Acetal Rod Machining Guide

A practical, shop‑floor reference for cutting, turning, milling & drilling Acetal (POM‑C) rod. Optimised for Australian workshop conditions.

Quick‑Reference Cutting Parameters

Use these starting values, then fine‑tune for your exact machine rigidity, tool wear, and part geometry.

Operation	Tool Material	Surface Speed (V_c) m/min	Feed Rate	Notes
Turning	Carbide (sharp uncoated)	600 – 900	0.15 – 0.30 mm/rev	Positive rake +8° to +15°
Milling	2‑flute Carbide End‑Mill	400 – 650	0.05 – 0.20 mm/tooth	Climb cut if machine is rigid
Drilling ≤ 10 mm Ø	HSS Jobber, 118°	275 – 450	0.10 – 0.20 mm/rev	Peck every 8×Ø to clear chips
Drilling > 10 mm Ø	Carbide or Spade Bit	200 – 350	0.15 – 0.30 mm/rev	Center‑drill pilot first
Sawing (Band‑Saw)	Raker set, 4 TPI	Blade speed ≈ 800 m/min	Manual feed, avoid heat‑soak	Cool with air blast

RPM calculation: RPM = (Vc × 1000) / (π × Ø). Example: 700 m/min on a 20 mm rod → ≈ 11 167 rpm.

1. Material Preparation

Acclimatise rod to shop temperature (ideally 18 – 25 °C) for ≥ 12 h to reduce dimensional shift during machining.
Cut blanks oversized by 2 – 3 mm length to allow for facing and cleanup passes.
Check for internal stress in larger diameters (> 100 mm) using a scribe; if the kerf opens, consider annealing at 160 °C for 2 h then slow‑cooling.

2. Lathe Turning

Tooling & Setup

Positive‑rake carbide inserts (sharp edge, no chip‑breaker required).
Secure rod with soft‑jaw chuck or padded collet to prevent marring.
Use steady‑rest or live center for L/D > 3 : 1 to curb chatter.

Technique

Face both ends to square.
Take roughing passes 1 – 3 mm depth at mid‑range feed.
Finish with ≤ 0.5 mm depth, feed ≈ 0.10 mm/rev.
Skip coolant if possible; if heat builds, use fine mist of compressed air.

3. Milling

Tool Selection

2‑flute or single‑flute O‑spiral cutters reduce chip re‑cutting.
Sharp‑edged uncoated carbide; polished flute preferable.

Best Practices

Clamp rod in V‑block or 3D‑printed cradle to stop roll.
Maintain high spindle speed, moderate feed to keep chips clear.
Use light climb‑cut passes for smooth finish.

4. Drilling

Acetal ejects long, stringy chips. Peck drilling and chip evacuation are critical.

Spot with 90° center drill to prevent wander.
Peck every 8× diameter (small) or 4× diameter (large) at full retract.
Use brad‑point or Forstner bits for flat‑bottom holes.
Compressed‑air blast preferred over liquid coolant.

5. Sawing & Parting‑Off

Keep blade sharp; dull teeth cause glazing and heat marks.
Set moderate feed; too slow = melting, too fast = edge breakout.
Support rod both sides of kerf to avoid whipping.

6. Finishing & Tolerances

Typical achievable tolerance: ±0.05 mm on diameters ≤ 50 mm.
For smoother surface (< R_a 1.6 µm) perform light skiving cut then polish with 1200‑grit wet‑and‑dry paper.
Degrease parts with isopropyl alcohol; avoid chlorinated solvents.

7. Troubleshooting

Chatter in deep turning passes: Check steady‑rest; increase feed; decrease speed slightly.
Burrs on drilled holes: Use sharper drill; apply back‑chamfer; increase feed.
Melting/Surface gloss: Reduce RPM or use air blast; ensure tool is razor‑sharp.
Dimensional creep after parting‑off: Stress‑relieve: oven 130 °C for 1 h per 10 mm thickness, cool slowly.

8. Safety & Handling

Fine acetal dust can irritate lungs—use dust extraction or N95 respirator.
Chips are slippery; keep floor clear to prevent slips.
Avoid open flame; acetal is combustible and produces formaldehyde fumes.

9. Downloads & Further Resources

Download the printable PDF cheat‑sheet

Looking for Acetal rod? Order online →

Disclaimer

The information on this page is provided as a general guide only. Machining outcomes vary with equipment condition, operator skill, and environmental factors. Always verify cutting parameters against your own trials, follow relevant Australian Standards, and consult your machine manuals before commencing work. Warlond Plastics Pty Ltd accepts no responsibility for any loss, injury, or damage arising from the use of this guide.