How to Design Parts That Don’t Blow Your Manufacturing Budget
Understanding the Key Cost Drivers in Product Design
1. Material Costs and Sourcing Dynamics
Material choice is one of the most significant factors influencing cost. While stainless steel might be economical for CNC machining, materials like Inconel can dramatically increase expenses due to difficulty in cutting.
In contrast, 3D printing powders such as stainless steel and Inconel often have similar costs, since the atomization process applies across materials. This shows that cost drivers vary depending on the manufacturing method.
Other material-related considerations include:
Availability and pricing volatility in global markets
Minimum order quantities (MOQs) that affect upfront expenses
Suitability for end-use applications
A deeper look at material sourcing reveals another hidden layer—regional cost fluctuations and supplier relationships. For instance, aluminum sourced locally may be significantly cheaper than importing specialty alloys. Additionally, manufacturers may negotiate lower costs if they maintain long-term supplier contracts, something designers can leverage early in the planning stage. Ignoring these variables often results in budget overruns, while proactive consideration ensures smoother scaling.
Takeaway: Choose materials based not only on performance but also on sourcing, processing difficulty, and production scale.
2. Geometric Complexity and Cycle Time
Modern technologies allow for previously impossible geometries, such as lattice structures, captured bodies, and interlocking parts. While this can improve strength-to-weight ratios, complexity often drives up costs.
For example:
3D printing handles complexity well but is inherently expensive at scale.
CNC machining becomes more costly with tight radii, thin walls, and intricate geometries that require multi-tool setups or higher-axis machines.
Excessive complexity can also hinder scalability and repeatability. A part that prints beautifully at prototype stage may become unreasonably expensive in mass production, requiring longer cycle times and higher machine maintenance. Furthermore, highly intricate designs can complicate inspections, leading to bottlenecks during quality assurance. Designers must weigh the benefits of advanced features against these downstream costs.
Takeaway: Strive for simplicity where possible — complexity should serve a purpose, not inflate costs.
3. Setup, Tooling, and Fixturing
Each additional setup or custom fixture increases both labor costs and the risk of error. For example:
A part designed for 3-axis CNC machining may require multiple flips, angles, and refixturing, adding significant time and expense.
Custom fixtures not only increase upfront costs but also reduce repeatability.
What often goes unnoticed is the compounding effect of setups on production speed. If a part requires multiple machine changes, downtime escalates, impacting lead times and delivery schedules. This not only raises direct costs but can also damage customer relationships when timelines slip. By designing with fewer fixturing requirements, manufacturers can run longer, more efficient cycles, ensuring consistency and scalability.
Takeaway: Design with the manufacturing method in mind, minimizing the number of setups required.
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4. Tolerances and Scrap Rates
Tight tolerances are sometimes necessary—but often they’re over-specified. This leads to:
Multiple tool changes
Longer cycle times
More complex quality inspections
Increased scrap rates
Another issue arises when during inspections. Scrap not only wastes material but also labor and machine time, multiplying costs. Designers should always evaluate whether a tighter tolerance provides genuine functional benefit or is merely overengineering. By collaborating early with manufacturers, teams can set practical tolerances that meet functional needs without inflating costs.
Takeaway: Always let functional requirements drive tolerances. Overly tight tolerances create unnecessary expense without improving product performance.
Designing to Reduce Waste and Labor
1. Design for Assembly and Reduced Part Count
Every additional part adds not only material costs but also assembly time. To reduce waste:
Consolidate parts into a single component where feasible
Use off-the-shelf components strategically
Eliminate excess fasteners and weak points that complicate assembly
A holistic view of the bill of materials (BOM) can uncover opportunities to reduce part counts and streamline workflows. For example, replacing several small brackets with a single molded component not only lowers assembly costs but also reduces potential points of failure. In addition, fewer parts often simplify supply chain management, resulting in smoother logistics and faster production timelines.
Result: Lower assembly labor, reduced inspection needs, and improved reliability.
2. Simplify Shapes for Easier Machining or Molding
Complicated shapes increase tool wear and failure risk. Consider:
Deep cavities → stress tools and cause breakage
Overhangs → require support structures in 3D printing, driving up time and material waste
Undercuts → often demand secondary operations or re-fixturing
By simplifying designs, companies not only reduce machine stress but also extend tool life. This minimizes downtime due to tool replacement and decreases maintenance costs. A streamlined geometry also speeds up cycle times, enabling more parts to be manufactured in less time. These cumulative savings are often overlooked but can represent significant cost advantages in competitive industries.
Result: Simple, thoughtful geometry improves manufacturability and lowers costs.
3. Minimize Secondary Operations
Each additional post-processing step — such as polishing, anodizing, or grit blasting—adds cost and time. If these steps require outsourcing, expenses grow even further.
Secondary operations can also create inconsistencies between batches, especially when outsourced. This reduces repeatability and can compromise product quality. By designing parts that achieve the required finish directly from the primary process, manufacturers can maintain tighter control and reduce dependency on external vendors. This strategy accelerates time-to-market while ensuring consistent product outcomes.
Result: Design parts to come off the machine as close to finished as possible, reducing dependency on secondary finishing and inspection.
Key Takeaways for Cost-Effective Product Design
Choose materials wisely based on both performance and sourcing factors.
Avoid unnecessary complexity unless it directly benefits the product.
Design for manufacturability with fewer setups and fixtures.
Set tolerances realistically to reduce scrap and inspection costs.
Simplify geometry and eliminate non-essential post-processing.
By applying these principles, companies can accelerate time-to-market, reduce waste, and achieve cost-effective production without sacrificing quality.
Trustbridge: Experts in Design for Manufacturability
At Trustbridge Design, the focus is on bridging the gap between innovative product ideas and scalable manufacturing. Backed by a global network of manufacturers, Trustbridge specializes in design for manufacturability, helping companies streamline production, reduce costs, and bring better products to market faster.
To learn more about how Trustbridge can support your product development, visit Trustbridge Design.
