Why Most DFM Advice Fails – And What Actually Works

Procision Manufacturing

Writer

A lot of manufacturers claim to offer DFM analysis. They publish blog posts and white papers, hoping to explain what DFM is and how it works.

Unfortunately, most of those definitions are misleading, incomplete, or just plain wrong.

Let’s clear the air. In this article, we’ll define what DFM actually means, what it doesn’t, and how a correct application of DFM discipline can improve your product, reduce your costs, and prevent painful production mistakes – before they happen.

What Is Design for Manufacturability, Really?

Design for Manufacturability is an engineering analysis that ensures a product design is optimized for its manufacturing process. While it’s often associated with production-scale methods like injection molding, its role is just as important for low volume manufacturing such as CNC prototyping. When done properly, good DFM analysis is conducted specifically to ensure the design is optimized for two things:

The process (or processes) that will be used to fabricate it
The design intent. For example, the function and purpose the part must fulfill

That second point is often ignored. But it’s critical.

Design intent aligns everyone around what the part must do, not just how it can be made. That means DFM can’t happen in a vacuum. It requires open communication between the designer and the product manufacturer – a shared understanding of goals, constraints, and tradeoffs.

Why Is Design Intent So Important?

Understanding design intent ensures parts aren’t just manufacturable, they must be functionally suited for the final product or application-specific design. You can optimize draft angles, wall thicknesses, and hole locations all day. But if the finished part doesn’t perform as intended, that’s not a win, it’s a waste.

DFM only works when the manufacturer understands the role of the part in the final assembly or product. With that insight, they can offer meaningful suggestions that enhance both form and function. Without it, even a perfect-looking part might be a complete functional failure.

No responsible manufacturer wants that outcome.

Material Selection and Its Impact on DFM

Material selection is another overlooked area in typical DFM conversations.

Yet material choice has a huge impact on function, durability, surface finish, and cost. A good DFM review will always assess whether the chosen material is the right fit, and whether a different alloy, resin, or grade could offer a benefit like:

Better surface treatment compatibility
Lower cost
Greater machinability
Reduced cycle times

Of course, any material suggestion must preserve the original design intent. That’s where experience and engineering judgment matter.

What DFM Is Not

Many discussions around DFM focus solely on high-volume production or PIM. But in reality, DFM is just as critical during rapid prototyping and low-volume CNC runs, where early decisions lock in downstream outcomes. Let’s debunk a few common misconceptions:

DFM is not

DFM is not dependent on order quantity. It applies equally to one-off prototypes and high-volume production.

DFM does not

DFM is not a cure-all for bad design. It can’t make up for vague specs, incomplete files, or unrealistic expectations.

DFM is also not

DFM is also not a cure-all for bad design. It can’t make up for vague specs, incomplete files, or unrealistic expectations.

Think of DFM as an intelligent design critique – grounded in real-world process constraints and built on a foundation of experience, not assumptions.

What Questions Should a DFM Review Answer?

An effective DFM review should walk through a short but powerful set of questions:

1. Can the part be made at all?

For example, extreme undercuts on plastic injection molded parts will cause them to lock inside the mold, making it impossible to release them later. Similarly, CNC machining can’t make a feature that isn’t in line-of-site of the cutting tool. Every feature and specification needs to be analyzed with an eye towards feasability.

2. What’s the best process to make it?

A good DFM review always looks for the most efficient way to manufacture a design, even if there are potentially several alternatives. As an example, CNC milling wouldn’t be the ideal way to make a cylindrical metal shaft, because it’s slow and expensive. In this case, CNC turning makes much more sense.

3. Is the material suitable for the part’s function?

In reality there may be several materials that could potentially fulfill the design intent, with different benefits and tradeoffs. Among the questions to answer: How long does the part need to last, under what environmental and mechanical conditions, at what cost and difficulty to manufacture? Are there cheaper alternatives that will work just as well? And how would I need to change the design to suit the material?

4. Can we improve manufacturability without compromising performance?

Here’s where a competent manufacturer really has the chance to shine. We might recommend reducing the number of critical dimensions on CNC machined parts, simplifying complex geometries, or increasing the draft angles on plastic injection molded parts – without compromising the part’s function.

You’d be surprised how many CAD files fail the very first question. And nearly every design, or the tooling used to make it – can be refined in some way to improve performance, cost, or throughput.

What Are the Benefits of DFM?

While results vary by project, DFM can offer significant benefits. Even in early-stage builds like CNC-milled prototypes, DFM helps catch costly design issues before tooling, molds, or high-run programs are ever created. These are some measurable advantages:

Fewer rejects. By reducing unnecessary critical tolerances or simplifying hard-to-machine features.
Better aesthetics. Through tweaks to mold parting lines, surface textures, or by recommending better-suited materials (e.g., 6xxx vs. 7xxx aluminum for anodizing).
Faster throughput. Especially in injection molding, where cooling channel optimization can significantly reduce cycle times.
Lower total cost. Reduced scrap, shorter runtimes, less tool wear, it all adds up to higher yield and lower spend.

These benefits matter most in high-volume manufacturing, where DFM has the greatest leverage. But even in rapid prototyping, good DFM ensures that what you build works – the first time.

Want to Get DFM Right? Work With the Right Team.

At Procision, DFM isn’t a buzzword. It’s a core part of every project we take on, from single prototypes to full-scale production. Early DFM reviews ensure your design is scalable, functional, and efficient.

Our engineers work directly with you to understand your goals, interpret your design intent, and give honest, expert feedback, before your parts hit the machine.