It's hard to guess things without source code and recipes.
https://github.com/Gearhartlove/bevy_jam_2/blob/master/src/mixer.rs#L15
https://github.com/Gearhartlove/bevy_jam_2/blob/master/src/slicer.rs#L9
https://github.com/Gearhartlove/bevy_jam_2/blob/master/src/furnace.rs#L12
Boss is different, you need to place components in eight slots:
https://github.com/Gearhartlove/bevy_jam_2/blob/master/src/boss_fight.rs#L318