Die Fertigung hat zwei Schwergewichte: Subtraktive Fertigung (Material wegschneiden) Und additive Fertigung (Schicht für Schicht aufbauen). Beide verwandeln Rohstoffe in Teile, Sie arbeiten jedoch auf entgegengesetzte Weise – jedes mit einzigartigen Stärken für unterschiedliche Projekte. Ob Sie eine Metallhalterung herstellen, ein Prototyp aus Kunststoff, oder ein komplexes medizinisches Werkzeug, Die Wahl des Falschen kann Zeit verschwenden, Geld, oder die Leistung Ihres Teils ruinieren. This guide breaks down their differences, uses real-world cases to show how they work, and gives you a step-by-step way to pick the right one.
Erste: What Are Subtractive and Additive Manufacturing?
Before comparing them, let’s get clear on what each process does. They’re opposites, and that’s why their uses vary so much.
Subtraktive Fertigung: “Cutting Down to Size”
Subtractive manufacturing starts with a solid block, plate, or rod of material (wie Aluminium, Stahl, oder Kunststoff) and removes excess material to shape it. Think of carving a statue from a stone block—you take away what you don’t need until you get the design you want.
The most common subtractive method is CNC-Bearbeitung, which uses computer-controlled tools (Bohrer, Mühlen, Drehmaschinen) to cut with precision. Other subtractive processes include laser cutting (for 2D shapes), Wasserstrahlschneiden (for tough materials like metal), und EDM (for tiny, detailed cuts).
Schlüsselmerkmal: Relies on “removing” material—so the final part’s strength comes from the original solid material (no weak layers).
Additive Fertigung: “Building Layer by Layer”
Additive Fertigung (better known as 3D printing) builds parts from the bottom up, stacking thin layers of material (Pulver, Filament, or liquid resin) until the design is complete. Imagine stacking sheets of paper to make a 3D cube—each layer sticks to the one below.
Popular additive methods include:
- FDM (Modellierung der Schmelzablagerung): Uses plastic filament (like PLA or ABS) melted through a nozzle.
- SLS (Selektives Lasersintern): Uses a laser to fuse nylon powder into parts.
- mjf (HP Nylon Multi-Jetting Fusion): Uses liquid agents and heat to bond nylon powder.
- SLM (Selektives Laserschmelzen): Uses a laser to melt metal powder (for metal parts like titanium implants).
Schlüsselmerkmal: Relies on “adding” material—layers can create complex shapes, but they may leave weak spots between layers (called anisotropy).
Side-by-Side Comparison: Key Differences That Matter
To choose between them, you need to compare their performance on the factors that affect your project: kosten, Geschwindigkeit, Materialoptionen, und mehr. The table below breaks down the critical differences (data from manufacturing industry studies and real-world quotes):
| Faktor | Subtraktive Fertigung (z.B., CNC-Bearbeitung) | Additive Fertigung (z.B., 3D Drucken) |
| Material Range | Wide—metals (Aluminium, Stahl, Titan), Kunststoffe, Holz, Glas, Stein, Schaum. | Limited—mostly plastics (Nylon, PLA, ABS), some metals (Titan, steel via SLM). |
| Teilstärke | High—solid material means parts are isotropic (strong in all directions). No layer weaknesses. | Medium—parts are anisotropic (weaker along layer lines). SLM metal parts are strong but costly. |
| Precision/Tolerance | Very high—tolerances as tight as ±0.025 mm (great for tight-fit parts like gears). | Lower—tolerances down to ±0.1 mm (SLM/DMLS is better, but still not as tight as CNC). |
| Komplexität | Best for simple-to-moderate shapes (Löcher, Threads, flache Oberflächen). Struggles with hollow/lattice designs. | Best for complex shapes (Gitter, hohle Innenräume, organic curves). Can make designs CNC can’t. |
| Geschwindigkeit (Kleine Chargen: 1–10 Teile) | Slower—setup takes time (Werkzeugauswahl, machine programming). A metal bracket takes 2–4 hours. | Faster—no setup beyond uploading a CAD file. A plastic bracket takes 1–2 hours (FDM/MJF). |
| Geschwindigkeit (Große Chargen: 100+ Teile) | Faster—setup costs are spread over more parts. 100 metal brackets take 8–12 hours (CNC). | Slower—each part is built layer by layer. 100 plastic brackets take 20–30 hours (mjf). |
| Kosten (Kleine Chargen: 10 Teile) | Higher—setup fees (\(50–)200) plus material waste. 10 aluminum brackets cost ~$150 total. | Lower—no setup fees, weniger Materialverschwendung. 10 plastic brackets (mjf) cost ~$80 total. |
| Kosten (Große Chargen: 100 Teile) | Lower—setup fees spread out. 100 aluminum brackets cost ~$500 total. | Higher—layer-by-layer printing adds time/material costs. 100 plastic brackets (mjf) cost ~$600 total. |
| Materialverschwendung | High—50–70% of raw material is cut away (chips/scraps). Some can be recycled, but most is waste. | Low—only uses material needed for the part. 3D-Druck (SLS/MJF) reuses 50%+ of unused powder. |
| Nachbearbeitung | Minimal—parts often have smooth finishes. May need sanding or polishing for aesthetics. | Required—parts have layer lines or loose powder. Needs cleaning (for SLS/MJF) or sanding (für FDM). |
Real-World Cases: When to Use Each (And Why)
Numbers tell part of the story—but real projects show how these differences play out. Let’s look at three examples where the choice between subtractive and additive made or broke the project.
Fall 1: Metal Automotive Brackets (Large Batch)
A car parts supplier needed 500 aluminum brackets for a new SUV model.
- Additive Option (SLM): Each bracket would cost \(12 (metal powder is expensive), plus \)200 for setup. Gesamt: \(12×500 + \)200 = $6,200. Vorlaufzeit: 2 Wochen (layer-by-layer printing is slow for large batches).
- Subtractive Option (CNC-Bearbeitung): Each bracket cost \(5 (aluminum block is cheap), plus \)300 for setup. Gesamt: \(5×500 + \)300 = $2,800. Vorlaufzeit: 3 Tage (CNC is fast for repeatable parts).
Ergebnis: The supplier chose CNC machining—saved $3,400 and got parts 11 days faster. The brackets needed to be strong and fit tightly (tolerance ±0.05 mm)—CNC’s precision was perfect.
Fall 2: Custom Medical Surgical Guides (Kleine Charge)
Eine Zahnklinik benötigt 5 custom surgical guides (nylon PA12) for implant surgeries. Each guide had to fit a patient’s unique jaw shape (Komplex, organic design).
- Subtractive Option (CNC-Bearbeitung): The complex shape would require custom tools (\(1,000 aufstellen) Und 10 hours of machining per guide. Gesamt: \)1,000 + (\(50×5) = \)1,250. Vorlaufzeit: 1 Woche.
- Additive Option (mjf): No setup fees—just upload the patient’s 3D scan. Each guide took 2 hours to print. Gesamt: \(30×5 = \)150. Vorlaufzeit: 2 Tage.
Ergebnis: The clinic chose MJF—saved $1,100 and got guides 5 days faster. The guides didn’t need ultra-tight tolerances (±0.1 mm was enough), and MJF’s ability to make complex shapes was critical.
Fall 3: High-Temperature Engine Part (Metall, Kleine Charge)
An aerospace startup needed 3 titanium engine parts that could handle 600°C heat. The parts had a hollow interior to reduce weight (complex design).
- Subtractive Option (CNC-Bearbeitung): Titanium is hard to cut—tools would wear out fast (\(800 aufstellen) and take 8 hours per part. The hollow interior would need extra steps (drilling from both sides). Gesamt: \)800 + (\(100×3) = \)1,100. Vorlaufzeit: 5 Tage.
- Additive Option (SLM): SLM melts titanium powder into the complex shape—no extra steps. Each part took 4 hours to print. Gesamt: \(200×3 = \)600. Vorlaufzeit: 3 Tage.
Ergebnis: The startup chose SLM—saved $500 and got parts with the exact hollow design they needed. SLM’s metal parts are strong enough for high heat, and the small batch made additive cost-effective.
Schritt für Schritt: How to Choose Between Them for Your Project
Follow these 4 simple steps to pick the right process—no guesswork needed.
Schritt 1: Define Your Project’s Core Needs
Start by asking:
- What material do you need? (Metall? Plastik? Holz?)
- How many parts do you need? (1–10? 100+?)
- How complex is the design? (Simple holes? Complex lattices?)
- What tolerance do you need? (±0,025 mm? ±0,1 mm?)
Beispiel: If you need 200 steel brackets (simple design, tolerance ±0.05 mm), your core needs are “metal, large batch, simple shape, tight tolerance.”
Schritt 2: Match Needs to Process Strengths
Use this cheat sheet to narrow down:
| Core Need | Best Process |
| Metal parts, large batch, simple shape | Subtraktiv (CNC-Bearbeitung) |
| Plastic parts, small batch, complex shape | Additive (MJF/SLS/FDM) |
| Metal parts, small batch, complex shape | Additive (SLM) |
| Wood/glass/stone parts (any batch) | Subtraktiv (CNC/Waterjet) |
| Tight tolerance (±0,025 mm) (any material) | Subtraktiv (CNC) |
Schritt 3: Calculate Total Cost (Don’t Forget Hidden Fees)
Cost isn’t just per-part price—include setup fees, Materialverschwendung, und Nachbearbeitung:
- Subtraktiv: Add setup fees (\(50–)500) and material waste (50–70% of raw material cost).
- Additive: Add post-processing costs (\(2–)10 per part for cleaning/sanding) Und, for metal, higher material costs.
Beispiel: 50 plastic parts (nylon PA12):
- Subtraktiv: \(2 pro Teil + \)100 aufstellen + \(50 material waste = \)250 gesamt.
- Additive (mjf): \(3 pro Teil + \)30 post-processing = $180 gesamt.
Additive is cheaper here.
Schritt 4: Test with a Prototype (If You’re Unsure)
If you’re on the fence, make a single prototype with both processes (if budget allows). Test the prototype for strength, fit, and finish—this will tell you which process works better for the final batch.
Tip: For plastic prototypes, use FDM (cheap, schnell). Für Metallprototypen, use SLM (if complex) or CNC (if simple).
Yigu Technology’s Perspective on Subtractive vs. Additive Fertigung
Bei Yigu Technology, we don’t force one process—we match it to your project’s goals. For clients needing large batches of metal parts (wie Kfz-Halterungen) or wood/glass components, we recommend CNC machining for its speed and cost savings. For small batches of complex plastic parts (like medical guides) or intricate metal parts (like aerospace components), we use 3D printing (MJF/SLM). We also help with prototypes: FDM for quick plastic tests, CNC for precise metal fits. Our team calculates total costs (aufstellen, Abfall, Nachbearbeitung) upfront, so you never have surprises. Für uns, the best process is the one that makes your part well, on time, and within budget.
FAQ
1. Can I use additive manufacturing for metal parts instead of subtractive?
Yes—but only if you have a small batch or complex design. SLM (Metall-3D-Druck) makes great complex metal parts, but it’s 2–3x more expensive than CNC for large batches. For simple metal parts (like bolts) or batches over 50, CNC is cheaper and faster.
2. Is additive manufacturing always better for complex shapes?
Almost always—additive can make hollow lattices, organic curves, and internal features that CNC can’t reach. The only exception is if the complex shape can be split into simpler parts that CNC can make, then assembled. Zum Beispiel, a complex plastic housing might be cheaper to CNC as two parts and glue together than to 3D print as one.
3. Which process produces less waste?
Additive manufacturing is far more efficient—SLS/MJF reuse 50%+ of unused powder, and FDM uses only the filament needed for the part. Subtractive manufacturing wastes 50–70% of raw material (chips/scraps), even with recycling. If sustainability is a priority, additive is the better choice.