PMMA-dat
PMMA Drilling
7 Key Tips to Prevent PMMA (Acrylic) Cracking During Drilling (Tested & Reliable)
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Place a Wooden Board Underneath the Sheet (Must Do)
- This is the most important anti-crack tip.
- Prevents the drill bit from tearing the PMMA when breaking through the bottom.
- Provides support and reduces vibration.
- Results in smooth hole edges without chipping.
- 📌 No backing board → almost guaranteed to crack.
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Use Medium Drill Speed (Not High, Not Too Low)
- Recommended speed: 800–1500 rpm (best)
- High speed: melts, overheats, and cracks PMMA.
- Low speed: stalls, doesn't cut, more vibration, also prone to cracking.
- Medium speed + steady feed is safest.
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Use a Sharp Drill Bit (Dull Bits = Source of Cracks)
- Dull bits cause:
- Friction and heat
- "Squeezing" cracks instead of cutting
- White holes, cracked edges
- Solutions:
- ✔ Use a new drill bit
- ✔ Wood spade bits, plastic-specialized bits, or step bits are best
- Dull bits cause:
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Apply Clear Tape Over the Drilling Area
- Very useful trick:
- Tape absorbs vibration
- Reduces cracking probability
- Protects hole edges from chipping
- How to apply:
- One layer on the front
- One layer on the back (best)
- Very useful trick:
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Apply Steady, Even Downward Pressure
- Too light → friction, heat, cracks
- Too hard → jams, vibration, cracks
- Correct method:
- 👉 Press down smoothly and steadily, like shaving wood
- 👉 Let the drill bit "bite" and produce chips (not powder or melted strands)
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Use Soapy Water as a Coolant (Simple & Effective)
- Do not use oil or alcohol.
- Soapy water/dish soap water:
- Cools
- Reduces friction
- Cleaner hole edges
- Lowers cracking risk
- Just a few drops are enough.
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Drill Large Holes in Steps (Drilling Large Holes at Once = Cracks)
- For example, to drill a 12mm hole:
- Start with a 2–3 mm pilot hole
- Then a 6–8 mm intermediate hole
- Finish with the final hole (hole saw/step bit/large drill bit)
- ⚠️ Drilling large holes in one go → 90% chance of cracking or chipping.
- For example, to drill a 12mm hole: