Process Resources Allocation

Resources Allocation with alternatives in complex production processes (Production in Line)

The dependency transition constraint appears in many cases in complex processes, especially for in-center or in-line production .

In these cases, resources are bound through several operations during the process. The selection in upstream operations could affect the resources choices in several other downstream operations.

The operations are bound by initial choice.

Many scheduling software give poor response to this crucial constraint, operations are treated as single entities regardless of the precedent placements.

With Sched the entity is one combination of a set of operations, a set of acceptable combinations being fixed in the process.

The best placement result is issued from the examination of all the planned combinations.

The process alternatives for one process are defined by sched as in-line resources combinations .

Sched examines all the in-line resources combinations possible and keep the best ( in “automatic mode”) or propose to valid the choices among all possibilities (in “choose mode”)

Resources alternatives or no-line combinations are also authorized at the same time.

Sched offers two levels of combinations: one with in-line resources and the second for no-lines resources.

Sched Ressource allocation grammar.

A convenient grammar has been developed for sched permitting the description of work flows alternatives and complex resources allocation for a process.

This grammar is useful for all process type treated by sched, basic, in-production center and in-line production.

More mixing part of each within the same process is authorized with the grammar.

Many examples showing process description are provided in evaluation software and user's guide.

It is too long to described this here we will illustrate the grammar use with a single example.

Note : this example do not illustrated all ressource allocation tecniques.

Example of Process description with sched.

Production in Line with in-line and No-lines Resources Combinations.

Suppose a complete process named PRO24. Activities could be affected to several fully automated lines named L1, L2 & L3 which have not necessarily similar performances but could produce the same product.

Each line can handle filling (engine GRO1,GRO2 & GRO3 with 4 operators skill R4) , individual boxing (engine KAL1, KAL2, KAL3 with 2 operators skill R7) , cellophane wrapping and packing in boxes (engine SOL1, SOL2, SOL3 with one operator skill R9) under the strict control of a line chief (skill R2) ; thus with nine operators at the same time for the production operation.

A technician (skilled T3) is shared by the three production lines (33% of his time for each line).

2 other No-line combinations are accepted for the production operation :
one with 11 operators (saving 20% in time), the second one with only 6 operators (loss 20% in time)

During the production process an operator (skill &R18) supplies the line with components. The time needed for this operation is 10’ an hour.(16%)

Final control (operation P4) is done by operator H17

Each installation has a setup time of 1hour ; this set-up time is done by one technician with skill R8. If 3 technicians are available at the same time , each could be assigned to one installation.
When the set-up is done ,the production begins: all the 3 installations in the line are working together.

In that case , the 3 lines (and , of course, the 3 engines) are the in-line resources , all other resources (technicians, operators, line chief) are no-line resources.

With sched process PRO24 will be described in two parts :

a) First : the description of authorized in-line resource combinations

3 in-line resources combinations allowed

Note : Production Time on L3 is increased by 25% due to poor performances.
Imagine a complete process named PRO24. Activities could be affected to several fully automated lines named L2, L3 & L4 which have no similar performances.

b) Secondly : Operations will be described as :

Other levels alternatives for no-line resources are allowed.

Notes :

1. The event time for A02 and A03 is noted A01 meaning these operations could begin as early as possible after the beginning of operation A01 according to the availability of resources with skill &R8.
2. The in-line resources selection for A03 is limited to SOL3; only the third engine on the line is concerned for this operation.
3. The supplying time 10’ (16%) spread over all the production time.
4. The final control is done by H17 , no installation on the line is necessary
5. 3 the no-lines alternatives for operation B02

Operation P04 control is attached to the process but do not consume line