Math questions Student: Please answer Review and Discussion Questions at the end of each chapter. Each Chapter has to be separated by chapter. Answers should be detailed and formulated from the book...

ch12/12_Shop_Floor_Control.docx
12    Shop Floor Control
Questions for Review and Discussion
1. Shop floor control is often called Production Activity Control .
2. What is the difference between backward scheduling and forward scheduling?
Backward scheduling
Backward scheduling is the scheduling of the operations necessary to complete parts and components in the same manner as MRP was backward scheduled from the required completion date. For example, the fixed jaw plate must be deburred before the jaw is complete and ready to send on to assembly. Working backwards you will identify the latest time the deburring operation can begin to enable you to meet the required completion
Forward scheduling
In forward scheduling the activities necessary are scheduled for as soon as possible after the order is received. Subsequent activities are scheduled for as soon as possible after the initial activities. With forward scheduling the due date is ignored, which means work can be completed ahead of the due date. The result of completing ahead of the due date is that inventory can rise, and other work with an earlier due date may be delayed because work with a later due date is scheduled. The argument for forward scheduling is that you can never recover lost time. Time cannot be stored, you either use or lose it—it is better to attempt to make parts as soon as you can rather than risk losing time.
3. What are some ways in which capacity can be adjusted short term?
a.) Overtime. The most common method of increasing capacity is by working overtime. Working overtime can be a quick and effective method of increasing capacity. It can be implemented just hours ahead of time— although union restrictions on who, who, when, how much, and amount of advance notice often apply. A plant working a single 40 hour shift could increase capacity at a workstation by 37.5% each week if overtime was scheduled for two extra hours per day and five hours on Saturday morning. Loading schedules, whether infinite or finite, should allow you to identify when and how much overtime is needed, and if overtime will solve the problem.
b.) Subcontracting. Sometimes overtime will not solve the problem. Little can be gained by overtime if the plant already operates three shifts around the clock. Subcontracting is an agreement with another company to have them produce work for you. One major advantage of planning is that the company can project ahead to see when subcontracting may be necessary. Thus, companies that can do the work can be identified, and price agreements can be worked out.
c.) Alternate routing. Many products and components can be produced in several different ways. Those working in the methods area of production have primary authority for the methods used and therefore the routing of material. They should have identified the most efficient routing for the work. Alternative routes may exist that may be a little more costly than the most efficient route, but they are cost effective and could get the work done more quickly under certain circumstances. It is not unusual for an alternative route to be identified on the routing sheet.
d.) Temporary Employees. Temps have become increasingly more popular in some industries. The reasons for this are mostly financial (costs of pay
and benefits), rather than with production. These financial aspects are beyond the scope of this text.
Temporary employees are an alternative because there is a limit to the
amount of overtime people are willing to work. Prolonged periods of over 55 hour work weeks often lead to production problems.
Many people only want temporary work. For example, students many times look for temporary summer work to earn enough money for the next school year. Another example are adults with school-age children that pre- fer not to work during the summer months.
4 A company had planned input to a machine for five days as 90, 90, 45, 92, 92 and actual output was 89, 86, 46, 90, 92. What is the cumulative variance for the week?
        Input / Output Report
        Period (date)
        1
        2
        3
        4
        5
        Planned input
        90
        90
        45
        92
        92
        Output
        89
        86
        46
        90
        92
        Cumulative variance
        -1
        -5
        -4
        -6
        -6
5.     Using control charts, develop three recommendations for AAA Printing Company. AAA Printing produces the literature that goes with a bicycle. Downtime often occurs with the machine used. This affects delivery times. Over the last month (20 working days), the daily downtime in minutes has been as follows:
20 35 15 65 15 20 40 30 10
15 15 10 20 40 15 20 15 35
25 15
The company checked the last four days and found that the machine had stopped for five reasons—reasons A, B, C, D, and E.
On day 1 the stops were because of B, then D E A C A C B E A C
On day 2 the stops were because of A, then E C B E C C A D
On day 3 the stops were because of B, then C B A C D E C D
On day 4 the stops were because of C, then A D C A C B D C
ch12/chapter12pdf-5el1zc3h.pdf
ch13/13_Kanban.docx
13    Kanban
Questions for Review and Discussion
1. Name and describe the seven categories of waste.
· Waste from overproduction
· Waste from transportation
· Waste from unnecessary stock on hand
· Waste from time on hand (waiting)
· Waste from processing
· Waste from unnecessary motion
· Waste from defective goods
2. Which categories of waste can be reduced by having parts and materials arrive just-in-time?
· Waste from overproduction
· Waste from transportation
· Waste from unnecessary stock on hand
· Waste from time on hand (waiting)
· Waste from processing
· Waste from unnecessary motion
· Waste from defective goods
3. Which category of waste is Kanban used to control?
    All seven categories of waste
4. List and discuss the six rules of Kanban.
i. Do not allow defective products to go to the subsequent process. This is considered to be the worst offense against cost reduction. Because of the small number of parts moved, Kanban relies on only good parts flowing through the system. Observance of this rule leads to a more rapid discovery and correction of the cause of the defect, because defective products will lead to a rapid shortage of parts and an equally rapid buildup of defects. Defects have to be moved, checked, corrected, checked again, and moved back.
ii. The subsequent process withdraws only what is needed. Withdrawals are made at the time materials are needed, in the quantity needed. As a result, no process has to be concerned with information about when materials are to be supplied, or how many materials are to be supplied to the subsequent process. To ensure that the subsequent process will not arbitrarily withdraw from the previous process, there are three rules used:
A. No withdrawal is made without a kanban.
B. A kanban must always accompany each item.
C. Items withdrawn cannot exceed the number on kanbans submitted.
iii. Produce only the exact quantity withdrawn by the subsequent process. There are two rules used to accomplish this:
A. Do not produce more than the number on kanbans received.
B. Produce in the sequence in which the kanbans are received.
iv. Equalize production through load smoothing. As you read earlier, load smoothing increases efficiency by equalizing the amount of work to be done in an even sequence. If production is not smoothed, there will be waste in capacity because some resources sit idle for long periods of time, and there will also be waste in inventory because parts are produced ahead of need.
v. Kanban provides the means used to fine-tune production. Because Kanban is the source of information for production and transportation, production can be fine-tuned in response to the latest conditions. It can only be effective where load smoothing exists.
vi. Stabilize and rationalize each process. This is a requirement for implementing the fourth rule, equalizing production, and the first rule, preventing the transfer of defective parts. If the process is stable and rational, the necessary reliability will exist for Kanban to work.
5.    Describe the five-step method for reducing set-up time.
Step 1:    Study the existing set-up procedure. This step often exposes the most glaring weakness in organizations where setup has not been studied systematically. The most common problem is there is no established procedure. The process of setting up different activities is done differently by different people. Even the same person may set up differently. This not only varies the set-up time but can also affect the quality and variability of parts being produced.
Step 2:        Consider whether elimination of the existing setup is possible. Elimination of the setup reduces the set-up time to zero. This would be the perfect situation because you would then have a lot size of one. Although it is often not possible to eliminate the setup directly, it is sometimes possible to simplify the design of parts to reduce the number of setups in manufacturing products.
Step 3:    Identify which set-up activities can be performed while the previous job is running. Many of the activities in the...