Even experienced designers and engineers can run into pitfalls when ordering custom aluminum machined parts. Avoid these common mistakes to improve chances of success with your next machining project.

Mistake 1: Overly Ambitious Tolerances

Specifying ultra tight tolerances everywhere inflates costs and increases risk. Only apply tight tolerances where function truly demands.

Mistake 2: Ignoring Design for Manufacturability (DFM)

Ignoring tool access, draft angles, fixture design, and toolpath constraints often leads to features that are difficult or impossible to machine. Collaborate early with the machinist.

Mistake 3: Underestimating Material Waste & Yield

Using oversized raw blocks or nonstandard shapes may cause excessive waste. Choosing bars or round stock closer to final dimension reduces cost.

Mistake 4: Poor Drawing Clarity & Missing Specifications

Incomplete or ambiguous drawings lead to misinterpretation. Always include complete tolerances, surface finish notes, material specification, heat treatment, and inspection requirements.

Mistake 5: Neglecting Surface Finish Requirements

Assuming “machined finish is fine” may backfire when the end application demands a specific finish, appearance, or corrosion resistance. Specify finish up front.

Mistake 6: Not Considering Plan for Post-Processing

If coatings, anodizing, or other finishes are needed, account for them in the design (clearance, added thickness) and lead time.

Mistake 7: Skipping Testing or Prototyping

Jumping to full production without validating prototypes often leads to surprises. Always run pilot batches to detect issues early.

Mistake 8: Inadequate Communication & Feedback

Changes midstream, delayed responses, or lack of clarity in comments can derail a project. Keep communication frequent and clear.

Mistake 9: Not Protecting Intellectual Property

Failing to have NDAs or agreements in place may risk your designs being shared or used improperly. Use confidentiality agreements when sharing proprietary designs.

Mistake 10: Choosing Based on Lowest Price Alone

The lowest quote may reflect compromises in machine maintenance, quality control, or support. Aim for value—balance between cost, quality, delivery, and reputation.

By being aware of these common pitfalls and avoiding them, your custom aluminum machining project is more likely to go smoothly, stay on budget, and produce parts that meet your performance expectations.