All About Wood 3D Printing Filament: Materials, Properties, Definition

Wood 3D printing is a process where wood-based waste materials are re-purposed and used as ingredients in the construction filament for additive manufacturing. Wood is one of the most popular 3D filament additives because it makes parts look like they’re carved out of wood. For more information, see our all about 3D printing guide.

Wood filaments are composite filaments that typically use PLA (Polylactic Acid) as a base and some form of wood as an additive. Manufacturers offer many types of wood, such as: birch, cedar, bamboo, cork, ebony, pine, olive, and even coconut. The standard composition of wood filament is usually 30% wood component and 70% PLA, although these values can differ between products and manufacturers. Because the main component is PLA, most of the filament’s properties are linked to this material. There are, however, some altered properties – like increased brittleness and a wood-like finish – that come into play when wood is added.  Figure 1 below is an example of a wood filament:

The properties of wood 3D printing filament are listed below:

1. Wood filament has a very low tendency to warp or shrink.
2. Wood filaments are biodegradable and recyclable.
3. Wood 3D printing filaments are very stiff and rigid and are not intended to be flexible.

Comparison of Wood Filament Properties

Table 1 below compares the properties of wood 3D printing filament to a selection of other 3D printing filaments with no additives:

There are some challenges associated with wood filaments. These include:

1. Wood 3D printing filament mimics the durability of PLA rather than that of wood itself. Wood prints are inflexible and brittle and it is not recommended to use them to support loads. 
2. Wood filaments are very brittle and can easily break if the filament’s path from the spool to the extruder is not smooth.
3. Unlike other composite filaments (such as metal or carbon fiber filaments), wood filaments can catch fire and burn when exposed to high temperatures. 
4. Wood filaments can damage brass nozzles due to their abrasive nature. 

Listed below are some of the advantages of printing with wood filament. 

1. Wood filament prints imitate a wood-like finish that looks and feels like real wood.   
2. The grains in the wood filament hide seam lines between layers. 
3. Layer thicknesses that look ugly in plain polymer are not as conspicuous when wood is incorporated. 
4. Wood prints can easily be sanded with standard sandpaper.

Why is Wood Used in 3D Printing?

The main reason for 3D printing with wood is the unique aesthetics that it delivers, especially compared to regular plastic filaments. Models printed with wood filaments have a finish that closely resembles the natural grainy finish of pure wood. It is possible to create complex or intricate designs and patterns with 3D printing that would be difficult or impossible to achieve with traditional woodworking techniques. Wood filaments are also significantly less abrasive than other composite 3D printing filaments that contain carbon fiber or metal, and they are less likely to warp or shrink. 

How to Use Wood in 3D Printing

To achieve excellent results in wood 3D printing, remember the following tips:

1. Wood 3D printing filament does not have the same level of adhesion as PLA. It requires a print adhesive to bond to an unheated build plate. Print tape, gluesticks, or hairspray adhesives are usually sufficient. 
2. Use the correct nozzle diameter and nozzle material. Hardened steel nozzles are the best options. To avoid clogs, a nozzle size of at least 0.6 mm is recommended. It provides a good balance between print quality and printing speed. If smaller nozzle diameters are used, adjust the flow rate. 
3. Wood filament is hygroscopic and can absorb moisture from air very quickly. Store it away from moisture in an airtight container and dry the filament before use. If the filament bubbles as it gets extruded, that’s typically a sign that it has been infiltrated by moisture.  
4. Post-process the part either by sanding or polishing your print.

Listed in Table 2 below, are the printer settings that you can apply when printing with wood filament:

The ideal wall thickness for 3D printed wood parts depends on its end-use application. PLA filaments infused with wood are slightly weaker than regular PLA because the wood particles interrupt some of the polymer bonds. To address this problem, it is advised to use a minimum wall thickness of 1.2 to 3 mm (nozzle diameter = 0.4 mm).  

What is a Good Wall Density for 3D Printing Wood?

A minimum infill density of 20% is usually advised, though it can vary depending on the application. Though load-bearing applications are not advised, an infill density of 50 to 100% would be required depending on the amount of weight to be supported. 

Yes, when heated, the fumes emanating from the wood filament can be toxic. It also releases carbon monoxide, carbon dioxide, and hydrocarbons if it is burned. It is, therefore, important to print in a well-ventilated area. 

Yes, wood filament is considered mildly abrasive. Due to their relatively soft surfaces, brass extruders can be damaged by wood filaments. Steel extruders are more resistant to the abrasiveness of wood filaments, but they are still not immune to damage.

Yes, wood filament is 100% biodegradable. This biodegradability is because PLA, a cornstarch-based polymer, and wood are both considered biodegradable. It takes up to 2 years for the components to decompose. 

Yes, in most cases, wood filament is recyclable. Make sure to confirm with the manufacturer. Most indicate that both the filament and item printed with the filament can be melted and reused in another application.

No, wood filament is not food-safe. This property is because PLA is primarily used as a binding agent and the mix of heat and chemicals in its processing could pose health risks. An additional concern is the printed materials are porous, so harmful bacteria can accumulate in the microscopic cracks. 

What is the Difference Between Wood and PLA in 3D Printing?

A primary difference between wood and PLA filaments is in the surface finish of the final product. Wood-printed products have a wood-like finish, whereas PLA can have different types of surface finishes - matte, glossy, or even silky. Wood filaments and parts tend to break more easily than regular PLA. The extrusion temperature of both materials is also different. Compared to regular PLA, wood filament should be extruded at slightly higher temperatures. 

This article presented wood 3D printing filament, explained what it is, and discussed the different factors to consider when using it for 3D printed parts. To learn more about wood 3D printing filament, contact a Xometry representative.

Xometry provides a wide range of manufacturing capabilities, including 3D printing and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.

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