What Are Common Design Mistakes?

Designing a part for manufacturing is both an art and a science. At Glover Precision, we’ve seen countless designs come through our doors—some flawless, others with room for improvement. While creativity drives innovation, certain design oversights can lead to manufacturing challenges, increased costs, or parts that don’t meet expectations. In this article, we’ll explore some of the most common design mistakes we encounter and offer tips to help you avoid them. By refining your designs upfront, you can streamline production and ensure your parts meet specs the first time.

1. Overly Tight Tolerances

Mistake: Specifying tolerances that are tighter than necessary for the part’s function.
Why It’s a Problem: Tight tolerances increase machining time, require more precise tools, and elevate costs—sometimes significantly. If a tolerance isn’t critical to the part’s performance, it can unnecessarily complicate production.
Solution: Define tolerances based on the part’s functional requirements. Ask yourself: “Does this feature really need a ±0.0005-inch tolerance, or will ±0.005 suffice?” When in doubt, consult with our team—we can help balance precision with practicality.

2. Ignoring Material Properties

Mistake: Designing without considering the material’s characteristics, such as machinability, strength, or thermal expansion.
Why It’s a Problem: A design that looks perfect on paper might be impractical for the chosen material. For example, thin walls in a brittle material could crack, or a complex feature in a hard alloy might wear out tools quickly.
Solution: Match your design to the material’s capabilities. If you’re unsure about material selection, let us know your part’s application, and we’ll recommend options that align with both design and manufacturability.

3. Inadequate Wall Thickness

Mistake: Creating walls or features that are too thin for the manufacturing process or material.
Why It’s a Problem: Thin walls can deflect during machining, leading to dimensional inaccuracies or even part failure. They may also be prone to warping or breaking during use.
Solution: Follow general guidelines for minimum wall thickness based on your material and process (e.g., milling, turning). For metals, a minimum of 0.030–0.050 inches is often a safe starting point, though this varies. Reach out to us for material-specific advice.

4. Unreachable Internal Features

Mistake: Including deep pockets, sharp internal corners, or complex geometries that standard tools can’t access.
Why It’s a Problem: Machining tools have physical limitations—radius tips can’t create perfectly sharp corners, and long tools may deflect in deep cavities, compromising accuracy. These features often require costly custom tooling or secondary processes.
Solution: Design with tool access in mind. Add fillets (rounded edges) to internal corners and avoid excessively deep or narrow features unless absolutely necessary. Our team can suggest design tweaks to simplify machining without sacrificing function.

5. Missing or Unclear Annotations

Mistake: Submitting drawings or models without complete dimensions, tolerances, or surface finish specifications.
Why It’s a Problem: Incomplete documentation leaves room for interpretation, which can lead to parts that don’t meet your expectations. For example, omitting a surface finish callout might result in a rougher finish than intended.
Solution: Double-check your files before submission. Ensure all critical dimensions, tolerances, and notes are clearly defined. We prefer solid models in .stp, .step, or .iges formats and drawings in PDF—make sure both are fully annotated.

6. Designing for One Process Only

Mistake: Creating a part optimized for a specific manufacturing method without considering alternatives.
Why It’s a Problem: Locking into one process (e.g., CNC machining) might overlook more cost-effective options like casting or additive manufacturing, depending on quantity and complexity.
Solution: Keep your design flexible where possible, or let us know your production goals (e.g., prototype vs. high-volume). We can recommend the best process to match your needs and budget.

How Glover Precision Can Help

Spotting these mistakes early can save time, money, and frustration. At Glover Precision, we’re more than just a manufacturer—we’re a partner in your success. If you’re unsure about your design, feel free to submit it through our secure portal at https://www.gloverprecision.com/quote and ask for feedback. We’ll review your files and suggest adjustments to enhance manufacturability while preserving your intent.

What If You’ve Already Made a Mistake?

Don’t worry—mistakes happen, and we’re here to assist. If a part doesn’t meet specs due to a design issue, email our Quality team at Quality@GloverPrecision.com with the details (and your Purchase Order Number, if possible). We’ll work with you to resolve the problem and get your project back on track.

Design Smarter with Glover Precision

Avoiding common design mistakes is all about collaboration and preparation. By keeping tolerances practical, considering material properties, and providing clear documentation, you’ll set the stage for a smoother manufacturing process. Ready to get started? Submit your design today at https://www.gloverprecision.com/quote, and let’s turn your vision into a precision-engineered reality!