Modelling complex manufacturing systems using the IDEF modelling languages

Hi all,

I'm wanting to model a complex manufacturing system using the IDEF languages, specifically IDEF0 and IDEF3. To do this I am performing a top-down approach (Process decomposition), whereby the high-level organisational processes are defined then each layer below the high-level is defined through processes, activities and finally tasks.

I am confused which of IDEF0 and IDEF3 is best to model the high-level processes and which for the low-level processes? Any help on these languages or other way of modelling manufacturing systems will be appreciated.

Example: High-level = planning > machine setup > operation > post-processing > inspection > delivery.

Planning subprocess = feasibility assessment > risk management > develop manufacturing plan etc.

feasibility assessment subprocess = costing > resource assessment > production scheduling etc.

This sort of decomposition until the full manufacturing system is broken down into individual task and work instructions.

Thanks

Duncan

Duncan -

I used IDEF0 quite extensively a long time back. Also IDEF1X (for entirely different purposes) and dabbled in IDEF3. For BPM, I think there are probably better choices than IDEF3 these days, but I am out of date in that area.

I found IDEF0 (or SADT) to be a very useful high level modelling tool in the right circumstances. The trick is using it in a way that actually gains you a useful perspective.

From your initial post it seems that you have been asked to model a manufacturing system. This is OK, but the first question you need to ask is 'what do we want to get from our model'. If you can't answer this question clearly and simply, I expect that you will spend a lot of time analysing the system and end up with some fascinating diagrams that will not get used for anything productive. You need to probe the reasons why you need a model before you start.

Given that you do have that clarity I think IDEF0 is a powerful tool. It is basically so simple that you can use it to communicate results with management without having a massive gap of understanding. I used to explain how IDEF0 worked in about 15 minutes to people who had never been exposed to it and then go on to show what the model could tell them about the system being considered.

Expect to spend a lot of time talking to people who work in this system (assuming it already exists!) and gathering information. Without some significant thought in this area your model may be pretty but invalid.

Alongside IDEF0 you need some understanding of some basic information theory concepts, which IDEF0 is very good at illustrating. Things like convergent and divergent flows within an organisation : the best place to exert control is where flows converge etc....

I'm sure you are aware of the defence origins of these tools (hence the DEF bit) and that the basic papers are publically available. For IDEF0 the book that I used years ago was 'SADT Structured Analysis and Design Technique by Marca and McGowan. If you don't have it, I would buy it. There are plenty of second hand copies available on UK Amazon.

There are other modelling approaches of course. For the right type of problem, Soft Systems Methodology is extremely powerful, but quite different to IDEF0.

Try to define what you want to acheive and why you are starting this modelling project and I (and others) will be able to help you more specifically.

Thanks for the information. Will research those topics and book you suggested.

Much appreciated
Duncan