Can You Drill Acrylic Plastic?
You can drill acrylic plastic with clean results when you use the right bit geometry, steady feed, and controlled speed. Acrylic is hard and brittle compared with many plastics, so technique matters. With proper preparation you can produce round, crack-free holes suitable for fastening, lighting cutouts, and display hardware.
Table of Contents
Tools and materials
Plastic or acrylic-ground drill bit, step drill, or brad-point bit with zero rake and a tip angle between 60 and 90 degrees
Drill press for best control, or a variable-speed handheld drill
Sacrificial backing board made of MDF or plywood
Clamps or a soft-jaw vise to hold the sheet flat
Masking tape for the entry and exit sides
Coolant such as clean water, a drop of dish soap in water, or compressed air
Deburring tool or a wide-flute countersink
Safety glasses and dust mask
Preparation
Leave the factory protective film on both sides as long as possible to prevent surface scratches.
Support the entire sheet so it stays flat, then clamp the workpiece and backing board together.
Mark the hole with a center punch that creates a small dimple rather than a sharp crater, or start with a tiny pilot hole.
Tape both sides of the hole location to reduce chipping at entry and exit.
Choosing the right bit
Acrylic or plastic-ground twist bit with a zero rake cutting edge reduces grabbing and heat.
Step drill is excellent for larger diameters because each land removes a small amount of material and lowers the risk of cracking.
Brad-point bit can work for small holes because the spur establishes the center and the lips cut cleanly.
Avoid aggressive metal bits with split points and high rake angles that tend to bite and pull.
Step-by-step drilling
Set a low to moderate speed, then test on a scrap from the same sheet.
Align the work so the bit is perfectly perpendicular to the surface.
Start with light pressure until the bit begins to cut, then feed smoothly without forcing.
Use peck drilling for deeper holes. Advance a few millimeters, retract to clear chips, let the hole cool, then continue.
Keep the chips flowing. If they turn gummy, reduce speed, reduce feed, or add a little coolant.
As the bit breaks through, support the exit side with the backing board and reduce pressure to avoid breakout.
Speed and feed quick guide
These ranges help prevent melting and edge cracking. Always confirm with a test piece because cast and extruded acrylic behave differently.
| Bit diameter | Sheet thickness | Drill speed rpm | Feed guidance |
|---|---|---|---|
| up to 3 mm | up to 3 mm | 1500 to 2000 | Light and continuous, frequent chip clear |
| 3 to 6 mm | 3 to 6 mm | 800 to 1200 | Steady feed, brief peck every few seconds |
| 6 to 12 mm | 4 to 10 mm | 400 to 800 | Peck drilling, add coolant or air |
| 12 to 20 mm with step drill | 4 to 12 mm | 200 to 400 | One step at a time, pause between steps |
Prevent cracks and melts
Prefer cast acrylic for machined holes because it cuts cleaner and resists heat better.
Keep the bit sharp and polished. Dull tools rub, build heat, and cause stress whitening around the hole.
Never force the feed. Let the cutting lips do the work and clear chips often.
Maintain full support at the exit side. The backing board should touch the sheet firmly.
For multiple holes, rotate between parts to allow cooling time.
Finishing and countersinking
Lightly scrape the rim with a deburring tool or a sharp utility blade held at a shallow angle.
If you need a countersink for flat-head screws, use a wide-flute countersink at very low speed and almost no pressure. Touch the edge, lift, inspect, and repeat until the screw seats flush without stress marks.
Clean with mild soap and water only. Avoid solvent cleaners near freshly machined edges.
Common issues and fixes
| Symptom | Likely cause | Fix |
|---|---|---|
| Melting or smeared chips | Speed too high or dull bit | Reduce rpm, use pecking, sharpen or switch to an acrylic-ground bit |
| Star cracks radiating from the hole | No backing board or feed too aggressive | Support exit side, reduce pressure at breakthrough |
| Oval or tapered hole | Drill not perpendicular or work not flat | Re-clamp, use a drill press, check for sheet bow |
| Chatter marks on rim | Loose clamping or bit grabbing | Clamp closer to the hole, use zero rake geometry |
| White stress ring around hole | Heat buildup and chip packing | Clear chips more often, add a little coolant |
Fast path for production work
If you need repeatable holes with tight tolerances, flame-polished edges, or CNC-pattern drilling, consider outsourcing to a specialist. YUCHENGDINGSHANG provides cut-to-size sheets, precision drilling, and routing for displays, lighting, and architectural fixtures. This saves time on setup, reduces scrap, and ensures consistent fit across large batches.
Summary
Drilling acrylic is straightforward when you control heat and prevent mechanical shock. Use bits designed for plastics, clamp and back up the work, run at modest rpm with smooth pecking, and finish the rim gently. With these steps you will get clean, round, and crack-free holes ready for assembly.