What do you mean it keeps pulling the items non stop? you have 2 ways i can think of to automate a metallurgic infuser:
1.You get a different infuser for each recipe and have different crafters for each, then just keep each infuser full with redstone/diamond/coal/obsidian/tin dust/mushrooms/biofuel depending on the recipe you are trying to make.
OR
2. you can have 1 infuser for all recipes, point the crafter into a chest, extract items from the chest using item conduits and put redstone/diamond/copper/obsidian/tin dust/mushrooms/biofuel into the side that accepts the infusion material, then have the item you want to infuse go into the side that accepts the item that is being infused
I personally prefer the second way, but its your choice.