Drilling acrylic is not difficult if you have good tools and are drilling the right kind of acrylic sheet. Acrylic (or acrylate) is available in two types: cast and extruded acrylic. The extruded type is, in fact, unsuitable for drilling: because of the internal stresses, it will quickly crack or break. Drilling it is not impossible, but great caution is required. Drilling in cast acrylic sheet is easy to do; in this article, we give you some tips to make drilling acrylic a piece of cake.
Preparations for drilling acrylic sheet
When drilling acrylic, it is important that the sheet is well supported. Place the sheet on a flat surface that supports it well and which the drill can run in to, for example, a wood board. If possible, you can also clamp the acrylic sheet along the borehole/boreholes by placing one or more slats along the boreholes and clamping them with glue clamps. If you want to drill holes along the edge of the sheet, the distance between the edge of the sheet and the edge of the borehole must be at least twice the sheet thickness. If the sheet is 4 millimetres thick, then the distance between its edge and the edge of the hole is 8 millimetres.
Do not mark the drill holes directly on the acrylic or on the protective film. Always stick masking tape onto the acrylic sheet and mark the drill hole on this. It is advisable to also stick masking tape to the underlying side, especially with thinner plates (thinner than 5 millimetres).
You can drill acrylic with a normal steel drill or an HSS drill. It is important that the drill is not brand new, as the sharp cutting angle can cause the drill to bite into the sheet, causing it to tear. If you drill a few holes in wood or aluminium first, the sharp edge will be worn down a little and you can then use the drill for drilling acrylic.
Drilling holes in acrylic sheet
Place the drill perpendicular to the acrylic sheet and set the drill to medium speed immediately. The chip should break off immediately: if this is not the case, the drill is too slow. Press only lightly on the drill, the drill must sink itself through the material. Support the drill well when it is almost through the sheet, and allow the drill to run into the underlying support. Let the drill continue turning while you lift it out of the hole.
Requirements for machining acrylic sheets:
• Drill HSS in increasing thicknesses. Pre-drill with a small drill that has at least the diameter of the core of the next (larger) drill
• Drilling machine with variable speeds
• Glue clamps or locking pliers
• Slats for support
• Base plate in which the drill can run out