May 19, 2022

Michigan Tech researchers recycle wood furniture waste into composite 3D printing material –

A) PLA during mechanical mixing with waste wood powder, B) PLA and WPC based on waste wood powder after mixing and cooling to room temperature, C) Chipped WPC and D) homogeneous WPC material after the first passage in recyclebot.

From works of art, instruments and boats to gearshift knobs, cell phone accessories and even 3D printers, wood has often been used as a 3D printing material. It’s a valuable renewable resource that stores carbon and is easily recycled, so why wouldn’t we think about using it in 3D printing projects?

A trio of researchers from Michigan Technological University recently published an article titled “Recycled 3D printing filament made from wood furniture waste“, which seeks to see how viable it is to use wood furniture waste, recycled into a wood-polymer composite (WPC) material, as a 3D printing raw material for furniture construction.

The summary reads: “The Michigan furniture industry produces over 150 tonnes / day of wood-based waste, which can be recycled into a wood-polymer composite (WPC). This study examines the viability of using furniture waste as a raw material for 3D printer filament to produce furniture components. The process involves: crushing / milling off planks made from both LDF / MDF / LDF and melamine / particle board / paper impregnated with phenolic resins; premix wood-based powder with polylactic acid (PLA) biopolymer, extrude twice through open source recycling robots to make a homogeneous 3D printable WPC filament, and print with open source FFF-based 3D printers. The results indicate that there is a significant opportunity for waste-based composite WPCs to be used as a 3D printing filament.

Although much of the wood is wasted by burning it, it may be better to recycle it into WPC, which contains a wood component in the form of particles inside a polymer matrix. These materials can help reduce costs and environmental impact, while providing better performance.

A) 3D printed 0.15mm layer height drawer knob with screw hole for fixing. B) Completed drawer knob fully attached to the left of the wood block with a sample hole pre-printed to the right of the block, 30% by weight waste wood furniture.

“There is a wide range of wood modification techniques involving either active modifications such as heat or chemical treatments or passive modification, which changes the physical properties but not the biochemical structure,” the researchers wrote. “However, WPCs still have limitations due to production methods, such as waste generation or direction-dependent manufacturing, which can be mitigated with alternative manufacturing techniques such as additive manufacturing.”

While many manufacturers of PLA composites are already in the market to make virgin wood-based 3D printing filaments, the Michigan Tech study investigated the use of scrap wood furniture as a printing raw material. 3D for the WPC filament, which could then be used to make new furniture components. .

“The process uses the crushing and grinding of two furniture waste: scrap planks made up of both LDF / MDF / LDF (where LDF is light density infill and MDF is medium density infill) and melamine. / particle board / paper impregnated with phenolic resins. A pre-mixing process is used for the resulting wood-based powder with PLA granules, ”the researchers wrote. “This material is extruded twice through an open source recyclebot to make a homogeneous 3D printable filament in wood volume fractions: PLA from 10: 100 to 40: 100. The filament is tested in an open source industrial 3D printer based on FFF The results are presented and discussed to analyze the opportunity to produce composite filaments from waste.

Surface contours of a drawer handle personalized with the Herman Miller emblem. A change in coloring from the outside to the center is shown due to the temperature changes induced during printing to provide a shaft ring.

The team received wood-based waste, both in the form of sawdust and bulk, from several furniture manufacturing companies, and took some important steps to turn the wood-based waste into WPC for the filament of 3d printing:

  1. Reducing the size of the macro and meso scale to the micro scale
  2. Mix a fine wood-based filler with a matrix polymer
  3. Extrude the filament feed material of uniform thickness and density

Then the material was loaded into a RepRap delta 3D printer, as well as an open-source Re: 3D Gigabot 3D printer, to make a high-resolution drawer knob that was “attached to a block of wood printed using the printer. ” a wood screw threaded into a pre-printed hole.

“The wood screw was easily twisted through the two objects with a Phillips screwdriver and the resulting connection withstood the normal forces expected in everyday use. Additionally, due to the flexibility of 3D printing orientations, unique or custom surfaces can be printed onto objects, ”the researchers wrote.

“This is illustrated by the particular geometries or printing directions which can be changed directly by modifying the gcode, or more conveniently by modifying the parameters in the cutting programs. This allows for large-scale customization of not only furniture components with wood, but also any part 3D printed using recycled plastic composites made from waste.

Once an optimized 3D printing profile was obtained, the WPC filament made from recycled wood furniture waste was able to produce parts without too many errors. However, there was a higher frequency of filament blockages and nozzle clogs with this material, compared to pure PLA.

Five consecutively 3D printed office cable passage pieces, 30% by weight of wood furniture waste.

“This study demonstrated a technically viable methodology for recovering wood furniture waste into 3D printable parts usable for the furniture industry,” the researchers concluded. “By mixing PLA pellets and recycled wood waste, a filament was produced with a diameter of 1.65 ± 0.10mm and used to print a small variety of test pieces. This method, although developed in the laboratory, can be extended to meet the needs of industry because the process steps are simple. Small batches of 40% by weight of wood were created, but showed reduced repeatability, while batches of 30% by weight of wood showed the most promise in terms of ease of use.

The researchers wrote that further work on creating waste-based WPC filaments should include quantifying the mechanical properties of the material after the first cycle, and then comparing it with other materials, such as pure PLA and powder. of modified wood fiber. In addition, industrial equipment and bundled 3D printing nozzles should be evaluated in terms of process extension.

The co-authors of the article are Adam M. Pringle, Mark Rudnicki and Joshua Pearce.

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