3D printing is a method of fabrication which builds a 3D object from successive layering of plaster powder and resin.
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With the 3D printer you can have your digital models built directly from the 3D model file built in Max or Rhino or other programs. It builds the model from very fine plaster and a binding agent. For a full description of the building process see here. The printer can print you model in an extensive range and combination of colours and the material finish is usually smooth.
The 3D printer has certain parameters which must be met in order to get a successful model printed.
1. Filetype The printer can only print STL files. Most 3D modelling programs can export models in this filetype.
2. Size The printer has a bed size of 200mm x 200mm. The height of the chamber is 250mm. Therefore your model must be able to fit within that space.
3. Tolerance This is the central parameter. The minimum thickness which the printer can print is 2mm. Anything thinner than this will collapse under its own weight i.e. it won¿t be self-supporting. Your model must therefore not at any place be thinner than 2mm.
Otherwise, the printer can print whatever form you have. It is especially well suited to printing curved surfaces. Remember that the model must have a hole somewhere in it by which excess plaster power can be released after printing is complete.
It is likewise essential that you discuss you model, prior to submitting it to the 3D printer dropfolder, with the technician in charge of 3D printing. Some students even prefer to come in and discuss their digital model with the technician prior to making it. Contact Media Centre to determine a suitable time to discuss your work.
Surfaces of your model can be strengthened post-print by applying superglue to the surface. This is the student¿s responsibility after having collected the printed model. Normal superglue is appropriate for the job such as Duro superglue. The glue has to be liquid and usually it should dry clear. It sinks into the plaster and with a few layers (however one layer is sufficient) of it the surface is greatly strengthened. A little goes a long way.
After having consulted the 3D printer technician, made and finalised your model, you are ready to submit you work to be printed. Typically, you will follow a pathway like this one:
1. Export the model as an STL file from a 3D modelling program.
2. Name the file as you do for other dropfolders in the School:
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="50f27b78-e0d5-477f-b710-8a545d50c5d0"><ac:plain-text-body><![CDATA[ · i.e. [UPI][filename][number of copies]copies.stl
· e.g. jdoe001_facade study_1copy.stl
3. Collect your model from the 3D printer workshop. So long as there are no errors - and the main reason for consulting the technician prior to printing is to eliminate potential errors – your model should likely be printed within 24 hours of submission to the dropfolder. The technician will contact you by email if there are any errors printing. Therefore it is important to make sure you contact details are up to date, and that you check your email account regularly. It is best therefore to allow 2-3 days in total in case errors are found in your file.
Note that you should make you digital model specifically for the 3D printer. Many students in the past have hoped to simply be able to reduce the scale of the model they are already using for renders etc with full details and materials and submit it to 3D print. But if you are modelling a wall at 100mm thick full scale, reducing it to print in the 3D printer would likely give you a wall thickness of around 1mm which is under the 2mm tolerance the printer can work with. Therefore, that wall will just collapse after printing. You must pay attention to this tolerance and use it to your best advantage.
Plaster: cost per cubic cm - $1.00
Binder: cost per ml - $0.50
Colour Ink: cost per ml - $2.43
cost per unit (plaster+binder): $1.50
The cost of the 3D printer is $1.50 per unit – a unit being a blend of plaster powder and binding agent. The technician will be able to tell you the likely cost of your model when you consult him or her. The average cost though sits somewhere around $60 -100.
Over and above those strengths and weaknesses listed already, the 3D printer at present is:
+ + Very good at printing curved surfaces and complex geometry.
++ Excellent at printing in a wide range and combination of colour.
- Poor in that you can¿t easily paint the model after it has been printed. In order to paint it you must first apply a primer (any standard primer, available from Resene or Gordon Harris).
- Poor in that it usually takes a long time to print, and is therefore expensive. But of course compared to hand modelling, especially when you are dealing with curved surfaces, you will find the printer a much faster option.
- Poor in terms of touch-up-ability. If for example the model were to crack after being printed it is not possible to put the thing back in the chamber and re-apply power and agent. The printer cannot repair. However, the main reason the model might crack is if the 2mm tolerance is not respected.
To get you started Media Centre suggest the following tutorials:
Beginner A: Intro to Z Printer
Beginner B: Minimum thickness
First published Mon. 1 Feb. 2010