V-Core 3.1 wide boy (with motion system from 4) has high vibrations in y at 125 hz
Im building a retro fitted 3.1 wide boy with v-core 4 motion system and toolheads from the 4 (named 3.1.4 from chiefdotjs :D) i have freshly rebuilt the frame and im using beacon on the one toolhead and a nozzle adxl on t1.
The printer is standing on my wooden floor (colleague suggested that maybe a rug could influence that)
I have checked all the screws they should be tight, i when i manually execute
I have checked all the screws they should be tight, i when i manually execute
oscillate freq=125 time=60 axis=y i cant feel the electronics panel vibrating which was one cause in another thread i checked
I have checked the belt tension via west3ds belt tension meter, tried 2.5 and 3 on all belts. The rails moved freely before belting and adjusting the frame with beacon
My bed mesh is within .18mm which should be good enough
So im out of ideas on what to do/try, any suggestions maybe? 😄
Im also using the 35mm nema 17s with 48V and gates belts
29 Replies
hey @CHIEFdotJS did you have any similar high oscillations at 125 hz?
Could it be cables?
Umbilical?
i'll go check here in a few minutes
I didn't really pay a lot of attention to my shaper graphs. 😃
as you can see, my graphs aren't anything to dial home about
I haven't bothered to look into resonance compensation at all my main concern so far has been accuracy over speed
also, if you're following my build, I did wind up having to chop about 4mm off my Z1 linear rail
nice in x, y is something 😄
what accelerations are you running with?
i have mainly built upon your forked onshape document
im checking your newest version now
@CHIEFdotJS by adding that tiny 3030 you can keep the vaoc permanently installed right?
whats the reason behind the change in z coupling mechanism
repeatability?
Mi e is an original not a fork, so I would need to know which version of mine your fork is based on.
If you are talking about the 3030 between the back panel spine support and the rear z rail support?
Yes by moving the electronics panel back to the rear, it made enough room to permanently install VAOC. The tiny 3030 is there for support
I need to add the other supporting braces to CAD iirc though
https://cad.onshape.com/documents/6c59c4863dd5144976500b22/w/88cff2807f18ed6e42cc73d4/e/fd8a05783f2b012dae26e626
i forked your document 😄
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my panels are not full length
which sucks a bit
for that
Yeah I have to cut 47 mm panels because I moved that back
I also added the supports on the sides
I have some ACM panels that I'm going to cut today and fill those gaps in
whats the reason behind the change in z coupling mechanismI believe the VC4 POM inserts are critical to the operation of VAOC. This is jut a guess, but I like them better anyways, so I designed them into my system. We would have to ask @Helge Keck to confirm if what I suspect here is true or if I'm just smoking something good. Here's my theory... I'm guessing that POM inserts solve a thermal expansion problem with bed movement that didn't affect VC3 because it didn't have a relative positioning component like the VAOC. With VAOC it's critical that your geographaic relationship to the VAOC and the bed remain the same. The VC4 pom inserts ensures that the effects of thermal expansion are guided in a constant way so that the VAOC relationship in space to the center of the bed never changes...whereas the VC3 sliding system has enough play to change things up enough that it limited the accuracy of the VAOC even if that's all just BS... I like the fact that they hold my very expensive MRW plate in place without risking accidents like I had a few times on the VC3 system and it could be as simple as that for why the VC4 uses them as well
pom inserts hold the bed in z axis as well, old vc3 had only the 2 pins, bed could jump at high speeds
I've experienced this when the X rail is not perfectly stiff, ie, the joiners actually bind somewhat due to the material that is holding them pusshing inwards.
Wdym by 2 pins, isn't VC4 held per hand by 2 pins as well? Or do you mean by the anti backlas nut?
arent we speaking about the bed arms pom inserts?
Yeah, thus my confusion, v core 4 has 2 bolts per pom right?
vc3 had metall pins where the bas was laying on
it wasnt contrained enough
the pom inserts fix that issue
Ah, you mean the magnet thigns?
Rather than VC4's inserts that "click" on the bed.
yes, there was also a magnet involved
I haven't tried to tune yet. I haven't been really worried about graphs and speed, but this is good info. I used fewer screws (only 7 iirc) on the gantry instead of every other hole, thinking that would help a bit with the bi-metal affect.
Saw this tip on the video that one guy made about squaring the frame on VC3.
I imagine based on your thoughts here, this tip could actually be contributing to this undesired resonance though.
I imagine based on your thoughts here, this tip could actually be contributing to this undesired resonance though.
The rail itself being not stiff means you have to be absolutely sure its not what so ever twisting due to how the rails are setup.
Its a really big process to get to fully stiff.
I have not 2-3 months ago tried it once more and it took a lot of unscrewing and makign sure its fully set and flat, as belt itself can induce twist if its not properly fastened.
This is why I mostly ditched the dual rail, as its easy to twist it with the current way I think we are setting it up.
I highly suggest going TI/Steel as they are really stiff.
I'm actually wanting steel and will to trade speeds.
As its far flatter than TI can be "cheaply" grinded, compared to steel, but ofc its far far far heavier.
With my wider frame, that's going to be hard for me. When I finish my cabinet build I'm going to downsize the frame to VC4 standard size, and I've got both steel and ti tubes ready to go for that size.
Where did, you get the steel one?
hmmm I really confused on what to do with the vibrations on 133 Hz
Reprinted and tightened everything again
(the umbilical mount)
it's all rock solid now and my shaper still freaks out
And I can feel the hotend vibrate like crazy and the belts going wild
Umbilical is not vibrating as much
locally sourced