Polycarbonate build plate…. No bed heat Success!!!
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We're not talking about lack of adhesion while printing – we're talking about effects AFTER the part is removed from the build surface... nobody is attacking your idea.
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I wasnt saying they were sorry if it came off that way. I am not the best at expression through text.
I made the mistake of addressing a couple of his issues in a single post i guess is where the miscommunication is coming from.
In his post he was having issues with part removal
I was adressing that as one of the issues with my comments about proper sanding technique. If you read back a few posts you will see he ventured off the path a bit which is why he is experiencing this.
The second issue i was addressing is exactly what you state regarding after the part is removed. And again I am not experiencing these issues although the largest i have printed is about 80mm in both x and y directions.
I suspected heat at first because there are only two situations that i see too great of adhesion one is improper sanding and two is heat on filaments that shouldnt have heat so naturally i thought that must be the source of his cupping as well.
So that is why i asked next for the readings of his heaightmap and also suspect bad filament because PETG is easy to print with and his results are far different by his description. please keep in mind i am slowly typing from a phone… i didnt see you and djs replies till after i had finished posting.
There are a few others using this build plate that have had success and not reported this issue and no i cannot take credit for this, i was just exploring sanding black PC because my clear PC Flesk3d build plate did not work with the IR sensor
And for the year that i was printing with the Fleks3d build plate i did not see this effect nor did i read about any of their other customers reporting this issue.
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Okercho what size parts are you experiencing this cupping with?
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Okercho I apologize if i came off harsh during my frusteration. I try my best to express properly through text. I am a bit rough around the edges when it comes to social situations.
I believe this might be a filament issue as there is others in another thread who have difficulties with PETG as well. My ignorance of only ever using premium PETG products made me short sighted on this.
If you could share your readings from the heightmap and the size parts you are experiencing this cupping with it will help narrow it down.
Also when you get a chance "wet" sand your PC with 60 grit and you will see better performance with part removal.
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Hi there,
I think that my "lost in translation" came from the wet sand thing, as in spanish the sand paper I bought is called "Papel de lija al agua" (water sandpaper), and as I never heard about "wet sanding" I thought I was doing the right thing xD.
Anyway, after looking some manuals, I think I know what I should do, and I will use 60 grit sand paper (I need to check at home, but I think I have 40, 80 and 120, as those came with the tool… anyway I've bought at amazon some 60 grit, will get them tomorrow). So if I understood it correctly, I should just use the 60 grit, a bit of water (with a spray), and the movement should be straight lines instead of circles. Is that correct?
Regarding PETG, I have two brands, one is PrimaSelect and the other one is 3DCPI (my favorite spanish brand for PLA, the best one I've used so far) , but I've only used the 3DCPI with the PC surface. I'm thinking about testing rigid.ink PETG too... (any opinions about it? What brand are you using?). My problems with PETG, apart from the removal issue (that will be addressed with the wet sanding) is that sometimes it seems is under extruded and sometimes over extruded (so some big layers seems to be peeling off and some little layers are "fat"), I've been playing with the flow but results are a bit random... also the parts are not strong (PETG its supposed to be stronger than PLA, but in some test I've been doing with PETG and PLA for the same design, durability of my parts printed in PETG are less than 1% of the same part printed in PLA), and tend to loose bits when removing it (so poor layer adhesion between the first and the second layer). I'm printing PETG at 245 with no heated bed, no fan, 40mm/s speed (first layer at 25mm/s) and 0'25mm offset from the bed (I'm using DjDemonD piezo sensor, so is the real offset).
About the heightmap, here is a capture of the output after using the right side of the cup and the bulldog clips:
And the part I was printing was this:
The diameter is around 50mm, I will take some pictures when I get home, but as far as I remember, I broke a bit the first layer during removal and the bottom wasn't perfectly flat even though there wasn't warp at all from the surface, and the part was cool when I removed it (so no deformation due to still warm plastic). It's not the only one that came out that way (some others don't, same plastic and options) but was the smaller one.
Regards
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So by the looks of that height map you still have a cup in the bed. also the front spring could be lowered a little to improve.
do a mesh map of your bed without the PC, i would like to see it…. my aluminum bed has a permananet warp in it.... i wonder if you might have something similar but bowed up in the middle.
Your parts definitely should not be breaking when being removed. I hope you will order something like Taulman TechG (Preferred) or RigidInk PETG if taulman isnt available in your area... this way will elliminate the filament variables and we can get on with calibrating your machine correctly.
You are correct Water, i just wet it and sand to a paste and wet a few more times repeating the process this gets the most even results because PC is a difficult to sand surface, you wont be able to damage the surface and yes i do circular motions.
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When you take the clips off do the edges of the PC raise up a little off the bed?
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For the sake of always being on the same page we will refer to cupping as middle of plate upward and edges curling downward. and warping as the middle being down and the edges curling up
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I've ordered some PETG and ASA (did you tried it?) samples from rigid.ink, and the 60grit sand paper will arrive tomorrow, let see how much the post takes from UK to Spain. I will do the testing and come back when I get home…
Thanks!
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I have not tried ASA but I have been eying it from a couple vendors primarily 3dxtech and rogidink.
Dont forget to run that mesh bed without the build plate?
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Hi there,
I've done several mesh, all of them with a homing first, the nozzle without residues and a temperature of 120C in the nozzle (as recommended by DjDemonD for the Piezo sensor).
First, without PC, just the buildtak that I still have in my plate:
It seems that I will need to re-level a bit the bed, is not too bad but can be easily improved.
Second with the transparent PC sheet, the one that is "warped" as per your definition (corners up, center down), attached to the bed with 4 bulldog clips (2 in the front, 2 in the back, near to the corners)
Third one with the white PC sheet, this is the flattest one, no warp/cup is observed without bulldog clips. The mesh was performed with the 4 bulldog clips in the same position as before tough.
Here a comparison between both PC sheets, without bulldog clips:
The left one is the transparent (warped) one, you can easily see that the corner is upward, if I press the edges or the corners with my fingers, the sheet go down a bit. The right one is the white sheet, it's hard to see because is a bit bigger than the builtak, but I can assure you that is flat, I can press anywhere in the surface and it sheet don't move down.
Here you can see the warping as described before:
Both parts were printed with 3DCPI PETG, same parameters, and both in the transparent PC Sheet AFAIR (I need to test this with the white flat one, but as it's not enough sanded yet, if I use it, I cannot unstick the part… I will wet sand it tomorrow when the 60grit arrives and test it again). The nearest one is a Z motor mount, and you can easily see that the part is not flat, the other one is the half of a cylinder for the spool holder, and the bend is not too noticeable, however, if I press a bit in one side (like I'm doing for the picture), you can see it.
I will try to do tomorrow the proper sanding, the leveling and I've got more bulldog clips to put in the center too, let see if I can get a green height map :D.
Cheers!
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Okay so the first heightmap with buildtak, how is the buildtak secured? are you leaving the buildtak under the PC?
That first heightmap i see cupping…. I am curious if you still have cupping with the raw build plate.... any chance you can remove the buildtak, clean the surface and run another heightmap? of just the raw build plate then one again with the clear PC clamped without buildtak under it.
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The Buildtak is sticked to the surface by the auto-adhesive it came with, and I'm leaving it under the PC as I'm not sure I can remove it without ruining it… I will try today to remove it and I will run the mesh again. I've got more bulldog clips, will use them too.
Regards
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Ok, so I've removed the buildtak sheet (without ruining it… I think I still can use it if I want to) and I've wet sanded both PC sheets... the surface now feels different (not sure how to say it honestly), this is a picture of the white (flattest) one:
Left, the wet sanded side, Right the other side, with regular sanding (I just wet sanded one side to be able to compare).After removing the buildtak I ran a homing+mesh@120ºC with the clean alu surface:
Now, the white (flattest) PC sheet (again, homing+mesh@120ºC) with 4 bulldog clips, front and rear corners:
And the transparent (warped) PC sheet (same, homing+mesh@120ºC) with 4 bulldog clips, front and rear corners:
Now I'm gonna level the bed (without PC) and repeat the testing.
Cheers
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Interesting, your warped PC appeared to have similar results to the bed both show cupping one of the things you can do after you level your bed more, is experiment with clips in different places. I ran a lot of mesh bed routines until I found the ideal location for clips on my med since my bed isnt flat
When you say 120c are you talking about the nozzle or the bed? is the bed at 0?
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120ºC at the nozzle, as per DjDemonD recommendations, the bed is at 0 (room temp) always.
I've leveled the bed:
This is the bed without the PC (just the bed), I cannot adjust it better, as I can only set 5 screws (3 in the front, 2 in the back) due to the location of the Z motors (left and right, at the same place than the holes =_=) and the bed cables in the back (around the middle)Here is the white (flattest) one after leveling:
I will put some clips in the left and right side, and do the mesh again to see if it improves, and then I will do a print test…How much offset from the bed are you using?
Cheers
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Personally before printing I would run a bunch of mesh leveling routines on both the clear and white with different clip positions, then compare the results of the two. Your test earlier showed better results with the clear than the white but that could change after changing up clip placement. The cup of the clear sort of acts to your advantage because you cannot clip the middle of the bed…. though once sorted you might find that is the reason the prints end with cups because the clear is following the shape of your bed so the white, might work better.
Your wet sanding job looks great btw, that sheen before from the 120 is what I was talking about.... when the sheen comes back things start to stick too well and its time to resand... I try to have my sanding such that I rarely have to remove the clips to remove a print.
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After using 8 clips (2 front, 2 back, 2 left, 2 right) the leveling is… exactly the same xD
I will need to redesign the Z bed attach to allow me to add an adjustment screw… anyway, for the moment, I will need to rely in the RRF mesh algorithm to compensate this....
I will do some print tests and let you guys know.
Thanks!
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It seems, most of the mesh levelling problems could be avoided by using a thick base plate ( glass/mirror suddenly is a good option ) and a thinner PC sheet?
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Quick update.
Not sure if you're following the PrecisionPiezo thread, where I posted some accuracy testing I did, as I found something quite interesting IMHO. I'm obtaining an accuracy of 0.002mm doing 36 tests over the same point, which is awesome, however, if I do it after homing, I was obtaining a deviation of 0.07Xmm (70 microns) from the Z homing test. This caused that the first layer sometimes was too low (and squished the filament) and sometimes was too high (and it didn't stick for the circles). I tried several things for Z homing (home X, Home Y, move slowly to Z, G30, Home Z again), and during several tests I got a better deviation (around 10-15 microns from the Z Homing heigh) and a mean of 0.002 for the testing in the same point. I still need to do more testing to be confident about the repeatability of the measures, but this explains why I got some of my issues with PETG, where I was unable to un-stick it (too close from the bed!).
Last night I printed another PrecisionPiezo support mount (in my trusty PLA), using the white (flattest) PC sheet, and this is the result:
I just had a couple of minutes this morning to check the print, but so far, my impressions:
- Circles and details in the first layer were perfectly printed, with some under extrusion (more about this in the last bullet point)
- It was really easy to remove, the bigger one I was able to remove by hand, for the low height ones, I just bended a bit the sheet and both came off perfectly
- I couldn't observe any warping/cupping, but I will check it closely when I get home tonight.
- I couldn't see elephant foot either, but I will do more tests with different Z offsets.
- I've detected that I'm having under extrusion problems after retraction… I've checked and my bowden tube is a bit too short after I setup the new sensor, and is a bit tight, so I'm gonna replace it for a bigger new tube. I've also observed that my acceleration/speed settings are the default ones and seems to be too low for my setup, compared with the settings I used to have in marlin before, so I will adjust that too and test again.
I will do the adjustments and report back, but the problems with the extruder may explain my low performance printing PETG, meanwhile the defective sanding I did and the random Z homing heigh can explain why I wasn't able to remove sometimes the part (60-70 microns is "nothing", but can be the difference of a squashed PETG impossible to remove and a good one).
Cheers!
