Making your 3D Model
The most important part of using a 3D printer is having the 3D model to print from. The following section describes the printing requirements and considerations when working with the Ackuray.
Supported File Formats
Ackuray printers read the following print slice files that are created from 3D printing programs:
|VBF||Visualizer Print File|| This is the standard print file format used
with the Ackuray. Visualizer and Visualizer+
output their print files in this format.
|ACK||Ackuretta Print File|| This file format is created by the Ackuretta
Print Assistance Tool. Use the Print Assistance
Tool when you already have a set of slice
images but you want to add Ackuretta settings
to those slices.
|SLC||Slice File|| This is an open-source format that uses the STL
convention for making slice files.
Ackuray printers support STL and MGX file formats, which provide vector information in the form of numerous triangles. The STL file format is supported by most CAD and 3D modelling software. If you have OBJ, 3DS, LWO, or Blender files, use your 3D modelling program to convert those files to STL.
Ackuray printers have the following key requirements for models:
This set of dimensions is specific to the Ackuray printer stating exactly what sizes the printer is capable of printing. If you want to print an object larger than the maximum build volume, split the object into multiple connectable parts and join them together. Objects smaller than the minimum build volume may be unstable with the necessary support material.
|Maximum build volume:||96 x 54 x 130 mm||135 x 76 x 130 mm|
|Minimum build volume:||2 x 2 x 2 mm||2 x 2 x 2 mm|
|Minimum detail size:||0.05 mm||0.07 mm|
Hollow Spaces with Drain Holes
Ackuretta recommends using hollow spaces if possible, because hollow objects require less material and the printing time is shorter. Use hollow interiors and cavities as long as the object’s strength is not a major concern, like in the case with prototypes or display objects.
When creating a design with a hollow interior, you will need to at least make an exterior shell, and usually will have to connect the shell with some interior supports. The object will trap resin inside during the printing process, so you will also need to place drain holes in the model. The requirements for your individual print vary based on how strong the object must be, but the dimensions shown here are the minimums when using Ackuretta resins.
|Minimum exterior shell thickness:||0.15 mm|
|Minimum interior support thickness:||0.20 mm|
|Minimum drain hole diameter:||2.00 mm|
Multiple Connected Parts
In order to print all parts in sequence, Ackuretta recommends saving all parts as a single component in your CAD file. Ackuretta Visualizer is able to queue the parts for printing and save the settings for each part. You will still need to prepare the printer and perform post-processing on each print individually, but keeping the settings on the same file reduces the chance of a misprint.
When assembling pieces, the parts may not fit perfectly with each other, so it is a good idea to design your parts with additional resin that you can later reduce if necessary for tight assembly. Similarly, if the pieces are meant to be tight fitting but free-moving, you may need to reduce the print size for free-moving tolerance. Use the following suggested tolerances when creating models for Ackuray printing:
|Tolerance for tight-fitting parts:||0.20 mm (added to initial size)|
|Tolerance for free-moving parts:||0.50 mm (removed from initial size)|
Best Practices for 3D Modelling
Hollow Spaces with Support Material
As noted in the Model Requirements, Ackuretta recommends printing hollow objects when possible, but not all objects are created equally. Some hollow objects may need internal support material to maintain a solid structure during printing, and as such, these objects will need a way to remove that material.
Many programs have systems that count the number of 3D shells, the type of infill, and the infill percentage. Additionally, you have to consider that the interior support material needs to have some sort of exit, so you will need at least one hole that you can easily remove the support material through. For the majority of prints, the following are the preferred ways to configure these options:
|Number of shells:||2-5 (1 is usually too few, and more than 5 becomes unnecessary)|
|Infill types:||Hexagonal / Honeycomb (most efficient for strength vs. material used)
Triangular (stronger than hexagonal and good for thin/narrow objects)
|Infill percentage:||10%-20% (increase this number for smaller prints)|
|Removal holes:||5 mm (large enough to pull through with tweezers)|
If you need more rigidity, flexibility, or translucency, adjust these numbers for your specific case. The primary point of using hollow spaces is to reduce material used, so when testing different print numbers, always estimate higher than lower. If you use too little resin in either the walls or the support, your print may become unusable. In that case, you would need to reprint, defeating the purpose in using a hollow design.
Mesh Repair and Optimization
Before finalizing your print, make sure to run your 3D model through a mesh repair or optimization program. These programs can solve a variety of difficult-to-detect problems, including:
- Holes in the exterior of the model
- Non-manifold faces or edges
- Invalid orientations
- Negative volume areas
Many popular 3D modelling tools and companies have mesh repair and optimization programs. Some common programs include:
Several of these tools can also be used as complete 3D modelling suites, depending on what you need. Research what kind of tool you will need for your task, and determine what program or tool is best to do the job.
3D Modelling Tools
There are many ways to design your model. If you have physical access to an object that you want to duplicate, you can use a 3D scanner or photographs to use with photogrammetry software. If you want to construct a model yourself, there are numerous products on the market, usually with specific niches. Of course, you can ask a friend or colleague, commission a work, or find a free model online.
The following list is not comprehensive, but shows some commonly used software and tools within certain industries:
|General Purpose||Autodesk 123D||http://www.123dapp.com/|
|Autodesk 3DS Max||http://www.autodesk.com/products/3ds-max/overview|
|XYZprinting Da Vinci|
|Autodesk 123D Catch|