Thickness of wood that can be cut is limited by power output of the laser. The wood must be strong enough to resist the heat and motion of the beam in order to contain it, preventing it from escaping through the wood.
Typical wood used with lasers is Birch plywood or MDF (Medium Density Fiberboard). Birch wood is light colored, which can be used to highlight the design, and has a better finish than wood such as Oak. MDF is dark brown or black in color and has an extremely smooth surface on one side of the material thickness.
It is not necessary to have a completely smooth surface, but the closer it is to being smooth, the less wood that will be burnt away by the laser cutters.
Plywood typically has 7 wood layers in total. These are called “plies” and each ply gives off a distinctive color when cut with a laser cutter. The top layer has a wood color, such as yellow or green, and this is called the wood’s grain. The next layer under it has a wood pattern of its own and is referred to as the wood’s cross-grain (or X-Grain).
The wood colors and patterns will be inverted on the backside of cut plywood because of how wood is layered. This wood pattern is called the wood’s cross-grained image (or X-Grain Image), and can be a distinct difference between wood that has been cut from the top or bottom of the wood sheet.
What is the maximum thickness can laser cut wood?
Depending on the wood type, wood should be no more than 1/8″ thick to ensure that it can withstand the force of the laser cutting through it.
The wood thickness must also remain consistent throughout the duration of cutting; otherwise, burning will occur and possibly cause damage to surrounding wood or potentially start a fire. Although wood is burnt by the laser cutters, it can cool and harden before burning completely. If wood is not cut all the way through and starts to burn, it will quickly expand and be blown outward by the force of air circulating around the wood as a result of its high temperature.
This could potentially damage wood that has already been cut or any pieces of wood stacked above it. To prevent wood from burning and expanding, a wood thickness of 1/8″ is optimal for laser cutting machine.
If wood is thicker than 1/8″, the wood will need additional support from wood that has been extended to reach its full length or placed on supports. In both cases, wood might also need to be cut along the wood’s grain to prevent rippling in the wood surface. If wood is extremely thick, additional support might need to be added to ensure wood can withstand cutting.
If wood thickness is too thin, it will burn before being fully cut through or not produce a clean result once being cut.
Thinner wood also means wood might need to be cut along the wood’s grain to prevent rippling in the wood surface. If wood is too thin, it can also warp or break depending on its thickness and wood type.
Once wood has been placed inside the laser cutter, wood should not exceed 1/8″ thickness because wood will start burning before reaching its full length.
Burning wood is a risk because wood expands as a reaction to heat and will break, split, or crack wood that has been cut previously. Wood must remain within the laser cutter during cutting wood due to this transformation from wood to ash.
There should be no areas where wood starts burning before being fully cut through. If wood is not cut all the way through and starts to burn, it will quickly expand and be blown outward by the force of air circulating around wood as a result of its high temperature.
What is limit for laser cutting thickness?
In order to do so, first we need to know few things about lasers and their properties.
Most common lasers used for laser cutting are CO2 laser power range from about 10W up to 100W. This type of lasers emit light in infrared region of color spectrum with wavelength around 10 micrometer (10×10^-6 meter).
Infrared radiation is characterized by low speed of light, approximately 300 000 km/s which is slow when compared with speed of light in vacuum which is 3*10^8 m/s. As a result, in many cases it’s possible to treat laser beam as a wave, which is characterized by certain parameters like wavelength and frequency.
Speed of light in air is significantly lower than speed of light in vacuum because it depends on the density of that medium through which waves are propagating. This phenomenon can be demonstrated with help of simple experiment using prism to disperse white beam into all colors of spectrum.
Combined spectrum shows distinct dark gaps between each color. These gaps are caused by absorption at characteristic wavelengths for any given thick material through which radiation travels.
Because thicker materials absorb particular parts of infrared spectrum, they also have specific spectral signature for absorption which give them unique color when illuminated with lasers at those wavelengths, allowing us to differentiate between them visually if their thickness is sufficient.
Laser beam also exhibits similar phenomenon described above but on much smaller scale because there are many different types of lasers with very different parameters.
How thick wood can 7 watt laser cutters through?
A 7 watt laser sintering system will cut through approximately 1/2 inch (12.7mm) of wood. Be aware that the machine can only go up to 1/2 inch but the kerf, or thickness of the material which is cut away, may be in excess of 1/4″.
If you are interested in printing with thicker wood filament then our laser will be able to accomplish that task. See the video below for a quick demonstration. Although PLA is much easier to laser cut, it has been done in our shop with a laser. Wood is much more difficult especially when it comes to fine detail.