Choosing the right kind of material is essential for CNC routing wood.
With so many types of woods and wood-like materials, it can be daunting to pick the ones ideal for CNC work.
In this guide, I go through the best wood types for each application and the reason why it is the best for that purpose.
The best wood types for CNC routing work are Maple, Walnut, Cherry, and Ash among hardwoods. Among softwoods, Cedar and Cypress are the best for CNC work. For getting the best results while CNC routing wood, use the right bit, and optimal feeds and speeds.
Best Wood for Beginners in CNC Routing
If you are learning woodworking on a CNC machine or if your budget is limited you should stick to affordable softwoods in general for reducing cost.
The price of wood varies depending on your location. Wood that is available locally would be more affordable.
For practice cuts, you can use particle boards, plywood, or low-cost MDF boards.
Pine, spruce, and cedar are some affordable softwoods. If you need an affordable hardwood you can choose maple which has excellent toughness.
With the right wood and a little bit of creativity, you can try out several wooden CNC projects that sell to make some extra money.
Best Hardwoods for CNC Routing
Harwoods are considered exotic wood and are used when you need high durability and quality on your product.
Due to their tight grains, they are tougher than softwoods.
For best results you should use a wood CNC machine that's rigid enough to mill hardwoods.
Hardwoods blunt your tools, and hence making products from hardwood can be costly.
However, they are better than softwoods for doing detailed and intricate carving work.
But the quality and the visual appeal does stand apart from other woods.
Ash wood is a heavy wood with a light color, and its grain has several rings in it.
It has excellent mechanical properties such as stiffness and hardness, making it suitable for almost any CNC project like chairs, tables, hockey sticks.
You can even turn a piece of Ashwood on your CNC lathe to make baseball bats or route them to make tennis racquets.
The hardness and shock resistance of Ashwood makes it the second-best choice for tool handles after hickory.
Ashwood has a moderate blunting effect on tools used on it because of being a hardwood.
Beech is similar to Ash in terms of strength and can be bent easily to form legs of chairs and tables.
You can mill Beechwood with ease as they do not splinter. They are suitable for making goblets and turned products.
Beechwood is odorless, and hence you can use them to make spoons, plates, and cutting boards.
However, Beechwood is not a recommended wood for carving. Due to its hardness, it can sometimes chip off.
Birch is a Harwood, and its hardness is comparable to that of oak and walnut. It has a light color and wavy grain.
Birchwood does not dent or nick easily, making it a good choice for woodworking on a CNC router.
It has good strength and holds screws well. You can use it for bracing the structural components of furniture.
Cherry wood has a light reddish-brown color and has good strength.
It does not warp so easily, and hence you can use it for carving projects.
When machining cherry wood on any CNC mill, you must make sure that the cutting edges of the tools are sharp. If you use blunt tools on Cherry wood, you might end up leaving burn marks on your project.
You can use Cherry wood for turning, carving, and cutting. They are suitable for any purpose you have.
You can make beautiful furniture, musical instruments, and carvings as Cherry wood has a natural smooth finish and radiant color.
Cherry wood is a hardwood and is challenging to carve, but it is preferred for carving due to its excellent finish and color.
Elmwood has a light to medium reddish-brown color. Although considered hardwood, it is on the softer side in the hardwood spectrum.
It can tear out easily when cutting across the grain, so you have to make sure not to use a low-powered spindle for cutting Elmwood.
You can make furniture, cutting boards, decorative paneling, bats, and hockey sticks using Elmwood.
Mahogany is popular for its looks and strength with a solid reddish-brown look.
It is resistant to water damage and makes it a good choice for constructing boats. You can turn a block of Mahogany on your CNC lathe to make beautiful chalices.
Apart from that, Mahogany wood is suitable for making furniture, musical instruments, and for paving floors.
It is among the hardest woods available and is used for its durability. Maple wood is used for making items that take abuse.
It is effectively used for making desks, workbenches, and pavers for floors. Moreover, it is used for making butcher blocks which is a testament to its hardness.
Maple woods do not require fillers for finishing after machining, unlike most of the other woods.
Oakwood is heavy and hard resists breakages. In addition, it has a prominent ring grain making it suitable for items with aesthetic importance.
It is moisture and weather resistant making it suitable for outdoor furniture and shipbuilding.
You must make shallow passes while routing end grains on Oakwood and use a backing board for cross-grain to ensure a splinter-free cut.
Oakwood can dull your cutters, so it is better to use a carbide-tipped cutter.
Walnut wood is expensive and is a strong, durable brown hardwood. It can take on shocks with ease, and hence it has been used for gunstocks predominantly.
It is a favorite choice of woodworkers for sculptures, relief carvings, turned bowls, furniture, and musical instruments.
Walnut does not burn as easily as other woods while machining but be sure to make your cuts shallow to prevent tear-out.
As walnut is quite expensive you should price your CNC router work accurately before you take up any project with walnut.
To make items like turned bowls, you should turn walnuts at 800 - 1000 RPM and use sharp tools.
Best Softwoods for CNC Routing
They are the go-to option for budget CNC woodworking.
Softwoods are the most widely used wood type for projects by hobbyists and makers because of their comparable quality to hardwood and costs lesser than hardwoods.
Moreover, softwoods are easy to mill on a CNC router. However, there are exceptions to this as some softwoods are as hard as hardwoods.
They are not as challenging as hardwood to mill and do not cause much blunting to your tools.
It has a distinct, pleasing aroma with a reddish-brown color. The wood has several knots in it, making it difficult to mill.
It has good weather resistance, and you can use it for outdoor furniture, boats, fences, and poles.
Unlike most hardwoods, Cedarwood does not burn easily at slow feed rates, which allows you to use slow feed rates on Cedarwood to prevent tearing.
Cypress wood has a good decay resistance. Being a softwood, it is easier to mill than hardwoods, but the knots in the wood make it difficult to mill large pieces.
You can use it for furniture, cabinets, windows, trims, and paneling.
Firwood is easy to work with and has a consistent pattern.
Even though it is softwood, you can use it for purposes considered suitable for hardwoods like furniture and flooring.
It has excellent durability that is comparable to hardwoods. In addition, it has a moderate blunting effect on cutters.
Pinewood has a lighter pale color, with lightweight. It does not shrink much and can hold its form.
Pinewood is a softwood, but it is quite hard enough to make it difficult for machining. The hardness makes it difficult for detailing work and carving.
To control splintering, you should reduce the length of cuts when working with pine wood.
Use faster spindle speeds on pinewood than you use on hardwoods for drilling and routing applications.
Redwood is popular for its red shade and resistance to sunlight decay. The weather resistance makes it a good choice for outdoor projects.
Machining redwood is effortless due to its softness. It can be carved with ease and produces good detail.
You have to use sharp tools to reduce tearing and splintering when working with redwood.
Spruce wood is among the harder woods in the softwood spectrum. It is is fairly lightweight but susceptible to decay.
Spruce is easy to work with and is used for making sounding boards for musical instruments and interior furniture and paneling.
Best Engineered Woods for CNC Routing
Engineered woods are man-made. They are created using various techniques for achieving various desirous properties.
Engineered wood is the most affordable choice when you need to mill full-size 4x8 sheets for your projects.
It is made from broken-down hardwood and softwood residues by combining them with wax and resins. They are denser than plywood.
Wood has good strength in a particular direction, but MDF has equal strength in all the direction, this is because of the structure of MDF board which does not follow any pattern.
MDF boards are a popular choice for making vacuum-holding beds in CNC machines.
MDF is a really great material for CNC routing. In addition, you can use it for carving as it does not splinter or break easily and gives you a smooth finish.
However, you will not get the grains that natural wood offers. If your product requires a coat of paint, MDF is a good choice.
The spindle RPM and feed rates need to be balanced appropriately to prevent burning as MDF can heat up pretty quickly.
Cutting MDF produces fine dust particles, which, when inhaled, can be harmful. Therefore, you must provide a proper dust collection system and use masks while working with MDF.
Plywood is made from multiple thin sheets of wood that are glued together to form a layered structure.
Plywood weighs less than other types of materials for woodworking and is suitable for making hanging cabinets.
You can use it for making practice cuts as they are not as expensive as the other materials and for projects that need to be economical.
Plywood tends to splinter when being cut and hence is not a recommended material for 3D carving.
However, people use plywood for 3D carving when they need that layered texture on the edges of their carving.
Best Wood for 3D Carving
3D carving requires wood that does not tear off easily and should provide a smooth finish. 3D carving involves varying cuts in different directions which can lead to splintering and fuzzy grains. A wood with uniform distribution of grain is to be preferred for 3D carving.
These wood are the best choice of wood for 3D caving:
Best Router Bits for 3D CNC Carving on Wood
The type of carving, speed of work, resolution, and finish of the end product depend on the type of router bit you choose.
- Spiral Cutting Router bit: good for straight cuts in wood, available in varying diameters.
- Ball Nose Bit: best for 3D contours and carvings. Best for making topographical maps. A tapered ball Nose bit will eliminate tool marks if you are working with intricate 3D carving.
- V bits: for lettering or sign making.
- Spoil Board cutter or flycutter bit: for flattening large boards.
The length of the bits also affects the output. Having an excessively short or long bit produces rough cuts. Usually, ½" or ⅜" shank bits are preferred.
A tool with a higher flute count will make the cuts precise due to more number of cuts per revolution of the tool, but the material removal rate per cut is reduced drastically.
Note that a router bit is different from an end mill. End mills are primarily used to mill metals.
Factors to consider while CNC cutting wood
1. Grain size
Grains can be coarse or fine. Softwoods are fine-grained, and hardwoods are coarse-grained.
Oak and Ash are coarse-grained, and pine and maple are fine-grained wood.
Fine-grained wood are easier to mill than coarse-grained wood. But coarse-grained wood exhibits better smoothness and finish than fine-grained wood.
2. Moisture content
Moisture content in the wood plays a significant role in determining the various properties of the wood, like flexing and durability.
But for carving, the moisture content determines the finish and feed rates one can achieve.
The ideal moisture content for all woods for carving is around 6 - 8 %.
The moisture content determines the tool temperature. The average tool temperature while woodworking is around 600 - 700 Fahrenheit.
With each 1% increase in the moisture content, the temperature will rise as much as around 70 Fahrenheit.
You must make sure the moisture content is within acceptable levels before carving.
Low moisture content will result in excessive tear-out on the surface of the wood while carving.
High moisture content will cause fuzzy grains on the surface. Fuzzy grains are the hair-like strands that appear on the surface of the wood.
Knots are portions inside the wood where the branches join the trunk. Knots have fibers in different directions, which makes them hard.
When the cutter of your CNC machine reaches this portion, the sudden change in hardness can cause shock loading to the machine.
If your workpiece contains knots, you must use reduced carving parameters to prevent shock loading.
However, it is best to use woods with fewer knots or design your tool path to avoid the knots.
4. Feed rate
Feed rate is the speed at which the spinning tool passes over the surface of your workpiece.
When you work with wood, a low feed rate can cause burn marks on the surface of the wood, and a high feed rate can cause splinters. So you need to balance your feed rates for a perfect finish.
Most CNC manufacturers provide the feeds and speeds suitable for their machines for various materials.
However, if such data is not available for your machine, you can use various online calculators to calculate the speeds and feeds based on your machine's parameters.
The structure of the wood makes it prone to splintering, and hence you should be careful about the cuts you make and choose the best router bit for the job.
Upcut: Upcut tools remove the chips in an upward direction. They can tear the top edge of the workpiece when working on wood.
Downcut: These tools push the cut wood downwards, which gives you a smooth top edge, but it can cause tears at the bottom of the cut.
Straight cut: These tools are not angled to the cutting surface and provide a balance between downcut and upcut tools.
However, the material removal is not as good as the former two. This can lead to heating of the tool easily.
Compression: This tool type has few millimeters length with upcut and rest with downcut, so you can achieve upcut or downcut by controlling the depth of cut.
Usually, the bottom is upcut, and the top is down cut so that you will end up with smooth upper and bottom edges on the wooden workpiece.
The tools get worn out over time, and for woodworking, you should use tools with sharp edges to prevent tearing and burning.
For cutting metals, the tool's material plays a significant part, but for wood, you can use almost any tool that is available.
It would help if you avoided long cuts when working with wood, as this will cause the tool to heat up quickly.
Frequently Asked Questions (FAQ)
What is the spindle power requirement for machining wood?
You will need to choose a spindle with at least 1 - 1.5 hp of power for a decent speed while machining wood. Spindles/routers with higher powers will enable you to cut faster.