It sounds like a bold claim, I know. In my two decades in investment casting, I’ve found that most engineers see cost reduction as something that happens on the factory floor—squeezing efficiency out of cycles and supply chains. But in my experience, the single most powerful lever for cost savings is pulled not on the production line, but on a CAD workstation during the prototyping phase.
The truth is, a design optimized for machining or fabrication is rarely optimal for casting. What looks like a minor, inconsequential feature in a prototype can be the primary driver of complexity, scrap, and cost in high-volume production.
Where Does the Money Go? The Hidden Cost Drivers
Let me break down what we typically see in initial designs and how they silently inflate the unit cost:
- The “Un-castable” Geometry: This is the big one. Sharp internal corners, for instance, are a nightmare. They create hotspots during solidification, leading to shrinkage porosity and cracks. The result? A higher scrap rate that you ultimately pay for. A simple change to a radiused corner isn’t just a design preference; it allows the metal to flow and cool evenly, dramatically improving yield. I’ve seen a single, poorly placed sharp corner increase scrap on a complex manifold by 8%.
- The “We’ll Machine It Later” Mindset: I see this all the time. A designer specifies a solid block of material with deep, small-diameter holes that must be drilled afterward. The material cost is higher, the machining time is extensive, and tool wear is brutal. By simply redesigning the component to incorporate cast-in holes, even if they’re slightly oversized and only need a finish ream, we’ve routinely slashed 20-30% off the machining cost alone. The casting process can form these features for almost nothing.
- Over-Engineering and Uniform Wall Thicknesses: Uneven wall thicknesses are the enemy of a quality casting. They cause warping, sinks, and internal stresses. But many designs have them unnecessarily. By working with our engineering team to core out unnecessary mass and balance the wall thicknesses, we do two things: 1) We create a more robust and reliable part, and 2) We use less material, which is a direct and ongoing saving on every single unit you produce.
A Real-World Example from My Files
I’ll give you an anonymized case study. A client came to us with a bracket for a heavy-duty hydraulic system. The original design was a 4.2 kg fabricated and machined weldment. It was strong, but it was labor-intensive and costly.
During our joint Design for Manufacturability (DFM) review, we suggested a seemingly minor change: consolidating the three separate welded plates into a single, hollow, thin-walled casting with internal ribs for strength.
- The result?
- The part weight dropped to 2.8 kg, a 33% reduction in material.
- The number of manufacturing steps fell from 12 (cutting, welding, stress-relieving, multiple machining ops) to 4 (casting, heat treat, shot blast, minimal machining).
- The unit cost was reduced by 18%.
- The final part was stronger and more consistent due to the elimination of weld failures.
That 18% saving didn’t come from haggling over the price of metal; it came from a smarter design, conceived before the production tooling was ever cut.
This is Why We Offer Collaborative Engineering Before You Finalize Your Prototype
Our process isn’t just about giving you a quote for your drawing. It’s about rolling up our sleeves and asking “why?” Why this shape? Why this tolerance? Why this material?
We’ll provide a detailed DFM report that highlights specific, actionable changes. We might suggest:
- Adding draft angles to allow for clean pattern ejection.
- Modifying a junction to prevent stress concentration.
- Suggesting a more castable alloy that meets your performance needs at a lower cost.
The goal is to make the part not just possible to cast, but optimal to cast.
So, to answer my own question: Yes, a minor design change in the prototyping phase can absolutely save you 15% or more. In fact, I’d say it’s the rule, not the exception. The real cost of a part is locked in during the first 10% of its design lifecycle. Once the dies are made and production begins, your leverage disappears.
Don’t just send us your CAD file for a quote. Send us your challenge. Let’s schedule a 30-minute engineering review and find that 15% together. I can almost guarantee it’s hiding in plain sight.