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Fix bed variance / warp using flat springs  

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Tiago
(@tiago)
Reputable Member
Topic starter answered:
Re: Fix bed variance / warp using flat springs


Been printing 24/7 Black PetG for the last 2 weeks.
What I found is that on 85 deg C the bed is withing 0.07 to 0.115 and is different with each print. In the beginning with PETG i had a lot of troubles with first layer sticking to the bed , then found that 20 mm/s or lower for the first layer fixes everything . Now I get perfect first layer even the support base , that was worst

Its normal to get different variance, also if you use different temperatures pinda will be affected.
I think updated profiles now print first layers at 20mm/s stock

Posted : 06/11/2018 5:58 am
Tinkerwest
(@tinkerwest)
Trusted Member
Re: Fix bed variance / warp using flat springs


I'll add my name to the list of people that have implemented some sort of spring based leveling. Just because I'm a glutton for punishment, I went with 2.5mm springs and 5mm spacers, with the springs undernearth the spacers so that the heat bed is sitting on the spacer and not the springs. I don't have have pictures, but I went from ~700um of variation down to ~15um variation. It made all the difference in the world. Prior to leveling with springs, I couldn't get a first layer print that was good, even with leveling compensation.

Now:

Really like your approach, would you consider sharing where you got your spring and spacers.

Thank you in advance.

Posted : 08/11/2018 4:56 am
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
Re: Fix bed variance / warp using flat springs

spacers: https://www.mcmaster.com/94669a007
wave springs: https://www.amazon.com/gp/product/B07B45Y37D/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

If I were doing it again, I might try and find slightly stiffer springs. The 9N/mm (~2lb/mm) spring rate is a bit low and when loosening the heat bed screws, it can take a little while for the springs to push the bed into into new position as it is effectively trying to flex the bed. The last time I leveled the bed, I found it work better if I manually flexed the bed by pushing down then pulling back near the screw I had just adjusted.

I will also say that you need a very good pair of tweezers and plenty of patience to get things in place.

*edited* to add a picture of my setup. Not the best picture in the world, but you can make out the spacers riding on top of the springs.

Posted : 08/11/2018 7:59 am
EagleRock
(@eaglerock)
Active Member
Re: Fix bed variance / warp using flat springs

Thank you for the great guide, i managed to get my bed to 0.017mm at room temp, but when i heated the bed to 60c then the level changes to 0.15mm. Anything i can do to improve that ?

Posted : 20/11/2018 10:25 pm
Tiago
(@tiago)
Reputable Member
Topic starter answered:
Re: Fix bed variance / warp using flat springs


Thank you for the great guide, i managed to get my bed to 0.017mm at room temp, but when i heated the bed to 60c then the level changes to 0.15mm. Anything i can do to improve that ?

PINDA output different values under heat. Always tune your bed with the gcode for fix temp

Posted : 20/11/2018 10:44 pm
EagleRock
(@eaglerock)
Active Member
Re: Fix bed variance / warp using flat springs

So just to understand this as long as i start with the same temp pinda every time i print then it should be even and flat ?

Posted : 20/11/2018 10:53 pm
Tiago
(@tiago)
Reputable Member
Topic starter answered:
Re: Fix bed variance / warp using flat springs


So just to understand this as long as i start with the same temp pinda every time i print then it should be even and flat ?

It should give +/- the same values every run if you repeat. And yes you should start print always at same temp if possible.
Use the gcode on first post

Posted : 20/11/2018 11:38 pm
EagleRock
(@eaglerock)
Active Member
Re: Fix bed variance / warp using flat springs



So just to understand this as long as i start with the same temp pinda every time i print then it should be even and flat ?

It should give +/- the same values every run if you repeat. And yes you should start print always at same temp if possible.
Use the gcode on first post

I'm having same problems as christian.b13, my bed is at 0.018 at 60c, if i print a flat piece at 35c pinda, the left side of my bed is lower.
I'm thinking that it could be the powder coated sheet, maybe there is a low spot with the paint on the left side ??

Posted : 27/11/2018 9:28 am
Tiago
(@tiago)
Reputable Member
Topic starter answered:
Re: Fix bed variance / warp using flat springs




So just to understand this as long as i start with the same temp pinda every time i print then it should be even and flat ?

It should give +/- the same values every run if you repeat. And yes you should start print always at same temp if possible.
Use the gcode on first post

I'm having same problems as christian.b13, my bed is at 0.018 at 60c, if i print a flat piece at 35c pinda, the left side of my bed is lower.
I'm thinking that it could be the powder coated sheet, maybe there is a low spot with the paint on the left side ??

Do you also tune your bed with 35c PINDA?
After severe wrap you need to give some print time to bed shape to normal / flat form. It happen to me before when i have 1mm variance, right after the mod it still not perfect on one side, but with the time bed went good and now print perfect every side.
You can do a gcode to speed up this process, heat to 100ºc one hour, another hour cooldown and repeat some times

Posted : 27/11/2018 3:18 pm
randolph.l
(@randolph-l)
Honorable Member
Re: Fix bed variance / warp using flat springs

An inexpensive item like this ($8.35 for both items)
https://smile.amazon.com/HTS-161S2-Locking-Straight-Hemostat/dp/B000W1Y9YU/ref=sr_1_4_a_it?ie=UTF8&qid=1543335463&sr=8-4&keywords=kelly+clamps
will be your best friend for all kind of work on your printer but I find it invaluable for work on the bed attachment and its spacers.

Posted : 27/11/2018 5:23 pm
EagleRock
(@eaglerock)
Active Member
Re: Fix bed variance / warp using flat springs



It should give +/- the same values every run if you repeat. And yes you should start print always at same temp if possible.
Use the gcode on first post

I'm having same problems as christian.b13, my bed is at 0.018 at 60c, if i print a flat piece at 35c pinda, the left side of my bed is lower.
I'm thinking that it could be the powder coated sheet, maybe there is a low spot with the paint on the left side ??

Do you also tune your bed with 35c PINDA?
After severe wrap you need to give some print time to bed shape to normal / flat form. It happen to me before when i have 1mm variance, right after the mod it still not perfect on one side, but with the time bed went good and now print perfect every side.
You can do a gcode to speed up this process, heat to 100ºc one hour, another hour cooldown and repeat some times

Yah i tuned it at 35c PINDA and 60c bed, which shows 0.018-0.023mm. but if i print at the same setting then i still have the low spot on the top left corner.
the bed should be flat with these numbers right? im thinking that the problem might be with the sheet ?

Posted : 28/11/2018 3:10 pm
Tiago
(@tiago)
Reputable Member
Topic starter answered:
Re: Fix bed variance / warp using flat springs

What was your variance before this? And spot is the same as before mod?

Posted : 28/11/2018 3:47 pm
EagleRock
(@eaglerock)
Active Member
Re: Fix bed variance / warp using flat springs


What was your variance before this? And spot is the same as before mod?

If i remember correctly it was around 1.2mm, same spot before the mod yes. that was the reason why i was looking for a solution.
btw this is the springs i'm using: https://www.federnshop.com/en/products/compression_springs/d-145a.html

Posted : 30/11/2018 10:07 am
Tiago
(@tiago)
Reputable Member
Topic starter answered:
Re: Fix bed variance / warp using flat springs



What was your variance before this? And spot is the same as before mod?

If i remember correctly it was around 1.2mm, same spot before the mod yes. that was the reason why i was looking for a solution.
btw this is the springs i'm using: https://www.federnshop.com/en/products/compression_springs/d-145a.html

Yeah, exactly like me what happened. Just follow what i said about preheat bed to unwarp

Posted : 30/11/2018 3:23 pm
EagleRock
(@eaglerock)
Active Member
Re: Fix bed variance / warp using flat springs




What was your variance before this? And spot is the same as before mod?

If i remember correctly it was around 1.2mm, same spot before the mod yes. that was the reason why i was looking for a solution.
btw this is the springs i'm using: https://www.federnshop.com/en/products/compression_springs/d-145a.html

Yeah, exactly like me what happened. Just follow what i said about preheat bed to unwarp

Thank you, I'll do that tomorrow and see, my prints keep lifting up in that area ...

Posted : 30/11/2018 9:19 pm
michael.k95
(@michael-k95)
Active Member
Re: Fix bed variance / warp using flat springs

I’m still in the process of testing this but...

Probably it would be a good idea in instructions to level the x axis before taking measurements.

For example, if the x axis isn’t level, and you calibrate to the bed, the bed could get skewed to compensate for the skewed x axis. If you try to align the x axis to the bed like in instruction manual, it won’t work since the springs could be a varying heights vs rigid stock spacers.

What I found easy was to take two glue sticks and put them between the frame and stepper motor, and lower the z rod holders down and level that way.

Hope this works! I had this mod working fine, but after some bed re-leveling, x axis releveling against the bed, I started getting some bad skew. I think leveling x axis first, then leveling the bed is the correct way to go about it...hopefully!

Posted : 24/12/2018 9:48 pm
tyler.h8
(@tyler-h8)
Eminent Member
Re: Fix bed variance / warp using flat springs

OPK

I went ahead and put in an order for the same springs as you found. These look like the perfect plug and play springs.

They holding up okay? Ordered from Zoro, will take about 2 weeks bleh.

To do the Prusa Mesh thing, I need octoprint correct? Is there no other way to do this without that? Wanted to avoid going through the hassle. I don't need the extra features, just a flat bed.

I also plan to print a 2-3" high square, and I'll place them on opposite ends under the X Carriage to ensure that's parallel to the bed too. You guys have no idea how excited I am to get this bed perfectly flat.

Posted : 01/01/2019 9:45 pm
OPK
 OPK
(@opk)
Trusted Member
Re: Fix bed variance / warp using flat springs

@tyler.h8

They are holding up perfectly - since the first tuning the results have barely changed.
Yes, you do need Octoprint to see which spring needs loosening/tightening. I dont know any other way...

Posted : 01/01/2019 10:04 pm
tyler.h8
(@tyler-h8)
Eminent Member
Re: Fix bed variance / warp using flat springs


@tyler.h8

They are holding up perfectly - since the first tuning the results have barely changed.
Yes, you do need Octoprint to see which spring needs loosening/tightening. I dont know any other way...

Wanted to post an update. Installed the springs today, ran calibration and got within .019mm Total Variance using the Mesh Plugin. Did not feel the need to go any further.

Printed a 1st layer test square, and this machine has NEVER printed this consistent across the square!!!

Going to print out a Rasberry Pi 3 B+ enclosure for this bad boy now.

Even if the springs do settle over time or something, very easy to make adjustments. Love this setup. This is a must have for quality prints.

Posted : 10/02/2019 8:19 pm
Erik
 Erik
(@erik-3)
Estimable Member
Re: Fix bed variance / warp using flat springs


Even if the springs do settle over time or something, very easy to make adjustments. Love this setup. This is a must have for quality prints.

I've had springs without spacers installed for a few months now. The only times I've adjusted them is when I was messing with the printer. I had to do a full calibration. After about 200 hours of printing PETG they hadn't moved at all.

Posted : 11/02/2019 2:39 pm
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