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Hi there,

I'm curious how to use the "CUTOFF injection moulding-RER" flow, specifically, and in what context it's appropriate? I am attempting to do an LCA of a product that has 3 components, each made out of different amounts of different types of plastic (polycarbonate, PA66, TPU), but all using injection molding. I did not want to include the production of the injection molding machine within my system boundaries.

My plan was to use this "CUTOFF injection moulding-RER" flow + a TPU flow (for example) + an electricity flow as the inputs to the respective "product component production" process. 

However, I'm confused what to put as the "amount" of the "CUTOFF injection moulding-RER" flow? it asks for a number of kg...is that the kg of material (TPU in this case) being inputted into the injection molding machine? I'm confused what else it would be, but also not sure. Any help would be greatly appreciated, thanks! 

in openLCA by (260 points)

1 Answer

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by (107k points)
Hi, basically, a cutoff flow is a "remainder" from other LCA softwares which require always processes producing a product to be able to calculate systems (like e.g. SimaPro). In openLCA, we do not have this limitation, if you have products in your life cycle where you exclude the supply chains from your system, because you do not have the information or because of goal and scope system boundaries, you can simply have a product flow as input, without setting a provider, and then create the product system so that only flows with providers are autoconnected.

As result, you will see in your calcuated inventory results the product as input, it is not hidden as it is in other LCA software but will be transparently visible. Of course you should still set the amount of the input product (if this was your question?).

In newer ecoinvent versions, we do not have product fows named "CUTOFF" any more.
by (107k points)
if you have no elementary flows in your processes then you will not get impacts, so this is not an error.
Best wishes, Andreas