ÜRETİM YÖNETİMİ

Facility Layout decisions are very important for organizations. Although there are many reasons for this, three main reasons are as follows:
• Large expenditure of money and effort for the construction of facilities and no compensation for this.
• The result of layout decisions covers a long period. Therefore, it is very difficult to
overcome the mistakes to be made.
• The decision about facility layout significantly affects production efficiency and production cost.

Facility layout planning is to decide how to place the physical production resources used in the transformation process such as labor, machinery, raw material, product, intermediate product and personnel.

Comfort of employees: In the production process, it is necessary to ensure that the
working conditions of the personnel are appropriate. Ergonomic factors such as
noise, temperature and lighting should be considered in the layout planning.

In a fixed--position facility, the product is not moved due to its structure and size. Instead, production resources are moved around the product.

In the process layout, parts are transported between workshops by flexible transport methods such as forklifts. Hospitals in the service sector can be given as examples of facilities where the process layout is applied.

The general characteristics of the product layout are summarized below.
• Production resources are designed for the purpose of high-speed production.
• Automation systems used to improve production speed and performance result in high installation costs.
• The process rate is faster as all the resources are ordered for efficient production.
• The arrangement of production resources according to the product, the proximity of the production lines to each other leads to lower material transportation costs compared to the process layout.
• The warehouse requirement for inventory is lower.
• Since all facilities and resources are customized for the production of certain products, there is no flexibility when a new product is added to the system or when substantial changes to the product are required.

The number of options in the process layout is calculated by the factorial of the number of workstations. 4! = 1x2x3x4 = 24 different options can be created in a plant with four workstations.

C= Production Time/Required Output

C=300*60/400=45

Quick response to customer demands can be made by overproduction. Many customers want to get ready for the product instead of waiting for the product.

Determination of long term capacity needs is based on forecast of future demand. When companies need to make long-term forecasts, they examine patterns of long-term variability, such as trends.

Four basic approaches in this chapter are discussed.
• Fixed-position layouts
• Process Layouts
• Product Layouts
• Cell layouts

Advantages:
• Machine utilization rates are high and require fewer machines.
• Flexible use of production resources is possible.
• It requires lower investment costs.
• High utilization rate of its production facilities.
• The level of flexibility in the distribution of work is high.
• The satisfaction of the staff is higher.

Process Layout          Characteristics               Product Layout
High                              Product variety                       Low
General purpose             Resource usage                 Specialized
Labor intensive               Resources feature         Technology intensive
High                              Product flexibility                    Low
Low                               Production speed                    High
High                              Material handling cost             Low
Low                               Stock area                             Low

Process Layout               Characteristics               Product Layout
High                                  Product variety                          Low
General purpose                 Resource usage                    Specialized
Labor intensive                   Resources feature          Technology intensive
High                                  Product flexibility                      Low
Low                                   Production speed                     High
High                                  Material handling cost              Low
Low                                   Stock area                              Low

The steps to be followed for balancing an assembly line are listed below.
1. The order of relations between tasks is determined using the precedence diagram. The diagram consists of circles representing tasks and arrows showing the ordering between tasks.
2. Calculate for a day the cycle time of the required workstations using the following formula

C =  Production time

     ________________
       Required output

3. Using the following formula, the minimum number of workstations sufficient for cycle time is theoretically determined. (The calculated value is rounded to an upper integer)

Nt =T(sum of task times)

     ____________________

      C(cycle time)

4. The primary and secondary rules are used for assigning tasks to the workstation. The primary rule allows the workstation to decide which task to start with and the second rule to decide which task to select first among multiple tasks. By applying these rules, a task is assigned to the workstation.
5. Tasks are assigned to the workstation so that the total duration of the tasks on the workstation does not exceed the cycle time. Repeat step 4 until all tasks are assigned to the workstations.

C= Production time  = 12X60X60 =27

     _____________     _________

    Required output       1600

These decisions are closely related to cost, revenue, capital, quality, speed of meeting customer demand, dependability of supply and flexibility.
• Costs are affected by the balance between capacity and demand. If the capacity is higher than demand, the unit cost of the product increases.
• Revenues are also affected by the balance between capacity and demand. If the capacity level is equal to or greater than the demand, it prevents loss of income.
• Making a production decision on stock to meet high demand will adversely affect working capital. This decision will ensure that the demand is met but there will be no income inflow until the products are sold.
• A capacity plan that meets fluctuations in demand through the use of temporary personnel may adversely affect product or service quality. Employing inexperienced personnel increases error rates.
• Quick response to customer demands can be made by overproduction. Many
customers want to get ready for the product instead of waiting for the product.
• Dependability of supply is also affected by the close proximity of capacity and demand levels. This proximity makes it difficult to remedy disruptions in product or service deliveries.
• Flexibility, in particular volume flexibility, is closely related to excess capacity. The balance between demand and capacity may make it impossible to respond to unexpected increases in demand.

Input measures                  Output measures                                                                                          Number of beds                  Number of patients treated per week
  Number of seats                 Number of customers watching movies per week
  Labor time per shift            Number of cars produced per shift
  Generator size                    Produced electric megawatts
  Production tank capacity      Liters produced per week

Short- and mediumterm capacity strategies are listed below:
• Stock
• Delay
• Labor level
• Employee training
• Subcontractor use
• Process design

Decision tree is a modeling tool used to evaluate independent decisions that must be made in sequence.