Regular surface distortion pattern towards end of larger first layers VC4

[random ledge]

Not all steels have the same thermal expansion. The linear rails are 440c stainless unless you got the non stainless ones for whatever reason. Pretty sure ratrig sends stainless though.

https://psec.uchicago.edu/thermal_coefficients/cte_metals_05517-90143.pdf

[untold berry]

Ah okay 👍

[random ledge]

If you're trying to eliminate bimetal effect then that's your option. Otherwise, titanium is as good as it gets.

[untold berry]

Do you know which one ?

[untold berry]

And the rail have 11 ppm/C or ?

[random ledge]

They are 440C https://www.aliexpress.us/item/3256803290250677.html?spm=a2g0o.order_list.order_list_main.5.4a241802cXlmkI&gatewayAdapt=glo2usa

[untold berry]

Ahhh now I understand 😁

[indigo sleet]

You can also search YouTube to get some mechanical engineering lessons to understand the physics behind it. It’s usually a 5 years study but could be good for your knowledge if you want to stepp deeper into this topic 😉

[untold berry]

Okay now I saw at a length of 750mm it is only 0.04mm difference between titan and this steel

I have ordered some ptfe washers and maybe they are enough that the rail can move these 0.04mm more 🤔

[dusty rover]

You are welcome to give it a go, but just be warned that a major source of force is the friction between the rail and the tube, and this is created/affected by the screw preload. And with PTFE washers under the screw head you actually would get more preload with the same tightening torque. So be careful. To be effective, the washers would need to go between the rail and the tube. And even there there is the risk of stiction, i.e. the release of the tension might be sudden, and cause artefacts in the print.

Hope that was not too discouraging, it is good to try, perhaps there is a solution to this somewhere..

That seems to a bit worse than my experience with PLA on the 400, but I guess you have a 500? What is your first layer height? What material, bed temperature, enclosure heating?
And yes, the head will slowly move up, as I showed in the earlier graph, but I seem to able to lay down a 0.2 mm first layer as long it takes less than 20 mins.

[indigo sleet]

The printer was heated up for 15 min and now I got a very smooth first layer. That’s basically the way to go I assume, if you do not want to mod the printer

[untold berry]

Yes I have a 500.
abs with 105 bed temp and chamber 40 degrees

I heat up from 20 degrees with the head in the middle of the plate and 2mm height and after 40 min I start the print

[dusty rover]

Ok, ABS is a bit more challenging as the temps are higher :/.

[main spoke]

I have been printing ASA with 95c bed and 55c-60c chamber temp. (Chamber temp is monitored, but not controlled, so it will fluctuate a bit over the 20hr+ print cycle.) Even after 60+ min heat soak, I have to watch the first layer and baby step it for a good bit.

[untold berry]

Do you have a ti tune

Tube

[main spoke]

I was just thinking of a setup like this the other day.

[main spoke]

No, completely stock IDEX gantry setup.

On a 500

[chrome turret]

Hey there,
we bought a VC4 500 into our company and observed simillar issues
Printed loads of ASA parts, 95° bed 270° on 0,6 nozzle, 0,3 layers (closed chamber heats to around 55° -we use the reading on inactive IDEX toolboard)
With 60 min. heat soak there was like 0.1 - 0.13 z-offset adjustment needed during the first layer (the squish as guys mention here)
With 100 min. soak it was quite less at 0.05-0.06

Btw one of the steps we did was heating it up for a few hours and loosening almost all the screws of the X rail except those in the center and then tightening from the center outwards and that also helped to reduce the bow in preheated status.

Regarding this research here - I read posts from October and I admire your resolve here!
Is there any recent summary I could use to catch up?

[untold berry]

Would you say to tighten the screws of the x gantry while it’s hot is better then if it is cold ?

[main spoke]

Sounds about what I was seeing too using a 0.6 and 0.4 nozzles. I added a thermistor for the chamber that is tucked up in the underside of the right side extrusion for the Y linear rail.

I did loosen and tighten the x rail again after resting at operating chamber temp for 30min, but only once.

I wouldn’t say this has been detrimental, as I watch the first layer anyways. No point in trying to save 23min of labor just to lose a 24hr print and 750g of filament.

[dusty rover]

Not really a recent one, but have you read the pinned message?

Hot-tightening the gantry has the potential to make the overall variance of the height map lower. However, I have not seen reliable results indicating that it would significantly reduce the dritf. If someone has numbers to show this, I would be interested.

[shut portal]

try preheat with hotend also at printing temp(unload filament first) and toolhead in the middle

[chrome turret]

Thx for pointing me there, reading the article on notion

[shut portal]

what if we print some spacer with heat inserts, so rail would be attached to it instead of TT itself and thus allow it to expand and stretch the plastic. but toolhead would probably need redesign for extra space

[untold berry]

Now after preheat to the chamber temp of 40 degrees (which is the temperature while printing) and then make heatsoak for 30min
Then it look good or even good enough that the first layer looks perfect after the print.

It needs 30 min to go to 40 degrees

So 1 hour heatsoak from roomtemp looks good so far (tested two times now )

[ornate onyx]

how does the heat affect the indicator? do you lift the probe until ready to take a reading so it's not sitting on the hote bed?

[untold berry]

So this is one of the final designs
This one weight 390g out of 440c so only 40g more then the aluminum gantry

This is the second design it weight 453g

I made these two designs because I don’t know how much one cost because the second design is much easier to produce I think

[random ledge]

Straight bar?

[untold berry]

No

[random ledge]

If you can find 440C in anything other than solid bar form lmk. I looked for a very long time. Otherwise you gotta mill the entire inside out of which I could not find 20mm anyways. You’re basically looking into custom production of the bars themselves. Perhaps an alibaba or madeinchina distributor will do it but you will be constrained to importing by the ton. If you find a US manufacturer then the cost has now gotten astronomical.

Don’t get me wrong, if you can get it done great but I did a very deep dive into it myself and decided it was not worth it.

[untold berry]

Yes I will look I asked Xometry (I have a contact there) and now I have to wait if anyone can produce it and how much it will cost

[random ledge]

https://tenor.com/view/sounds-expensive-curtis-payne-house-of-payne-s9e12-sounds-pricey-gif-27043457

[untold berry]

Haha we will look

Out of stainles steel it cost round about 450€ but if I order 10 pieces then only 170€ so if I found anyone who can produce it I just need a few more people how wants one to get a better price

And in my case it is worth the 170€ if I have then a perfect first layer

[untold berry]

.

[random ledge]

Where are those prices from and does that include milling or just the steel?

[untold berry]

It includes milling
The prices are from xometry

[random ledge]

So now you need to hunt down a 20mm square 440 supplier?

[untold berry]

Yes 😁 I already send it to xometry and they are looking for a supplier

[random ledge]

Well, keep us informed I suppose.

Curious how they have a price for you without a supplier but idk.

[untold berry]

No it is for the stainless steel 316L

Just to have a little range I looked at this

[untold berry]

Oh yeah 😂 we will see

[random ledge]

Vs

Best of luck tho haha

[chrome turret]

Just fyi - this is from EN norms reffering to S235,275,355,420,450 and 460 construction steels:

And i.e. SS410 which is quite more common stainless steel has 9,9 (440C is supposed to have 10,1) which is darn close and could save you some money!
https://www.hpmetals.com/-/media/ametekhpmetals/files/technical-data/stainless-steel/ss 410.pdf

(in Europe you are more likely to get 1.4021 that is supposed to have 10,3 expansion, but I am afraid thats going to come as square/round stock only https://www.aalco.co.uk/datasheets/Stainless-Steel-14021-420-Bar_311.ashx)

[untold berry]

Ah nice will take this too

[chrome turret]

Regarding other points I read on the neatly written site (appreciate the systematic work 🙂 ) than getting as similar μm/mK to 440C for gantry materials:

1. As for **fans **- side blower appears to make the most sense, maybe with some optimised airflow that would make the air spiral around the heat sink before leaving out the side?
2. As for the point that active heating/cooling the gantry probably won't help - I don't think you need to give/take heat. Anything that would help increase the thermal conductivity and redistribute the heat more evenly might help.
   a) One way could be a blower that would help distribute the heat
   b) Other way would be a material that would fit the requirement for similar expansion but would have better conductivity - in that regard one of my tables (local to Czech sorry 😄 ) says that Red Bronze is supposed to have 11,3 coef. of exp. (the rail is 440C at 10,1)
   c) Also inlaying some conductive material into the extrusion slot to bridge the gap might help as well (i.e. squish a copper tube in there) because the air in the extrusion slot acts as insulator between the front bottom and front upper "fin" (for lack of better term)
   d) And finally the gantry shape might help - if it was a "square tube" there would be a lot more up-down convection going on in there, that would help reduce the bottom to top thermal gradient again. (This part actually makes the most sense to start with, if you want to make the gantry out of different metal to be as simillar to the rail as possible). And side note - the square tube shape would allow you to run a fan through the axis of the tube to facilitate heat distribution -> a).

[untold berry]

Titanium is 8.6 so 1.5 away and your red bronze is 1.2 away so I don’t think this changes very much if you have a titan tube :/

[chrome turret]

Yeah that was listed as theoretical, not practical at all 😄

[fading ermine]

@untold berry : I like your process I am curious to see what you come up with. However, every now and then I get messages likes this:

I am not entirely sure if it really is a gantry issue at this point

[dusty rover]

My analysis of the situation with the Ti is nowhere near as complete or systematic as what we did with the alu, but so far it would seem like the Ti/Steel combination suffers from the issues, but to a significantly less degree. The one new issue with it is the non-monotonicity of the deflection. But regardless, the Ti is an excellent improvement over the alu/steel combination.

If you have other sources than gantry that you feel could be causing the issues with Ti, let us know an we can try to improve our understanding of the behavior.

[fading ermine]

I am totally with you. It still is there, but from my experience (and customer feedback) 15-20 min of heat soaking is now enough for the first layer issues to disappear (because he COTEs are now closer together). And for shorter gantries (the above quote saying "no heatsoaking required" is for a 300 printer) some customers don't heat soak at all and have no issues.

Unfortunately, besides a Bi-metal effect of the Y-Axis - which can be counter by mounting a 2nd rail opposite the existing one- I have no ideas

[dusty rover]

That second y-rail actually would be a worthy try. Easy, cheap, and has very few downsides. Ofc one issue is that we have not seen major shape changes that would be compatible with the y rail bending. But inability to detect does not mean the thing could not be there 🙂

[fading ermine]

That is only speculative on my part. I mounted the old rails anyway as otherwise I would have thrown them away

[dusty rover]

A side-blowing fan seems indeed a good choice. Just fitting one in the current toolhead is a bit of a challenge, especially if you also need to keep the width at a minimum. That is why the “side-exiting/plenum” design was chosen as the next best option. And btw, I have now printed a few kg of PLA in a closed chamber, with enclosure temperature between 30-40C with that design, and have not had any heat creep issues, so it seems to adequate for that use case.

[untold berry]

I have the 500vc4 and even after 30 min heatsoak I have a little twist
Yesterday I „Accidentally“ preheat 2 hours and then the first layer was perfect really perfect

[random ledge]

A little before/after with titanium. 110C vs 100C but my 100C before mesh was actually worse at 0.915

Since the cte of titanium is lower, it actually improved my mesh.

[patent knoll]

Funssor sells carbonfiber tube for vcore 4. Is it any good for this?

[untold berry]

The same thing …

[main spoke]

From what I have read in this server, Funssor is a gamble.

And not with good odds.

[untold berry]

So I got the offer
One of this out of AISI 440C costs 324€
And if I take 5 Then it Costs 147€per piece

So who wants one ?

I can order one for a Sample piece so I can check if everything is good and then I can order the others within 2 weeks

[untold berry]

Okay I ordered one to test it …

[random ledge]

Man, idk how you got it for that. Ship to the US you gotta add a little more but I’m very interested to see how it works out.

[untold berry]

No problem I can ship it. But we need to found more who wants one to get this price

[random ledge]

I’m all set on my stuff personally but thank you tho.

[untold berry]

Yes maybe today evening more people will write

[main spoke]

Had an extra long warm up of 90-120 min the other day and required very little adjustment compared to normal 45-60min soak. We are still using the original aluminum extrusion.

[untold berry]

Yes that is why I bought the 440c steel gantry

[main spoke]

Definitely interested to see your results. Boss is wanting to order a second machine for redundancy soon. Perhaps I can convince him to invest in a couple of rails if your results are good.

[untold berry]

Yes I will report here

[latent raft]

I have a question to the experts of this bowing topic... I was talking to a buddy from work about this issue and we ended up calculating the lenght difference for 55°C temp difference with the cte for pure titanium (might be off since toro is some alloy?) and the cte for a common alloy steel (might also be off slightly from the actual cte of the alloy used in the rail) and then compared it to results with aluminium extrusion... The values were pretty small compared to what we are seeing in the bedscans (0.15mm)... And also the cte of titanium and steal have the roughly the same ratio as steal/aluminium (steal roughly double of titanium and aluminium double of steal) so the forces resulting on the rail should be reversed, but the lenght difference is almost the same... So we were asking ourselves how this results in this large bowing effect we are seeing and why titanium actually fixes it if the cte is rougly off by the same factor just reversed... Hope this is not a dumb question... Just trying to better understand whats exactly happening in detail...

[fading ermine]

How did you calculate it?

[random ledge]

The steel rails should be 440C which has a bit lower cte than other steels at 10.2. Idk about the titanium precisely but it’s gonna be slightly under that. Idk the exact aluminum for the extrusions either but for something like 6061 that misumi lists, it is over double 440 steel.

[latent raft]

it wasnt really meant to be a precise calculation, just to understand the tendency and where the deflection is coming from... and we noticed, what I described...

think we were calculating it for a 730mm lenght (I didnt know the excact lenght of the extrusion and just guessed it at the time) and we took the following values and formula for the lenght difference:
pure aluminium coefficient: 0.0000238 1/°C
alloyed Steel: 0.000161 1/°C
pure titanium: 0.000009 1/°C

formula: delta l = coefficient * lenght * delta temperature

I think we were calculating it for delta t of 45°C or 55°, not sure anymore... but you dont even have to really calculate you can already see that the ratios are not too different between the coefficients (atleast for the pure materials)...

maybe the specific alloys are off by more than I thought, I thought it wouldnt matter too much for this sort of quick "rough calculation" for understanding where this issue is coming from and how much lenght difference we are talking off roughly... just to get a feel for the order of magnitude...

[fading ermine]

So you are disregarding the shape and young's modulus?

That is not how that calculation works

[limpid bluff]

So I am vastly unqualified to comment here but why does the rail need to be steel could it be made from titanium as well if you fit that to the titanium gantry wouldn't that solve the problem. Anyways I was just curious.

[fading ermine]

Because it's surface is too soft

You can't harden Titanium as you can harden steel

[limpid bluff]

Ok got you thank you

[latent raft]

how does it work?

can you show how a complete calculation of the issue would look like?

[latent raft]

isnt it also super hard to machine?

[fading ermine]

Most practical solution is to run a FEM simulation

[dusty rover]

I also did a fully theoretical calculation, not based on FEM but just on the young modulus, geometry, temp coefficients and temp change. That gave results that are roughly in line with what we see with measurements with the alu. The deflection we see is lateral shift, not longitudinal. So, small changes in length will cause large(r) deflection.

[fading ermine]

You show off...doing it by hand 😄

[prisma galleon]

Love it my guy.

Entering senior year in mechanical engineering, love to see the things applied

[prisma galleon]

One must be able to do it by hand to know their model is accurate ;)

The model is only as good as the modeler

[latent raft]

would love to see the calculations... ye that a small change in length will result in a larger deflection was also my guess from my primitive look at the change in length... but I wasnt able to imagine how exactly it results in that... would be nice to see a simulation of this so you could see what excactly is happening

would love to know how the geometry and youngs modulus effect the way it expands and deflects

[carmine slate]

Maybe something to share also here

#1360247935496884265 message

looks like the same problem (haven’t read the tread sorry), i have created a macro to correctly heatsoak the gantry so it doesn’t change during the print due to thermal expansion

[main spoke]

Been running back to back prints recently with an insulated chamber. Even after 27hrs at 58-60c, I have to micro step the first 30 min of printing. I have both extruders idle at 100c while I pull the part from the build plates and load a new roll of ASA. Right now it has been about 0.240mm of stepping. Print temp is 260 for both extruders. Chamber temp doesn’t dip more than 5c when I change the plate and load the material.

I then let it heat back up to 58-60c with extruders bumped to 150c before starting the next print.

Forgot to mention, original alum X beam. VC4 500 IDEX

[craggy bobcat]

Another trick I've found is to simply print the first layer as fast as possible. As long as the nozzle is moving all over the place, it seems to not drift nearly as much as it would with a slower start

[dusty rover]

I second that. Not sure whether the movement itself has an effect (I have not investigated), but the shortened time for the first layer means there is less change/drift. I normally use 200mm/s with 0.2 layer height and 0.4mm nozzle. You probably could be more aggressive, but this seems to be quite reliable.

[distant loom]

Maybe a bit of an old topic, but I managed to at least reduce my drift by adding contact z-tilt adjust to my config:

variable_beacon_contact_z_tilt_adjust: True
variable_beacon_contact_z_tilt_adjust_samples: 3

Doesn't solve it, but significantly improves it.

[pastel charm]

Mounting the rail on the front of the X gantry eliminates first layer issues due to thermal changes in the gantry.

[untold berry]

Do you have an head for the Ratrig vc4 with mounted on the front

[pastel charm]

Yes. The Ultralight works on both the VC3 anbd VC4 with the Full Frontal Gantry (FFG) mod

[untold berry]

Do you have a link 🤩

[pastel charm]

https://www.printables.com/model/1368881-rat-rig-v-core-full-frontal-gantry-mod

Let me know if you have any questions

[untold berry]

Thank you 🙏

[surreal lantern]

Note that from a few tests with a front mounted rail setup, any bowing that's a deflection in Y (that is, the gantry looks like a banana when viewed from above) will lead to bowed lines of extrusion when moving along X. On a 500 with 2020 alu gantry, the thermal deflection at the midpoint of the gantry can be over 1mm as measured with the stock rail on top configuration, and I would expect a similar effect with rail on front, but I've not explored/measured this.

[untold berry]

Yes, I also noticed that in retrospect

I just measured a bend of 0.8mm with the 300ratrig after 40 minutes even though I installed the Titan Tube

And 40 min for preheating is a lot of time

😩

How do the other people handle this ? Do they just ignore it ?😂

[surreal lantern]

I'm surprised that you're seeing a 0.8mm deflection with a titanium gantry on a 300. Is it a toro tube? I'd discuss that with other ti users on the toro discord. Or if it's funssor, maybe ask on #v-core-4 .

[untold berry]

Yes it is a toro tube

[surreal lantern]

While titanium tubes can require a fair bit of manual tuning (kapton tape shiming, detwisting etc), many people seem very happy with the result.

[untold berry]

Yes I don’t know why I have such a big difference

[surreal lantern]

Indeed, it's odd. I'd see what people have to say over on the toro discord https://discord.com/channels/1095621864912588810/1139194752940654642

[untold berry]

I have asked thank you

[main spoke]

.8mm is more than I am seeing on a VC4 500 with the original aluminum extrusion. What XY connectors are you using?

[untold berry]

Yes I measured false this was the 500 Ratrig with the time after heating up

[distant loom]

Is there any update on this stainless tube? Does it help? Quite curious here... 🙂

[distant loom]

@untold berry ?

I redid the screws on the gantry with the gantry heat soaked and got a perfect 1st layer. Next print I had to baby step again though, so probably a steel gantry would indeed be the way to go. Running a ti-tube at the moment btw.

[untold berry]

I have an material that is really near the 440c material of the rail. But I have to order 5 pieces or I have to pay 400€ for just one

If I buy 5 pieces then it is „just“ 200€ per piece and I don’t want to pay 400€ just to test it 😁

[distant loom]

Yeah, that might be a bit much for just testing 😄

I guess making it easier for the rail and the mounting bar to move respectively to each other should also do the trick, like what you did with less torque on the screws. This does not seem to be a very permanent solution though. I'm currently testing with less screws: the rail is now attached with only 3 screws with 0.8Nm torque, so let's see what this brings...
Since I'm using a Funssor XY joiner I could in theory also play with less torque on the screws there as well, so that the titanium tube can move and expand more easily in the X-direction. Not sure how much that would help though.

[distant loom]

So less screws doesn't seem to matter much.... It seems like the (titanium) gantry is bowing upwards primarily when the toolhead is moving over it. Maybe it's an idea to insert some gcode with random movements while the chamber is heating up?

[distant loom]

OK, I've managed to make some progress with using only three bolts to hold the rail to the gantry:

First try was 1 screw in the middle, and the other 2 on the most extreme ends of the rail, but this was obviously still enough to have the rail and the gantry push/pull on each other enough to make me have to baby step the z-offset for the first layer.

My current try is 1 screw in the middle, and the other two only 4 holes down on each side (so 3 empty holes between each screw). I'm currently on my 2nd print with a perfect first layer with no need to interfere.

I guess a potential downside could be that the rail will loosen up from the gantry after a while with only 3 screws holding it down, causing it to wiggle slightly. This would obviously not be good for print quality, but I guess a check every now and then could mitigate this.

Anyway, not sure how alive this thread still is, but I will post some updates every now and then on how this setup is going.

[untold berry]

I am still here so yes please give updates haha

Maybe you can use locktite to minimise the loosing problem

[distant loom]

Loctite could be a good one indeed!

Currently running a 7 hour print with lots of movements, so let's see where we end up 🤞

[quick lichen]

I also still read this thread every time someone posts in it even if I have nothing to add

It’s a good thread

[pastel charm]

My toro tube used both with rail on top previously and now with rail on front with Full Frontal Gantry mod does not banana from hot to cold. How are you measuring your deflection? with a dial gauge, bed mesh or other?

Even if I did have bowing (which I don't) it wouldn't effect first layers now.but it would still effect print precision as it print moves in X direction would be deflected slightly in Y direction.

[untold berry]

Yes I have a measurement mistake so forget this 😂

[untold berry]

How is it going ?

Maybe I have a solution, I ordered the first test part (a steel gantry) but with the weight like the toro tube 😋

In a few days I know if the theory is the same in practice and then I will update here

[main spoke]

Toro tube, Mandala Rose Works joiners, and Chube hotend on the new machine is virtually perfect. On a 20min first layer, I have yet to adjust the offset.

Next test will be to install the same components on the first printer and see if I get the same results. Right now I am having to adjust from 0.10mm-0.20mm on the first layer for that machine. I will update when we get some inventory built up and I can have a week to update and maintenance the first machine.

[distant loom]

Looking forward to see your update!

Update from my side of things: with only three screws close to the middle of the gantry I found there was some play on the end of the rails, both in Y and in Z. I don't really think this should matter much, there shouldn't be much stress in Y since I'm running IDEX/Hybrid. For Z I really had to put some weight on it to push it down, so I don't think the hotend assembly has much effect on this either. Still, I was not super comfortable with this, so I'm now still running with 3 screws, but two almost at the end of the rails again. The one in the middle at 0.8Nm and the ones on the ends at 0.4Nm, almost no torque at all 🤪 . The idea again that the rails can move in X relative to the ti-tube. We'll see, have to do a couple of prints before I can say anything.

Good to see there are more people experimenting!

[distant loom]

I just came across this in the voron community:
https://github.com/tanaes/whopping_Voron_mods/tree/main/extrusion_backers

They're basically trying to counteract the bimetallic effect with a trimetallic effect. According to their simulations this should work (in theory).

[untold berry]

Yeah I have something like this but not with titan I have steel which have more or less the same Heat expansion as the linear rail

And also that can be installed instead of the x rail …

[untold berry]

Annex k3 also do this

[distant loom]

So then you now have Steel rail - Titanium Tube - Steel plate?

[untold berry]

In the end it looks like this

[untold berry]

But this is just a test at the moment I am waiting for the new ones and then I will change the titan tube with this one (in the Ratrig 500) and will do tests then

[distant loom]

How thick is the plate? It's not sagging due to the weight of the toolhead?

[untold berry]

Just 3mm for the 300 vc4 but for the 500 it will be 5mm

This one was 500mm long and I don’t have problems with this one

[distant loom]

Very interesting! Looking forward to your results!

[distant loom]

Isn't 5mm going to be a bit heavy? A quick calculation tells me that a 3mm plate will weigh about the same as a 2020 extrusion.

Also, with the Voron mod in mind, don't we have the same bimetallic effect on the Y-axis? One that pushes the z-offset down since it's Alu/Steel. So many variables....

[untold berry]

What material do you use ?

[distant loom]

For the weight calculation? I use 8gr/cm3 for steel, and I assume the plate has a width of 20mm.
So for my V-core 400 which uses a 625 long tube, a steel plate would be 100gr for every 1mm of thickness.

[untold berry]

And what does it weight your tube ? You have a titan tube or ?

[distant loom]

Ah, I'm currently running a titanium tube from Funssor, but I got lucky and have straight one :). It weighs about 190gr or so

[untold berry]

Okay so the 3mm variant will weight round about 289g so yeah more than your titan tube but less then the standard aluminum tube

And in my opening these 100g extra are worth that I don’t have any z issues anymore haha

[distant loom]

I would agree

[distant loom]

@untold berry how did you find out what type of steel rail is made of?

[untold berry]

The rail ? You can find it on the internet
99% of the rails are out of 440c this is the standard for rails

[distant loom]

Makes sense. I was just wondering because the linear thermal expansion of steel seems to vary a lot by type.

[untold berry]

Yes of course that is why I am searching now for over an year for the perfekt material 😅

[distant loom]

Hehe 🙂 In my area I can find a lot of 20mmx20mm square steel (hollow) bars for cheap, but absolutely no details on the type of steel

[untold berry]

So now I have the parts just need the screws to test it

[untold berry]

#1424809731582857347 message

I will write here the Result of the tests and updates

[surreal lantern]

Can you add a server link, it shows as unknown for me.

[untold berry]

https://discord.gg/- - -E8mNQTRRp

you will have to take out the 3 —- and copy to your browser then the link should go

[gleaming notch]

So any updates on this topic? How did you guys solve that?

[shut portal]

@untold berry can you update invite link? or tell how it's going with the steel rail

[dusty rover]

A quick update that the 4.1 upgrade addresses most of the issues discussed in this thread

[shut portal]

Addressed yes, but is it solved?)

[dusty rover]

Remains to be seen :). For me, yes. We (the dev RR dev team) have been running the 4.1-like gantry for quite some time, and the experience is good. I can start a print and walk away. No babystepping or noticable elephant foot. 0.2 (0.4 nozzle) or 0.25mm (0.5 mm nozzle) first layers are pretty much flawless, even for long (>30mins) first layers. Heatsoak is abt 15 mins max, and potentially not even needed for small jobs, even though I use it for all jobs. I do not yet have much experience with the 4.1 toolhead, as it is so new.

[proud magnet]

I have VC3.2H. Anychance we will receive the same gantry/mod?

[dusty rover]

Don’t know. Better ask RR directly, I believe.

[distant loom]

So it uses Beacon at the mid point of the bed to detect when height changes stabilize, correct?

In the new RC4

[shut portal]

looks like it, you can even downlad chart data from debug section in configurator. it shows Z distance change and Z derivative (?). so when dZ flattens to the set level it starts printing

[dusty rover]

Yes, although it is a bit more involved than that. We also look at the second derivative and try to estimate the future

[distant loom]

Would it be possible to visualize this in a chart in mainsail?

[dusty rover]

Wel.. I did a simple virtual temperature sensor that shows the rate of change, and reads 100C when the rate is zero. I found that pretty informative during development, but it is probably a bit too mysterious and difficult for general consumption, :). We did not include a rate-of-change-indicator for this release. We might considers a bit more robust display for the future if mainsail would allow for other things than temperature be displayed. The O2s suffers from the same issue, it shows the hotend power consumption as Celsius :/

[distant loom]

Well, if this ever becomes an option for the future, it would also be nice to have the option to break-off the heatsoak and continue to printing. For small parts a full heatsoak might not be required for example. There are probably some limitations in klipper regarding this, since it seems to execute macros in chronological order, and every macro needs to be finished before the next one starts?

With a graph one can asses more easily when to break-off the heatsoak

[dusty rover]

Indeed, we hope to improve that in future releases

[dusty rover]

Yes, you need to add logic/delayed macros/something so that you can emulate breaking a long-executing macro