Aluminum sheet metal can be cut with a variety of methods ranging from manual tools to highly advanced industrial systems. In this posting we will take a look at some of the most common types of cutting aluminum. When determining which method of sheet metal cutting is right for you you should take into consideration the factors of flexibility, speed, accuracy, finish, cost and automation.  There are a few basic properties of aluminum that affect how it can be cut.  One factor which helps aluminum is that it is a relatively soft metal.  This means that chisels, snips, hacksaws and hand shears are effective on the thinner gauges. If your working from a garage or custom job shop a few inexpensive tools can get you well on your way.

Hand Tools

Cost : $20 – $100
Flexibility : Low
Speed : Very Slow
Accuracy : Very Low
Finish : Poor
Automation : None

Chisel and Hammer

Cutting aluminum sheet metal with a hammer and chisel is relatively straight forward, line up the edge of the chisel along the line you wish to cut and strike the chisel with a hammer. Using a softer piece of material such as wood as a backer will allow the chisel to push through the metal and prevent wear on the chisel’s tip.  You will  have  to continue your way down the cut line cutting the metal like a can opener.  This process of cutting aluminum is very slow and labor intensive. It may be appropriate if you’re working on a small project in your garage.  The edge quality of this method is going to be very poor and you’ll probably need to take a file to the edge of the metal to make it safe for handling.

Snips

Tin snips, also known as aviation snips are basically highly leveraged and rugged scissors which can be used for cutting through aluminum. You will be limited to the gauge of aluminum which you can cut,  anything  above 18 gauge is going to be a challenge. For a reference on gauge thickness see our gauge chart.  these snips come 3 basic varieties allowing for straight, left hand curved and right hand curved cuts. For most applications it is necessary to file and clean up the edges left by a snip.  When cutting with tin snips it’s advised that you keep the top blade seated on the metal and pull the bottom blade up into the top blade.

Hacksaw

A hacksaw can be particularly effective for cutting small lengths of sheet metal but lends its self to cutting tubing and bar stock because the hacksaw will  have  a limited throat depth, meaning it can cut very far into the metal.  Cutting aluminum with a hack saw will wear the blades down relatively fast compared to wood, but not nearly as fast as steel or stainless steel will.

Hand Shear

Disk blade shears are a tool which is basically a specialized can opener which features a round cutting blade and snip.  Good for tight corners and leaves a nice edge compared to other hand tools, though it still may require cleaning.

 

Bench Tools

Cost : $100 – $1000
Flexibility : Medium – Low
Speed : Slow
Accuracy : Low
Finish : Poor
Automation : None

Straight Bench Shears

Bench mounted shears are able to cut through relatively thick sheets of aluminum though their design will tend to limit your cuts to straight lines.  These types of shears lend themselves towards hobbyists and sheet metal shops doing custom or repair work.  Most machines are built well and will last a lifetime if the blades are kept clean and sharp.

Beverly Throatless Shears

A common throatless shear known for one of its major manufacturers, Beverly, are common to small sheet metal shops because of their versatility and reliability.  By properly spacing the cutting edge from the back plate you can achieve a nicely rounded edge which may not require additional cleaning. These shears come in three sizes, B1, B2 and B3 depending on the size and power required.

Band Saw

A carbide tipped or even standard steel blade will typically suffice for most gauges aluminum up to 1/4” thick, though you’ll have to move relatively slowly on the heavier stuff.  Putting a piece of particle board or plywood under the sheet metal is said to help with the process. This may help to pull heat away from the aluminum which has the  tendency  to absorb the heat. In addition to this masking tape on top of the metal will also help.   There ware various waxes and cutting oils which help keep the metal cool and allow the teeth to cut smoothly.

Stationary Nibbler

A single tool Punch Press which is set up to perform a  nibbling  operation, these tools can cut any profile within its throat however they require a wide kerf and leave a  serrated  edge.  While cutting the aluminum it’s important to remain  conscious  of the eject chips from these  machines, they can  easily  accumulate and cause a safety hazard..

 

Power Tools

Cost : $75 – $300
Flexibility : Medium
Speed : Medium
Accuracy : Low
Finish : Mixed
Automation : None

Angle Grinders

Cutting aluminum with any sort of grinding device is particularly  challenging.  Because the metal is able to absorb the heat energy and has a low melting point it can melt and  re-solidify  around the blade during operation causing it to bind up dangerously.  Cut with the intention of removing the metal, not griding it away.

Power Shears

Hand held micro shears are very effective for cutting aluminum sheet metal because they can be directed across the sheet with relative ease.  They do not generate any where near the heat of an angle grinder so melting of the metal is not a general concern.  Noise, sheet vibration and the finish edge quality are common draw backs of power shears.  Unless you are able to stabilize the work piece with clamps you should be familiar with how the tool is going to move itself and the sheet.

Electric Jigsaw

Handheld jigsaws provide a very mixed bag when it comes to cutting aluminum, with the right tool and the right bit or blade you can easily cut through thick sheets and other forms of stock. However with the wrong saw and wrong blade you will find yourself damaging both the workpiece and the tool.

Nibbler

Portable nibblers exhibit the same pros and cons as their bench top models. The softness of aluminum makes them viable for most light gauges.


Heat Cutting

Cost : $200 – $900
Flexibility : Medium
Speed : Medium – High
Accuracy : Low
Finish : Poor
Automation : None

Oxygen-Hydrogen Torch

Oxy-hydrogen torches are superior to acetylene version because of its clean flame.  The heat from the torch combined with a steady stream of oxygen rapidly oxidizes the sheet metal and blows the weakened metal away.  Cutting with an Oxy-hydrogen torch creates a lot of heat and sparks but can cut thick sheets of aluminum and move at a relatively high speed.  The torch doesn’t need any sort of backing and is portable, which makes it ideal for working in difficult to reach spaces.

Plasma Torch

The plasma torch works similarly to an oxy-hydrogen torch however instead of  oxidizing  the metal the plasma ionizes it with a strong electro magnetic field.  The speed of which you cut the aluminum will  determine  your edge quality, aluminum should be cut at a higher speed compared to steel. In addition to the heat from the torch this weakens the sheet metal under the torch and allows it to be blown away with high pressure air. The plasma torch is very versatile when it comes to the type of material it can cut and, like the oxy-hydrogen torch, it is easily maneuverable along a sheet and in tight places.  This makes it a common choice for custom sheet metal shops.

Industrial Cutting

Cost : $10,000 – 5,000,000+
Flexibility : Very High
Speed : Very High
Accuracy : Very High
Finish : Excellent
Automation : Many Options

Plasma : A CNC controlled plasma bed is basically the cheapest form of industrial cutting available.  Cutting speeds for aluminum are going to be different than those of steel.  The faster you cut aluminum the cleaner the edge will be.

Water Jet

Probably the preferred method for cutting intricate or thick aluminum the  water jet focus a very thin stream of water mixed with abrasives at  extraordinary  pressures and very high speed into the sheet metal.  This jet of water eats away at the metal and leaving a clean smooth edge.  Heat  dissipation  is not a concern with aluminum because unlike the laser systems the water jet is not melting the metal, meaning there isn’t a significant difference in the energy required to cut steel or aluminum.  Water jets are  surprisingly  capable of cutting very thick sheet metal, up to a few inches thick with very high accuracy.  Their main  advantages  are the finished edges, variety of materials and accuracy.

Punch Press

Punch presses use shaped tools to knock out geometry in sheet metal.  Larger presses can be loaded with dozens of different types of tools for special cutting and forming.  They are not typically as quick as lasers but they offer the ability to stamp, roll and form the metal while cutting.  This allows for the formation of louvers, jogs,beads, and impressions which lasers cannot form.  They are  also  typically cheaper on the front end when compared to lasers however there are maintenance costs associated with the tooling.

Lasers

Modern lasers will be effective on cutting light to medium gauges of aluminum.  Because  aluminum  is able to more readily absorb heat compared to steel an industrial laser will require a large amount of power to melt the aluminum to allow the gas to blow through.  This is possible with modern equipment and cutting 1/2” thick aluminum plate is possible.  The challenge is as always the heat dissipation.  See our post on laser cutting for more  information.