To all who master the python ;)
Because of the shrinking of the extrudate tension builds up inside objects, but also in the raft. I sometimes get warped objects because the raft snaps loose. I mitigated this to the extent that now it is more rare, but I did that by depositing a fatter raft than before at a higher temperature. But with less material, I think that it should be possible to prevent the raft from detaching.
Right now the foundation layer of the raft is laid down in straight lines.
When it shrinks, the tension builds up along the entire length of the raft.
The build platform constrains it imposing a shear force on the filament (I'm not mechanical engineer, so I could be getting this wrong). The only way to shrink further is to detach at the end, by curling upward until where the stickiness of the platform is bigger than the tension.
We could allow it to stretch a bit, by laying out the filament (as in the picture below, on the right). This could prevent detachment, save material and speed up extrusion of the raft. I have produced 420 grams of rafts already, although I'm saving it for when I can recycle it myself. It's probably over 10% of all material that I consumed (I printed a lot of things on duct tape, without a raft). Other than the waste issue, it would prevent us from having to buy as much filament.
Of course in many cases the raft could have a smaller footprint than it has now.
Now that the amount of people printing increases the ratio of structural vs. sacrificial material should be improved. I hope that someone would like to write a replacement raft system. I'm not sure how difficult it is, but I'm sure that it can be done if you know python (unlike myself, aargh!...)
P.s. Enrique, thanks for adding a note about my script. I'm working on a hosted version for people that don't like installing the PHP cli.
Because of the shrinking of the extrudate tension builds up inside objects, but also in the raft. I sometimes get warped objects because the raft snaps loose. I mitigated this to the extent that now it is more rare, but I did that by depositing a fatter raft than before at a higher temperature. But with less material, I think that it should be possible to prevent the raft from detaching.
Right now the foundation layer of the raft is laid down in straight lines.
When it shrinks, the tension builds up along the entire length of the raft.
The build platform constrains it imposing a shear force on the filament (I'm not mechanical engineer, so I could be getting this wrong). The only way to shrink further is to detach at the end, by curling upward until where the stickiness of the platform is bigger than the tension.
We could allow it to stretch a bit, by laying out the filament (as in the picture below, on the right). This could prevent detachment, save material and speed up extrusion of the raft. I have produced 420 grams of rafts already, although I'm saving it for when I can recycle it myself. It's probably over 10% of all material that I consumed (I printed a lot of things on duct tape, without a raft). Other than the waste issue, it would prevent us from having to buy as much filament.
Of course in many cases the raft could have a smaller footprint than it has now.
Now that the amount of people printing increases the ratio of structural vs. sacrificial material should be improved. I hope that someone would like to write a replacement raft system. I'm not sure how difficult it is, but I'm sure that it can be done if you know python (unlike myself, aargh!...)
P.s. Enrique, thanks for adding a note about my script. I'm working on a hosted version for people that don't like installing the PHP cli.
