Introduction: Design Considerations for Support Structures in SLA/DLP/LCD 3D Printing
Photocuring 3D printing is often used for presenting intricate objects with accurate details. Most times, we need to add support structures for overhangings and bridges. Also to increase the adhesion to the build plate, prevent warping and avoid the prints being floated around in the vat, SLA/DLP/LCD 3D printing require the use of support structures in almost all cases.
Support structures in SLA/DLP/LCD 3D printing is like thin ribs whose small tips are very thin and slightly touch the part to save resin material and make them easier to remove. The usage of support structures deeply impact the print quality after post-processing work and printing success rate. So when designing support structures in SLA/DLP/LCD 3D Printing, there really is a lot to consider.
Step 1: Take Full Advantage of Slicer Software
For most designers especially the green hand, it’s perplexed to detect when and where the support structures are needed. If there is a experienced mentor to give some reasonable suggestions, most problems will be solved. Maybe this living mentor can not be always available, but slicer software is online all the time.
The slicer, also called slicing software, is a computer software used in the majority of 3D printing processes for the conversion of a 3D object model to specific instructions for the printer. Quality of supports greatly depends on slicer. For example, the number of supports, their location, where they touch the model and the structure can be calculated by ChiTuBox, a free SLA/DLP/LCD slicing tool. Then ChiTuBox will generate supports automatically depending on the shape, orientation and weight of the part being printed.
Now things left for you are only to manually adjust those generated supports by further analysis. ChiTuBox allows you to modify almost all parts of supports. If you want to get a better understanding of those parameters, please click: Best Support Settings for Resin 3D Printing(SLA/DLP/LCD)
Step 2: Avoide Supports on Complex Surface
SLA/DLP/LCD is very often used for applications where appearance or a smooth surface finish is required. In this case, it’s important to design your part to avoid that the forward-facing areas of your print are not in contact with support structures.
Orientation plays an important role in this moment. If the aesthetic appearance of a surface on a component is paramount, orientating the part so that there is little to no support in contact with that area can also be an option.
Step 3: Reorient the Part
Part orientation plays a crucial role on where support is located for SLA/DLP/LCD 3D Printing. By reorienting a part, the amount of support can be drastically reduced. Besides, reorienting a part can also be beneficial for the improvement of surface quality as mentioned above.
In ChiTuBox, there are two ways to reorient a part. Click the orientation button, gradually increase/decrease XYZ angle by 15°each time or directly enter the value in the input box.
Also you can also directly double click the mouse to activate the rotation indicator line and reorient the part by moving the mouse in X (red rotation indicator line) /Y (green rotation indicator line) / Z (blue rotation indicator line) direction.
Step 4: Check the Contact Depth
Support structures in SLA/DLP/LCD 3D printing is like thin ribs with only small tips actually touching the print surface which make them quite easy to remove manually, either by hand or using pliers. However, this also means the connection may be very fragile if the parameter of contact depth is too small. In this case, you only get support and raft structures on the build plate after 3D printing instead of the intended object for a bottom-up stererolithography 3D printer.
In general, contact depth of more than 0.4mm is recommended. Also you can select "shepre" shape in ChiTuBox to increase the contact area between the print and the support. In addition, when removing the support, diagonal cutting pliers can be used to cut off the sphere from where the support is connected, making it less likely to damage the model.
Step 5: Distribute Supports Evenly
For a bottom-up stererolithography 3D printer, the object will be stressed uniformly by distributing supports evenly. The places where the supports are dense will hold the tug of war between the build plate and the FEP film in the bottom of the vat. While the sparse ones may separate from the supports which will be hung up to result in misrun or distortion.
Step 6: Use Interconnected Supports
When generating supports, it’s better to bridge supports together instead of placing them individually. If your slicer can't bring it to achievement, just abandon it. Such interconnection among supports in ChiTuBox greatly reduce chances of support failures. This technique will produce stiffer set of base and secondary supports that are less prone to breakage and failures.
Step 7: Avoid Supports Overlapping With Model
The actual part to touch the print surface can only be small tips of support structures. For complex models, sometimes you may overlap supports with model surface if not editing carefully. When removing the supports in post-processing, the touching area will leave a stick which may damage the surface when polishing.
Model source: https://www.thingiverse.com/thing:3306294