Setting recipy to Foundry

[Katmans]

Hello!

So, after being new to Factorio and loving it, it seems that I have reached an issue that I find hard to solve. I am trying to set the recipy of my foundy to molten iron/copper depending on the needs I have.

I have been able to do this without any problem for doing molten iron into iron plates or steel, but the molten recipies seem to give me a hard time.

I can:

Set the recipy based on my signals and have one foundry produce both products

However, I am struggling with:

Whenever the recipy changes the foundry (apparently, this is what it seems like to me) has to empty all its trash slots before it can continue on its next recipy. It seems that rather then finishing its current contents it swaps directly, leaving me with a foundry full of stuff which to eject.

Other issues I have ran into but found a work around for is the inserter hand holding the incorrect ore, but it all seems like im trying to workaround a simple solution that I have missed. Has anyone else dealt with this issue and/or do you have some suggestions to explore?

Thanks a ton in advance!

[jaylawl]

Using circuit networks you can read whether the foundry is currently working / producing an item. Ensure that your foundry is not currently producing anything before setting the recipe and that's one problem off your list.

[jdrexler75]

If the recipe signal stays on until it starts crafting, it will finish that crafting. So you can get one cycle with careful circuitry but it is tedious. And yes, when the recipe changes, everything needs to be unloaded first.

One solution is to just control how much gets loaded in the first place, by counting how much the inserter is placing in it, but that gets pretty complicated.

What works better is to change the recipe less often, for example with a memory latch to implement a hysteresis: start smelting when molten metal is below a threshold and stop when it is above a different threshold. That also takes better advantage of the productivity bonus. Basically set the molten recipe when smelting should start, and have a latch keep that signal active, until you send it a reset signal to stop based on the higher threshold.

I have a working example of that here if you want to see my setup: viewtopic.php?p=648222#p648222
Just one foundry for both molten copper and molten iron (with careful priming/emptying of the pipes when starting up) and production of various items from them, which can be done with only two deciders and a constant box, with one decider for all the recipes plus the latch for the smelting recipes only.

Even then as you noticed, it loses a lot of time while unloading/reloading during recipe changes. So I think that sort of setup really only makes sense in the constraints of space platforms, on the ground I now just build enough foundries that at least the smelting ones never change their recices. For the others, unloading fluids is instant so they can change quickly for most recipes.

[Katmans]

Thanks for the replies!

While I have not been able to directly fix it yet you have given me some excellent lines to continue on.

Controlling the inserter really killed by throughput (I just stopped it from working if it was full, causing a delay on each craft) so while I am still working at it and at this point it would probably be easier to just extend my platform and make a second foundry, Ill keep breaking my head over this issue for a little bit longer.

Thanks again!