Modelling a Job Shop using OntoGui

Case Description

Job shops machines are aggregated in shops by the nature of skills and technological processes involved, each shop therefore may contain different machines, which gives this production system processing flexibility, since jobs are not necessarily constrained to a single machine.

Formal model

formal-model

The job shop is composed by 5 machines and 5 buffers as depicted in Figure 2. Each buffer is associated to the machine in front of it (e.g. B1 is associated only with M1). All the machines are physically connected each other and the path of a part type inside the system is defined by its production process. The processing time of each machine depends on the part (class) to be worked.

formal-model-1

Production processes

Consider the production of 3 parts (classes), whose production processes are reported in Table6. Each part type has a different process and flows through the system following a different path. In this table and for each part, only the machines to be visited have a process duration. In the case of open system, the generation rate is reported in Table 6.

failure-probabilities

The failure and repair probabilities for each machine

buffer-size

The sizes of the buffers are reported in Table

Modelling of Job shop( Using OntoGui)

System Creation

create-ontology-module

1. Write ontology module name

2. Click 'Create New'

open-system-design

1. Click 'system design'

create-production-systems

1. Write production system name,

2. set the class 'manufacturingsystem'

3. Click 'create'

4. write machine name

5. Click 'Add'

add-failure-mode

1. Click 'Add' in the 'Manage Failure Modes of Machine' section

2. Enter mean time to failure value

3. Enter mean time to repair value

4. Click 'save'

Add-Buffer

Switch to 'Buffer in System' section

1. Write name of buffer

2. Click 'Add New'

3. Write buffer size

upstream

1. Select Upstream item of B1

2. Click 'Add'

Part Creation

Note:

• Creating Part-A as a WorkpieceType in Job-Shop

• In the use case it asks to formalize system with one part at first.

part

1. Write part name

2. Set the class 'WorkpieceType'

3. Click 'Create'

production-process

1. Write process plan name

2. Click 'Create'

process-steps

1. Write name of process step

2. Set the type of process

3. Click 'Add New'

4. Click 'Set Time'

5. Enter process step time value

6. Click 'Save'

successor

1. Select the process step

2. Select successor of the process step

3. Click 'Add'

Machine assign

1. Select the process step

2. Select the machine to be assigned

3. Click 'add'

Multi class (all the three parts), closed system

• We will enter all the parameters for Part-B and Part-C as Part-A

• Assignment of machines form the same production systems

part-b

1. Write part name

2. Set the class 'workpiecetype!

3. Click 'create'

Note: Follow the same steps for Part-C

process-b

1. Write process name

2. Click 'create'

process-steps

1. Write name of process step

2. Set the process type

3. Click 'Add new'

4. Click 'set time'

5. Enter the time value

6. Click 'save'

successor

1. Select the process step

2. Select the successor of the step

3. Click 'add'

4. Select process step

5. Select machine to be assigned

6. Click 'Add'