First off i want to declare that this is a longshot from my side. Most of you certainly don't have the time to help a complete rookie like me
I am a student that is doing my thesis-work in Sweden at a factory that have a very mixed production unit. Don't know if I am allowed to be any more specific.
I'm new here and also a new user to the Plant Simulation 13 software.
I've previously worked in ExtendSim and Simio and consider myself an intermediate user in those programs.
My main problem is due to the fact that I am stuck in the thinking-pattern associated with ExtendSim and Simio, Plant Simulation seems pretty different/hard to grasp.
The target of my simulation is to see what will happen if the company changes base material to one that is tougher to machine.
The basic layout of the production line is seen in the figure below:
Every frame seen in the model is a separate production unit. (Which I will model later when I get the overall logic working)
Pink flow - Main line
Blue flow - Order/information flow
Red flow- Hardening flow (long lead time)
Green flow - Hardning flow (short lead time)
Black flow - Exit to EDC (some products sold as semi-finished)
Cyan flow - Exit to other in house production unit.
Entities: Don't know yet? Five selected representative products (A to E) with vary varying volumes/quantities
I want to make a flow that is both pushing and pulling (this is the way it looks today)
The initial pull should come from the European Distribution Center (EDC) when they place an order.
The order will be placed at the unit "Front end Machining" which will start to work with delivering/pushing downward the main flow to the next station.
"Front end Machining" produces products in small batches (~6 to 40pcs), and get their material from the unit "storage".
I want to control the unit "Rear end Machining" with an order-point system connected to the stock-levels in the buffers at the unit "storage". The unit "Rear end Machining" currently produces in larger batches (~10-300)
My initial thougt is to simulate the different process times for whole batches of varying sizes, due to the nature of the factory. The process times for the processes in the simulation will be calculated using Excel, and then imported to Plant-Sim.
To give an example: "Machining one piece takes 40s - so machining a 10 piece batch will take 400s", which is used as an input to the processes.
See the figure below to get a feeling of the many different combinations:
(Example ac4 - a stands for product a, c stands for current process time, 4 correlates to the volume)
As there are alot of combinations in products and batchsize there will be many attributes to the entities. Another possible solution would be to create an entity for every combination...
I have started experimenting in a test-model of the storage unit to be made. (lines to make it more visual for myself - will be removed later). See picture:
I currently try to fill the buffers using the entities attributes. For an example an entity with the attribute "ac40" will dismantle and fill the buffer "buff_a" with 40 products.
(I do not know how to solve this in an "easy way")
I want to empty the buffers in a similar way, using the "order_from_front_end". Correct batchsize with the correct product. Much like a Kanban-system - but the KanbanTools seems pretty limited.
(I do not know how to solve this either)
Lastly i want to trigger a new order to the "rear end unit" when the stocks in the five product buffers reaches a certain level.
(Ooh you guessed correctly, no clue of how to do this either)
Sooo... to summarize, maybe I've taken a plunge in the "I've made my model to complex pool" already, or do you Plant-Sim geniuses have any tips and tricks for me?
Best regards - Lindback "the rookie"
PS - Sorry for the long post, here have a cookie
You ask a lot of questions. It is good to start with the rough main flow. Please build small test models for specific principle first, then implement them in the larger model. If you then have specific issue, post them on this forum.
In general, it can work well to combine Assembly and Dismantle stations to model pull systems.
Okey, thank you for your answer Nomden.
Yes I know that the post became terribly wrong, but I just wanted to give you a proper background to the problem.
I've used the same type of system with assembly/dismantle before to simulate a pull in other softwares, but do you think it is the proper way of doing this? Or should I focus more on the premade "Kanban-tools"?
Actually, it is not that difficult to create your own logic for a re-order point system.
My best advice for you is actually to keep your Input data in proper tables. Make sure to use the Row and Column indexes. Then you can very easily obtain the correct settings at any place in the model, as long as the MU and equipment has the right identifying attribute (e.g. name, label).