Y-limit max travel issue
Hi all,
I am looking for some help on the max travel settings of the printers, I hope somenone here can help me?
For a project where I want to print on cylindrical surfaces, I've rebuilt the Prusa i3 MK3S; I reconnected the motor of the Y-axis to a custom made rotating mandrel placed on top of the printer bed, instead of leaving in connected to the heated bed (which I do not use anymore, see picture). I use manual G-code programming with Pronterface to run the printer, which is functioning rather well. The only thing I have to keep in mind is that a distance traveled in the Y axis, is now actually just the mandrel rotating. I have had multiple successful prints (they only need to be one layer tall, so this process functions nicely).
The problem that now occurs is the following:
Once you make a full rotation with the mandrel (which is for me 32 mm in the Y-axis for example), the printer head is hanging above exactly the same place as before. If I want to print a helical strand, that just means I have to provide the printer with a code to move both in X and Y at the same time (a slanted line becomes a helical strand). The problem occurs if I want to print a helical strand with a very low angle, this means, for every distance travelled in X, the distance in Y is very large (= the mandrel spins a few times). When I want to provide the printer with a code to move to Y-position 400 for example, it seems that the printer is not doing that (only going to roughly Y=200). This position is for a mandrel still possible (a Y-limit actually does not exist here), but off course the printer does not know that and it seems to limit the Y-axis movements always to roughly 200 mm. I have been able to solve the issue by rotating the mandrel back a few turns when it hits the limit, but this does not result in fine, uniform strands.
Is there a way to overwrite this Y-limit, so I can print full strands in one go? Is this something there is a G-code for, or is this something that has to change in the firmware. I am not really familiar with changing firmware, so I also would not know where to find this?
I hope someone in this community can help me with the issue, looking forward to your answers.
Best,
Alexis