Design for Manufacturing: CAD Tips That Save Real Money

By MechaniCADD Design & Drafting Solutions

A great CAD model means nothing if it can’t be made efficiently. In product development, cost isn’t just material and time.... it’s machine passes, tool access, tolerances, fixturing, rework and how cleanly a part moves through fabrication.

Design for Manufacturing (DFM) bridges the gap between the computer screen and the machinist’s spindle. When designers apply DFM principles early, teams reduce scrap, shorten lead time, and avoid the “beautiful model, expensive part” problem.

Below are practical, real-world CAD habits that make manufacturing smoother and measurably cheaper.

1. Avoid Unnecessary Tight Tolerances

The #1 hidden cost in manufacturing is over-tolerancing. Many parts go to production with ±.001" when ±.005" would have worked perfectly.

Tighter tolerance = slower machining + more inspection + higher cost.

Guidelines:

• Use tight tolerances only where function demands it

• Match tolerances to the capability of the process (CNC vs laser vs waterjet vs plasma)

• Apply fit tolerances intentionally (press, slip, clearance)

Sometimes a loosened tolerance saves hours of machine time with zero performance loss.

2. Reduce Deep Pockets and Thin Walls

Deep pockets require long tools → more chatter → slower feeds & speeds. Thin walls deflect, vibrate, and often require extra finishing passes.

Better approach:

• Increase wall thickness where possible

• Add relief openings or ribs

• Split into multiple parts if necessary

Manufacturing prefers parts that are rigid, reachable, and stable under tool load.

3. Avoid Sharp Internal Corners

Sharp corners can’t be milled without secondary operations like EDM — which is costly.

Instead:

• Add fillets that match real cutter radii

• Use standard end mill sizes (⅛", ¼", ½", etc.)

• Increase radii on internal pockets where possible

A simple corner fillet can turn a multi-operation setup into a one-operation cut.

4. Think About Tool Access Before Finalizing Geometry

If a tool can’t reach it, it can’t be machined — at least not cheaply.

Ask during design:

• Can a cutter approach from Z?

• Will this require custom tooling?

• Do I need to split the part for access?

Good DFM minimizes fixturing complexity and maximizes single-setup machining.

5. Simplify Weldments for Fit-Up and Repeatability

Welders love precision — but they hate surprises.

Common issues:

• Inconsistent gap spacing

• No locating features

• Hard-to-access weld seams

Solutions:

• Add tabs, slots, and alignment features

• Design joints to self-locate where possible

• Leave room for torch/nozzle access

Good weld design reduces jig complexity and eliminates guess-and-check assembly.

6. Standardize Holes, Fasteners & Features

Every non-standard feature is a decision point, and decisions cost time.

Choose standards whenever possible:

• Hole sizes → match standard drill sizes

• Fasteners → use one type across the assembly

• Chamfers/fillets → standardize edge treatments

Standardization speeds machining, assembly, and purchasing.

7. Involve the Shop Early

The best DFM improvement comes from one place:

Talk to the machinist before you finalize the design.

They know what runs well, what slows production, and which features cost money. A 10-minute conversation can save thousands — usually more.

Summary — Good CAD Saves Money Before It Hits the Shop

Design for Manufacturing isn’t extra work — it's smarter work. By applying practical DFM principles early, you can:

✔ Reduce cycle times✔ Lower machining & fabrication costs✔ Prevent redesigns & mid-build changes✔ Improve quality and assembly fit✔ Build products that scale

At MechaniCADD, we help teams develop production-ready models, drawings, and workflows that move seamlessly from idea → CAD → fabrication.

Need help optimizing your drafting packages?

We offer:

• Mechanical design & 3D modeling• Fabrication & shop drawings• DFM review & drawing clean-ups• Standardization + PDM/organization support• CAD onboarding & training for teams

Get in touch to start your next project with confidence. Contact Us to get started!