Composite Filament Fabrication Process

6 months ago by ampringl@mtu.edu

Which problem are you trying to solve?

To reduce the ecological impact of waste material generated by society.

How are you going to solve the problem?

By creating composite filaments with waste material and bio-polymers.

What is the impact of your project?

Re-purposing waste material not only improves ecological sustainability, but allows that material to be made useful
again in the form of commercial products. Which eventually may be recycled as well.

How can the project be manufactured in the OpenLab?

BOM: Grinding mechanisms to gain particles sub 200um. Recyclebot(filament fabrication). 3D printers(varying nozzle
sizes). As well as an assortment of bio-polymers for matrix material.

Describe your project in detail

Abstract___The goal of this project is to develop a manufacturing process taking waste material and breaking it down
into sub 200um (80um ideal) particles, then mixing said particles with polymeric material and extruding them as 3D
printable filament to be printed as products. Ideally the materials used for filament would be 100% waste material to
truly promote ecological sustainability of the
biosphere.
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Introduction___In general, any material which is stable
(solid and relatively non-reactive) within the temperature range of 0-200C may be used for this project. The particle
waste material is physically bound in the polymer matrix when homogeneously mixed leading to uniform properties. The
properties exhibited by the composite would be a mix between the in-fill material and the polymer matrix. Thus,
different composites may be used for different applications for aesthetic, structural, or other various commercial
reasons. 3D printers are powerful devices for customization and prototyping. Typically, polymer materials are used for
filament due to their low melting temperatures and modest mechanical properties. Two primary benefits are the capability
of user generated content allowed through open source software and the speed at which an idea may be conceived, modeled,
and then printed. Therefore, it is quite appropriate to base the proposed project upon utilization of this innovative
and creativity based technology.
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Method___Step one: Waste material
procural – matrix material selection___Of the many waste materials produced by society, there are several which
exhibit superior properties and allow composites of more useful property values (i.e. higher ductility or tensile
strength) to be created. Metals, plastics, and paper products as an example all may be reduced to small particles sizes
relatively easily and would work nicely for this project. Additionally, those three material groups are often waste
materials meaning supply shouldn’t be a concern. Choosing a polymeric matrix material is critical when envisioning
what product will be printed. Some polymers such as poly-lactic acid (PLA) are bio-polymers but degrade in sunlight,
while others such as acrylonitrile butadiene styrene (ABS) are synthetic polymers and do not degrade in sunlight. PLA
and ABS for example could both be used but, ideally for specific waste material composite applications as their material
properties differ. Polymeric waste material may even be taken and used specifically as the matrix material leading to a
100% waste material printable filament. Muti-material or material blends could also be incorporated, but would be more
complicated.
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Step two: Material reduction___To use waste material,
it must be in a physical state capable of being combined with a polymeric matrix and be small enough to be extruded
through a 3D printer. Typical printers have a 0.5mm nozzle size, but 1.0mm nozzles are common for larger prints. As the
clear majority of waste material is greater in size than powders a process to reduce the size of the waste material is
necessary. Several solutions would be industrial grinders, ball mills, grinding mills, or even hand sanders. The general
idea is to go from macro-scale to meso-scale to micro-scale. Particle size should largely influence the bonding of the
filler material to the matrix material. Smaller particle sizes would have less of a chance of clogging a 3D printer
nozzle However, to accommodate larger particle sizes, larger nozzles may be
used.
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Step three: Particulate material and matrix mixing__Homogeneous
properties make products reliable and useful. With particulate sizes sub 200 microns, the matrix material ideally would
be of comparable size (but commercially is easily available in pellet form of about 4mm diameter for most 3D printable
polymers). Then the process is effectively to add heat and mechanical forces to mix the two materials and extrude into a
filament. One method would be to use a dual auger system attached to a recyclebot. Each auger feeds in a material to a
heated central auger which then mechanically mixes the materials. After traveling through the central auger, the
combined material is then extruded through a hole(drilled in a metal cap at the tail end of the central auger) of
specific size to create filament of a specific diameter. The now mixed filament leaving the hole end of the recyclebot
then is spooled and then ready for printing. 3mm and 1.75mm filament are typical standards for 3D printers, there may be
benefits to doing one or the other diameter given a particulate size.

__________________________________________________
Step four: 3D printing a product and optimization of
properties__Depending on printing parameters and 3D printer the part properties change. There are three general steps to
3D printing: One, select a 3D model or stereolithography (STL) file or create one from programs like OpenSCAD or
FreeCAD. Two, import the file into an appropriate slicing software such as Cura or Slic3r and determine the printing
parameters needed for the part application. These printing parameters control the print such as layer height(ex.
0.15mm), printing temperature(ex. 210C), or infill percentage(ex. 25% for normal non-structural). Three, upload the part
via gcode file to the firmware of the printer to be used and print. Several iterations of parts would be needed to
optimize and test printing parameters.
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Conclusion and closing
statement__The concept proposed is relatively simple: reduce the size of waste material, find an appropriate matrix
material, heat all materials up and mix together, extrude as filament, and finally print a product. If successful, this
project would effectively allow a significant reusability of waste material. By using both waste polymer and waste
filler particulate material 100% recycled products may be fabricated. Additionally, there is potential for products to
be recycled multiple times within the materials lifetime further extending material reusability. The success of this
project would be a strong step toward a more sustainable and economical future for the biosphere as it emphasizes
specifically a goal of 100% recyclability.

Attachments

Comments

mmoritz 6 months ago
Wow-great idea! have you built a prototype yet?
ampringl@mtu.edu (Submitter) 6 months ago
@mmortiz We've been able to make a similar process work for wood waste materials. Basically took furniture waste
and reduced the size to 80micron and mixed with a PLA matrix. Successful prints, but small sample size.
It would be nice
to see the effect of different materials(plastics/metals) and different matrices(Other printable polymers).
Othman 6 months ago
This is an amazing idea. I saw many people recycling their filament waste but the shredder and other machines are
difficult for me to manufacture. Some people do it at a very low cost but they have the machines to do it and I
don't.
Really interesting project wish you all the best and please share your updates after you finish the
project.
diego 5 months ago
I think it's a great idea not only for the future but also that we need to reduce all the pollution that there are
super good things
me parece una gran idea no sólo para el futuro si no que necesitamo ya para reducir todo la
contaminación que hay súper felicidades
TechUser 5 months ago
Very useful! Where do you see the main problems and/or development potential of your project? Did you test waste paper
as well? The application of waste material is a good thing. The waste separation and a proper preparation of the waste
material is one basic prerequisite for the process, which has an impact on the ecological awareness as well.
Omarhasayn89 5 months ago

A great project that facilitates the disposal of waste by converting useful materials ... The recycling process should
be continuous so as not to return to the first problem .. For the process of manufacturing must take when we planning
the bad gases that may arise if exposed to plastic materials to heat
ampringl@mtu.edu (Submitter) 5 months ago
@TechUser The main problems for this project are probably going to be correct waste material - polymer matrix paring to
maximize composite properties(mechanical and chemical). This is really hard potentially, because having the proper
attractions(functional groups for matrix) on the molecular level will be difficult unless the waste material is
thoroughly sorted via material type.
Waste paper was not directly tested. If there is a relatively easy process to
break apart the paper fiber connectivity and leave isolated fibers, then it would be straight forward to utilize waste
paper. Problem here is getting uniform particle size.
If the mentality suggested by this project is adopted on a large
scale, I believe we would see drastic changes in waste material and see profound ecological impacts in the long term as
material is recycled and effectively upcycled.
ampringl@mtu.edu (Submitter) 5 months ago
@Omarhasayn89 I am not sure I understand, in your comment you mention the possibility of returning to the first problem,
what specifically is that?
To overcome the polymer degradation process issue, the waste materials will have to be sorted
to quality of the material and observed for consistency. It is important to note that degradation/contamination may
occur over the lifetime of an object before it becomes waste. This is especially relevant for polymeric materials as
higher molecular weights generally mean greater mechanical properties and degradation creates a mixture of molecular
weights and thus melting temperatures which complicates the recycling process.
Omarhasayn89 5 months ago
I meaning in ( the first problem) is the starting point ... I mean here there are wastes that have not been disposed
of...good luck my friend ^_^
Tamba 5 months ago
Very important
With the development of 3D printers we really need
yassineaskri 5 months ago
good , but try to make the process more efficient ! good luck !