Modelling guide
Loading the next unit while the machine works
A machine has two fixtures, a turntable or a shuttle table: the next unit is loaded while the current one is processed, so loading costs no machine time.
Approximation Close, with a stated limit.
How
Give the machine positions: 2 and position_mode: "parallel", and the capability's time as the time one unit takes from loading to unloading. With two positions the machine finishes a unit every time / 2 seconds.
What it leaves out
- Both positions are modelled as working at the same time for the whole
time; a real two-fixture machine cuts one unit while the other is only loaded. The output rate is right when loading takes about as long as cutting; when loading is much shorter, givetimeas cutting + loading and expect the machine to look busier than it is. - With a shared operator pool, give the loading time as
operator_start_sso the operator is free while the machine cuts (see machine-tending).
Check
A 9-minute machining cycle on a two-fixture mill gives a housing every 270 s, so one mill meets the 300 s takt and the shift's 96 housings are made.