3D Printer yet?

[olkipukki]

I have here an offcut of 2040 V-Slot from a reputable supplier. The centre core measures 19.95mm, the total width is 39.90mm, the 'wings' 19.76mm aross their full width and 19.6mm for the last mm or so. The widest inside dimension of the slots is specced out at 11mm - on the 40mm face, this measures exactly 11.00mm on my samples. On the 20mm face, it measures 10.89mm. The main opening is specified at 6.25mm, on the 40mm face it's 6.4mm, on the 20mm, 6.27mm.

Wondering how much did you pay for this to a reputable supplier?

[Monkeh]

I have here an offcut of 2040 V-Slot from a reputable supplier. The centre core measures 19.95mm, the total width is 39.90mm, the 'wings' 19.76mm aross their full width and 19.6mm for the last mm or so. The widest inside dimension of the slots is specced out at 11mm - on the 40mm face, this measures exactly 11.00mm on my samples. On the 20mm face, it measures 10.89mm. The main opening is specified at 6.25mm, on the 40mm face it's 6.4mm, on the 20mm, 6.27mm.

Wondering how much did you pay for this to a reputable supplier?

Look up the price of Openbuilds extrusions..

[mnementh]

So you're saying it has similarly proud center rail to the 40x40 we were talking about? Yeah; still not fit for purpose. I mean yeah, 7 thou is nowhere near as bad as what HobGoblyn showed us, but still... if I'd bought any quantity of that, and had the kind of problems as he's having getting things square, I'd probably raise holy hell with the supplier. If it was OpenBuilds, I'd expect a resolution... other sources; probably not, and have to open a ticket with PayPal. 

[EDIT] Mhmmm... doing the math, it looks like that should produce at worst ~1-2mm runout across 400mm length of the opposing part, provided the facing end of the opposing part was cut true. I probably would just ignore that and tweak it during assembly.

mnem

[KaneTW]

What 3D printer do people recommend in the <4k range? I was considering a Formlabs Form 3, but the build size is a bit small for a general purpose printer and it's limited to resin.

No strong requirements, but I would like something where I don't have to spend a lot of fiddling getting it to print with reasonable repeatability. I would also like to print PVDF for parts that require PVDF's chemical resistance.

Not sure what the state on 3D printing threads nowadays is, but not having to tap the finished part or use inserts would be nice.

[olkipukki]

I have here an offcut of 2040 V-Slot from a reputable supplier. The centre core measures 19.95mm, the total width is 39.90mm, the 'wings' 19.76mm aross their full width and 19.6mm for the last mm or so. The widest inside dimension of the slots is specced out at 11mm - on the 40mm face, this measures exactly 11.00mm on my samples. On the 20mm face, it measures 10.89mm. The main opening is specified at 6.25mm, on the 40mm face it's 6.4mm, on the 20mm, 6.27mm.

Wondering how much did you pay for this to a reputable supplier?

Look up the price of Openbuilds extrusions..

Do you mean like this https://ooznest.co.uk/product/v-slot-linear-rail-20x20mm-cut-to-size/ ?

There are quite bold statements, understandable who a target audience, but still...
They mentioned their extrusion done from 6063 T-5, in my understanding is an economy alloy and cheap, what you would expect then, especially "These extrusions are manufactured in the UK."  ?!

[mnementh]

What 3D printer do people recommend in the <4k range? I was considering a Formlabs Form 3, but the build size is a bit small for a general purpose printer and it's limited to resin.

No strong requirements, but I would like something where I don't have to spend a lot of fiddling getting it to print with reasonable repeatability. I would also like to print PVDF for parts that require PVDF's chemical resistance.

Not sure what the state on 3D printing threads nowadays is, but not having to tap the finished part or use inserts would be nice.

That's like asking "What motor vehicle under 4K is best for me?"

Kindof need more info on what you actually plan to do with it before we can even hazard a guess.

mnem
 

[Monkeh]

Do you mean like this https://ooznest.co.uk/product/v-slot-linear-rail-20x20mm-cut-to-size/ ?

There are quite bold statements, understandable who a target audience, but still...
They mentioned their extrusion done from 6063 T-5, in my understanding is an economy alloy and cheap, what you would expect then, especially "These extrusions are manufactured in the UK."  ?!

No, I mean Openbuilds, which is why I have stated several times what it is. The profile from Ooznest is equivalent, and I do, in fact, have some, but that is not what I measured, because that's not a short offcut on my desk at this time..

[Monkeh]

So you're saying it has similarly proud center rail to the 40x40 we were talking about? Yeah; still not fit for purpose. I mean yeah, 7 thou is nowhere near as bad as what HobGoblyn showed us, but still... if I'd bought any quantity of that, and had the kind of problems as he's having getting things square, I'd probably raise holy hell with the supplier. If it was OpenBuilds, I'd expect a resolution... other sources; probably not, and have to open a ticket with PayPal. 

I stated my measurements - which are in line with what HobGoblyn demonstrated. I've no need for a resolution as no part of my present usage of it depends on that face.

[KaneTW]

That's like asking "What motor vehicle under 4K is best for me?"

Kindof need more info on what you actually plan to do with it before we can even hazard a guess.

mnem
 

Yehhh, it's a complicated topic. In general, printing various functional parts either as a replacement for existing plastic parts or for some new design.
Possibly masters for casting silicone for e.g. coarser microfluidics devices. That's probably a better fit for SLA though, I think FDM will have trouble with the feature sizes required.

Material-wise for FDM, the more options the better. I don't think I'll need super high temperature materials like PEEK or PEI, but apart from the standard polymers definitely PVDF and possibly FPE.

Build size... depends on the tradeoff between accuracy/precision and costs.


I'm mostly looking for a rough overview of the market really. Too many manufacturers and some have wildly varying prices for the same on-paper features.

[mnementh]

So you're saying it has similarly proud center rail to the 40x40 we were talking about? Yeah; still not fit for purpose. I mean yeah, 7 thou is nowhere near as bad as what HobGoblyn showed us, but still... if I'd bought any quantity of that, and had the kind of problems as he's having getting things square, I'd probably raise holy hell with the supplier. If it was OpenBuilds, I'd expect a resolution... other sources; probably not, and have to open a ticket with PayPal. 

I stated my measurements - which are in line with what HobGoblyn demonstrated. I've no need for a resolution as no part of my present usage of it depends on that face.

I'm going to pick one little nit here... what you measured is roughly .007 inch proud; less than the thickness of 2 sheets of the really cheap, thin copier paper. That would not even be visible in HobGoblyn's demonstration. What he shows is more like 20-30 thou, maybe more.

As I stated above; after looking at the math, that would result in at most around 1-2mm runout at 400mm length; little enough that I'd probably just tweak it during assembly. 

mnem
 

[Monkeh]

So you're saying it has similarly proud center rail to the 40x40 we were talking about? Yeah; still not fit for purpose. I mean yeah, 7 thou is nowhere near as bad as what HobGoblyn showed us, but still... if I'd bought any quantity of that, and had the kind of problems as he's having getting things square, I'd probably raise holy hell with the supplier. If it was OpenBuilds, I'd expect a resolution... other sources; probably not, and have to open a ticket with PayPal. 

I stated my measurements - which are in line with what HobGoblyn demonstrated. I've no need for a resolution as no part of my present usage of it depends on that face.

I'm going to pick one little nit here... what you measured is roughly .007 inch proud; less than the thickness of 2 sheets of the really cheap, thin copier paper. That would not even be visible in HobGoblyn's demonstration. What he shows is more like 20-30 thou, maybe more.

As I stated above; after looking at the math, that would result in at most around 1-2mm runout at 400mm length; little enough that I'd probably just tweak it during assembly. 

mnem
 

I can generate a plenty fine rock on top of this extrusion, and it would, as you've said, create several millimetres of runout at length. His may be worse than mine - my point was merely that this sort of error exists even with the 'good stuff'. I can't speak to 80/20, but they don't make V-Slot, so it's a moot point.

[HobGoblyn]

Edit, read this post on my Ipad and it had all the wrong pictures including some from a future post. Cleared my cache on my PC and noticed the same thing was happening. Have now fixed the weird problem.

Creality got back to me about the unlevel c-slot, their response,

-------------------------------------
I think it is unlikely that the frame is the problem. If you are not sure if it is square though you might be best to lay it on a flat surface then tighten up the bolts to make sure the base is flat. There is normally a bit of play in it that you can adjust a bit.
Once you have done this you should be able to assemble it again and it should go together fine. It might be worth checking the uprights and the top bar are not bent though.
-------------------------------------

Anyway, to recap.

Rebuilt with perfectly square frame.

Dual extruder, esteps calibrated (and stored).

I've done the hot end fix, extrusion is working 100% perfectly (capricorn tubing)

Lock Nuts put on the end of the bed levelling screws so they don't turn when I adjust bed level.

Springs replaced with yellow springs.

Tightened yellow springs all the way, then undid then about 3 turns, then set my end stop (not needed now as have bltouch), the adjustment wheels are now quite stiff so I haven't got to worry about them vibrating around.

Replaced magnetic bed with glass bed, reset my z stop (although not needed now)

Added BLTouch (also using it to set my Z stop).

Installed correct firmware from Bigtreetech for BLtouch being used as Zstop

Homed with my BLtouch, then calibrated my z offset  (and stored settings).

Did 4 corner paper levelling to get bed as level as possible.

Did BLtouch 25 point autolevel and stored.

Got a level test STL, sliced it in Cura and kicked off a print. I came into the room as it was near finishing and heard loud clunks where the head was smashing through the rear left of the print (retraction and z hop are enabled in Cura)

The file I was printing is the CHEP_bed_level_test.stl that I got from https://www.thingiverse.com/thing:3235018


Here is the result







Here are my Cura settings





Most of the rest of the print looked OK except for a layer shift in the final layer (and can also see a layer shift about 1/2 way up everywhere.   I'm not sure whether this may well have something to do with the nozzle clunking across the print rather than some other problem.





I started the print from scratch (after again running 25 point BLTouch leveling and storing it), I notice at the start of every square, it's over squished, then I stopped the print.






I downloaded another level test  from someone else, only gcode no stl, so edited gcode in notepad++ and altered the nozzle to 205 and bed to 60, and added

M280 P0 S160 ; BLTouch alarm release
G4 P100 ; delay for BLTouch
G28 ; home
M420 S1 ;Load saved ABL Mesh for BL Touch

Here are pics of the left hand rear and the right hand rear.







It doesn't come out properly on the left hand photo, but the filament at the far left corner (not the circle) is much more translucent than the right hand
Also the filament on the left hand pic is almost double the width of the right hand.

I've just given it one more go, this time replacing the gcode line

M420 S1 ;Load saved ABL M

with

G29 ; auto bed levelling

so that it does the BLTouch 25 point levelling before doing the print.

It's just finished printing, it's 100% identical to the previous left and right hand pics.

I've run out of ideas of what to try next.

[Brumby]

Knitting.

[xrunner]

Most of the rest of the print looked OK except for a layer shift in the final layer (and can also see a layer shift about 1/2 way up everywhere.   I'm not sure whether this may well have something to do with the nozzle clunking across the print rather than some other problem.

I ran into layer shifts a long time ago and did a lot of research on that. It turned out that I needed to set my jerk to 10 mm/s instead of 20 mm/s. After that the layer shifts were gone. Jerk setting is in the Speed settings area. You may have to open the full Settings menu to see it - Preferences - Configure Cura - Settings - Jerk.

[GeorgeOfTheJungle]

Is that the original bowden or have you put a direct drive extruder?

First thing I'd try is halving the max acceleration settings, to give more time to the extruder to do its thing better, properly, especially when approaching turns/corners and stops. As I've said before, the extruder (proper extrusion) is the most problematic / difficult thing to get right, IMHO.

Too low x/y stepper driver currents, and or too high acceleration, might also produce layer shifts.

[HobGoblyn]

Is that the original bowden or have you put a direct drive extruder?

First thing I'd try is halving the max acceleration settings, to give more time to the extruder to do its thing better, properly, especially when approaching turns/corners and stops. As I've said before, the extruder (proper extrusion) is the most problematic / difficult thing to get right, IMHO.

Too low x/y stepper driver currents, and or too high acceleration, might also produce layer shifts.

Replaced original with This one

[HobGoblyn]

Someone on Creality facebook said he had exactly the same problem printing the first file (where hot end hit rear left) but that all other files he tried were fine.

I was sceptical as the second level test I tried had thicket lines on the left than tyhe right.

But , whats another test, so I downloaded a third, and this is the result

Only a tiny error

This begs the question that two of the most recommended level tests appear to be corrupted in some way???

I was on the verge of sending it back as faulty and requesting a new one (fulfilled by Amazon)

[HobGoblyn]

Most of the rest of the print looked OK except for a layer shift in the final layer (and can also see a layer shift about 1/2 way up everywhere.   I'm not sure whether this may well have something to do with the nozzle clunking across the print rather than some other problem.

I ran into layer shifts a long time ago and did a lot of research on that. It turned out that I needed to set my jerk to 10 mm/s instead of 20 mm/s. After that the layer shifts were gone. Jerk setting is in the Speed settings area. You may have to open the full Settings menu to see it - Preferences - Configure Cura - Settings - Jerk.

Thanks, Jerk wasn't enabled in mine, when I enabled it, everything had a default value of 8 mm/s

[GeorgeOfTheJungle]

Ok, so it's still a bowden, right?

Bowdens only work well when the print is a continuous uninterrupted spaguetti, or, near interruptions/nozzle travels, with low acceleration.

Here is the proof:


IOW, that default 50 mm/s is too high a speed for the bowdens in these printers, those 20 something centimeters of filament between the extruder motor and the nozzle behave like a spring and make it almost impossible to cut/resume extrusion properly at high speeds => try the same print at lower speeds or at high speeds but decrease very much the acceleration, because if not the extruder can't keep up.

The best upgrade you can buy is a direct drive. Or make your own:




It works beautifully :-) , much much better than the bowden!

[xrunner]

IOW, that default 50 mm/s is too high a speed for the bowdens in these printers, ...

In your opinion it might be too high, but mine's been at 50 mm/s ever since I got it and I have no problems with that speed with the bowden. I have beautiful prints when there isn't the occasional other random problem we all encounter from time to time.

[GeorgeOfTheJungle]

IOW, that default 50 mm/s is too high a speed for the bowdens in these printers, ...

In your opinion it might be too high, but mine's been at 50 mm/s ever since I got it and I have no problems with that speed with the bowden. I have beautiful prints when there isn't the occasional other random problem we all encounter from time to time.

Perhaps that's what you think, but even the atmega that comes built in can't keep up at those speeds... so maybe you think it was printing at 50 mm/s but it wasn't.

[xrunner]

Perhaps that's what you think, but even the atmega that comes built in can't keep up at those speeds... so maybe you think it was printing at 50 mm/s but it wasn't.

Perhaps that's what you think, so maybe you think it can't print at 50 mm/s but it was.

[GeorgeOfTheJungle]

Perhaps that's what you think, so maybe you think it can't print at 50 mm/s but it was.

Don't you ever see any hiccups?

[xrunner]

Perhaps that's what you think, so maybe you think it can't print at 50 mm/s but it was.

Don't you ever see any hiccups?

Nope. Besides I have a Bigtreetech SKR board so your comment doesn't apply to me. In any event it never had any problems even before that (with that setting). If it's set to 50 mm/s, and it's just able to physically do some slower speed that the software doesn't know about (but thinks it's actually doing 50 mm/s), then is the print going to come out OK? 

[GeorgeOfTheJungle]

If it's set to 50 mm/s, and it's just able to physically do some slower speed that the software doesn't know about (but thinks it's actually doing 50 mm/s), then is the print going to come out OK? 

Sort of ok-ish: Process a in the cpu translates gcode to stepper pulses and puts them in a buffer, process b pulls from the buffer and feeds pulses to the i/o ports, if the buffer ever gets empty (isn't being filled quick enough), you've got a hiccup, the trajectory will still be ok, but won't happen at the right time but a bit late(r).