Please add a hook for on_research_finished. Otherwise works great.
This is the modification I've made
-- Reload storage on game load
local function on_load()
-- Ensure event handlers are registered again on load
script.on_event(defines.events.on_built_entity, on_built)
script.on_event(defines.events.on_robot_built_entity, on_built)
script.on_event(defines.events.script_raised_built, on_built)
script.on_event(defines.events.script_raised_revive, on_built)
script.on_event(defines.events.on_entity_died, on_destroy)
script.on_event(defines.events.on_pre_player_mined_item, on_destroy)
script.on_event(defines.events.on_robot_pre_mined, on_destroy)
script.on_event(defines.events.script_raised_destroy, on_destroy)
script.on_event(defines.events.on_research_finished, process_combinators)
script.on_nth_tick(60, process_combinators)
end
-- Register events
script.on_init(on_init)
script.on_load(on_load)
