Netlogo Minifactory

What is it?

This model simulates a factory.

It is meant for education and inspiration.

I wrote a detailed tutorial:

• English: Introduction to simulation with NetLogo: how to create a small factory?
• French : Introduction à la simulation avec NetLogo : comment créer une petite usine ?

Mechanisms are partially inspired from:

Martin, K. and Wilensky, U. (2021). NetLogo Robotic Factory model. http://ccl.northwestern.edu/netlogo/models/RoboticFactory Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

Moving agents are robotic crates with parts inside.

Static agents are workstations. Manufacturing machines, control posts, shipping and sales.

The following mechanisms have been implemented:

• Operations now take time and only one operation can be achieved at the same time. This is done by relying on decaying links.
• Defects can appear during manufacturing operations.
• Control operations delete the defective crates
• We monitor the margin
• All production parameters can be modified by sliders
• There are also switches that bypass controls

How it works

Robots move toward a destination.

The destination is defined workstation per workstation.

Each time a robot comes to a workstation, it receives the next destination.

However, when they are at a workstation, the robots are linked to it.

The duration of the link represents the duration of the manufacturing, shipping, or control operation. Links also infer a cost.

There are different types of operations:

• Get and cut the material. A steel rod.
• Forge the steel rod by stamping, it creates the raw shape of the part.
• The deburring operation is not included for simplicity reasons. Let's say it is part of the forge.
• Polish the part to make it shine.
• Machine tool the parts on a CNC Lathe
• Ship the part
• Gain money if the shipped part is good.
• If there is a defect, however, the gain is negative.

How to use the UI

Base

• setup Install the workstations and robots inside the factory
• go launch the simulation

Global parameters

• crates defines the number of robotic crates
• batch defines the number of parts in each crate
• price defines the gain from a part sale (minus costs not related to manufacturing)
• penalty defines the money lost from shipping a crate with defects

Per workstation

• cost_... defines the cost of the operation (monetary)
• time_... define the time taken by the operation
• defects_... define the proportion of crates becoming defective at this workstation
• do_control_... allow to test the effect of bypassing a control post

Important

** /!\ This model is not meant to simulate an actual factory.**

The author will take no liability. This is a simplified simulation for learning. It may be used as an extendable base if you know what you are doing and why. Then, you are responsible for what you do with this model.

Things to try

Try to deleted intermediary controls. Except for the last one.

If there is a relatively high amount of defects, you will lose money.

With a small number of defects and/or economic controls, you may have a positive income.

Extending the model

We are far from a realistic manufacturing process. In the real world:

• it is probable that only x% of a crate has defects.
• we lose some parts at each step due to quality issues
• industrial processes are permanently being improved or modified
• defects rates are higher at the start, so there are more controls on new parts
• there are several types of control. Dimensional, visual, tensile strength...
• some controls are made on a part of the crate, so some defects can still go through controls
• ...

Netlogo features used

• agents
• links

Licence

This model is released under a CC BY SA 4.0 license.