What is a DFM checklist?

A design-for-manufacturing checklist is a short list of design rules that keep a part cheap and reliable to make. It covers the universal principles (loosen tolerances, use standard materials, cut part count) plus the specific rules for the process you will use, such as uniform walls and draft for injection molding or reachable pockets for CNC.

When should I run a DFM check?

As early as possible, and again before you commit to tooling or a production run. The cheapest time to change a part is before it exists, and most of a product's cost is locked in by design decisions long before you get a quote. Run it during design, then once more at design freeze.

Does this replace a manufacturer's DFM review?

No. This checklist helps you catch the common, expensive mistakes before you send your design out, so the manufacturer's review goes faster and your quotes are better. A good manufacturer will still do their own DFM review against their exact equipment, and you should want them to.

The rules for my process seem to conflict. Which wins?

The process you will actually use always wins. The universal rules apply to everything, but the per-process numbers are specific to how that process physically makes a part. If you are not sure which process fits your product and volume, start with the manufacturing guides linked below.

Design for Manufacturing (DFM) Checklist

Updated November 14, 2026

Most of what a product costs is decided at the design stage. Run your design through this checklist before you send it out for quotes or tooling: the universal rules first, then the specific ones for the process you will use. Tick items off as you go, and print or save it to share with your designer or manufacturer.

The one rule that saves the most money

If you do only one thing on this list, loosen your tolerances. A tolerance is how much a dimension is allowed to vary, and every step tighter adds inspection, slower machining, and scrap. The cost climbs fast:

Tolerance	Rough cost vs standard
±0.5 mm (standard)	1x (baseline)
±0.1 mm	about 1.5–2x
±0.05 mm	about 2–3x
±0.025 mm	about 3–5x
±0.01 mm	about 5–10x

Hold a standard tolerance across the whole part and tighten only the few features that truly need it, the ones that mate, seal, or bear a load.

Where this comes from

The rules and numbers here are drawn from established 2026 design-for-manufacturing guidance across injection molding, CNC machining, and additive processes. They are sensible defaults, not absolutes: your manufacturer will have exact figures for their own equipment and materials, which always win. For the full explanation, see our guides on design for manufacturing, design for manufacturing and assembly, and DFM guidelines by process.

Want to design a product that is actually cheap to make? The idea-to-shelf program teaches design for manufacturing as part of the full path from idea to production.

Frequently asked questions

What is a DFM checklist?: A design-for-manufacturing checklist is a short list of design rules that keep a part cheap and reliable to make. It covers the universal principles (loosen tolerances, use standard materials, cut part count) plus the specific rules for the process you will use, such as uniform walls and draft for injection molding or reachable pockets for CNC.
When should I run a DFM check?: As early as possible, and again before you commit to tooling or a production run. The cheapest time to change a part is before it exists, and most of a product's cost is locked in by design decisions long before you get a quote. Run it during design, then once more at design freeze.
Does this replace a manufacturer's DFM review?: No. This checklist helps you catch the common, expensive mistakes before you send your design out, so the manufacturer's review goes faster and your quotes are better. A good manufacturer will still do their own DFM review against their exact equipment, and you should want them to.
The rules for my process seem to conflict. Which wins?: The process you will actually use always wins. The universal rules apply to everything, but the per-process numbers are specific to how that process physically makes a part. If you are not sure which process fits your product and volume, start with the manufacturing guides linked below.

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