How to use the machining cycle time calculator
Quoted hours go wrong more often on cycle time than on anything else, because tool changes, part loading and rapid moves add up far faster than people expect. This tool separates cutting time from non-cutting time and reports the cycle time for one part, the total run time for the whole quantity, and the resulting parts per hour.
Cutting time is the travel distance, meaning cut length plus approach and overrun, divided by the feed rate in inches per minute. Moving 8.4 in at 12 IPM takes 42 seconds per pass, so two passes come to 84 seconds. Adding 30 seconds of non-cutting time gives a 114 second cycle.
The approach and overrun allowance covers the lead-in before the tool engages and the clearance after it exits. Milling often uses half the cutter diameter plus a tenth or two of an inch, while drilling is based on the drill point cone. Leaving it out makes the estimate look faster than the machine will ever run.
Parts per hour here is a theoretical figure derived from cycle time alone, so schedules still need setup, first article inspection, tool wear replacement and operator breaks added on top. For parts that pass through several operations, calculate each operation separately and sum the results.
Frequently asked questions
Cutting time is the cut length plus approach and overrun divided by the feed rate. Multiply that by the number of passes and add non-cutting time such as tool changes and rapid moves to get the cycle time for one part.
It covers the lead-in before the tool engages and the clearance after it exits. Milling commonly uses half the cutter diameter plus 0.1 to 0.2 in, while drilling is based on the drill point cone length.