Didem Tarkun(503101304) - 1st week - definitions

Zero inventory

Zero inventroy is a term which is used to describe Just in Time (JIT) inventory control system where emphasis is placed on reducing inventory to minimal levels to reduce costs and promote organizational effectiveness. This can result in sizable profit increases. Although an actual level of zero inventory is unlikely, a strategy to reduce inventory should result in lower expenses associated with warehousing, spoilage, and so forth. The term is sometimes used synonymously with just-in-time inventory.

Statistical Process Control (SPC)

Statistical process control (SPC) is the application of statistical methods to the monitoring and control of a process to ensure that it operates at its full potential to produce conforming product. Under SPC, a process behaves predictably to produce as much conforming product as possible with the least possible waste. While SPC has been applied most frequently to controlling manufacturing lines, it applies equally well to any process with a measurable output. Key tools in SPC are control charts, a focus on continuous improvement and designed experiments.
Much of the power of SPC lies in the ability to examine a process and the sources of variation in that process using tools that give weight to objective analysis over subjective opinions and that allow the strength of each source to be determined numerically. Variations in the process that may affect the quality of the end product or service can be detected and corrected, thus reducing waste as well as the likelihood that problems will be passed on to the customer. With its emphasis on early detection and prevention of problems, SPC has a distinct advantage over other quality methods, such as inspection, that apply resources to detecting and correcting problems after they have occurred.
In addition to reducing waste, SPC can lead to a reduction in the time required to produce the product or service from end to end. This is partially due to a diminished likelihood that the final product will have to be reworked, but it may also result from using SPC data to identify bottlenecks, wait times, and other sources of delays within the process. Process cycle time reductions coupled with improvements in yield have made SPC a valuable tool from both a cost reduction and a customer satisfaction standpoint.

Process capability
A process is a unique combination of tools, materials, methods, and people engaged in producing a measurable output; for example a manufacturing line for machine parts. All processes have inherent statistical variablity which can be evaluated by statistical methods.
The Process Capability is a measurable property of a process to the specification, expressed as a process capability index(e.g., Cpk or Cpm) or as a process performance index (e.g., Ppk or Ppm). The output of this measurement is usually illustrated by a histogram and calculations that predict how many parts will be produced out of specification.Process capability is also defined as the capability of a process to meet its purpose as managed by an organization's management and process definition structures ISO 15504. Two parts of process capability are:
1) Measure the variability of the output of a process
2) Compare that variability with a proposed specification or product tolerance.