Series
From the shop floor
Shop-floor craft as it happens: one situation per article, the choices you have and what each one costs.
From the shop floor is about craft as it happens in the shop. Each part takes one situation a cost engineer or manufacturing engineer knows: a part that could be turned or milled, a mill-turn machine that does or does not pay, plastic that behaves differently from aluminium, an alloy that has to stay flat, a tolerance or roughness that calls for an extra operation, a thin wall and a repeat order.
For each situation we set the choices side by side and show what each one costs, line by line, with a worked example in round numbers and a rule of thumb you can use tomorrow. No stories about one customer and no promises of time saved, only the trade-offs that set the price in practice.
The order follows the work itself: first the route, then the material, then the requirements on the drawing and finally what makes a second order cheaper. Each part stands on its own, so start with the situation on your desk this week.
All parts
- Part 1
Milling or turning: which route costs less?
A part with round and flat features can come from bar or from a block. Here is how to choose the route and find the quantity at which it tips.
- Part 2
Mill-turn: when does one machine pay off?
A turned part with a spanner flat and a cross hole can travel across two machines or come off one finished. How to check, part by part, which route costs less.
- Part 3
Machining plastics: POM, PA and PEEK in the price
Plastic machines fast but costs money in different places from metal: in the block, in stress and size, and in scrap. How to build the price up line by line.
- Part 4
Choosing aluminium: 6082, 7075 or 5083?
Which aluminium alloy and which stock form suit a milled or turned part, and what does that choice do to distortion, anodising and the price per part?
- Part 5
Which tolerances make a part expensive?
A tolerance only costs money when it calls for an extra operation, another gauge or another machine. How to find those dimensions on a drawing and cost them.
- Part 6
Roughness and finishing: what Ra 0.8 costs
A lower Ra costs money only on the face that carries it. Choose the route per face, ask if sizes apply before or after coating, and cost the finish separately.
- Part 7
Thin walls: when the wall sets the price
A thin wall adds no material, but it costs passes, setups and scrap. How to cost each measure as a separate line, with the reason beside it.
- Part 8
Repeat orders: what makes the second run cheaper?
The program and fixture are paid for, the first article inspection in part. What drops out of a repeat order, what gets shorter and what must be redone?
Your craft. In every quote.
Blake lays out the requirements from drawing and model as proposals and builds the cost per operation, with your own machines and rates. Your team decides.