PEI sheet on glass with IR probe
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I was never ever to get the paint to stick well enough to work. It always ended up scraping up. I switched to black construction paper and haven't looked back
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Also accidently shorted my IR sensor on the heater block today and now it reads all over the place… only seems to be reliable for the initial z home... but without mesh compensation i have not had any issues with this build plate
If shorting the sensor on the heater block caused a permanent fault, that suggests that the heater block is live i.e. shorted to +12 or +24V. One possible cause issues faulty heater cartridge. I suggest you check this with a multimeter before it causes any more damage. The short may only occur when the cartridge is hot.
The assembly instructions advise putting Kapton tape over the back of the IR sensor if it is close to the heater block.
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Thanks DC, ill check it out… yeah its really wierd, it seems to handle the homing probe just fine but mesh bed is all over the place now where before i was all green. Ill have to order some kapton tape.
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Is it the original IR probe with the wire-ended optical components, or the newer one with SMD optical components? Of it's the older sort, the problem may be that the optical components have been bent out of alignment after a head crash.
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Here is for anyone that wants to see the beauty of using black polycarbonate sheet… this is a single wall vase mode. It popped right off after just by flexing the plate in a few directions and there were no issues sticking to the plate without glue or anything, stuff sticks too well sometimes and needs help of a scraper after flexing.
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Is it the original IR probe with the wire-ended optical components, or the newer one with SMD optical components? Of it's the older sort, the problem may be that the optical components have been bent out of alignment after a head crash.
SMD
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Today I tested PEI Sheet rubbed with 1200grit sandpaper to get a rougher surface. The measurement were all over the place and useless. Here is some output from the probing.
When probing the glass sheet it's ok-ish flat with two exceptions that I got no idea where they are comming from. It's only -0.03mm so no biggie but when increasing the probe points it's +0.03mm so it chages direction and it's on the same spots on the bed. Looks more like a bug. Anyways these are just for a reference to show that it works fine on glass.
77probe points - on glass
96 probe points - on glass
And finally 77 points on PEI sheet glued on top of glass.
I've done multiple probings of the PEI and glass probing before/atfter pei just to confirm that the sensor is doing it's job. My conclusion is that PEI, even scruffed down with 1200grit, doesn't work with the IR sensor. Going to try a FSR sensor next time for PEI.
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Could you give link to the polycarbonate you bought from Amazon please?
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Today I tested PEI Sheet rubbed with 1200grit sandpaper to get a rougher surface. The measurement were all over the place and useless. Here is some output from the probing.
When probing the glass sheet it's ok-ish flat with two exceptions that I got no idea where they are comming from. It's only -0.03mm so no biggie but when increasing the probe points it's +0.03mm so it chages direction and it's on the same spots on the bed. Looks more like a bug. Anyways these are just for a reference to show that it works fine on glass.
I've done multiple probings of the PEI and glass probing before/atfter pei just to confirm that the sensor is doing it's job. My conclusion is that PEI, even scruffed down with 1200grit, doesn't work with the IR sensor. Going to try a FSR sensor next time for PEI.
How did you mount the sheet? is it air bubbles causing the issue?
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I used 3M double sided sheet to attach it to the glass. I can see some air gaps under there but the probing results looks so random so I doubt that is it. I'll do a couple of probe runs now just to rule that out tho.
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Ok here is 3x probe runs with 1.18.1 without touching the bed. Actually it's pretty consistant. The first image is from 1.19 and then I tried squishing the bed some but didn't matter much. I then did a zero and it gave consistant probings so I set the offset and fired up a print. Like predicted it's all over the place. Some places It's 2mm+ over the bed and some places it squishes it hard to the bed. The firmware also reported a lot of errors on 1.19 that it couldn't reach probe points prolly because it dived without finding anything at expected height? Anyways I can't spot much of an error when using a ruler on the bed so I think the IR probe isn't smart to use on this type of PEI sheet.
Errors likes this:
Warning: skipping grid point (196.0, 20.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 20.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 20.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 33.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 33.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 33.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 46.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 46.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 46.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 59.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 59.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 59.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 72.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 72.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 72.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 85.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 85.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 85.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 98.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 98.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 98.0) because Z probe cannot reach it
Warning: skipping grid point (222.0, 111.0) because Z probe cannot reach it
Warning: skipping grid point (209.0, 111.0) because Z probe cannot reach it
Warning: skipping grid point (196.0, 111.0) because Z probe cannot reach it -
idkn what to think. Those deviations showing on my previous glas probings is now far worse. I get spots with 0.3mm peaks like this screenshot and the glass bed is clean and nice. Even when i change number of probe points I get the spike and the glass bed is smooth and without anything on it. It's never been more tempting to go FSR just to see if that solves it. The printing on glass is fine even with these odd measurements inbetween tho.
Wish I could click a point in the probe map and mark it as not counting so it became an average of the points around it.
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Could you give link to the polycarbonate you bought from Amazon please?
I have another thread on here called "polycarbonate no bed heat success", there is links and a lot more info in that thread.
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Replaced the IR sensor to test a Piezo pressure sensor mounted on the Titan Aero today. This is really consistant on both glass and pei. Doing some testing still but it looks like it handles it better then the IR sensor for now.
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I tried doing the same thing and gave up. Now I use a BL Touch and it works good enough although not as repeatable as a good old fashioned micro switch. Never bothered to make a servo to deploy because at the end of the day they are 3D printers not milling machines and they do not need the accuracy. Yet…....
