Engineering Drawing Design Review Checklist

We all get “tunnel vision” from time to time at work. That’s especially true for designers trying to balance quality, cost, and timeliness.

In engineering, the goal of a drawing review isn't to eliminate every possible question before RFQ. It's to eliminate avoidable ambiguity while clearly communicating what the manufacturer needs to make good engineering and quoting decisions.

Since powder metallurgy (PM) comes with its own unique design considerations, we’ve created a handy checklist for your next engineering drawing review.

Our goal is to help you arrive at a production-capable design sooner while supporting quality, manufacturability, and overall project value. Whether you're developing a new powder metal component or evaluating an existing design, this checklist can facilitate productive back-and-forth with your vendor and identify opportunities for optimization before production.

How Does a Design Engineering Review Work?

There are certain areas of a design a manufacturer is going to cover when evaluating feasibility and preparing a quote.

In our experience, these are the areas that most frequently benefit from additional review and discussion during the quoting process:

• Geometry that is PM-friendly
• Tolerances that are practical
• Dimensions that are accurate

Some manufacturers may be comfortable relying on a solid model for guidance. However, doing so can leave GD&T (geometric dimensioning and tolerancing) requirements open to interpretation, which may influence quoting and manufacturing decisions.

Once you’ve sent your engineering design for review, several steps happen in order:

The concerns and suggestions a manufacturer will raise may depend on the history of the design. Are you seeking a quote for a part that’s already been produced via powder metallurgy for years? Are you trying to convert a part from another manufacturing process? Be sure to explain the background of the project’s manufacturing process.

This early phase of the project should be a completely open-ended conversation between your engineers and the vendor’s. The more context exchanged up-front, the more effectively both teams can evaluate ways to improve manufacturability, performance, and long-term production success.

Your 6-Step Engineering Design Review Checklist

This checklist will help you RFQ and start production more quickly with your manufacturer of choice – and save some money along the way:

✅ Make sure your geometry is PM-friendly.

Is the drawing dimensionally complete, unambiguous, and – above all else – compatible with the powder metallurgy process?

PM-friendly geometry depends on the relationship among:

• Part size
• Wall thickness
• Levels
• Features – holes, undercuts, steps, etc.
• Radii
• Fill depth
• Compaction direction
• The equipment needed to produce it

The exact limitations of shape and size aren’t universal in powder metallurgy – they depend on the press. Equipment capabilities, tooling designs, and manufacturing approaches can vary, making early design review an important step in evaluating manufacturability.

Also, traits like wall thickness, part size, and the location of features can affect how the manufacturer presses the part – and the tooling required to produce it. Even seemingly minor geometry choices can influence tooling design, manufacturability, and long-term production efficiency, particularly when they result in thin walls or sharp edges and corners.

Because powder is compacted along a defined axis, consider how the orientation of holes, steps and other features may affect tooling and manufacturability. Compaction direction is an important design consideration that can influence tooling design, manufacturing strategy, and the feasibility of certain features.

A simple example is a feature that's perpendicular to the compaction direction. A straightforward vertical punch can't necessarily create a conventional side hole or lateral undercut; that may require a different tooling approach or secondary operation. Likewise, multiple levels along the vertical axis can affect punch/tooling complexity.

You should also evaluate transitions between thin and thick wall sections during design review. Changing from a thin wall to thicker wall geometry can increase manufacturing complexity and may cause part and tool cracking. Reviewing these transitions early can help identify opportunities to support a sturdy tooling design and efficient production.

Your move: If your design contains complex geometry, strongly consider sending extra context. This could include an assembly drawing, STEP file, sample, prototype, or existing production part. Providing supplementary information gives manufacturers valuable insight into design intent and supports more productive technical discussions.

✅ Are your tolerances based on functional needs?

Are “nice to have” features constraining the manufacturing process?

The objective is to achieve the required performance while identifying the most effective and efficient manufacturing approach.Unnecessary complexity can result in:

• Additional punches
• Higher tool cost
• Poor tool life
• Chipping
• Redressing
• Replacement
• High scrap rate

In most cases, complexity comes down to tight tolerances.

Ultra-precise requirements should be evaluated alongside manufacturability goals to determine the most effective production approach. In some cases, secondary processes such as machining or sizing may be required to achieve specific dimensional requirements. While these operations can provide additional dimensional control, they may also add processing time and cost.

It’s important to remember that “loose” powder metal tolerances are still much tighter than those in casting operations, but a little looser than the typical machining operation. Often, we see engineers transfer tolerances from their previous machining method to powder metallurgy – but do they really need them? When transitioning from machining or another manufacturing process, it can be beneficial to review inherited tolerances and confirm they align with actual application requirements.

Even just minus a half-thousandth on inner diameter requires a secondary operation – and a higher price tag.

Your move: Tell the manufacturer what truly matters functionally so they can optimize the manufacturing approach to match those needs. If the application requires ±0.0005", say so. If it doesn't, carrying that requirement into the RFQ may add secondary processing and cost for no functional benefit.

A collaborative review of critical dimensions helps ensure engineering and manufacturing resources are focused on the features that have the greatest impact on part performance.

✅ Communicate the part’s relevant performance and operating criteria

Keeping trade secrets just that – secret – is understandable. However, your manufacturer needs to understand what your part will actually experience in the field.

The more clearly application requirements are communicated, the better equipped your manufacturing partner is to evaluate materials, processes, and quality controls that support long-term performance.

A drawing can be dimensionally complete but still leave the manufacturer guessing about conditions that affect its own decisions. Where relevant, identify things like environmental exposure, wear conditions, loading, corrosion resistance/salt-spray requirements, and interaction with mating components.

Your move: Identify conditions that could affect manufacturing and material selection decisions:

This information helps your vendor better understand your priorities and reassess its production approach as necessary. It may also reveal opportunities to optimize materials, processes, or secondary operations.

✅ Verify material requirements – but stay open to alternatives

Design engineers, especially those converting from another process, are often unfamiliar with the traits, possibilities, and limitations of powder metal materials.

And that’s OK! But you will need to communicate what the material must accomplish, rather than simply listing the material with no context.

We’ve seen many cases where the designer had one material in mind, but we introduced an alternative powder that could eliminate downstream processing. One example is using a sinter hardening material rather than a material requiring a separate quench-and-temper operation.

In some applications, alternative materials can achieve the same performance while reducing processing steps, improving manufacturability, or enhancing overall value.

Your move: Material selection, as you know, depends on the application. Here’s a place to start your search:

In powder metallurgy, you're not merely choosing “steel A versus steel B.” Properties can change substantially with material composition, density and processing condition. That’s why communicating performance requirements is often more valuable than simply listing a material spec, particularly when it originated from a previous manufacturing process. Sharing your desired performance outcome gives the manufacturer’s engineers greater flexibility to come up with the most effective solution possible.

✅ Are required finishes and secondary operations identified?

Powder metallurgy can do a lot of heavy lifting in the material selection and sintering phases. Still, even with its ability to produce net-shape and near-net-shape parts, your project may need a little extra performance boost after leaving the furnace.

• Heat treatment (i.e. quench-and-temper) increases properties such as hardness, strength, and wear resistance.
• Steam treatment creates an oxide layer on iron-based components, adding corrosion resistance and sealing surface pores.
• Plating applies a protective metallic coating to meet corrosion-resistance requirements and potentially other surface performance needs.
• Machining adds or finishes features that aren’t practical to produce during compaction and sintering.
• Tumbling removes burrs and sharp edges, improving the surface condition of a component.
• Lubrication, including oil impregnation where appropriate, can reduce friction and enhance wear performance in applications involving sliding contact with mating components.

Post-sintering requirements can influence upstream decisions, including tooling design, material selection, and processing methods. Identifying these requirements early helps align the manufacturing strategy from the beginning, freeing you from unnecessary revisions later in the project.

If your engineering print is based on legacy specs or requirements from another manufacturing process, your vendor may recommend alternatives that better align with powder metallurgy’s capabilities. If you haven’t yet made your application clear, the manufacturer may also request a technical review and discuss relevant secondary operations with you.

These discussions can help ensure the selected manufacturing approach supports performance requirements while maximizing the advantages of the powder metallurgy process.

✅ Are testing, inspection, and acceptance requirements defined?

Your manufacturer needs to know what you plan to test to.

Clearly defining testing, inspection, and acceptance criteria helps establish alignment between design intent, production expectations, and validation requirements.

Common requirements include:

• Capability ➡ Acceptable levels for key properties
• Safety ➡ Any safety-critical characteristics, regulatory mandates, or validation tests the part must satisfy
• Cleanliness ➡ Limits for residual oils, particles, or other contaminants that can affect cleaning, inspection, and packaging processes
• SPC (statistical process control) ➡ Monitors part characteristics for trends that could indicate the process is drifting over time

Your move: Do you have a performance test, inspection requirement, or acceptance threshold that’ll determine whether the part succeeds? Tell your vendor before manufacturing assumptions are locked in.

Change Now & Save Later

An RFQ drawing doesn’t have to – and sometimes shouldn’t – represent a completely finished design.

Therein lies the value of getting your manufacturing partner involved before the concept is 100% locked down. Changing the design later can mean revisiting tooling months down the line.

Better up-front decisions can reduce tooling complexity, tool wear, scrap, processing steps, and back-and-forth discussions. And, ultimately, save you time and money.