Investment Casting vs. CNC Machining: Which Manufacturing Method Is Right for Your Project?
When planning your next metal component, you may wonder: Should I choose investment casting or CNC machining? Both are powerful manufacturing methods-but each excels under different conditions.
At Modulus Metal, we provide both investment casting and precision CNC machining services in Turkey. Here’s a comprehensive guide to help you decide.
🔍 What Is Investment Casting?
Investment casting (also called lost-wax casting) involves creating a wax model, coating it with ceramic, and then casting molten metal into the cavity left after the wax is melted away. It’s ideal for complex, near-net-shape parts and medium to high volumes.
Advantages:
- Produces intricate shapes and internal cavities
- Supports a wide range of metal alloys
- Suitable for thin walls and lightweight parts
- Cost-effective for larger batch sizes
Typical Material Grades Used in Investment Casting at Modulus Metal:
- Carbon Steel: AISI 1020, AISI 1045
- Alloy Steel: AISI 4140, AISI 4340, 20MnCr5
- Stainless Steel: AISI 304, AISI 316, AISI 410, AISI 420
- Tool Steel (limited cases): X210Cr12
- Heat-resistant steel: GX40CrSi25-20
- Aluminum Alloys: A356, 319
- Duplex and Super Duplex (on request)
Tolerances:
We follow VDG P690 (superseded by ISO 8062-3) standards:
- Typically D2 for general tolerances
- D3 for tighter dimensions
👉 View Investment Casting Tolerance Table
🔧 What Is CNC Machining?
CNC machining is a subtractive process where computer-controlled tools remove material from a billet. It is best for parts requiring high dimensional precision and excellent surface finish.
Advantages:
- Extremely tight tolerances
- Ideal for low to medium quantities or one-offs
- Quick turnarounds with no tooling investment
- Suitable for a wide variety of materials
Typical Material Grades Used in CNC Machining at Modulus Metal:
- Carbon Steel: C45, CK45, S235JR, S355J2
- Alloy Steel: 42CrMo4, 16MnCr5, 20MnV6
- Stainless Steel: 1.4301 (304), 1.4404 (316L), 1.4021 (420), 1.4462 (Duplex)
- Aluminum Alloys: EN AW-6082, EN AW-7075, EN AW-5083
- Copper & Brass Alloys: CuZn39Pb3, CW614N
- Plastics: POM (Delrin), PA6, PTFE
- Cast Iron (machining only): GG25, GGG40
Tolerances:
General tolerances are applied per ISO 2768-1 and ISO 2768-2:
- Medium (m) or Fine (f) grades, depending on application
👉 Learn More About ISO 2768 Tolerances
⚖️ Key Comparison Table
| Feature | Investment Casting | CNC Machining |
|---|---|---|
| Best For | Complex geometries, medium to high volume | High-precision parts, low to medium volume |
| Material Options | Wide (mostly metals) | Very wide (metals + plastics) |
| Typical Alloys | 304, 316, 4140, A356, 20MnCr5 | 42CrMo4, 7075, 1.4404, POM |
| Dimensional Tolerance | ±0.2-0.4 mm (D2/D3) | ±0.01-0.05 mm (ISO 2768-f) |
| Surface Finish | Ra 3.2-6.3 µm (may require polishing) | Ra ≤ 1.6 µm (as-machined) |
| Tooling Cost | High (molds) | Low |
| Lead Time (First Part) | Longer | Shorter |
| Production Volume | Best for 100s to 1000s | Best for 1 to 500 parts |
| Post-Processing | Often required | Usually minimal |
🧠 Which Should You Choose?
✅ Choose Investment Casting if:
- You have complex shapes with internal channels or thin sections
- You need hundreds or thousands of parts
- You want to reduce machining on complex forms
- You need parts made from casting-grade stainless or alloy steel
✅ Choose CNC Machining if:
- You need tight tolerances and perfect finishes
- You are working on small batches or prototypes
- You’re using high-strength alloys, plastics, or exotic materials
- You want quick production without tooling delays
🔄 Hybrid Approach: Casting + Machining
Many industrial customers choose to:
- Cast the part using investment casting
- Finish critical areas (e.g., holes, threads, mating surfaces) with CNC machining
This combines the best of both worlds-cost efficiency + precision.
📦 Modulus Metal: Your Trusted Manufacturing Partner in Turkey
We specialize in:
- Investment Casting (Steel, Stainless, Aluminum)
- Precision CNC Machining
- Post-processing, assembly, and quality control
- ISO 9001-certified workflows
- Serving clients in Europe, USA, Canada, and MENA
📞 Need Advice or a Quotation?
Let us evaluate your 3D model or drawing and recommend the most suitable process based on:
- Part geometry
- Material selection
- Tolerance and surface finish needs
- Volume and cost target
📧 [email protected]
🌍 www.modulusmetal.com