planning in production systems operation scheduling slovak university of technology faculty of...
Post on 19-Jan-2018
212 Views
Preview:
DESCRIPTION
TRANSCRIPT
Planning in production systems
Operation scheduling
Slovak University of TechnologyFaculty of Material Science and Technology in Trnava
Operation scheduling the lowest level of planning detailed description of that, what would be
produced, when and on which machines
Heuristic methods: they are not optimizing methods these methods in majority of cases find
suitable solution, which suits to limiting conditions
it is not obvious, to what extent the solution is good, because optimal solution is not known
they are based on experiences, using knowledge from some previous action
Main aims of scheduling maximum utilization of machines maximum degree of completion and
minimal continuous time minimize of inaccuracy function
Scheduling objectives1. assign operations to production facilities –
entering into production with aim to design a removal profile of capacity units Two basic approaches:
forward loading backward loading
2. to define processing order of individual products in process of production – sequencing
Forward loading it starts with actual point in time, products
are assigned to workplaces towards future on the workplaces the capacity demands
which are under consideration time periods are cumulated; it is possible to consider of final or unlimited workplace capacity
time scheduling horizon could be overrun – no fulfilment of product delivery time
Backward loading products are starting to assign into
workstations from the term of their eduction backwards, in actual term, assigning starts at latest possible term, minimalization of working out, short continual periods
it is possible to over step capacity border of workplace
terms of overrun are not over stepped
Assignation order of processing production task it is necessary to define superior selection
rule – according it the products are chosen from line and are assigned to working places
it is necessary to assign rule for choice of machine, that performs right operation
Hand made Gantt diagram - forward loading
Hand made Gantt diagram - backward loading
Techniques and methods of scheduling Conventional methods
Mathematical programming approaches – linear programming, dynamic programming
Heuristically oriented approaches New methods
Techniques of artificial intelligence and knowledge systems
Techniques with use of neuron netsTechniques with use of modeling and
simulations
Place of scheduling in PPS systems Source
requests of plan
Aggregate production planning
Rough capacity planning
Operation planning
Capacity requests of
plan
Material requests of
plan
input/output
analysis
Workshop system of scheduling
Dynamic management
Offer management
Required input and output information
Input information Output informationProduction plan Input in productionProducts structure, components Production orderProduction procedure, operations Working sheetsTechnologies used, productionsources
Production currency
Working sourcesCalendar of changes
top related