While 3D printing on a desktop class printers has been relatively new, 3D printing prototyping process for product design has been around for decades. Its invaluable contribution to the development and testing cycle is well understood, but previously cost-prohibitive.
With the Ultimaker, it is now possible and extremely affordable for engineers and designers of all levels to take advantage of this amazing process. Products can be designed, refined, printed and tested daily at a fraction of the cost and time in a commercial office environment. With the complete printer system costing less than some industrial one off prints.
In order to be successful deploying this method, understanding the limitations and how to slice and generate supports is essential to producing useful prototypes. In this guide, we’ll show you how to print a manifold, and how to deal with some uncommon problems with support generation and odd internal shapes.
This manifold model has internal tubing structures that would be difficiult to re-create in traditional model making methods. It has all the characteristics that make it difficult for FFF type printers to print. Awkward overhangs, thin walls, hollow internal structures and strong support requirement.
What You Need
Start by downloading the model files for free here on YouMagine:
You can see the internal structures in this rendering with different materials.
Our recommended settings are listed below. Pay special attention to the support settings. In this case, we generate a brim since the model has a small footprint, it also helps the support structure stick to the bed as it becomes thin at certain places.
Support is generated “everywhere” since there are overhangs on-top of overhangs on this model.
If you click on the “...” button beside “everywhere” in the support section, the expert settings window will appear for the support generation. This is especially important because there will be a large amount of supports being generated, so it’s essential that you choose the correct settings for the job.
The most important setting for this particular model, is the “distance Z” setting in the “support menu”. It determines the gap between the support and the model. Too large of a number and it will not properly support the overhang which would result in bad surface quality and potential adhesion issues. Too low of a number will make supports difficult to remove. We chose 0.2mm because the majority of the supports generated will hold up a round overhang. 0.2mm would be too close for a flat surface but perfect for a round object. Depending on your material selection, and general calibration, you will need to adjust this number to find a good medium. Play with some settings and do some tests using our numbers as a baseline.
When generating supports, always check the layer view to see where Cura is placing the supports and try to predict any failures before printing.
Another notable setting we’re using is 0% infill. Because the manifold walls are so thin, anything with a thickness of 1.6mm or less (2 perimeters of 0.8mm) will be completely solid.
In the screenshot above, you can see how the tubes are solid even though infill is 0%. Adding an infill will cause tiny amounts of infill to be generated inside the small gaps and add a huge amount of retractions and time to your print with no functional purpose. With an infill of 0%, there are minimal travel lines (the blue lines). Always check your layer view before printing!
While you can print in any material for this object, it is recommended to adjust your support settings accordingly. ABS has weaker layer adhesion compared to PLA, so supports will be easier to remove.
Some stringing may occur on this print. While the Ultimaker is quite good at minimizing stringing with retractions, you may notice stringing occurring on this print in particular. This is because the part is essentially solid so there is no room for any excess material to go. Any oozing will manifest itself as tiny globs that will create strings or artifact in your print. This is easily removed with a hobby knife or file. Alternatively, you can fine tune your temperature and extrusion settings to reduce this unwanted effect.
When the print is done, clean the supports with pliers starting with the easy parts, and work your way towards the more difficult pieces. If you find your supports are too difficult to remove, print with a larger value for “distance Z” in the support expert settings.
For the large flat parts, you can work a hobby knife between the supports before you use pliers to ease the removal for a cleaner finish. A straight wood carving chisel works well too. You may want to file down the surface for a cleaner edge after removing the supports.
Try twisting the supports inside the round internal cavities rather than crushing them for easier removal.
And that’s all there is to it! From concept to finished product. Try running water through the manifold to test the internal channels yourself.
Also, check out the Cura Beta which has a lot more support options for you to explore and customize. Mastering the use of properly generated supports will allow you to tackle even the strangest of shapes. If you have any more questions, don't hesitate to ask us on the forum!