When performing a "Gap Fill" without a reduction, the head may violently shake left to right. For a machine with a light bowden extruder this isn't much of an issue. But on any machine with one or more direct drives. There is far more torque. Not only does this require more powerful motors, but also better drivers, to avoid loose of tracking. Say that loss of tracking isn't an issue, the machine is vibrating itself apart in the process. (edit: Marlin 2.1.x firmware has a function now to reduce high speed vibration from zig zag movements) Honestly, I hate Gap fill. When I see gap fill, its like the pathing tool could not have been bothered to Finnish it's job and left a hole for no good reason. Now it remains a hole or the machine becomes a jack hammer every time I need to fill it in.
Another good reason for some kind of dynamic reduction of speed.
Take a circular pattern. Start the outer perimeter. Speed is set to F1800, and it's working really great.
But with each line, As the head gets closer the the middle, the machine starts shaking as the revolutions per min is increasing, though the speed of the line is drawn remains the same. Get the picture? It takes less and less time to create each loop, not only causing vibration but also reducing the amount of time the line has to cool, increasing the over all temp of the material in that area.
There are many other great reasons to have some kind of dynamic speed reduction.
This is a function that must be implemented in the slicing engine.
Edit: Using S3D as it is: Unlike per layer where I can simply generate a new FFF. This cannot be done within a layer. Not without a separate object. So if I was to make a solid cylinder. I would need to use my modeler to break it down into multiple objects. Each can have its own print speed. Its a manual way of forcing the slicer to reduce the speed of the head as the radius decreases. I really need the support of S3D on this. But given the silence. I feel like the request is simply being regarded as a joke. I see this as a powerful tool in the Swiss army knife that is S3D.
Last edited by rflulling
on Sun Nov 05, 2023 11:25 am, edited 1 time in total.