Definition
Work preparation is the step between the order and the shop floor. The work preparer reads the requirements, chooses the sequence of operations, decides the setups, reserves tooling and material, records the times per operation, and puts all of it into a routing. In smaller shops the same person often does the estimating as well.
What it means for the calculation
A large share of a part's eventual cost is often effectively locked in here, before a single chip is cut: the sequence of operations and the number of setups drive the time, and the choice of machine and tooling drives the rate. Work preparation is a cost item in its own right: on a new, one-off part it can take hours, and those hours land on the first order. On a repeat order the routing already exists, which is a common reason repeat work is cheaper.
Where this comes up
As a role on the shop floor, and as the routing, the tool list and the time standards it produces. In a shop's own system this step sits between the quotation and the production order.
Common mistakes
Hiding work preparation hours in an overhead percentage, which makes a one-off part with heavy preparation look as cheap as a repeat order. Also quoting without thinking the sequence of operations through: with no sequence there is no setup count, and with no setup count there is no time.
A large share of a part's eventual cost is often effectively locked in here, before a single chip is cut: the sequence of operations and the number of setups drive the time, and the choice of machine and tooling drives the rate. Work preparation is a cost item in its own right: on a new, one-off part it can take hours, and those hours land on the first order. On a repeat order the routing already exists, which is a common reason repeat work is cheaper.
See how Blake reviews a partFrequently asked questions
Is work preparation the same as estimating?
Not quite: estimating produces a price, work preparation produces the plan that price rests on. In small shops it is one person.
What does a work preparer deliver?
A routing with operations, times, machines, tooling and setups, plus the material needed.
Why is repeat work cheaper?
Because the routing, the program and the fixture already exist.