17 03 2015 basic factory physics 01
DESCRIPTION
factories phisicsTRANSCRIPT
-
Basic Factory PhysicsProf. Hyun Chung
Mar. 17 2015
1
Definitions
Manufacturing system: A manufacturing system is an objective-oriented network of processes through which entities flow.
2
-
GT revisited
Classification: arranging items into groups according to some principles or system where by similar things are brought together by virtue of their similarities and then separated according to their differences
3
GT revisited
Code: A system of symbol (alpha-numeric) used in information processing in which a combination of numbers and letters have a certain meaning
4
-
Applying GT
Direct Clustering Algorithm
Similarity Index
Dendrogram
McAuleys single linkage cluster analysis
5
Definitions
Workstation: A workstation is a collection of one or more machines or manual stations that perform (essentially) identical functions.
Synonyms: station, workcenter, process center
6
-
Definitions
Part: A part is a piece of raw material, a component, a subassembly, or an assembly that is worked on at the worstations in a plant
Synonyms: intermediate product, interim product
7
Definitions
End item: A part that is sold directly to a customer
Synonyms: product
The relationship between end items and their constituent parts (raw materials, components, and subassemblies) is maintained in the bill of materials (BOM)
8
-
Definitions
Consumable: for the most part, consumables are materials such as bits, chemicals, gases, and lubricants that are used at workstations but do not become part of a product.
What about glue and solder?
9
Definitions
Routing: A routing describes the sequence of workstations passed through by a part.
Order: A customer order is a request from a customer for a particular part number, in a particular quantity, to be delivered on a particular time
10
-
DefinitionsJob: A job refers to a set of physical materials that traverses a routing, along with the associated logical information (e.g., drawings, BOM)
Every job is triggered by
an actual customer order
anticipation of a customer order (forecasted demand)
11
Definitions
Throughput: The average output of a production process (machine, workstation, line, plant) per unit time
can be defined at various levels
Synonyms: throughput rate
12
-
Definitions
Capacity: An upper limit on the throughput of a production process
Raw material inventory (RMI): the physical inputs at the start of a production process
13
Definitions
Finished goods inventory (FGI): The stock point at the end of a routing
used to gather different parts within the plant before further processing or assembly
14
-
Definitions
Work in process (WIP): the inventory between the start and end points of production routing
Synonyms: inventory
15
Definitions
Inventory turns: a commonly used measure of the efficiency with which inventory is used
Synonyms: turnover ratio = the ratio of throughput to average inventory
16
-
Definitions
Cycle time: The cycle time of a given routing is the average time from release of a job at the beginning of the routing until it reaches an inventory point at the end of the routing
Synonyms: average cycle time, flow time, throughput time, sojourn time
17
Definitions
Lead time: the lead time of a given routing is the time allotted for production of part on that routing
Synonyms: build time
18
-
Definitions
Utilization: the utilization of a workstation is the fraction of time it is not idle for lack of parts.
includes the fraction of time that workstation is working on parts or has parts waiting and is uable to work on them due to a machine failure, setup, or other detractor.
19
Parameters
Bottleneck rate: the bottleneck rate of the line is the rate (part per unit time or jobs per unit time)of the workstation having the highest long-term utilization
20
-
Parameters
Raw process time: the raw process time of the line is the sum of the long-term average process time of each workstation in the line.
21
Parameters
Critical WIP: the critical WIP of the line is the WIP level for which a line with given value of bottleneck rate and raw process time but having no variability achieves maximum throughput with minimum cycle time.
22