Die Casting vs. Investment Casting: Complete OEM Selection Guide

1. Cost Structure

Die Casting has high upfront tooling costs (steel dies can cost $10,000–$100,000+) but offers extremely low per-part costs at high volumes (>10,000 pcs/year). Ideal for mass production.Investment Casting has lower tooling costs (wax patterns and ceramic shells) but higher per-part labor and material costs. More economical for small to medium volumes (<5,000 pcs/year) and prototyping.

2. Dimensional Tolerance & Precision

Die Casting typically achieves ±0.1–0.2 mm (CT6–CT8) for standard features, with excellent repeatability. However, thin walls and large flat surfaces may warp.Investment Casting offers superior precision metal casting tolerances of ±0.05–0.1 mm (CT4–CT6), especially for complex internal cavities and fine details, with less draft angle restriction.

3. Surface Finish

Die Casting produces as-cast surfaces of Ra 1.6–3.2 µm, often with a smooth, shiny skin that requires minimal secondary finishing.Investment Casting yields slightly rougher surfaces (Ra 3.2–6.3 µm) due to the ceramic shell, but this can be improved with polishing or machining – still, it rarely matches die-cast smoothness without extra cost.

4. Applicable Materials

Die Casting is limited to non-ferrous metals with high fluidity: aluminum alloys (A380, ADC12), zinc (ZAMAK), magnesium, and copper-based alloys. Cannot cast ferrous metals (steel, iron) or high-temperature superalloys.Investment Casting works with virtually any castable alloy, including stainless steel (304, 316), carbon steel, tool steel, cobalt-chrome, titanium, and nickel-based superalloys (Inconel) – making it the go-to for aerospace, medical, and automotive structural parts.

5. Part Size & Complexity

Die Casting excels at thin-walled (0.8–4 mm), medium-sized parts (up to ~20 kg) with uniform sections and simple to moderate complexity. Undercuts require sliding cores, increasing tool cost.Investment Casting handles highly complex geometries, deep cavities, curved internal passages, and parts from a few grams up to 100+ kg, with near-net shape that reduces machining.

Final Recommendation:

If your annual demand exceeds 10,000 pieces, your material is aluminum/zinc, and your design allows draft angles – die casting is the most cost-effective.

If your part requires steel, superalloys, intricate cores, or tight GD&T without machining, and volume is below 5,000–10,000 pieces – investment casting is the clear winner.

We offer both precision metal casting solutions and can provide a side-by-side DFM (Design for Manufacturing) analysis with firm quotes for each process. Please share your 3D model, target annual quantity, and material preference – we will respond with a tailored ROI comparison within 48 hours.

Let us help you make the right call for your OEM metal parts.

Looking forward to your drawings and specifications.

2、《Understanding Tolerances and Surface Roughness in Precision CNC Machining》

In precision CNC machining, tolerances and surface roughness are interdependent variables that directly determine your part's fit, function, and final cost—we typically hold standard tolerances of ±0.025–0.05 mm for general precision features, tighten to ±0.005–0.015 mm for critical mating surfaces (bearing seats, valve spools, medical shanks), and can achieve ultra-precision down to ±0.001 mm on request, but we always advise applying the widest acceptable tolerance to non-critical areas to reduce machining time and tool wear by 15–30%. For surface finish, our as-machined standard ranges from Ra 1.6–3.2 µm for most structural components, while fine finishing with high-speed toolpaths delivers Ra 0.8–1.6 µm for dynamic seals and sliding interfaces, and grinding or lapping can bring surfaces down to Ra 0.2–0.8 µm or even mirror-like Ra 0.05–0.2 µm for optical or medical applications—though each 0.2 µm reduction typically adds 20–50% to cycle time, so we recommend specifying only the roughness your application genuinely needs. Beyond machining, we offer comprehensive post-processing: zinc plating (5–15 µm, 240h salt spray resistance) for steel parts, electroless nickel (10–30 µm, HRC 50–55) for uniform wear protection, hard anodizing (10–100 µm, up to 60 HRC) for aluminum components, powder coating (60–150 µm) for thick decorative/corrosion barriers, spray painting for cost-effective large-part finishing, passivation for stainless steel corrosion enhancement, and black oxide for anti-glare oil-retaining surfaces—all with masking or post-plate threading/grinding to protect critical dimensions. Our in-house CMM, optical profilometers, and SPC-backed inspection ensure every tolerance and finish is verified, and our CAM programmers apply adaptive roughing plus high-speed finishing strategies to maintain consistency even in deep cavities or hardened materials (up to HRC 62). To optimize both cost and performance, simply send us your 2D/3D drawing with GD&T callouts, required Ra/Rz values, and service environment details—we will return a DFM analysis, a QC plan, and a tailored coating recommendation within 24 hours, backed by real automotive, aerospace, and industrial automation case studies.