GlossaryKind of term: Manufacturing termTime booking
What is time booking?
Time booking records the time spent per order, operation, machine or person, as the basis for actuals, payroll and planning.
When the same booking also records the number of good and scrapped parts, it is usually called production data capture. The booking is made on a job card, through a terminal or MES on the shop floor, or automatically from the machine control. A manual booking and a machine signal are not the same thing: the first is a declaration, the second a measurement of machine state. The signal does not by itself say which order or operation the time belongs to.
What decides how useful time booking is?
Labour hours and machine hours do not run in step. An operator tending two machines books fewer labour hours than there are machine hours, and a machine running unattended accumulates machine hours with no labour hours at all. A booking that records labour hours only gives an incomplete picture of machine time. The level of detail determines what you can trace later: one total per order, or a time per operation and setup. Booking after the fact, rounding and indirect time that lands on an order all blur the data.
How does time booking work in practice?
Booked times are what an estimated machining or setup time is checked against. The same hours also include breakdowns, running in a new batch, waiting for inspection or a shift change. Whether a time is representative of the next batch depends on the conditions it arose under, so those belong in the booking too: machine, setup, quantity and anything unusual. Adjusting a standard on a disturbed booking can skew the price of the orders that follow.
What is time booking often confused with?
Time booking is not the actuals: it supplies the hours, the actuals compare them with the estimate. Nor is it actual cycle time: that is one measured time per part, while time booking also covers setup, inspection, breakdowns and indirect time.
Frequently asked questions
Why is a booked time not the new standard straight away?
Because it also contains time you do not want to count, such as downtime from a breakdown or an operator who turned the feed down. Only once you know the conditions the time arose under can you say whether it is representative.
Which booked times are most useful for estimating?
Hours per operation and per machine, with the setup noted, plus the number of parts made and scrapped. Keep machine hours and labour hours apart when one operator runs several machines or machines run unattended.