Why inserters don't fill factories to max?

[hazardoustorm]

I'm sorry if this is else where, but I can't seem to find it on this forum or the wiki. I am trying to automate everything and am using fast inserters to do so. I thought that using the inserters would work since they would constantly fill all my furnaces and such, but I've noticed that the inserters only seem to put 2 items into the furnace (or any object other than chests) before stopping, treating it like 2 or 3 is the max. Is there a reason for this? or is it a bug? or am I just doing something wrong?

Thanks,

[Rockstar04]

Your not doing anything wrong at all. When placing items into assembly machines inserters normally place twice whats required to create an item. This is so the machine start creating items sooner if the recipe takes multiple items. You don't want to wait for an inserter to put 200 copper wire into the machine, before one iron plate to make a green circuit.

When using speed modules, inserter will put more items in to help make user the machine wont run out of items when crafting at high speed.

[Koub]

This is correct. You don't want your assembling machines to act as a 1 stack buffer for all the components they need to craft something. You'll end up with probably hundreds assembling machines, and that would get you to tens of thousands of unused components, some of them really costy in terms of raw materials.