Wood, plastic, aluminum, or steel? Your material choice determines the tools, parameters, and ultimately the success of your CNC project. This overview shows which materials you can machine with a CNC milling machine and what to watch out for in each case.
Material Overview
| Material | Difficulty | Key Requirement | In-Depth Guide |
|---|---|---|---|
| Softwood | Easy | Sharp tools, dust extraction | Wood Guide |
| Hardwood | Easy-Medium | Sharper tools, lower feed rates | Wood Guide |
| MDF/Plywood | Easy | Dust extraction essential! (fine dust) | Wood Guide |
| Acrylic (PMMA) | Medium | Do not stop moving, single-flute cutter | Plastics Guide |
| POM | Easy | The "machinist's dream" among plastics | Plastics Guide |
| Aluminum | Medium-Hard | MQL, single-flute cutter, rigid machine | Aluminum Guide |
| Brass | Medium | Sharp tools, moderate speed | — |
| Mild Steel | Hard | Very rigid machine, heavy-duty spindle | — |
Wood — The Perfect Starting Material
Wood is the most popular material for CNC beginners — and for good reason: it is forgiving, relatively inexpensive, and the results are immediately visible.
What Makes Wood Special
- Grain direction matters: Milling with the grain gives better surfaces than across
- Moisture content varies: Dry wood machines better, but can warp
- Variety: From balsa to oak — each species has different properties
Quick tip: Start with pine or spruce — forgiving and inexpensive.
Plastics — Versatile and Forgiving
Plastics are excellent CNC materials. Each plastic has its own characteristics:
- POM (Delrin): Best machinability, barely any burrs, dimensionally stable
- PMMA (Acrylic): Beautiful optics, but tends to melt if you stop moving
- PA (Nylon): Tough and elastic — tends to produce long stringy chips
- PE/PP: Soft and flexible — difficult to clamp, tends to deform
Aluminum — The Premier CNC Metal
Aluminum is the most commonly milled metal on CNC gantry milling machines. It combines light weight with good strength and excellent machinability.
The Challenge: Built-Up Edge
The biggest problem with aluminum milling: the material becomes soft from frictional heat and sticks to the cutting edge. The solution: MQL (minimum quantity lubrication), single-flute cutters, and fast cutting speeds.
→ Complete Aluminum Milling Guide
Other Metals
Brass
Brass is excellent for CNC milling — it cuts cleanly, produces beautiful surfaces, and is popular for decorative applications. No lubrication required.
Copper
Similar to brass, but softer. Tends to produce long chips. Good for circuit boards and decorative work.
Mild Steel
Possible on rigid BZT machines (PFH series) with appropriate spindles and carbide tools. Requires low cutting speeds and solid workpiece clamping.
Materials You Should Avoid
- Stainless steel: Too hard for most gantry machines
- Titanium: Requires industrial CNC with flood cooling
- Hardened steel: Not possible with milling — requires grinding
- CFRP/GRP (hand-laid): Extremely abrasive, produces hazardous dust
Quick Decision Guide
| Your Goal | Recommended Material | Why |
|---|---|---|
| Learning and experimenting | Softwood (pine, spruce) | Inexpensive, forgiving |
| Precise functional parts | POM (Delrin) | Best machinability, dimensionally stable |
| Transparent parts, displays | Acrylic (PMMA) | Beautiful optics, polishable |
| Lightweight strong parts | Aluminum (AlMg3, 6082) | Strength + low weight |
| Decorative items, signs | Wood, brass, two-layer plastic | Beautiful aesthetics |
FAQ — Frequently Asked Questions
Can my machine handle aluminum?
Most BZT machines can handle aluminum. Important: rigid construction, minimum quantity lubrication, and the right tools. Start with light engraving, then gradually increase.
Which material is the cheapest to learn with?
Softwood. A board from the hardware store costs a few euros and is perfect for practice.
Do I need different tools for each material?
Ideally yes. At minimum: wood cutters (2-flute) and aluminum cutters (1-flute polished). Using the wrong tool leads to poor results or tool breakage.
Conclusion: Start Simple, Grow Ambitious
Start with wood and simple plastics. Once you have mastered the fundamentals, move on to aluminum and more demanding materials. The beauty of a CNC gantry milling machine: you can machine almost any non-ferrous material — with the right setup.
Unsure which material is right for your project? Our technical team is happy to advise you.
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