Prints suddenly stopped working at 2mm Why and is it vref or somethin?

Jonners59 · 2021-02-17 16:15:10

I was thinking the same at the start of all this TBH. It all started after I had taken the Z-Axis apart and just seemed odd.

Can you can point me in the direction of some, please.. I have found a pair with the whole unit for $15, but it costs another $55 in postage... I would like to find something here or at least cheaper. Getting ripped off for postage.

bigfilsing · 2021-02-17 16:36:13

LM8UU ( just double check your Z rods are indeed 8mm!!)
https://www.ebay.co.uk/itm/LM8UU-8mm-Li … Swhl1e0tK9

or ( from the same people)
https://www.ebay.co.uk/itm/Igus-DryLin- … SwwrNgBhbJ

Jonners59 · 2021-02-17 17:47:11

Thank you. Have ordered 2 of each. Should arrive Saturday. I assume that after removing the split ring I have to force them out....

bigfilsing · 2021-02-18 01:13:58

Jonners59 wrote:

Thank you. Have ordered 2 of each. Should arrive Saturday. I assume that after removing the split ring I have to force them out....

Yup they are typically a press fit.

However there maybe 2 per side . 1 on top of the other. I cant see properly from your photo Or they have used the longer version of the LM8UU which is the LM8LUU

If the LM8LUU has been used you can just replace the faulty one with 2 LM8UU's

Last edited by bigfilsing (2021-02-18 01:29:05)

Jonners59 · 2021-02-18 10:12:46

bigfilsing wrote:

Jonners59 wrote:
Thank you. Have ordered 2 of each. Should arrive Saturday. I assume that after removing the split ring I have to force them out....
Yup they are typically a press fit.
However there maybe 2 per side . 1 on top of the other. I cant see properly from your photo Or they have used the longer version of the LM8UU which is the LM8LUU
If the LM8LUU has been used you can just replace the faulty one with 2 LM8UU's

Ah, OK. Well I ran the hex driver they supply down the inside of the smooth part and it hit a ridge about 1/2 down, so I am safely assuming 2 x 20mm as the total length seems to be circa 43mm. So allowing for a slapdash approach to measuring and maybe a gap or something, and logical 20mm not 21.5mm...

You say push-fit. Now my experience of push-fit with bearings in the 70s was the use of a compression tool. How do I get them out and replaced?

bigfilsing · 2021-02-18 10:30:21

Jonners59 wrote:

bigfilsing wrote:
Jonners59 wrote:
Thank you. Have ordered 2 of each. Should arrive Saturday. I assume that after removing the split ring I have to force them out....
Yup they are typically a press fit.
However there maybe 2 per side . 1 on top of the other. I cant see properly from your photo Or they have used the longer version of the LM8UU which is the LM8LUU
If the LM8LUU has been used you can just replace the faulty one with 2 LM8UU's
Ah, OK. Well I ran the hex driver they supply down the inside of the smooth part and it hit a ridge about 1/2 down, so I am safely assuming 2 x 20mm as the total length seems to be circa 43mm. So allowing for a slapdash approach to measuring and maybe a gap or something, and logical 20mm not 21.5mm...
You say push-fit. Now my experience of push-fit with bearings in the 70s was the use of a compression tool. How do I get them out and replaced?

Get something round n hard and about the outer diameter and a hammer
And follow one of my life moto's "If at first you don't succeed get a bigger hammer" :-)

bigfilsing · 2021-02-18 11:36:51

I was just messing around and figuring out the new ( well new to me) layout of NanoDLP
and came across this , see below. Maybe thats the setting for the delay we've talked about !!

The default is 0.1 seconds !!

Jonners59 · 2021-02-18 12:16:05

1.

bigfilsing wrote:

Get something round n hard and about the outer diameter and a hammer
And follow one of my life moto's "If at first you don't succeed get a bigger hammer" :-)

I feared you'd say that!

bigfilsing wrote:

I was just messing around and figuring out the new ( well new to me) layout of NanoDLP
and came across this , see below. Maybe thats the setting for the delay we've talked about !!
The default is 0.1 seconds !!
https://i.ibb.co/K6f1SCC/wait-before-print.jpg

Ah, NO. Just remembered what that is. The wait before is allowing the resin to settle (esp important as it is so thick) after the build plate returns to the VAT bed, before starting the next phase, the print. So before the UV and image turn on.

OK to the bearings arrived and fitted. I removed the old. They were single units, and have swapped them out. One fell apart as it came out, so there was the faulty one. They are rather better quality though from an engineering perspective if poor materials. Anyway. new in and set up. I shall add some resin and have a quickie. Then I'll do a print - sorry, bad taste joke.

Last edited by Jonners59 (2021-02-19 12:43:34)

Jonners59 · 2021-02-20 10:41:20

Test print worked well at 0.20um. Whilst I scaled it right down I do not think the model justified the resolution, but it was fun and it worked. Its total height was about 20mm so got past the 2mm issue. Now trying my wheel rim. See what that does.

One difference I noted between your GCode and the one I had was that yours only lifts a small bit after the print has finished, the other went to the top. What I do NOT know is how it calculated where the top was and it could be a bit worrying if it did that without calculating its current position and knowing how far up it can go - top end stop. The new is safer but I did wonder if it MAY be an answer to my top limit - end stop - question?????

Helps me work out the finest detail I should be able to get before the rotations go out of sync, in theory, and subject to resins and other tolerances. THEORY. I may have a go at the 0.009375mm (9.375um) for fun.
https://blog.prusaprinters.org/calculator_3416/

bigfilsing · 2021-02-20 12:29:44

Jonners59 wrote:

Test print worked well at 0.20um. Whilst I scaled it right down I do not think the model justified the resolution, but it was fun and it worked. Its total height was about 20mm so got past the 2mm issue. Now trying my wheel rim. See what that does.
One difference I noted between your GCode and the one I had was that yours only lifts a small bit after the print has finished, the other went to the top. What I do NOT know is how it calculated where the top was and it could be a bit worrying if it did that without calculating its current position and knowing how far up it can go - top end stop. The new is safer but I did wonder if it MAY be an answer to my top limit - end stop - question?????
Helps me work out the finest detail I should be able to get before the rotations go out of sync, in theory, and subject to resins and other tolerances. THEORY. I may have a go at the 0.009375mm (9.375um) for fun.
https://blog.prusaprinters.org/calculator_3416/

Yup its all about getting it working . Ive never had a need to go below 50um but its interesting to hear its working as low as 20um

Im just about to receive some "rubber" resin for a project im working That should be fun to calibrate :-)

Let me know how the rim goes

Cheers
Phil

Jonners59 · 2021-02-20 13:12:15

bigfilsing wrote:

Yup its all about getting it working . Ive never had a need to go below 50um but its interesting to hear its working as low as 20um

Yeah, it's all about what it is for. I can see most 50 is fine or even 100, but for me it is all about fine detail. These wheel rims have tiny holes for the spokes that would not exist if not high enough res.

bigfilsing wrote:

Im just about to receive some "rubber" resin for a project im working That should be fun to calibrate :-)

Sounds wiered using rubber, but there are so many materials. i am going to try clear resin with fine metal dust to get a metal effect....
PS: If you know of a really good detail resin that would be of interest.

bigfilsing wrote:

Let me know how the rim goes
Cheers
Phil

Will do. I didn't realise it would take 24hrs! So tomorrow for breakfast.

Jonners59 · 2021-02-22 15:45:49

Well, it worked. I am just fine-tuning some resins at very high res, before I have another go at my wheel. The print at 20um left much detail out, namely, the spoke holes, so I think it was over curing as it used to be better, have more showing.

One thing I would like and would like to explore is this end stop at the top. If there was a way to max the top and raise the build plate to the top after a print....

Print Stop Code:
M104 S0 ; Switch off UVLED
G4 P10000 ; Dwell / delay 10000ms
G91 ; Set to relative positioning mode
G1 Z10 F150 P1 ; Move Z axis up 10mm at speed 150
[[WaitForDoneMessage]]
M18 ; Disable stepper motor

Old setting
M104 S0
M106 S0
G04 F30000
G90
G1 Z190 F300
M84

bigfilsing · 2021-02-23 12:15:04

Great news its now working

As for the end position you could , instead of
G91
G1 Z10 F150 P1

In theory you could not switch to relative mode and stay with absolute mode
G90
G1 Z"whatever your max height is" F150

I would definitely do a couple of dry runs to make sure this edit works

Cheers

Jonners59 · 2021-02-23 13:00:18

bigfilsing wrote:

Great news its now working
As for the end position you could , instead of
G91
G1 Z10 F150 P1
In theory you could not switch to relative mode and stay with absolute mode
G90
G1 Z"whatever your max height is" F150
I would definitely do a couple of dry runs to make sure this edit works
Cheers

OK, I'll do that. I have a full-blown run on my wheel rim. The test, but it is telling me it will take 82 hrs. Hate the nano ETA it is never accurate and goes up and down like a yo you. Other apps get it right, so don't know why nano can't.

Would be nice to add to the TOP button on Z-Axis as that does nothing. I even think it is slightly greyed out.

bigfilsing · 2021-02-23 16:09:45

Jonners59 wrote:

bigfilsing wrote:
Great news its now working
As for the end position you could , instead of
G91
G1 Z10 F150 P1
In theory you could not switch to relative mode and stay with absolute mode
G90
G1 Z"whatever your max height is" F150
I would definitely do a couple of dry runs to make sure this edit works
Cheers
OK, I'll do that. I have a full-blown run on my wheel rim. The test, but it is telling me it will take 82 hrs. Hate the nano ETA it is never accurate and goes up and down like a yo you. Other apps get it right, so don't know why nano can't.
Would be nice to add to the TOP button on Z-Axis as that does nothing. I even think it is slightly greyed out.

Greyed out is usually a sign that something isn't set up . It probably only works if you have a top endstop installed and configured. ( Just guessing here as ive never actually tried it or had a top endstop
You could make a macro and assign a button That's already quite an accessible feature in Nano
However you need to be careful . Absolute positions are only valid if the build plate has been homed at some stage. The machine can only move to Z100 ( for example) if it knows where Z 0 is !!!

Jonners59 · 2021-02-24 11:20:00

bigfilsing wrote:

However you need to be careful . Absolute positions are only valid if the build plate has been homed at some stage. The machine can only move to Z100 ( for example) if it knows where Z 0 is !!!

OK, but it is standard practice to send the build plate mount to HOME/"FLOOR", which is stopped by the end stop circuit breaker. And to then with loosened fixing screws/bolts to push the build plate down firmly on to the FEP/vat bottom and tighten the nuts/bolts and hence have a perfect Z-Axis = 0

The top is added by the VERY BADLY explained/described "Record Current Height as Axis Height" in Setup -> Z-Axis Control, on the left under "Platform Information". When at the max height this "button" is clicked and it then sets the max height in mm and pulses. It also adds this to "Machine Settings" -> "Axis Movement" -> "Z-Axis Height" at the bottom in pulses and a side note in mm. In my case 148,000 pulses and 185mm. See the link below for images.

Image of screenshots and inputs. Max Z-Axis Setting

So I do NOT understand why this is such a big problem and why it is not done as standard. I know I do not know GCode and the finer technicalities, but it seems crazy to me that it knows where the bottom is, it knows where the top is and it knows where it is, yet it can't tell itself not to go past a certain point, the max pulses/mm.

The only case where it MIGHT get lost is if it is mid-height and has been rebooted, MAYBE it won't until HOMED know where it is, but even that can be addressed by adding a HOME at the start-up (though if HOME = 0 hasn't been set or there are gummy bears/debris on the vat bottom that could cause problems), and TBH if I recall it does show where it is.

Confused, very.

Last edited by Jonners59 (2021-02-24 11:33:11)

Jonners59 · 2021-02-24 11:32:00

This is something you and I have discussed Your thoughts welcomed too.

bigfilsing · 2021-02-24 11:41:19

And this where a lot of people get confused
A relative position is ( obviously relative to current position) is used to move from where the print platform is currently to where you instruct it to go. plus X mm or minus Xmm
An absolute position is a height in mm from home but the machine can only know "home" if its been homed . In many way an absolute position is relative to home !! Confused yet.

Just try setting the end print gcode as previously mentioned
Dry runs are your friend . Just generate a small print height object print and test it goes to max following the print
Good luck

Last edited by bigfilsing (2021-02-24 11:41:57)

Jonners59 · 2021-02-24 11:56:17

bigfilsing wrote:

And this where a lot of people get confused
A relative position is ( obviously relative to current position) is used to move from where the print platform is currently to where you instruct it to go. plus X mm or minus Xmm
An absolute position is a height in mm from home but the machine can only know "home" if its been homed . In many way an absolute position is relative to home !! Confused yet.
Just try setting the end print gcode as previously mentioned
Dry runs are your friend . Just generate a small print height object print and test it goes to max following the print
Good luck

VERY CONFUSED!

bigfilsing · 2021-02-24 13:59:20

Ok heres an example

So we have homed the Z axis and , for example, sent it to 20mm up from the build plate home position.
G28 ; home axis and set to zero
G90 ; absolute position mode
G1 Z20 F150 ; move print head to 20 mm above home at speed 150.

If we then do
G90 : not absolutely necessary but just to be safe set to absolute position mode
G1 Z20 F150 :
It wont move because its already at absolute position 20.

If we do
G91 ; relative position mode
G1 Z20 F150
it moves to 40 mm above home position . The original 20mm plus another 20mm because in relative mode it moves relative to where it was at the start of the Gcode command.

Jonners59 · 2021-02-24 18:08:42

bigfilsing wrote:

Ok heres an example
So we have homed the Z axis and , for example, sent it to 20mm up from the build plate home position.
G28 ; home axis and set to zero
G90 ; absolute position mode
G1 Z20 F150 ; move print head to 20 mm above home at speed 150.
If we then do
G90 : not absolutely necessary but just to be safe set to absolute position mode
G1 Z20 F150 :
It wont move because its already at absolute position 20.
If we do
G91 ; relative position mode
G1 Z20 F150
it moves to 40 mm above home position . The original 20mm plus another 20mm because in relative mode it moves relative to where it was at the start of the Gcode command.

Yes, I get that. One means that the Z-Axis tool, say up 100mm would mean up 100mm from the "HOME" and the other go up another 100mm, no matter where you are. But surely the nano can mix and match. SO the "TOP" could be absolute as per the "FLOOR"/"HOME" and the safety could also run in the background as a "TOP"= Absolute whilst any printing is done in relative mode, finishing with an Absolute to "TOP".?

bigfilsing · 2021-02-25 15:07:09

Jonners59 wrote:

Yes, I get that. One means that the Z-Axis tool, say up 100mm would mean up 100mm from the "HOME" and the other go up another 100mm, no matter where you are. But surely the nano can mix and match. SO the "TOP" could be absolute as per the "FLOOR"/"HOME" and the safety could also run in the background as a "TOP"= Absolute whilst any printing is done in relative mode, finishing with an Absolute to "TOP".?

It does that already as far as i know
Used to be just we had to calc the pulses but now i believe that what the set Z max stuff is about
Home Z then move up as far as it will go ( or youre comfortable with) and set Z max

Jonners59 · 2021-02-25 15:51:23

bigfilsing wrote:

Jonners59 wrote:
Yes, I get that. One means that the Z-Axis tool, say up 100mm would mean up 100mm from the "HOME" and the other go up another 100mm, no matter where you are. But surely the nano can mix and match. SO the "TOP" could be absolute as per the "FLOOR"/"HOME" and the safety could also run in the background as a "TOP"= Absolute whilst any printing is done in relative mode, finishing with an Absolute to "TOP".?
It does that already as far as i know
Used to be just we had to calc the pulses but now i believe that what the set Z max stuff is about
Home Z then move up as far as it will go ( or youre comfortable with) and set Z max

Yes, but the z-Max is pointless in so much as it is recorded but it does not stop the build plate going beyond it and crashing and grinding at the top. This is what I want to prevent and confused why it is not standard. practice.

I also have an issue with the time/ETA... Never come across a slicing and printing app, not that I know many that are so unreadable, wild and all over the place. Makes planning a build impossible, which is why I need to pick my time well to test the GCode you gave me. Pointless and possibly bad news if it finishes a print at 2 am when it said it would finish at 10PM. Anyway, that's for after all this.

My 3-day print failed. Gummy bear on base and build plate, so 3 days wasted!...

bigfilsing · 2021-02-25 17:09:35

It could be edited in firmware as max Z travel but then we don't have the firmware source files so that would be difficult.

Pity about the print. New FEP seems to always help if i have sticking issues

I'm having fun with the rubber resin stuff . Quite tricky and somewhat obviously prints need a load of supports . It also needs to be post cured in water to get rid of the sticky surface residue.

bigfilsing · 2021-02-26 03:46:54

You are not the only one >>>> https://www.nanodlp.com/forum/viewtopic.php?id=2976

nanoDLP

#51 2021-02-17 16:15:10

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#52 2021-02-17 16:36:13

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#53 2021-02-17 17:47:11

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#54 2021-02-18 01:13:58

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#55 2021-02-18 10:12:46

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#56 2021-02-18 10:30:21

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#57 2021-02-18 11:36:51

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#58 2021-02-18 12:16:05

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#59 2021-02-20 10:41:20

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#60 2021-02-20 12:29:44

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#61 2021-02-20 13:12:15

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#62 2021-02-22 15:45:49

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#63 2021-02-23 12:15:04

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#64 2021-02-23 13:00:18

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#65 2021-02-23 16:09:45

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#66 2021-02-24 11:20:00

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#67 2021-02-24 11:32:00

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#68 2021-02-24 11:41:19

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#69 2021-02-24 11:56:17

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#70 2021-02-24 13:59:20

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#71 2021-02-24 18:08:42

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#72 2021-02-25 15:07:09

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#73 2021-02-25 15:51:23

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#74 2021-02-25 17:09:35

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

#75 2021-02-26 03:46:54

Re: Prints suddenly stopped working at 2mm Why and is it vref or somethin?

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