My Final Year Project: 3D Printing

[tachyio 0]

Hi Folks!

I suddenly have the rare-exception of proposing my own university final year project in material science! And yes, its going to be about 3D Printing...

So I was wondering what to do my research on...when it occurred to me that my Ultimachine Filament was vastly superior to the stuff I got from Ultimaker (no offence, but my experience was better), and relatedly, Ultimaker Filament is vastly superior to the stuff a friend of mine gets from China...

So that got me thinking, that in addition to quantifying extruder performance, its also really important to quantify filament properties and how that relates to 3D Printers.

I've written a rather lengthy draft, and will send it along to the professor sometime this week. I'm wondering if any of you have other ideas, or feel that there are other more important research topics. I would like to contribute back to the community, so that's why I decided to ask all of you

PROPOSAL DRAFT:

Abstract:

Why are some plastic filaments more suitable for 3D Printing than others?

3D Printing Machines are precision devices which not only require accurate mechanical systems to function correctly but also plastic filament which has very uniform material property throughout its length.

There is a need to properly identify and characterise the ideal properties of a plastic filament that is used for 3D Printing, in order to improve a 3D Printer Operator's experience.

The Problem:

3D Printers rely on their plastic filament having very uniform and predictable properties in order to function properly.

Any change, for example in melting point or flow-rate, could damage a 3D Printer by causing 'cold extrusion' or cause printed objects to be weak 'under-extrusion', respectively.

Few studies have been done to relate filament morphology to parameters that are important to 3D Printers. As a result, most 3D Printer operators are forced to learn via trial and error the optimum settings needed to use a particular plastic filament. These 'optimum settings' do vary between filament batches, but more widely amongst different manufacturers.

These important parameters are:

(1) Plastic Filament adhesion-strength to Heated Glass/PCB Platform versus Platform Temperature in relation to Filament Morphology

Reason: How stable can the printed object adhere to the printing platform, and at what temperature is this adhesion strongest? Why do some filaments adhere better at lower temperatures and others at higher temperatures?

(2) Extrusion Mass Flow Rate versus Extruder Temperature in relation to Filament Morphology

Reason: How fast can a 'standard extruder' extrude a filament with respect to extruder temperature? This determines the speed of a 3D Printer, and consequently, how fine 3D Prints can be. Why do some filaments flow more easily than others?

(3) Plastic Filament self-adhesion strength versus Extruder Temperature versus Extrusion Velocity in relation to Filament Morphology

Reason: How strong is the final printed object? Does the object shear easily due to poor self-adhesion? What material phases contribute to the strength or weakness of the printed object? How do these material phases form in relation to extruder temperature/velocity? How does this compare to a standard injection moulded part?

(4) Plastic Filament Melting Point in relation to Filament Morphology

Reason: There is a need to identify the filament composition and relate this to the melting point of the material, in order to ensure that manufactured filament maintains a standard melting point. Currently varies from 180C to 260C.

(5) Plastic Filament warping degree versus Platform Temperature in relation to Filament Morphology

Reason: Part warpage is an on-going problem for the polymer industry, and 3D Printers are no exception. At too low/or high platform temperatures, 3D Printed Parts can warp causing structural instability. A short and simple study will be done to quantify the warpage versus temperature in relation to the filament morphology.

(6) Plastic Filament Glass Transition Temperature in relation to Filament Morphology

Reason: The Tg of printed parts is important as it determines their mechanical rigidity during everyday usage. There currently is no standardised Tg for plastic filaments, it varies widely from 45C to 65C, most likely due to non-uniform properties across the industry.

Procedure (Very Brief):

These (6) properties will be tested against PLA (Polylactic Acid) filament from different manufacturers, and adhesion and tensile tests as well as imaging of the material structure will be used to quantify the findings.

The Aim:

To identify the material properties which makes a plastic filament suitable for reliable and continuous 3D Printing.