Polycarbonate build plate…. No bed heat Success!!!
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I'm not trying to do things differently. If I did something in a different way is because I didn't understand it correctly, or because my DIY skills and tools are not the best for the job…
I'm not using heat bed since I'm using PC as build plate, also I'm only having "cupping problems" in the bottom of the parts with PETG, a material I didn't use a lot before (because I had warping problems) and which I'm still struggling with... With PLA I'm not having problems at all, nor for removing, nor for sticking, although is true that I din't find the right point yet, where there is not "elephant foot", I know I'm still squishing PLA a bit.
For PETG I tried different Z offsets, and I had a mix of results, sometimes I wasn't able to remove the part (and I broke it trying to remove it) because I was too close (0'20 offset) to the bed, and sometimes having problems with the circles in the first layer because I was too far (0'25 offset), apart from the fact that I'm having problems with the temperature and flow for this material, but that's another story.
Additionally I have 2 PC sheets, one transparent (at least, it was transparent at the beginning) and another one white. The transparent one is "cupped" (not sure about the word, but you all know what I mean), and with the bulldog clips well positioned, the bed seems really flat, you can press and the sheet won't move down in any point, and the probe says the surface is quite well leveled, however, when I remove the clips, the cup is more visible than at the beginning, and I can see the bottom of the part is "cupped" too when I remove it successfully. The white one is perfectly flat, but as I had a problem when I tried to remove one piece, I couldn't use it until today, when I sanded it again. PETG anyway is a material that makes a lot of force when cooling down, I used blue painter tape and it ripped out the tape from the bed when cooling...
@Whitewolf, I'm sorry if you felt like I'm criticizing you, I'm not, I truly appreciate what you did sharing this with us, and trust me, this is the best surface I've ever used (even if apparently I didn't follow the instructions :P), but you've been using it for a long time meanwhile I'm still learning how to use it, and I just ask to take advantage of your experience, to try not to fail in the same ways you failed in the past, anda I'm just trying to share my experience from a newbie point of view, sharing my failures, my successes, what I did and how, so I can receive advice and others can learn from me, same I'm trying to learn from you and others in this forum.
Regards
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The convex surface I describe is only on LARGE surface area prints – like 200 mm diameter flat circles, or large rectangular areas. Small prints like the ones which you (Whitewolf) show do not exhibit any convex bottom surface. Also, it does sound very similar to what Okercho is describing: the print is flat when adhered to the surface, the surface is flat when clamped (or bonded) to the tooling plate, but when the print is removed, the bottom surface sometimes reveals a convex condition.
At first, I too suspected heat -- perhaps the differential of surface temperature from the middle of the bed to the outer edge causes a differential contraction rate when printing/cooling. However, on printers with different surfaces, but which exhibit less even heating on the heat bed, I do not observe this phenomenon -- only on the printers which I run which have a convex/concave (depending on which way you look at the piece) print surface that has been clamped down do I observe this.
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This surface from what I read seems to behave like a surface I was testing for someone on reprap. 55 degrees is all it takes for difficult filaments anything more or any squash down on the first layer with abs especially and you won't get it off. The surface I tried was only very thin so I bonded it to glass and an abs part, as it contracted, held so well to the surface it cracked the surface.
This explains to me anyway why printbite works the way it does it only sticks at high temps so it releases at fairly high temps too. Not the best adhesion, but enough and with the convenience of being able get parts off fairly easily. But it's not $15 a sheet and isn't available more or less anywhere.
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Theres just a couple of things here, issues that you reported a few posts up about part removal. You sanded your plate with 120 yes you started with a lower grit but you finished with 120.
When i started this project it was with 120 and parts were sticking too well. When i dry sanded the sanding was not consistent and different edges of the part would stick differently. I settled on the combination of water and 60 grit which gave me the best balance of part removal and adhesion.
When the build plate eventually gets a sheen to it like found with 120 grit i find that its time to sand again because stuff starts sticking too well.
PETG is easy to print on this plate, if you are not using bed heat and your nozzle temp (what is your nozzle temp?) is in the lower range and you are experiencing warping then i suspect either a bad brand or bad roll.
The photos i provided above and in many photos before it are PETG.
When your clips are on and you do a mesh bed compensation what does the center of your bed say compared to the outside edges of your bed I am just curious if there is still a little cup in your bed, coupled with a bad filament
Here is some other examples, the pink single wall is PLA as you can see there is little to no squish. The clear one is PETG it is also the photo i provided above of the completed part without cupping. The white one is igus iglidur which easily warps like ABS which is why you see the brim but even after cooling none of these parts have that issue which is why i suspect other variables at play here. Nylon is the only filament that has given me a rough time with this plate
Sorry if i got frusterated, I just felt like i was pretty detailed in the methods that i found worked before ever posting this thread then i see people venturing off doing things a little differently then wondering why they experience different results. Results that i myself experienced until i found what worked.
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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
