Quick 3D Printing File Guide 3D Printing or Additive Manufacturing enables its users to create many objects in ways which were previously not possible, such as ready working parts or once impossible to machine forms. There are still some limitations, or things which will compromise the objects integrity. Some of the things to be aware of have been described here in this quick guide. This quick guide has been prepared for the ‘3d Printing for Creatives’ class of Industrial Design, RMIT. The build envelopes described are in reference to the machines available to the students at “The Future Is Here” exhibiton. The Makerbot Replicator 2 has been made available by Nigel Brockbank’ and ‘FreedSpace’ - http://www.inition.com.au/.
File Types
To 3d print we need surface or polygon based files. The most common file types are known as obj or .stl files. Polygon count should be under 1 Million, with file size corresponding to this. The larger the polygon count the longer and harder it is to slice the file for 3d printing. Use your export or save as function to create these file types with your CAD program.
.OBJ
Programs to clean and edit STL files Free Programs
Meshlab (medium) netfabb Studio Basic Meshmixer (easy) Blender (advanced) Paid Programs for cleaning and editing your .STL’s
iMaterialise Magics netfabb Studio Professional Rhino3d v.5
.STL
General Limitations Build Size
25
0
25
0
Fortus250
150
300
This is the limitation of size that we can make things in one piece. If this is too small, we can split your files to be fused together post printing. In special circumstances we can organise for bigger things to be made in one using alternate printers.
28
0
0
15
Makerbot Replicator 2
Build Material
During the build process certain shapes will require build material. Build material or support material is part of what enables you to make any form. However it also adds extra time and extra materials into your overall print job and post processing. Build Material is required for overhangs and draft angles:
overhang overhangs or geometry which floats in the air
30° angles over 30˚ will generally be supported
Good Meshes Basics
Polygon meshes need to be closed for a solid object to be printed. They need to be “watertight�, with no open surfaces and need to be made of complete solids. These closed meshes are also known as Boolean Solids.
Wall Thickness
Wall thickness should be at a minimum of 1.2mm unless in special cases. .8mm walls for clear filament - this increases failure rate
open surface
Open Surface
open surfaces will compromise you print job, as the printer will not be able to close the mesh with gaps appearing in the final result
Zero Thickness
polygons overlapping each other will create a zero-thicknesses which increase print times and reduces geometric integrtiy
Good Design Features
To be able to 3d print something it must have the physical dimensions which correspond to the chosen material’s ability to form. This means parts cannot be too small or too thin for them to physically work.
>3mm
Feature Size
To ensure a job always works, it best to have all features or parts that make up an object be above 3mm in size. It is possible to go smaller but this increases the chances of failure.
Tolerances
When printing moving parts, or parts that are going to join or snap lock etc. A tight join or snap lock is around .15mm and a loose join or snap lock is at .30mm
.15mm =TIGHT
.30mm =LOOSE
Print Settings Basics
Our basic print setting is always 250 micron with medium fill and maximum wall thickness, enabling good strength and resolution. For aestheiticly based work or parts that require maximum strength, our resolution we will adjust accordingly to produce the best result. All of these settings are automatically made by the 3d printing software
Infill
There are different levels of infill which provide a strong honeycomb structure.This includes an almost solid fill, medium fill, or an outer shell. Solid fill should only be used for parts that require the strength.
Layer Height
100 micron being superfine, and 400 having obvious stepping. 100mircon printing takes significantly longer and does not yeild a huge advantage in aesthetic quality past 200micron.