated with pull or just-in-time production systems. When streets are not at right angles, turning of vehicles can be more problematic.
In such instances, wider turning lanes might be required, particularly for delivery trucks. Parallel parking advantages: Perpendicular parking advantages: Diagonal parking advantages: A group technology layout is a candidate for consideration when a medium volume of a medium variety of products are to be produced. It is used when families of products can be grouped according to physical characteristics or production sequence information.
A fixed position layout would be recommended when the product is very large, awkward, or expensive to move. It is also a candidate when low or sporadic volume of low variety production occurs. Group technology layout using manufacturing cells is popular in JIT facilities because cellular layout encourages small lots, kanbans, simple material handling systems, short setup times, cross trained personnel, teamwork, and quality at the source.
Process layouts can result in complex flows, excessive handling, large inventories, and long production lead-times. There is sufficient capacity remaining in machine 4 in cell 2 to allow us to produce part 1 in that cell for the operation that requires machine 4. Therefore, as long as material movement was not an issue and scheduling we can use the minimum amount of machines to meet the production requirements by combining all machines into one cell. For the 2nd presented solution of Problem 3.
In this case the conflicts were resolved by adding machine 1 to both cells. We could eliminate the duplicate of machine 1 in the second cell for the same reason as in the 1st case. A kanban is a signal, typically a card, that indicates to the supplying workstation that the consuming workstation requests more parts. There are two types of kanbans: The benefits of kanbans include simplified production control, reduced inventories, increased visibility, improved quality, reduced material handling, and reduced lead-times.
Kanbans are a reminder that each employee has a customer, i. Kanbans are important in cellular manufacturing because of the limited space and need for better production control to prevent excessive work-in-process WIP.
Given the differences in numerical values a closeness rating was assigned, as shown in the activity relationship chart. Process improvement and quality activities Training for improved cross-functionality Production coordination Performance measures tracking Material handling The new roles impact resources less people, less inventories, less space and change the structure of traditional activity relationships storage at points of use, training and continuous improvement.
Research Question: Using the sum of the distances it takes for each product to complete production routings given in Problem 3. Typically, decreasing lot sizes increases the number of setups that must be performed. Therefore, although decreasing lot sizes lead to a decrease in the amount of storage space.
This trade-off may be alleviated by having tool-cribs located such that they serve several workstations instead of having tooling available at all stations this may have its own negative impact as it may increase setup times.
A well-fed employee is not necessarily a happy employee. Likewise, a happy employee is not necessarily a productive one. These two statements relate to pervasive philosophies held by some companies, and they are not universally accepted.
Because of particular company philosophies, facilities planners must adapt their plans to conform. Generally, if the location of the facility is in a cold environment, the employee may bring a coat to work. Also, the employee may bring a lunch, a change of clothes if working in a dirty or hot environment, and some personal toiletries.
These items can all fit into a locker. When parking spaces are assigned, there must be a 1: If there is a random parking philosophy at the company, then anywhere between a 1: Standard cars 86 , 90 because a perpendicular alignment has the best utilization of space , W2: Module width from Table 4.
Next, determine the number of cars that can be parked per module: If a 9 standard car width is used, then cars can be parked in the lot. If a 96 standard car width is used, then cars can be parked in the parking lot. Answers vary depending on the specific parking lot analyzed. The user should try various parking angles and pay attention to best placement of aisles and cross-aisles relative to entry and exit points in the lot.
The primary advantage of parking decks over surface lots is that parking decks can accommodate more cars per square foot of land, which is significant when land is expensive or unavailable. Also, parking decks provide shelter against the elements rain, snow, UV rays from the sun for the users and their vehicles.
However, parking decks are more expensive than comparable surface lots and take longer to construct. They may require elevators, adding to the expense. Many drivers have difficulty navigating parking decks and may take longer to find a parking spot and exit later. Finally, a parking deck leaves fewer options for future expansion than a surface lot that could be more easily built over.
There must be two restrooms, one for males and one for females. There must be a minimum of three water closets and three lavatories in each restroom from Table 4. In the mens restroom, one urinal can be substituted for a water closet.
Consequently, only l6 ft2 of space is required for the urinal. For each lavatory, 6 ft2 of space should be designated. For each water closet, 15 ft2 of space should be included. Also, 15 ft2 of space should be allocated for the entrance.
Since there are fewer than females employed in the facility, only one bed or cot should be provided. For each bed, 60 ft2 of space should be provided. The summation of space required for each genders restroom is as follows: Since an employee typically spends the first third of his lunch break preparing to eat and obtaining his meal, for a one-hour lunch break, dining shifts may begin every 40 minutes rounded up to 45 minutes because shifts must begin and end on 15 minute increments.
Consequently, 2 lunch shifts can be included in the The following table shows the shift timing for each lunch break. If employees eat during one shift at an industrial facility that has a cafeteria with 36 in2 tables, then the following space requirements are necessary for a vending machine and cafeteria food service: Vending Machine Area people 1 ft2 per person Cafeteria Area people If employees eat during two shifts at a commercial facility that has a cafeteria with 42 in2 tables, then the following space requirements are necessary for a vending machine and cafeteria food service: If employees eat during four shifts at an industrial facility that has a cafeteria with rows of 10 foot long rectangular tables, then the following space requirements are necessary for a vending machine and cafeteria food service: If employees eat during one shift at an industrial facility that has a cafeteria with 36 in2 tables, and lunch breaks are one hour, then the following space requirements are necessary for a serving line and cafeteria food service: Serving Line Area 6 lines ft2 per line Cafeteria Area people The reason why six serving lines are required with a one-hour lunch break for employees is that a serving line can serve 7 employees per minute.
In a minute time frame, one line can serve employees. If five lines are utilized only employees will be served in twenty minutes. Consequently, size lines are required. If employees eat during two one-hour shifts at a commercial facility that has a cafeteria with 42 in2 tables, then the following space requirements are necessary for a serving line and cafeteria foot service:.
If employees eat during four one-hour shifts at an industrial facility that has a cafeteria with rows of 10 foot long rectangular tables, then the following space requirements are necessary for a serving line and cafeteria food service: If employees eat during one shift at an industrial facility that has a cafeteria with 36 in2 tables, and lunch breaks are one hour, then the following space requirements are necessary for a full kitchen and cafeteria food service: If employees eat during two one-hour shifts at a commercial facility that has a cafeteria with 42 in2 tables, then the following space requirements are necessary for a full kitchen and cafeteria food service: If employees eat during four one-hour shifts at an industrial facility that has a cafeteria with rows of 10 foot long rectangular tables, then the following space requirements are necessary for a full kitchen and cafeteria food service: The space requirement in the health services are for the employment of two nurses and a part-time physician are as follows.
In office facilities, the restrooms must be the same size for the same amount of people. However, due to the fact that office personnel tend to have longer lunch breaks, the food services are does not need to be as large as it would for a production facility, because office personnel tend to go out to lunch for more than production personnel.
Also, office workers tend not to get injured as much as production personnel, so the health services area does not need to be as large in an office facility as they do in a production facility.
Finally, production workers that work in hot environments need more locker space and shower stalls than those people in an office environment. It is important to consult personnel such as the human resources department industrial relations department, or personnel department on the types of personnel requirements necessary for the facility. However, these people may not understand the cost effectiveness of their decisions, so the facilities planner should only gain insight from them, not use them to make final facilities decisions.
In a multi-level facility, there have to be more personnel service locations than in a single-level facility because a multi-level facility is much more decentralized. There have to be more restrooms because each level has to have one for men and women. Also, there should be more vending facilities in a multi-level facility than a single-level facility because it is more difficult for people to walk stairs to vending locations on different levels. Furthermore, on top of health service, food service and restrooms that must comply with ADA regulations in a multi-level facility, ADA compliance also must occur so that all disabled employees can reach all levels of the facility.
Also, if the classroom is above the ground floor, then ADA regulations state that the student must be able to access the room by other means than stairs. The elevator control panel must be at a height that is accessible to disabled students. All doors leading to the classroom must be wide enough to accommodate a wheelchair. The fire alarm and electric switches must be at a height where someone in a wheelchair can reach it.
The room between aisles of decks in the classroom must be at least three feet. For any sight impaired students, Braille instructions should be placed on the door so the student can determine where the classroom is.
Also, vending locations should be low enough so that people in wheelchairs can reach the service shelf and cash register without having to strain themselves. Finally, all restroom facilities should have doors that are wide enough for disables individuals and Braille instructions for sight-impaired individuals.
Sightimpaired individuals should have Braille instructions and Braille labels throughout the center, as well as seeing-eye dog access. Wheelchair-bound individuals should have their campus mailbox at a level where they can reach it. Any activities within the student center, such as bowling alleys, cafeteria, game rooms, movie theaters, and student organization offices should have wheelchair access.
The entrances and exits to the center should have ramp access, if necessary. All aisles within the facility should be wide enough to contain two wheelchairs side by side. Individual employees can give valuable input to verify and refine office requirements. This can be accomplished through personal interviews when the number of employees is small.
When the number of employees is large, survey can be used to get feedback on things to consider for employees to be more productive. It is important for employees to feel that they are part of the process of making the entire organization more efficient. Advantages of open office structure: Improved communications Improved supervision Better access to common files and equipment Easier to illuminate, heat, cool, and ventilate Lower maintenance cost Reduce space requirements due to space flexibility Disadvantages of open office structure: Lack of privacy Lack of status recognition Difficulty in controlling noise Easy access for interruptions and interference.
Campus office concept gives higher level of personal satisfaction. Every employee is provided with the same employee services and facilities, which put everyone in an equal status.
No one feels being treated unfairly. List of criteria to evaluate office plans can be looked at from different perspective: Employee Size Noise Proximity of facilities Proximity of colleague Supporting features such as a computer, internet, phone line, etc b.
Manager Visibility for supervision Productivity c. Company Maintenance cost Impact to business operation Proximity to supporting facility such as postal service. Work principle: The measure of work is material flow volume, weight, or count per unit of time multiplied by the distance moved.
The work principle promotes minimizing work whenever possible. Materials movement should be in as practically large amount as possible and material-handling devices should be fully utilized by carrying loads at its capacity.
Ergonomic principle: Ergonomics is the science that seeks to adapt work or working conditions to suit the abilities of the worker. Human capabilities and limitations must be incorporated into material handling equipment and procedures designed for effective interaction with the people using the system.
As an example, for humans picking in a warehouse, do not store any items above the top of the head. The optimum picking zone in order to minimize stooping and stretching is from the hips to the shoulder.
Unit Load principle: A unit load is one that can be stored or moved as a single entity at one time, such as pallet, container, etc, regardless of the number of individual items that make up the load. In this principle, product should be handled in as large a unit load as practical. As an example, instead of moving individual products, a number of products can be palletized and move as a single load.
However, the size of the load must be considered as excessive unit load can reduce the visibility of the forklift driver or may not be practical in utilizing truck space. Moving as large a unit load as practical must be exercised in the context of just-in-time delivery. There is no point in moving materials if it will not be used for a long duration. Space Utilization principle: Space in material handling is three dimensional and therefore is counted as cubic space and effective utilization of all cubic space is the essence of this principle.
If products are stored in a container, the product should fill up the container. In storage application, the storage dimension should be designed to fit a unit load with some tolerance for storage and retrieval. An illustrative example is given below. Environmental principle: Environmental consciousness stems from a desire not to waste natural resources and to predict and eliminate the possible negative effects of our daily action to the environment.
Practical application to this principle is to replace combustion engine forklift to electric forklift. Standardization principle: Standardization means less variety and customization in the methods and equipment employed. With unit load standardization, a common material handling device can be employed to move different products.
Higher space utilization can also be attributed to unit load standardization. Storage space is the same across all products; therefore there is no need for differentiating the storage area. By doing this,. The first dimension of pallet size correspond to the length of the stringer board and the second dimension correspond to the length of the deck board.
Two-way pallet - fork entry can be only on 2 opposite sides of the pallet and is parallel to the stringer board. Four-way pallet - fork entry can be on any side of the pallet. Two different cases will be presented in these examples: The vehicle is assumed to stop at point F. Case Unit load size 50, so assuming for every loads the vehicle will make the following trip: There are many other possibilities depending on the assumption.
Bridge Crane: A bridge crane can be classified into two basic types: The girders which functions as a bridge beam may support one or multiple trolley and hoist. The bridge travels along the runway on wheeled carriages called end trucks, which are mounted to each bridge end. The hoist body is either mounted on top of the bridge or suspended from it. The hoist moves along the bridge on a trolley. Bridge crane operates on three axes of movement and a swivel that rotates the load around the vertical axis is regularly featured.
An operator standing on the floor using a pendant, remote radio, or infrared control unit can do the controlling.
The operator may also be in a self-contained control cab in larger and faster cranes. Finally, automation is the last control option. Jib Crane: The main configuration of a jib crane is a horizontal beam that pivots along a vertical axis.
A trolley and hoist may be perched from the beam. Jib cranes have three degrees of freedom - vertical, radial and rotary. Jib cranes may be attached to a vertical wall member, or mounted to a mast attached to the floor, and some may be constructed to move along a wall. Jib crane is economical; uses little floor space, and pivots in a pieshaped area. However, it cannot reach into corners and it doesn't lift objects outside the circular area.
Another disadvantage is the lack of portability. Typical application includes localized activity like in a machine shop. Gantry Crane: A gantry crane is a bridge crane using a horizontal beam that is supported at each end.
There are two versions of gantry crane: Gantry cranes are used when overhead runway are not practical. It can be built on wheels for portability, is economical, and is able to lift heavy loads. Its major disadvantage is the limited reach since it cannot expand much beyond the inside span.
Attributes for comparing sorting conveyor: Maximum number of sorting capacity per minute Load range Load size Minimum distance between spurs Diverter impact on load Safety Initial cost Maintenance cost. Attributes for comparing automated guided vehicles systems: Attributes for comparing unit load storage system: Cost per position Potential storage density Load Access: Attributes for comparing unit load retrieval technologies: Vehicle cost Lift height capacity Aisle width - aisle width required for vehicle to operate Weight capacity Lift speed - the speed in the vertical axis Travel speed - speed of the vehicle.
Attributes for comparing small part storage alternatives: Attributes for comparing automated data collection systems: Real time - data collected will be straight recorded in the database Hands free Eyes free Cost.
Attributes for comparing bar code readers: Range - the range where the bar code can still be read Depth of field - orthogonal distance to read the bar code Scan rate Resolution Price. Attributes for comparing bar code printers: Platform truck is a version of industrial truck.
A platform truck uses a platform for supporting the load. It does not have lifting capabilities and used for transporting. A turret truck is mostly used on narrow aisle. A turret truck has a pivot point on the fork and a constant mask for more maneuverability along narrow aisles. Drive-in rack allows a lift truck to drive in to the rack several positions and store or retrieve a unit load.
A drive-thru rack is a drive-in rack that is accessible from both sides of the rack. It is staged for a flow-thru fashion where load is loaded at one end and retrieve at the other end.
Both racks have the same design considerations. Push back rack provides a last-in-first-out storage system. An illustration is given below. Bridge Crane vs. Stacker Crane: Bridge Crane is a bridge that spans a work area. The bridge is mounted on tracks. The bridge crane and hoist can provide 3 dimensional coverage of the department. A stacker crane is similar to a bridge crane, but instead of using a hoist, a mast is supported by the bridge.
The mast is equipped with forks or a platform, which are used to lift unit loads. Several important factors such as: Product type, Manufacturing, Marketing Distribution, Management Distribution, Human resource plans will be impacted by and will impact on the facility layout.
The material handling decisions can have a significant impact on the effectiveness of a layout. For example: Centralized vs. Fixed path vs. Single vs. The handling unit unit load planned for the system. The degree of automation used in handling. The type of level of inventory control, physical control, and computer control of materials.
Fixed Product Layout: It should be used when the product is too large or cumbersome to move through the various processing steps, e. Product Layout: It is used when high-volume production conditions exist. The product volume must be sufficient to achieve satisfactory utilization of the machine. Group Layout: It is used when production volumes for individual products are not sufficient to justify product layouts, but by grouping products into logical product families, a product layout can be justified for the family.
Process Layout: It is used when there exist many low-volume, dissimilar products to be planned. Soda Bottler b. Printing Shop c.
Meat-Process Plant d. Furniture Manufacturing Plant e. Computer Chip Maker f. Shipyard g. Refinery Plant h. College Campus. The construction type of facility layout procedure involves developing a new layout from scratch.
The improvement procedure generates layout alternatives based on an existing layout. All three layout procedures provide a systematic step-by-step methodology in designing a facility layout.
All of them take the activity interrelationship, space requirements, and etc. All of them are based on the construction type of facility layout procedure and improved upon the initial layout with consideration of other constraints.
SLP Approach: Since we do not have the activity relationship chart, we base our closeness rating on the material flow information. Flow-Between Chart Dept. From-To Chart Dept. Activity Relationship Chart Dept. Flow-Between chart is identical to the one presented in the solution to Problem 6. Determine the departments with largest weight: Select the third department to enter: Departments with largest weight: Both C and E have weights of C is arbitrary chosen 3.
Select the next department to enter: Department pair with largest weight: The layout cost, as computed by CRAFT, will be equal to zero units since the centroids of all the departments overlap. In general, the centroid-to-centroid distance measure can give unrealistic results when the centroid of a department lies outside the department. The following estimated layout costs are computed for the initial layout: The lowest estimated layout cost is 48 units with departments D and E exchanged.
The actual cost of this new layout is 48 units. Since none of the estimated layout costs is lower than 48 units the current layout cost , CRAFT stops and the above layout is the final layout. Note that the area of department B is equal to the area of department D. Given the flow and cost data, we have: Again, all the cij values are equal to 1. That is, the final solution obtained by either algorithm depends on the starting point and the particular set of departments exchanged in arriving at the final solution.
Therefore, both algorithms using two-way exchanges only will follow the same path and terminate at the same solution. CRAFT can capture the details of the initial layout, such as fixed departments, unusable space, and obstacles; 2.
CRAFT can generate many alternative layouts in a short period of time. Since the two programs will not necessarily follow the same path, they will most likely terminate with different layouts, and there is no guarantee that the cost of a layout generated by NEWCRAFT will be less than that obtained with CRAFT. BLOCPLAN uses three bands; if two non-adjacent or unequal-area departments are exchanged, it simply recomputes the width of the two bands affected by the exchange.
If the two departments are in the same band, the band width remains the same. A rectangular shape is often the preferred shape for a department; also, with rectangular departments it is straightforward to measure and control department shapes. If fixed departments or obstacles are present, it may be difficult or impossible to maintain rectangular department shapes; also, in some cases an L-shape may be acceptable or preferable for some departments.
To avoid unrealistic department shapes, we set Ri equal to two for all the departments. We obtain the results shown in the following Table by using the linear MIP model given by equations 6. To avoid unrealistic department shapes, we set equal to two for all the departments. Therefore, any two departments can be exchanged or more general exchange routines such as those implemented within simulated annealing can be used and the resulting layout can be constructed rapidly. However, department shapes are affected by the spacefilling curve; sometimes it may be difficult to ensure good department shapes and massaging will be necessary.
Spacefilling curves should not visit fixed departments or obstacles. Note that all the empty space if any will automatically appear at the end of the spacefilling curve. If one wishes to insert empty space at locations other than the end of the curve, then one must use dummy departments and place them in the appropriate position in the layout vector.
In part a , for example, department 4 D attains a "long-and-narrow" L-shape primarily due to the shape of department 5 E in the initial layout.
Assuming a 1 x 1 grid for simplicity and using the data given for Problem 6. Note that department labels A through F have been replaced by department numbers 1 through 6. A project to evaluate existing dock area, including receiving and shipping, will allow the determination of those aspects that can potentially prove economically advantageous.
The following is a partial list of such aspects that warrant attention. Eliminate the receiving area. For some materials, e. Reduce or eliminate staging in the receiving and shipping area. Determine the location assignment and product identification prior to receiving the product so that materials are stored as soon as they arrive, reducing the need for large staging area.
Employ the fastest and most productive receiving process possible, i. Palletized materials with a single SKU per pallet, floor-stacked loose cases, and backordered merchandise are excellent candidates for crossdocking. Bypass receiving staging and put materials away directly to primary picking locations, essentially replenishing those locations from receiving.
In direct putaway systems, the staging and inspection activities are eliminated, saving the time, space, and labor associated with those operations.
Minimize the floor space required for staging by providing storage locations for receiving staging. Prepare shipping from the time the materials are received, thus reducing the area for shipping. Ship materials in larger quantities and preferably in unit loads, i. Ship directly from storage and without the need for staging, having prepared the shipping information prior to picking. Reduce the number of docks, if possible. For example, can receiving and shipping be modified so that less frequent visits to docks are necessary?
This will save more space in and around the receiving and shipping areas. Modify docks to degree docks. Finger docks should be eliminated, if possible. Otherwise, can the largest angle finger docks be used? This will allow shrinking of maneuvering and staging areas inside the receiving and shipping areas. Eliminate dock levelers by requiring uniform-height carriers for loading and unloading, thus reducing or eliminating dock maintenance costs. Remove dock shelters in favor of a more streamlined dock, if dock shelters exist.
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