If you’ve downloaded the latest version of AutoMaker then you may have noticed that we’ve activated Spiral Printing for you to play with. Robox is particularly good at spiral printing as it offers the highest ranges of wall thickness without having to remove and replace the nozzle.
Below is a quick guide on how to best use this new feature.
There are a number of things that you should be aware of when trying this feature.
- Only place one object on the bed at any time.
Because of the nature of spiral printing the flow of material from the nozzles does not stop and start. Placing more than one object on the bed means that the models would be impossible to print in one continuous extrusion.
- Ensure that your print has only one continuous island from bottom to top.
This is for the same reason – multiple islands on any layer means that the flow of material has to stop and start. Spiral printing is designed to avoid this.
- Consider how thick you want the base to be
This is one of the few controls Automaker has for spiral printing, the number of layers you choose and the layer thickness will equate to your base thickness before spiral printing starts. The first layer is always 0.3mm and as a guide I would ensure that this is the minimum filament width to ensure good adhesion to the bed. The sequence layers heights are controlled by, yes you’ve guessed it, ‘layer height’. So for example if you’ve chosen a layer height of 0.2mm and 5 base layers your spiral print with have a 1.1mm thick base. (0.3mm + (4 x 0.2mm))
- Think about what wall thickness you want
After the base of your part is completed the system moves to the spiral printed section, continuously moving up as it orbits the perimeter of your design laying down a single line of filament. The wall thickness is controlled by the perimeter width and because its only going to be done in one pass you may want to increase it and use the larger 0.8mm nozzle to create wall thickness of up to 1.2mm. As a guide I’ve found that the ratio between layer height and wall thickness should be between 2:1 – 5:1, the thicker the wall and the smaller the layer height the more likely overhangs will be printed perfectly.
- The part must be solid, not hollowed out with a wall thickness
Because we are using ‘Solid layers at Bottom’ and perimeter thickness to control the thickness of your part the part needs to be a solid to start with. If you want an inner and outer shell, and don’t mind a hollow centre you can use an idea I had when designing the is thermal mug: add a very thin cut down through the part to make each layer a single perimeter again. On the photo below, you can see that the sequence of printing is outside surface of the bowl -> half the handle -> inside surface of the bowl -> half the handle -> outside surface of the bowl… and so on…
6 . Your design is less than 99mm tall
Robox has a 100mm Z-build height, but because of the way Cura adds the Z move to every move on the layer sometimes the sliced part will come out slightly above 100mm. The post processor will throw this out as impossible print, so to avoid this scale your part to ensure it is less than 99mm high.
You can download the cup above from this link. robox_spiral_mug.stl
Or the Vase with Support engineer Lee’s face on it by clicking the image above. LeeVase_Mk2.stl