Tools Used to Cut and Machine Acrylic Plastic
There are many reasons to want to work with acrylic plastics with tools. Some reasons maybe to build an acrylic aquarium, a custom CPU case, or to make functional or decorative items for the home. In any case, the tools to do so are readily available. Many of the tools that can work acrylic plastic are the same ones used for wood and metal work. Also, many tool companies now produce specialty bladed and tooling products for working with acrylic plastics.
Many of the tools that can work acrylic plastic are the same ones used for wood and metal work. Also, many tool companies now produce specialty blades and tooling products for working with acrylic plastics.— Jason Bosh
Precautions For Cutting And Drilling Acrylic
Cutting and drilling acrylic is not difficult but requires some precautions.
- Cutting edges on blades and drill bits need a zero or negative rake angle to control chipping and breaking the acrylic
- Band saws, jigsaws, hacksaws, and coping saws need blades that keep 2 to 3 teeth in contact with cut at all times.
- For table saw cutting acrylic, a carbide tipped blade with a minimum of 80 teeth is required. Blades designed for plastics and nonferrous metals are ideal.
- Extruded acrylic has a lower melting point than cast acrylic and a cutting fluid or compressed air should be applied to cut to keep heat build up to a minimum.
The most basic and least expensive tool for cutting acrylic sheet is a hack saw. It cost less than $20 and the blades less than $5. All that is needed is a blade with fine teeth. Ideally at least 18TPI. Although a hacksaw is hand operated and unlikely to overheat, a cutting lubricant will still be most helpful and keep the cutting action stay smooth. A mix of dish soap and water in a 50/50 mix should be OK. Adding some kerosene would make it even slicker. Be sure to use the entire blade in methodic and consistent strokes. Do not force the tool and support the acrylic plastic on both sides of the cut.
The coping saw is hand tool version of a scroll saw. Like the hack saw, it comes with various grades of blades with fine and coarse teeth. What is different is the blade is more narrow and allows tight radius curves. This allows for curved cuts and intricate shapes. It's important to consider the throat depth of the coping saw while making curved cuts in acrylic.
Band saws are power saws that can make both straight and curved cuts. The size of the blade is important. Blades 1/4" to 3/8" are for curved cuts. Blades 1/2' and wider are for long straight cuts. Blades for metal or bi-metal blades will remain sharp longer cutting plexiglass. There are band saw blades, called “skip tooth” or “buttress” blades, have been developed for soft materials such as plastics and are available with 2, 3, 4, or 6 teeth per inch. These blades should be used when cutting thicknesses greater than half an inch. These blades are hardened and will retain their sharpness for long periods when used only for cutting Plexiglas® acrylic sheet.
Cutting Acrylic With The Tablesaw
With the correct blade, cutting acrylic plastic is pretty straightforward with a table saw. Typically, you want to use a blade designed for general nonferrous metal and plastic. These blades are typically 80 to 85 tooth 10 inch blade. The teeth are carbide tipped. It is essential that you push the acrylic slowly at a steady rate to get a good edge. The video below explains this better.
How To Cut Acrylic On The Table Saw
Cutting Acrylic With Jigsaw
A jigsaw is one of the most versatile cutting tool a shop can have. It can cut wood, metal , and yes plastic. The blade reciprocated up and down and this can build up heat in the cut to the point the cut acrylic welds itself back together until the blade is encased. Two things need to be done to prevent this from happening. First, choose a blade with the right number of teeth. For 1/4" and thinner sheets, there are specialty blades with 20 TPI which have the correct tooth geometry. For cutting 3/8" and thicker acrylic a nonferrous blade with 12 TPI will do the job but the cut may require sanding.
When cutting extruded acrylic, look for gumming around the blade and apply coolant as needed. Cast acrylic can mostly be cut dry if you let the tool do the work and make sure chips are being produced. The chips being ejected indicate heat is being removed from the cut.
Step Drill Bit On Cast Acrylic
Drilling Acrylic Sheet
This is where acrylic plastic truly is above traditional glass. Not only does acrylic sheet transmit light better and can be cut with basic tools, it is also easily drilled. There is one caveat though. Normal twist drill bits have a positive rake on the cutting edge. What this does is draws the bit into the work piece progressing the drilling action. This is good for materials such as wood and hard metals like steel and stainless but bad for softer materials like brass and acrylic. What happens with acrylic is the bit gets stuck especially when it exits the opposite side and causes chipping and cracking the acrylic.
There are a number of methods to deal with this slightly difficult property of acrylics. It is possible to use regular twist bits if some preparation is taken. Filing the rake down on the tip to take the rake angle to zero. This allows the twist bit to go through the acrylic leaving a smooth intact hole behind.
Besides the rake angle another issue is the normally broad angle of twist drill bit. They are usually made in 118 or 135 degree tip angles. In a plastic like acrylic, this angle can generate heat which can cause excessive melting and chipping without a cutting lubricant. There are specially made drill bits for acrylic plastic. They have a narrow angle(about 60 degrees) which helps reduce friction. These bits can be a bit pricey though. A step bit also has low angle and can successfully drill acrylic sheet 1/4" and thinner. I wrote a separate article on the overall usefulness of the step drill bit.
The router is one of the most versatile tools used for woodworking. The router can easily cut dadoes, mortises for door hinges, and decorative edge work. Routers can be used on acrylic plastic too! It is best to use carbide tipped bits on acrylic at the bare minimum. But cutting or milling, solid carbide in up-cut or down-cut flutes are better suited for this particular work. Spiral bits wih "O" flute would be useful for softer plastics such as the extruded form of acrylic. Spiral router bits with "V" flutes are for harder plastics such as cast acrylic. High feed rates keep heat build up to a minimum.