mazas
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
I cannot really say any measurement about the tightness, but judging from some of the sounds/vibrations the head/carriage makes during IS graphing, and the fact that the umbilical has so much effect, I might be tempted to say it is not the tightest. I don’t know how to measure it, really. Perhaps a strategically placed dti with a known torque/force might work?
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
I think it is 0.8mm
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
I’m not running scan compensation. Got rid of the need to use it once I replaced the 1mm piano wire with a half-length sloppier version
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
For doing the test here, you should let the printer cool down for several hours, or actively cool it down with an external fan for quite some time. My target has been to start with a gantry that is within 0.2 from ambient.
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
I understand. But nevertheless, the measurement would be intersting to fully understand the behavior. And also to make sure my calculations are incorrect. They seem to be correct with alu, but I do not yet have a ti tube, so I cannot measure. Also, something that makes your measurement interesting is that you have a different funnel design in the microlight. Therefore, your measurement would not be directly comparable, but interesting nevertheless. An also, if we see that there is some measurable deflection (lets say 10um), and you do not have a problem with it, it would give us an indication as to what our target could be.
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
But the testing we do is different. The issue we see cannot ne compensated with standard heatsoaking. This is a new, previously unrecognized problem
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Did u try with cold bed, i.e. the effect of the toolhead only? It will be an interesting datapoint.
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
If you mean the poc flange, then feel free to experiment by all means, but I do not think we can consider it a a very effective solution, even with a ti tube. A bit more is needed, I’d think. Just setting expectations here 🙂
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
But anyway, the obvious solution to the problem at hand would be to remove the bimetal effect. The simple way to that is a ti tube. However, even Titanium does not remove the bending totally, we are still talking about tens of microns for the temperature changes seen here (given, once again, that my calcs are correct). The steel tube would be ideal, but obviously very hard to come by, as they do not exist yet. So, it might seem like a known-to-work solution near-term might be to decrease the thermal load the hotend delivers to the gantry and switch to ti (I ordered mine a few days back :)). Other solutions are of course welcome, and anything that helps is good in my books.
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
(I do not know if you can mill even a non-machined 1mm tube..)
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Hmm.. but if it is steel, could you not just drill holes on both sides? Or do you feel it would deform as a result of the drilling, and not have enough of material left for milling the top?
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
The torsional stiffness of an i-beam is orders of magnitude worse than a square tube, if my calcs are correct. I’d stick with a tube 🙂
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Just a note: I have first-hand experience from a lightweight tube on a 300 that was unusable because of of a torsional mode resonance that appears with that tube near the same frequency as where the main mode lateral resonance appears. Without the tube, with bare rail, the resonance seems to at some other frequency and does not materially seem to bother print results. So while obviously adding the tube added some rigidity, it is not always possible to predict the dynamics behavior from static tests. But that discussion is off-topic for the issue at hand, it was just an interesting thing I had not thought of before measuring it myself 🙂
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Or POM as @Helge Keck mentioned
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Yes, that works to remove the bend, and has proven to an effective “fix” for the bimetal issue. The challenge is that it introduces other potential sources of error, as we need to somehow control the fixing forces to keep slack out of the picture while still allowing for independent expansion. But this would be one way to solve the issue.
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Indeed. But let us first find those with the dti.
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
And even easier with the dti. Let is find a few such printers that do not bow, and examine why they are immune
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
Exactly, that is very crucial. If someone prints all the time, the problem is probably not going to be an issue. Also, if you print small items with high speed, it will reduce the issue. And using high first layer height helps as well
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
It would be nice to find a vc4 400 or 500 that clears the static test without deflection. If those exist, we should try to understand how they avoid the bending
1729 replies
RRCRat Rig Community [Unofficial]
•Created by tg73 on 10/8/2024 in #fix-my-print
Regular surface distortion pattern towards end of larger first layers VC4
I do not think that can be the case. I would be surprised to find printers that do not exhibit the same behavior. Then of course it might not bother some users. But it is hard to say what the situation is without having a sizable sample.
1729 replies