Fix MK2 PINDA  

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dragos ionut.g
(@dragos-ionut-g)
Active Member

Why won't Prusa fix the PINDA probe on the MK2(S) ?

The new MK3 and the new MK2.5 will contain a PINDA probe with a thermistor inside, which can be used to compensate the PINDA probe in temperature, thus giving the user a consistent Z height.

But Prusa decided that the MK2(S) users are not worthy of such fix, so the've embarked in creating a new product, the MK2.5, which also adds the complexity of those spring steel sheets and their bed (not to mention the half working filament detector).

The MK2.5 firmware is only compatible with the MK52 bed, thus it is impossible to upgrade just the PINDA probe, if you do that you will lose the Z axis because the Z metal dots for the PINDA are in the wrong spots.

So, if you want a simple fix for your Z problems on the MK2(S), then shell out some money and prepare yourself for some tweaking. But if you go that way, then you should have bought the MK3 in the first place.

The logical upgrade for the MK2(S) would have been that temperature compensated PINDA probe, but we will not be getting that !

Posted : 11/03/2018 5:47 pm
alexander.s27
(@alexander-s27)
Estimable Member


Why won't Prusa fix the PINDA probe on the MK2(S) ?

In my honest opinion, because there is no need for.
I wouldn´t say that the MK2(S) has any Z-problems at all.
Surely, having the pinda directly over the bed while heating the bed for PETG or ABS it may have some drift
but who would possibly want to do this?
Using S3D I modified my Start and Ending Scripts so that after the print the head is lifted to 10cm
to remain there until the next print starts where it stays pretty cool while preheating
which you would want it to for nozzle cleaning and maintenance, anyway.
Same goes for the start script which lifts the head again for cleaning.
Should be possible with other slicers as well...

Start...
M300 S440 P240 ; Play a Beep
M907 X500 Z830 E500 ; high power
G28 ; home all
M204 T2000
G92 E0
G1 Z60 F1000
G4 P3000
M300 S440 P240 ; Play a Beep
G4 P1000
G1 Z0.2 F1000
G1 X8.0 F2000
G1 X70.0 E4.0 F1000.0 ; prime
G1 X150.0 E8.5 F1000.0 ; prime
G92 E0
M907 X300 Z830 E450 ;silent

End...

M900 K0
M104 S0 ; turn off extruder
M140 S0 ; turn off bed
G91 ; use relative coordinates
G1 Z2 F5000 ; lift nozzle by 2mm
G90 ; use absolute coordinates
G28 X0 ; home X axis
G1 Y195 ; move Y axis to end position
G1 Z100 F5000 ; lift nozzle by 100mm
M84 ; disable motors
M107 ; turn off fan
M300 S440 P240 ; Play a Beep
M107

Posted : 12/03/2018 5:47 pm
nikolai.r
(@nikolai-r)
Noble Member

I'm using the same approach. Park the head at x=0,z=200 position after every print. And let the printer cool down for couple minutes between two prints. This way the first layer is very consistent with the same material/profile.

I'm also having about 0,15 height difference between ABS/PLA. I could compensate that in the slicer as-well. But I prefer to change it manually before the print starts.

There is no need for me to change the PINDA probe. Follow the rule to check always the first layer and get very reliable prints. You can't/shouldn't avoid this step. You can see how many new user are doing that and creating a tons of "first layer issue" posts in the MK3 forum section.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 12/03/2018 7:18 pm
richard.c12
(@richard-c12)
Eminent Member

Why does everyone think it is the bed causing the height drift problems, while ignoring there is a fan blowing heated air from the hot end right onto the PINDA probe. I often wonder if that fan should be sucking air, not blowing it, therefore the PINDA gets cool air across it.

...
Posted : 13/03/2018 2:59 am
nikolai.r
(@nikolai-r)
Noble Member


Why does everyone think it is the bed causing the height drift problems, while ignoring there is a fan blowing heated air from the hot end right onto the PINDA probe. I often wonder if that fan should be sucking air, not blowing it, therefore the PINDA gets cool air across it.

Because I'm preheating the bed first. Once bed temp is stable, hotend is being heated. The hotend heat time is pretty same independent of filament.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 13/03/2018 3:11 am
dragos ionut.g
(@dragos-ionut-g)
Active Member

I can confirm that the heat from the hotend can affect the PINDA probe, especially if you print ABS or PC, or any hot melting plastic.

The bed is the primary contributor to the PINDA heatup because of the fact that heat tends to go up.

Even if there is a work around for this, doesn't mean there is no reason to fix it!

The problem still exist and is more pronounced if your room temperature is less than 20degC.

Also, back to back prints WILL fail even if the workaround is applied.

Ever wondered why you have to set the first layer height differently for different materials ?

Posted : 13/03/2018 10:55 am
nikolai.r
(@nikolai-r)
Noble Member


Even if there is a work around for this, doesn't mean there is no reason to fix it!

I thought you want to have an inexpensive solution for MK2 printer.
Just telling how I solved this issue for me and alexander.s27 did the same. Raising the head, let the printer slightly cool down before two prints and there is no "PINDA issue". No need to invest money.

If you want to have new features and upgrades, you have to buy upgrade kits or a new printer. Or go any DIY route. Business as usual.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 13/03/2018 3:40 pm
roman.l8
(@roman-l8)
Active Member

I have "preheat pinda" enabled. It takes extra 2 minutes on each print, but i have consistient layer height (no matter materiał). However i ordered mk2.5, i think it is worth it's price (i had discount). For me mk2s is great printer (my 3rd) and with mk2. 5 it will be awsome.

Posted : 13/03/2018 7:44 pm
eric.k4
(@eric-k4)
Reputable Member


Why does everyone think it is the bed causing the height drift problems, while ignoring there is a fan blowing heated air from the hot end right onto the PINDA probe. I often wonder if that fan should be sucking air, not blowing it, therefore the PINDA gets cool air across it.

or the hot end at 200c+ nearly an inch away...

Posted : 14/03/2018 4:26 am
alexander.s27
(@alexander-s27)
Estimable Member



Why does everyone think it is the bed causing the height drift problems, while ignoring there is a fan blowing heated air from the hot end right onto the PINDA probe. I often wonder if that fan should be sucking air, not blowing it, therefore the PINDA gets cool air across it.

or the hot end at 200c+ nearly an inch away...

Guys, honestly....
Although some newer cars may have laser headlights, still the xenon ones are not bad or suddenly defective or to be replaced by manufacturer.

The MK2(S) does not have any issues with that, provided educated handling.
The probe may have a little temperature drift which for those switches is not unknown.
The bed is the main heat source and that could be avoided easily with the right commands in the end code.
The hot end in my experience could be ignored here, anyway. There is such a lot air flow and turbulence that even
if the pinda over the time may warm up somewhat, it would be during the print but certainly not before.

The last time I did a bed leveling and live Z-adjust was some 8 or 10 weeks ago after a regular maintanance.
I do not have any first layer settings or such, neither for 0,1mm or 0,3m.
Just printing on a thoroughly cleaned bed (water with a tiny drop dishwashing detergent in a spray bottle)
and believe me I get quite flawless prints. Even a new print with the printer "hot" after two hours has no first layer problems at all.

There a tons of reasons for problems with first layers, adhesion or z-adjustments. (new posts nearly every day here and elswhere)
but most certainly the pinda is not the point in that.

Posted : 14/03/2018 7:26 am
dragos ionut.g
(@dragos-ionut-g)
Active Member

As a side note, there is no laser in a headlight !

So what you are saying is that you have modified the start-up code so that it will not do the bed calibration every time the print starts. Well then you have spent money for nothing, as this is why the PINDA is there in the first place.

Also, room temperature plays an important role here, I my area external temperatures vary between -25degC to 45degC (winter - summer), and a 5degC swing will vary the Z detection distance with about 0.2mm.

Keep in mind that you set a fixed distance of the probe from the tip of the hotend during building, that distance is about 1.8mm. Now vary that with 0.2mm for each 5degC over/under the temperature at which you've done the initial setting and you have a recipe for disaster. I already had the probe hitting an ABS part while printing and curling it up and over the hotend.

>> The MK2(S) does not have any issues with that, provided educated handling.
That is just ostrich thinking !

>> There a tons of reasons for problems with first layers, adhesion or z-adjustments
Why not make it worse by not recognizing the PINDA has temperature drift ?

Also, why did Prusa changed the PINDA for the MK3 and MK25, if it is that good, it should not be changed !

Posted : 14/03/2018 9:06 am
alexander.s27
(@alexander-s27)
Estimable Member


As a side note, there is no laser in a headlight !

So what you are saying is that you have modified the start-up code so that it will not do the bed calibration every time the print starts. Well then you have spent money for nothing, as this is why the PINDA is there in the first place.

Sorry, I expressed myself unclear.
I certainly do a bed levelling before every print!
What I meant was the z-height calibration.

As for the laser lamps.... https://en.wikipedia.org/wiki/Laser_lamp
They are already in use for some upper class models.

I think I will leave this post, my prints come out well.
There are lots of reasons for first layer issues, each worth to be considered and solved if neccessary.
The pinda temperature-drift just a minor one and easily to be avoided.

About the MK3, that is technical progress but no reason to revise already sold machines.

Always happy printing!

Posted : 14/03/2018 9:38 am
dragos ionut.g
(@dragos-ionut-g)
Active Member

Because Prusa won't fix it, I will 😀 .

I have forked their github repo and ported the MK2.5 firmware to MK2S, it is now called the MK2SE.
Only the temeperature compensation for the PINDA probe is enabled, the rest of the annoyances are disabled thus the only thing you must changed on a current MK2S is the PINDA probe, the rest remains the same.

My github repos is here:
https://github.com/galagithub/Prusa-Firmware

So far it works ok on my machine, calibrates correctly and prints as before. Will need some time to check if the PINDA temperature compensation actually does it's job.

It would be great if someone else tested this.

Posted : 19/03/2018 8:12 am
ischlachter
(@ischlachter)
New Member

Any updates on this? Does it work reliably?

I'm considering of doing this mod..

...
Posted : 03/08/2018 3:08 pm
andreas.b2
(@andreas-b2)
Active Member

I've completed work on my PINDA V2 backport into Mk2 firmware at https://github.com/baloan/Prusa-Firmware . I have successfully calibrated my PINDA V2 probe. See the readme.md for my calibration matrix.
I started out with the Mk2 v3.1.0 release and added G76 calibration code from the Mk3/v3.3.1 release. Galagithub worked the other way round and amended the Mk2.5/Mk3 firmware to work with a Mk2/S. I haven't tried galagithubs firmware yet.

...
Posted : 29/08/2018 10:26 pm
Gromtech
(@gromtech)
New Member

@andreas-b2


Just wondering, do you know if it's possible to upgrade to the MK3 spring steel on an MK2 by modifying the firmware?

From what I've read it doesn't work out of the box because of  different bed levelling points on the new beds.

 

So if I did your Pinda V2 upgrade, and then modified the bed levelling points and used a spring steel would that work ?

Posted : 07/05/2020 11:39 pm
djspathis
(@djspathis)
Trusted Member

@gromtech

I believe there are magnets as part of the MK2.5 (MK52 vs MK42) heat bed to hold the spring steel sheet down in addition to different X,Y locations for the Pinda calibration points. You might find it acceptable to hold down the spring steel sheet with clips and customize the FW to account for the differences, but this is too much effort for my purposes. Prusa does provide a MK2.5 upgrade kit.

DJ...
Posted : 08/05/2020 2:08 pm
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