Custom metal parts are the backbone of industries from aerospace to medical—they fit unique designs, solve specific problems, and turn ideas into functional products. But customize metal parts isn’t a one-size-fits-all task: the right process depends on your material, budget, design complexity, and production volume. This guide breaks down 8 key manufacturing processes for custom metal parts, compares their strengths, shares real-world examples, and helps you pick the perfect method for your project.
First: What Matters When Customizing Metal Parts?
Before choosing a process, you need to clarify 4 core factors—they’ll narrow down your options and avoid costly mistakes:
- Design Complexity: Is your part simple (e.g., a flat bracket) or complex (e.g., a lattice-structured aerospace component)? Some processes handle curves and hollow shapes better than others.
- Material Choice: Do you need aluminum (lightweight), stainless steel (corrosion-resistant), or titanium (high-strength)? Not all processes work with every metal.
- Production Volume: Are you making 5 prototypes or 5,000 production parts? Costs and speed vary drastically by batch size.
- Tolerance Needs: How precise does the part need to be? A medical implant might need ±0.025mm tolerance, while a decorative part could use ±0.1mm.
Example: If you’re making 10 custom titanium surgical tools (complex design, tight tolerance), your options will be very different than if you’re making 1,000 aluminum brackets (simple design, loose tolerance).
8 Key Processes to Customize Metal Parts (With Pros, Cons & Cases)
Below are the most common methods to customize metal parts, each with how it works, best uses, and real-world success stories. We’ll start with the most versatile and move to specialized options.
1. CNC Milling & Turning (Best for Precision & Versatility)
How it works: CNC machining is a subtractive process—starts with a solid metal block and uses computer-controlled tools (mills for 3D shapes, lathes for cylindrical parts) to cut away excess material. It uses G-code (programmed via CAM software) for ultra-precise cuts.
Best for: Simple-to-moderate designs, tight tolerances (±0.025mm), and small-to-large batches (1–10,000+ parts). Works with almost all metals (aluminum, steel, titanium, brass).
Pros & Cons:
| Pros | Cons |
|---|---|
| High precision (ideal for tight-fit parts like gears) | Struggles with complex internal shapes (e.g., closed lattices) |
| Fast for repeatable parts (100 aluminum brackets = 8–12 hours) | Material waste (50–70% of the metal block is cut away) |
| Works with all common metals | Setup fees ($50–$200) for small batches |
Real-World Case: A medical device company used CNC turning to make 50 custom stainless steel dental drills. The drills needed a cylindrical shape with tiny, precise grooves (for cutting teeth) and ±0.03mm tolerance. CNC turning delivered consistent results, and the parts were ready in 3 days—faster than any other process.
Common Uses: Gears, brackets, surgical tools, automotive components.
2. Metal 3D Printing (SLM/DMLS) (Best for Complex, Low-Volume Parts)
How it works: Also called additive manufacturing, it uses a laser to melt metal powder (e.g., titanium, stainless steel) layer by layer, building the part from the bottom up. No tooling is needed—just upload a 3D CAD file.
Best for: Complex designs (lattices, hollow interiors), low batches (1–50 parts), and high-value parts (aerospace, medical). Works with titanium, stainless steel, and Inconel.
Pros & Cons:
| Pros | Cons |
|---|---|
| Makes shapes no other process can (e.g., internal cooling channels) | Slow for large batches (10 parts = 4–8 hours) |
| Low material waste (reuses 50%+ of unused powder) | Expensive per part (titanium part = $200–$500) |
| No setup fees (great for prototypes) | Lower tolerance than CNC (±0.1mm vs. ±0.025mm) |
Real-World Case: An aerospace startup needed 3 custom titanium engine parts with hollow interiors (to reduce weight). CNC machining couldn’t reach the inner cavities, so they used SLM 3D printing. The parts were 30% lighter than solid versions, handled 600°C heat, and were ready in 3 days—saving $500 vs. custom casting.
Common Uses: Medical implants, aerospace components, prototype parts with complex geometry.
3. Metal Casting (Sand & Investment) (Best for Large Batches & Simple Shapes)
How it works: Pour molten metal into a mold (sand for simple shapes, ceramic for detailed ones), let it cool, then break the mold to remove the part. Investment casting uses a wax model to create the mold—great for intricate details.
Best for: Simple-to-moderate designs, large batches (1,000+ parts), and low-cost metals (aluminum, iron, copper alloys).
Pros & Cons:
| Pros | Cons |
|---|---|
| Low cost for large batches (1,000 aluminum pipes = $5 per part) | Slow setup (mold making = 1–2 weeks) |
| Works with large parts (e.g., 1m-tall machine frames) | Rough surface finish (needs post-processing) |
| Low material waste (uses only the metal needed for the part) | Poor tolerance (±0.5mm—no good for tight fits) |
Real-World Case: A construction equipment maker used sand casting to make 5,000 iron brackets for excavators. The brackets were simple (flat with holes) and didn’t need tight tolerance. Casting cost $3 per part—vs. $8 per part for CNC machining—saving $25,000 total.
Common Uses: Pipes, machine frames, automotive engine blocks.
4. Die Casting (Best for High-Volume, Detailed Parts)
How it works: Similar to casting, but uses high pressure (hydraulic or pneumatic) to force molten metal into a reusable steel mold. Great for parts with small details (e.g., tiny holes, logos).
Best for: Moderate-to-detailed designs, very large batches (10,000+ parts), and low-melting metals (aluminum, zinc, magnesium).
Pros & Cons:
| Pros | Cons |
|---|---|
| Fast production (10,000 zinc parts = 1 week) | High tooling costs ($10,000–$50,000 for steel molds) |
| Smooth surface finish (no post-processing needed for cosmetics) | Only works with low-melting metals (no titanium/steel) |
| Consistent parts (ideal for consumer goods) | Not for complex internal shapes |
Real-World Case: A smartphone manufacturer used die casting to make 100,000 aluminum phone chassis. The chassis had tiny slots for buttons and a smooth finish—die casting delivered consistent results at $2 per part. CNC machining would have cost $5 per part, saving $300,000.
Common Uses: Phone chassis, automotive sensors, consumer electronics parts.
5. Extrusion (Best for Constant Cross-Section Parts)
How it works: Push heated metal through a mold with a fixed cross-section (e.g., tubes, L-shapes, window frames), then cut it to length. Post-processing (drilling, CNC) adds holes or details.
Best for: Parts with constant cross-sections (no changing shapes), large batches (1,000+ parts), and aluminum (80% of extruded metal parts).
Pros & Cons:
| Pros | Cons |
|---|---|
| Ultra-low cost (1,000 aluminum tubes = $1 per part) | Only for constant cross-sections (no curved or hollow interiors) |
| Fast production (extrudes 10m of metal per minute) | Needs post-processing for custom details (e.g., holes) |
| Smooth surface (great for painted or anodized parts) | No tight tolerance (±0.1mm) |
Real-World Case: A window manufacturer used extrusion to make 5,000 aluminum window frames. The frames had a complex cross-section (to hold glass and seals) but no changing shapes. Extrusion cost $4 per frame—vs. $10 per frame for CNC—and the parts were ready in 5 days.
Common Uses: Window frames, pipes, automotive trim, heat sinks.
6. Metal Injection Molding (MIM) (Best for Small, Detailed Parts)
How it works: Mix metal powder (stainless steel, titanium) with plastic, inject the mixture into a mold, then heat it (sintering) to remove the plastic and fuse the metal.
Best for: Small parts (under 100g) with tiny details (e.g., medical device components), large batches (10,000+ parts), and stainless steel/titanium.
Pros & Cons:
| Pros | Cons |
|---|---|
| Makes tiny, detailed parts (e.g., 2mm medical screws) | High tooling costs ($5,000–$20,000) |
| Low per-part cost for large batches (10,000 parts = $1 each) | Not for large parts (max 100g) |
| High density (stronger than 3D printed parts) | Slow setup (mold making = 2–3 weeks) |
Real-World Case: A watchmaker used MIM to make 50,000 stainless steel watch gears. The gears were 3mm wide with tiny teeth—too small for CNC machining. MIM delivered consistent, strong gears at $0.80 each, saving $2 per gear vs. manual machining.
Common Uses: Watch parts, medical screws, small automotive sensors.
7. Forging (Best for High-Strength Parts)
How it works: Heat metal to a malleable state, then hammer or press it into shape using a mold. No melting—preserves the metal’s natural grain, making parts stronger.
Best for: High-strength parts (e.g., tools, structural components), medium-to-large batches (100–10,000 parts), and stainless steel/iron.
Pros & Cons:
| Pros | Cons |
|---|---|
| Ultra-strong (20–30% stronger than cast parts) | No complex shapes (only simple, solid designs) |
| Low material waste (uses 90% of raw metal) | High tooling costs ($10,000–$30,000) |
| Good for high-stress parts (e.g., wrench heads) | Rough surface (needs post-processing) |
Real-World Case: A tool manufacturer used forging to make 1,000 steel wrench heads. Forged wrenches could handle 500N of torque (vs. 300N for cast ones) and lasted 2x longer. The cost was $5 per wrench—only $1 more than casting—worth it for durability.
Common Uses: Wrenches, hammer heads, automotive crankshafts, structural brackets.
8. Sheet Metal & Stamping (Best for Flat, High-Volume Parts)
How it works: Cut flat metal sheets (aluminum, steel) into shapes, then bend or punch them using a press brake. Stamping uses a die to mass-produce identical parts quickly.
Best for: Flat or slightly bent parts (e.g., enclosures, brackets), very large batches (10,000+ parts), and aluminum/steel.
Pros & Cons:
| Pros | Cons |
|---|---|
| Fastest process for large batches (100,000 parts = 1 day) | Only for flat/bent shapes (no 3D curves) |
| Low per-part cost ($0.50–$2 per part) | High tooling costs for stamping ($5,000–$15,000) |
| Lightweight (great for enclosures) | Poor tolerance (±0.1mm) |
Real-World Case: A computer manufacturer used sheet metal stamping to make 50,000 aluminum laptop enclosures. The enclosures were flat with bent edges—stamping delivered them at $1.20 each, vs. $3 each for CNC machining. The parts were ready in 3 days, meeting a tight product launch deadline.
Common Uses: Laptop enclosures, electrical boxes, automotive body panels, brackets.
How to Choose the Right Process (Cheat Sheet + Cost Comparison)
Use this table to match your project needs to the best process. We’ve also included cost data for a standard aluminum part (100mm x 50mm x 5mm) to show how prices vary by batch size:
| Project Need | Best Process | Cost for 10 Parts | Cost for 1,000 Parts | Cost for 10,000 Parts |
|---|---|---|---|---|
| Complex design, low batch (prototypes) | Metal 3D Printing (SLM) | $200 | $15,000 | Not recommended |
| Simple design, tight tolerance | CNC Machining | $150 | $5,000 | $30,000 |
| Constant cross-section, large batch | Extrusion | $50 (plus post-processing) | $1,000 | $8,000 |
| Small, detailed part, large batch | Metal Injection Molding (MIM) | $500 (setup) + $50 | $5,000 | $10,000 |
| High-strength part, medium batch | Forging | $300 (setup) + $100 | $8,000 | $50,000 |
| Flat part, very large batch | Sheet Metal Stamping | $1,000 (setup) + $20 | $2,000 | $7,000 |
Key Takeaway: For small batches, CNC or 3D printing is best. For large batches, extrusion, stamping, or MIM saves money. For strength, choose forging. For complexity, choose 3D printing.
Yigu Technology’s Perspective on Customizing Metal Parts
At Yigu Technology, we tailor custom metal part solutions to your unique needs. For precision parts (like medical tools), we use CNC machining for tight tolerances. For complex aerospace components, metal 3D printing (SLM) delivers unbeatable geometry. For large batches (like automotive brackets), we recommend extrusion or stamping to cut costs. We also handle post-processing—from polishing CNC parts to anodizing extruded aluminum—to ensure your parts look and perform perfectly. Our team works with you to balance cost, speed, and quality, so you get custom parts that fit your project, not the other way around.
FAQ About Customizing Metal Parts
1. What’s the cheapest way to customize metal parts for large batches?
For large batches (10,000+ parts), sheet metal stamping (for flat parts) or extrusion (for constant cross-sections) is cheapest. Both have high upfront tooling costs but ultra-low per-part costs—e.g., stamping a 100mm aluminum bracket costs $0.50 per part for 10,000 units.
2. Can I customize titanium parts with any process?
No—titanium is hard to melt and cut, so only a few processes work: CNC machining (best for precision), metal 3D printing (SLM, best for complexity), and metal injection molding (MIM, best for small parts). Die casting and extrusion don’t work with titanium (it has a high melting point).
3. How long does it take to customize metal parts?
It depends on the process and batch size:
- Small batches (10 parts): CNC = 3 days, 3D printing = 2 days.
- Medium batches (1,000 parts): CNC = 1 week, extrusion = 5 days.
- Large batches (10,000 parts): Stamping = 3 days, MIM = 2 weeks (due to tooling).
Setup time (mold/tool making) adds 1–2 weeks for casting, stamping, or MIM.