GlossaryKind of term: Manufacturing termDesign for manufacturing (DfM)
What is design for manufacturing?
Design for manufacturing is designing with production in mind: choosing shape, dimensions and tolerances so the part can be made in few steps.
Design for manufacturing, DfM for short, is designing so that a part's manufacturability and production cost count from the start, alongside its function. For machining that means concrete choices: internal radii that suit common cutters, pockets and holes no deeper than the tool can reach rigidly, features from as few machining directions as the function allows, standard sizes for holes and threads, and tight tolerances only where the function needs them.
What does design for manufacturing depend on?
A design choice carries through to the manufacturing route. A sharp vertical internal corner cannot be made with a rotating cutter: the smallest radius is the cutter's. A sharp corner needs EDM, shaping or broaching, or a relief in the corner. A smaller cutter reduces the radius but usually needs more conservative cutting data and more time. An angled face or a hole at an angle can need an extra setup or a 4- or 5-axis machine. A hole toleranced H7 usually needs a separate finishing pass such as reaming, boring or precise milling, plus a check. Which choice saves most depends on the machines, the tooling and the quantities of whoever makes the part.
How does design for manufacturing work in practice?
A DfM check in CAD software tests against generic rules, detached from any shop. Whether a design is cheap to make depends on the machines, workholding, tooling and rates of the shop that makes it. A supplier who reviews the design can propose a change with its reason and effect; the customer decides, and a changed drawing comes back as a new revision.
What is design for manufacturing often confused with?
DfM is not manufacturability: manufacturability asks whether a part with its requirements can be made, DfM is the design choice that makes it easier and cheaper to make. DfA, design for assembly, is about putting parts together. Both sit under DfX.
How do you see design for manufacturing in Blake?
In Blake material, machining, finishing, setup and programming are separate lines in the estimate, with your own hourly rate per machine. A design choice that adds or removes a setup or a finish lands in a line you can recognise. The result remains an estimate and is labelled as one. More on estimating.
Frequently asked questions
What are the design rules for CNC milling?
Common guidelines: internal radii slightly larger than the cutter radius, pockets no deeper than the tool can cut rigidly, no sharp vertical internal corners, holes square to a face and in standard sizes, few machining directions, and tight tolerances only where they serve a function.
Can a supplier suggest a design change?
Yes. Give the reason and the effect, such as one setup fewer, no EDM or a standard tool. The customer decides; if the drawing changes, you price the new revision.
What is the difference between DfM and DfA?
DfM is about making a single part: machining, forming, finishing. DfA is about assembling: fewer parts, fewer fasteners, parts that only fit one way.
Is the DfM check in my CAD software enough?
It catches generic mistakes, such as a radius that is too small or a hole that is too deep. Your machines, workholding and hourly rates are not in it, so what a choice costs only shows in the shop's estimate.