Author Topic: 3D Printers  (Read 37051 times)

Offline Frank3k

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Re: 3D Printers
« Reply #75 on: August 30, 2023, 07:43:15 AM »
Does anyone in your club have a 3D printer? If you can watch their workflow, you can learn quite a bit (including what not to do...)

Offline tsrjoe

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Re: 3D Printers
« Reply #76 on: August 30, 2023, 04:03:47 PM »
A little primer compiled for my students, might be of interest as background ... An introduction to 3D Printing,  Joe Warner Cherrie
3D printing, sometimes known as additive manufacturing, is a relatively new entrant to the craft and making scene but has been around longer than you might think. Having first been developed in the 1980’s, more recent developments in the technology and accessibility of use seemingly bringing about a true democratisation of the digital making process
The term ‘3D Printing’ is generic and covers a host of technologies, but they are all united by building up the desired object in incremental layers rather than the more traditional moulding or milling. While generally slower than mainstream technologies, it is increasingly finding a place as part of the manufacturing toolkit, e.g., where it can produce rapid prototypes without the need for mould making, allowing truly novel and intricate shapes which can’t be produced by other means, or where you need high levels of personalisation.
The technology is now seeing more applications with the utilisation of a multitude of materials, and in areas as widespread and demanding as the use of printed sintered metal alloys in critical elements of jet and rocket engines, to biological and organic materials used in the production of precisely tailored medical implants. Items such as personalised in-ear hearing aid or modern ‘Invisalign’ type dental braces utilise the 3D Printed process being common examples of the latter application.

The most common technologies for craft home use 3D Printing are based on either a solid filament extruded through a heated nozzle, ‘FDM.’, or a liquid resin cured by ultraviolet light, ‘DLP.’
-   FDM., or ‘Fusion Deposition Modelling’ (also known as FFF. ‘Fused Filament Fabrication’), uses a solid thermoplastic material which usually comes as a spool roll of filament. The most common materials are :
PLA. (Polylactic Acid), a polyester which behaves a lot like polythene and is derived from corn-starch and is biodegradable (see also ‘Vegware’ biodegradable plastics)
ABS. (Acrylonitrile Butadiene Styrene) which is a synthetic polymer commonly used for making things like LEGO bricks.
The filament is heated in a print head to a semi molten state and extruded through a fine nozzle which moves over the print adding a bead of plastic as it travels.
A number of alternative plasticised organic materials which can be used as filament include, wood pulp cellulose composites, ceramic clay, seaweed bioplastic, silk polymer, mycelium fungi and even chocolate
FDM has the advantage of being relatively safe, clean and very straightforward with a typical nozzle size of 0.4mm width and layer height of 0.2mm (you can go smaller although resulting in longer print times and higher failure rates) Entry level printers are generally below £150 and are often cheaper second hand as people try them out but get frustrated with recurring failures (generally self-inflicted)

-   DLP., ‘Direct’ or ‘Digital Light Processing’ uses a liquid resin tank with a transparent base and movable build stage suspended within very close to the bottom. UV. light is shone into the tank either as an image by a projector or through an LCD. with a negative mask, which cures the resin it strikes into a solid. The chemistry is similar to acrylic nails and white tooth fillings. The build stage is lifted by a tiny increment and the process repeated. Typical materials are based on epoxy and acrylic thermosetting resin. 
A similar process, SLA. ‘Stereolithography’ printing utilises a similar process utilising a laser to selectively expose the liquid resin to a light source (SLA.  laser, DLP.  projector)
 DLP./SLA. printing can be potentially messy (the resins used are viscous, sticky materials) and requires far more awareness of safe use of the material. The clean-up of completed prints needs rinse cycles, (in IPA. ‘Isopropyl Alcohol’ solvent or water depending on resin type) and further UV. curing. (UVA. Curing booth or sunlight) The resolution for even a cheap (less than £150) consumer printer is remarkably good with layer heights of 0.02mm and very fine parts possible.
Both FDM. And DLP./SLA. Printing have their place for the artist designer and desk top modeller and if you order parts from online services such as Shapeways you may see other technologies such as SLS. Selective Laser Sintering) and Polyjet which fuse powder particles together with either heat or a fine jet of glue.

You can find printable open source STL.  files online from a number of places like Thingiverse and Cults websites and many museums like the Smithsonian are scanning and making their collections available to download and use. Some sites charge for models and most have limits on things like commercial reuse. Even if you don’t plan to print, downloading a .stl file can be informative as most Mac and PC computers have built in 3D viewers which allow you to examine an object from any angle.

FDM. type printing has already been utilised to print ‘protein’s creating foodstuffs
Organic cells have also been utilised to ‘print’ body parts including valves and organs

… As for the future … who knows ?  A further democratisation of the technology through open access platforms and home printing ? or perhaps looking slightly further ahead one could postulate ‘Omni replicators’, printing almost anything using molecular reservoirs ? or imagine a doctor or pharmacist sending over a file to a ‘home printer hub’ to produce required medicines at point of use at low cost
Some useful/interesting resources …

There are also local FabLab or Makerspace’s to see/try these out for yourself :

Compiled with assistance from Alistair Reid (Gannet 3D) & Paul Boyle (PB Models)