Replacing P.I.N.D.A. Probe  

Re: Replacing P.I.N.D.A. Probe

Can't tell you the probe type, but I believe that it must work on a 5V rail; most probes will only work down to 6V and I believe that Josef had this one specially designed for the lower voltage.

Not sure why it needs to be more sensitive though; the supplied probe should trigger at about 1mm.

Peter

Re: Replacing P.I.N.D.A. Probe

I am guessing that that is just a "what if" question, and you are not serious about replacing the probe. The problem with height is not directly caused by the probe that is use, but is that of alignment. Once aligned the machine with the supplied probe works great. Now if you want to get a really good probe check this one out
http://www.keyence.com/products/measure/spectral/index.jsp

Re: Replacing P.I.N.D.A. Probe

I suggest the printbed with embeded metal is essential in the PINDA equation and alignment. My printbed is spot on in relation to the X axis. But the pinda probe position seems slightly out on the bottom left probing point. But is resolves overall, and I get great prints. So I am happy.

The issue I may have in the future, is the PINDA probe knocking the prints off the bed because of only aprrox 1mm height difference between the nozzle and probe height and some prints.

Re: Replacing P.I.N.D.A. Probe

Exactly, if the current probe can be replaced with a probe with a greater sensing range (for example 8 mm) there is less or no change the probe touches the print. I thought everything about the Prusa i3 was open source, but I just can't find the information about the P.I.N.D.A. probe.

Re: Replacing P.I.N.D.A. Probe

I find a problem with that suggestion. You are putting the probe within range of the screws and nuts holding the extruder body together.

The more sensitive the probe, the more false positives you will get.

Yesterday I was re-calibrating the nozzle gap with feeler gauges and noticed the probe was triggering when the feeler was under the nozzle and nowhere near to the probe, so the supplied probe is very sensitive; its just the inserts in the bed are very small.

Further, I don't understand your need for this. Why would a printed part be 1mm above the height of the nozzle? Yes, you can get high points, maybe 0.1/0.2mm above the print surface but 1mm? If that is really the case then regular Z-Lift settings (0.4mm) simply would not be sufficient and it would be the nozzle hitting the part and not the probe.

Peter

Re: Replacing P.I.N.D.A. Probe

You are right pjr and I am wrong. The nozzle would knock off the print first. I will shut up. And take more care in comments in the future. Sorry for misleading anyone. < a serious apology that I mean.

Re: Replacing P.I.N.D.A. Probe

Hi,

I do not fully agree on this point Peter. Most of the time, a layer is just slightly different from the layer below, so the nozzle tend to follow the same path and push on the existing perimeter then on the existing infill, which reduce side interaction. The PINDA probe, in opposition, is more likely to be on the side of the existing print, so have chances to grab it during print, even if it's 1 mm above. Having warping during print is the most concerning situation to be in this case.

That's to mitigate this risk I first designed my Pinda hat, and now PR made their own version in the Github STL files ( https://github.com/prusa3d/Orignal-Prusa-i3/blob/MK2/Printed-Parts/stl/PINDA_protector.stl ).

Re: Replacing P.I.N.D.A. Probe

You do know I was being sarcastic above in my reply to PJR I hope. Yes it depends on direction of travel. The PINDA probe can knock off the print as I said before. I have seen it. The best level sensing probe I have used before was on my original home built Kossel mini. It had a mechanical probe deployed by an axis belt and then stowed well out of the way after bed levelling by seeking a plastic mount on one side of the bottom triangular frame to stow it back in home position. All programmed in Marlin.

Re: Replacing P.I.N.D.A. Probe

So does no body know the answer to the question?

What would someone be looking for for a replacement probe? Good shout on the 5v PJR but is there any other info?

Re: Replacing P.I.N.D.A. Probe

OK, my opinion only...

Rather than looking to change the sensor (which may be a difficult find due to the 5V requirement), it may be better to increase the mass (not the area) of the 9 sensor points. I have not tried, but it may be possible to attach small neodymium magnets underneath the bed to effectively increase the sensitivity of the probe.

However the issue with magnets is that they will degrade with the constant heating and cooling, so an alternative solution may be required.

Peter

Re: Replacing P.I.N.D.A. Probe

pjr your suggestion above mixes mass with magnetic strength ie the addition on neodymium magnets and their affect overall with temperature variation. The mass will be added but not change, however the magnetic strength may vary a bit. But adding magnets is not the way. They would mess up the level sensing. The PINDA sensor detects metal embedded within the bed via induction . And uses software to do so, ie it is not an all or nothing sensor. The jiggle of the probing with the new firmware suggests this. Adding magnets would mess everything up and you know it PJR. And maybe wreck the PINDA sensor by magnetising it!

Your comment above pjr is provocative and shows you for what you are. A so called know it all and excessive commentator on this site.
May I ever be so humble.

http://www.instructables.com/id/Enable-Auto-Leveling-for-your-3D-Printer-Marlin-Fi/

Your comment above cannot be labelled as sarcasm, as your comment and suggestions would knowingly do harm PJR.

Re: Replacing P.I.N.D.A. Probe

Nigel,

could it be possible to disagree without diving into rants and personal attacks ? Please ?

Re: Replacing P.I.N.D.A. Probe

Christophe

Don't get involved; just leave the poor man to he own thoughts. It is very sad that he chooses to do this, but he shows himself up for what he is and if he concentrates his mind on me, then others will not suffer the same nonsense.

It really is not worth the effort to make the comment.

Peter

Re: Replacing P.I.N.D.A. Probe

I do not think Prusa has had a custom made one. Most pinda probes will work at 6v, 12v and also 5v. The problem at 5v is the probes sensitivity. Well to be fair that proves a good point with the Prusa probe. It is not that sensitive even after calibration!

I think if Prusa was to have had one custom made they would make it so it was not adjustable, in its own box out the way. Surely they would not have gone to all that effort to have one custom made then have it so you need to put some thread lock on to stop the nut undoing while you print 😮 that would just be stupid.
Lets face it, if it was custom made there would be no reason at all to adjust it. 😉

They have simply taken the most sensitive probe at 5v. So that could be a 12v-24v or specific 6v sensor. To make the sensor more sensitive you do not need more metal, more magnets. You simply need a slightly higher voltage. So what sensor would be available that could run from the 12v but still use the 5v endstop voltage from the board for the actual activation. the 12v for the running of the sensor (please note I am saying simply but you may still require a resistor of some sort).

I am not suggesting try it with the probe from Prusa but if you wanted a more sensitive sensor take the spur from the PSU rather then the Rambo.
The question that needs answering is more what probe would others suggest and copied from the first actual post still unanswered is "what kind do I need? Is it a NPN NO, NPN NC, PNP NO or PNP NC? And what are other factors I have to take into consideration?"

Re: Replacing P.I.N.D.A. Probe

Ben

There is a 12V supply available on one of the headers on the RAMBo. A resistor network for a 12V feed has been suggested here: http://shop.prusa3d.com/forum/software-f13/enabling-auto-leveling-in-firmware-t416.html#p2907

All 3 endstops in the firmware are set as INVERTING = false, so they are all NC (assuming my memory serves me well).

Peter

Re: Replacing P.I.N.D.A. Probe

Peter thank you that is spot on. I am going to be trying another pinda on a different machine but will have a look see if a little go at swapping will not harm anything.

Re: Replacing P.I.N.D.A. Probe

Sorry all. Father in law died last Saturday, wife and I stressed. He was 93 so did well, mother in law remains at age 94 we are worried about her. .Lots to do with registering a death within 5 days by law and getting death certificates and contacting all required parties . Also arranging a cremation and a funeral service. No excuse, but overall my comment about adding magnets being a bad move was a correct one and mess up overall.

There are more sensitive PINDA sensors out there able to detect 4 to 8mm above the bed (more expensive maybe) Stowing the sensor out of the way after use is the answer, because the PINDA sensor set at 1mm above the hotend nozzle, knocks off supports. I have had no successful prints when using supports, they are always knocked off by the PINDA. Due to bogies. And foul up the entire print. I have total success with my Kossel Mini(Duet board with DC42 Differential I/R level sensor 3mm above the hotend nozzle) with supports and my Ultimaker 2+ with manual level setting only. < once set never needed to adjust yet after 6 months. And is printing a 48 hour print now involving supports.

Tonights print on my Prusa I3 MK2 was great, no supports needed.

@PJR Adding magnets will destroy the levelling overall and the PINDA sensor rendered useless. Manual levelling is best I guess. Above what you proposed!

Good night. I will not be bullied by so called Pros off this forum. Please take note josef.

Re: Replacing P.I.N.D.A. Probe

Nigel

Sincere condolences for your loss.

Personally when printing supports, I do find that KISS behaves somewhat differently in that the support Z offset is applied after the first layer and the printer prints the supports, raises the nozzle, prints the model, etc.

However, supports are rather weak and I do use Z-Lift with them; this in the main avoids supports being knocked or dragged over by the nozzle.

Peter

Re: Replacing P.I.N.D.A. Probe

Peter

Thanks for your condolences. To top it all we are having a heatwave here in East Anglia, 34 deg C here today, mother in law struggling, we are all a bit tetchy.

I guess I will have to take a look at the slicer you advocate, KISS. I apologise to you for my rant, totally out of order by me.