Sanding Pyrex for better adhesion?
Posted by fittoextrude
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Sanding Pyrex for better adhesion? November 22, 2011 02:29PM |
Registered: 14 years ago Posts: 10 |
I am getting some mild warping at the corners of bigger prints of ABS printing on 5mm Pyro-Ceram (Pyrex) ceramic glass. The glass
is sitting on a Prusa PCB heated to approximately 110 degree Celcius. Checking with an infrared heat gun, the temperature seems to drop
from the middle out to the edges of the glass to about 90 degrees Celcius. There does not seem to be significant differences between printing
straight on the (smooth) glass and having Kapton tape applied to it.
I was browsing the forums to see if I could improve the adhesion of ABS to the glass surface and came up with the following list of points to consider:
1) Temperature of the printing surface at least 110 degrees Celcus (for ABS)
2) Proper bed leveling relative to the Nozzle
3) A nozzle height that allows for the first layer to be smeared onto the glass
4) Applying Kapton tape to the glass
5) Slowing down the print speed to half for the first layer
6) If printing on bare glass, sand the glass and clean it with Acetone with ABS dissolved into it
I have gone through steps 1 to five with mild lifting of larger printed pieces (X motor end) at the corners (only the corners facing the front of the printer.
In my desire to improve adhesion and get perfectly level prints I decided to take a stab at number 6 and sanded one side of the glass with 280 grit sandpaper.
I managed to get a perfectly consistent dull sheen of the glass. Then I cleaned that side of the bed with a mixture of acetone (nailpolish remover) and ABS
dissolved into it. I re-leveled the bed, adjusted the nozzle height and started printing....and.........no adhesion whatsoever!!!
Either the surface was not clean enough as the ABS picked up the glass powder embedded in the scratches or the ABS was repelled by the mixture of
acetone and ABS....it did not work. Next will be cleaining the surface with soap and water thoroughly and see what happens then. Fortunately I still have
a smooth glass surface on the other side to work with.
The other problem might be the differential in temperature from the middle out to the edges, creating a tensile strain within the material.
I have not tried the blue 3M painter's tape yet so that will be next......on with the experimentation.
is sitting on a Prusa PCB heated to approximately 110 degree Celcius. Checking with an infrared heat gun, the temperature seems to drop
from the middle out to the edges of the glass to about 90 degrees Celcius. There does not seem to be significant differences between printing
straight on the (smooth) glass and having Kapton tape applied to it.
I was browsing the forums to see if I could improve the adhesion of ABS to the glass surface and came up with the following list of points to consider:
1) Temperature of the printing surface at least 110 degrees Celcus (for ABS)
2) Proper bed leveling relative to the Nozzle
3) A nozzle height that allows for the first layer to be smeared onto the glass
4) Applying Kapton tape to the glass
5) Slowing down the print speed to half for the first layer
6) If printing on bare glass, sand the glass and clean it with Acetone with ABS dissolved into it
I have gone through steps 1 to five with mild lifting of larger printed pieces (X motor end) at the corners (only the corners facing the front of the printer.
In my desire to improve adhesion and get perfectly level prints I decided to take a stab at number 6 and sanded one side of the glass with 280 grit sandpaper.
I managed to get a perfectly consistent dull sheen of the glass. Then I cleaned that side of the bed with a mixture of acetone (nailpolish remover) and ABS
dissolved into it. I re-leveled the bed, adjusted the nozzle height and started printing....and.........no adhesion whatsoever!!!
Either the surface was not clean enough as the ABS picked up the glass powder embedded in the scratches or the ABS was repelled by the mixture of
acetone and ABS....it did not work. Next will be cleaining the surface with soap and water thoroughly and see what happens then. Fortunately I still have
a smooth glass surface on the other side to work with.
The other problem might be the differential in temperature from the middle out to the edges, creating a tensile strain within the material.
I have not tried the blue 3M painter's tape yet so that will be next......on with the experimentation.
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Re: Sanding Pyrex for better adhesion? November 22, 2011 03:01PM |
Registered: 15 years ago Posts: 581 |
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Re: Sanding Pyrex for better adhesion? November 22, 2011 05:25PM |
Registered: 14 years ago Posts: 10 |
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Re: Sanding Pyrex for better adhesion? November 23, 2011 01:15AM |
Registered: 15 years ago Posts: 862 |
I had a curly one recently, I print PLA on normal household glass cleaned with methylated spirit. I had printed about 20 sets of Prusa parts with no problems at all, then all of a sudden my prints started warping and nothing it seems would fix it. So I took the glass into the kitchen and scrubbed it clean with dishwashing detergent, dried it then left it to air dry completely. Now I am getting perfect prints again with only a wipe down with meths.
The only conclusion I have come to is it must have had a build up that meths wasn't removing anymore. Lesson I learnt. Take the glass to the kitchen sink every couple of weeks
__________________________________________________________________________
Experimenting in 3D in New Zealand
The only conclusion I have come to is it must have had a build up that meths wasn't removing anymore. Lesson I learnt. Take the glass to the kitchen sink every couple of weeks
__________________________________________________________________________
Experimenting in 3D in New Zealand
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Re: Sanding Pyrex for better adhesion? November 23, 2011 05:02AM |
Admin Registered: 19 years ago Posts: 7,883 |
Meths is good for finger prints but, unlike acetone, is doesn't dissolve PLA or ABS, and possibly whatever residue they leave.
The odd thing is some people (like me) remove all residue with acetone to restore grip and others deliberately add ABS solution.
I recently used Kapton on glass for ABS on my Prusa (which is not in a heated chamber) and it stuck very well, allowing me to make a bed full of big parts, for example 6 frame vertex. The problem is it was impossible to remove small parts like gears without breaking them. I switched to PET on glass and that allows me to remove small parts but I can no longer make large parts. I would need to put it in a chamber like my other machines which also use PET.
I do my first layer at 140C and the rest at 110C. That requires a 17V PSU. I don't know how anybody manages to do ABS with a 12V PSU.
There seems to be no consistency when it comes to what people can get to stick to what. Talk about YMMV!
Edited 2 time(s). Last edit at 11/23/2011 05:05AM by nophead.
[www.hydraraptor.blogspot.com]
The odd thing is some people (like me) remove all residue with acetone to restore grip and others deliberately add ABS solution.
I recently used Kapton on glass for ABS on my Prusa (which is not in a heated chamber) and it stuck very well, allowing me to make a bed full of big parts, for example 6 frame vertex. The problem is it was impossible to remove small parts like gears without breaking them. I switched to PET on glass and that allows me to remove small parts but I can no longer make large parts. I would need to put it in a chamber like my other machines which also use PET.
I do my first layer at 140C and the rest at 110C. That requires a 17V PSU. I don't know how anybody manages to do ABS with a 12V PSU.
There seems to be no consistency when it comes to what people can get to stick to what. Talk about YMMV!
Edited 2 time(s). Last edit at 11/23/2011 05:05AM by nophead.
[www.hydraraptor.blogspot.com]
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Re: Sanding Pyrex for better adhesion? November 23, 2011 07:49AM |
Registered: 16 years ago Posts: 818 |
nophead Wrote:
-------------------------------------------------------
> The problem
> is it was impossible to remove small parts like
> gears without breaking them. I switched to PET on
> glass and that allows me to remove small parts but
> I can no longer make large parts. I would need to
> put it in a chamber like my other machines which
> also use PET.
Maybe have a strip of 50mm Kapton for the small parts and the rest in PET for the bigger ones
I have always had Kapton on top of PET on my Prusa, but that's not on glass, just on the PCB bed. I must experiment with glass at some point.
[richrap.blogspot.com]
-------------------------------------------------------
> The problem
> is it was impossible to remove small parts like
> gears without breaking them. I switched to PET on
> glass and that allows me to remove small parts but
> I can no longer make large parts. I would need to
> put it in a chamber like my other machines which
> also use PET.
Maybe have a strip of 50mm Kapton for the small parts and the rest in PET for the bigger ones
I have always had Kapton on top of PET on my Prusa, but that's not on glass, just on the PCB bed. I must experiment with glass at some point.
[richrap.blogspot.com]
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Re: Sanding Pyrex for better adhesion? November 23, 2011 08:53AM |
Registered: 15 years ago Posts: 485 |
nophead Wrote:
-------------------------------------------------------
...
> I do my first layer at 140C and the rest at 110C.
> That requires a 17V PSU. I don't know how anybody
> manages to do ABS with a 12V PSU.
>
> There seems to be no consistency when it comes to
> what people can get to stick to what. Talk about
> YMMV!
I'm using the MG Prusa with the 12V supply from the kit; Kapton on glass for the heated bed. I usually start a print when the reported bed temperature is 100°C and the extruder reporting 200-220°C (depending on color). Adhesion to the tape is so strong that really large parts (spanning the diagonal of the bed) will pull the Kapton off the glass. (Heated chamber is on my list. For now, adding an anchor pad at the corners helps.) For small parts, waiting for the bed to cool almost to room temperature helps quite a lot with removal. Even then, on fresh, clean Kapton, I often need to use a knife to lift a corner of a part before the rest will come off.
So far, I've only sourced my ABS from MG. Perhaps your source has a slightly different formulation requiring higher temps?
-------------------------------------------------------
...
> I do my first layer at 140C and the rest at 110C.
> That requires a 17V PSU. I don't know how anybody
> manages to do ABS with a 12V PSU.
>
> There seems to be no consistency when it comes to
> what people can get to stick to what. Talk about
> YMMV!
I'm using the MG Prusa with the 12V supply from the kit; Kapton on glass for the heated bed. I usually start a print when the reported bed temperature is 100°C and the extruder reporting 200-220°C (depending on color). Adhesion to the tape is so strong that really large parts (spanning the diagonal of the bed) will pull the Kapton off the glass. (Heated chamber is on my list. For now, adding an anchor pad at the corners helps.) For small parts, waiting for the bed to cool almost to room temperature helps quite a lot with removal. Even then, on fresh, clean Kapton, I often need to use a knife to lift a corner of a part before the rest will come off.
So far, I've only sourced my ABS from MG. Perhaps your source has a slightly different formulation requiring higher temps?
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Re: Sanding Pyrex for better adhesion? November 23, 2011 09:28AM |
Admin Registered: 19 years ago Posts: 7,883 |
> Maybe have a strip of 50mm Kapton for the small
> parts and the rest in PET for the bigger ones
>
That doesn't help in the case of a bed full of small parts. More practical is to have two pieces of glass and swap between them. The only problem then is different z-calibration / leveling between the two.
> I have always had Kapton on top of PET on my
> Prusa, but that's not on glass, just on the PCB
> bed. I must experiment with glass at some point.
How do you keep it flat without the glass? Mine bows upwards in the middle so has to be held down from above.
Kapton on top of PET?
>So far, I've only sourced my ABS from MG. Perhaps your source has a slightly different formulation requiring higher temps?
Yes come to think of it I did have to raise my temperatures when I started getting ABS from reprapsource.com. And I think PET needs a higher fist layer temperature than Kapton.
[www.hydraraptor.blogspot.com]
> parts and the rest in PET for the bigger ones
>
That doesn't help in the case of a bed full of small parts. More practical is to have two pieces of glass and swap between them. The only problem then is different z-calibration / leveling between the two.
> I have always had Kapton on top of PET on my
> Prusa, but that's not on glass, just on the PCB
> bed. I must experiment with glass at some point.
How do you keep it flat without the glass? Mine bows upwards in the middle so has to be held down from above.
Kapton on top of PET?
>So far, I've only sourced my ABS from MG. Perhaps your source has a slightly different formulation requiring higher temps?
Yes come to think of it I did have to raise my temperatures when I started getting ABS from reprapsource.com. And I think PET needs a higher fist layer temperature than Kapton.
[www.hydraraptor.blogspot.com]
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Re: Sanding Pyrex for better adhesion? November 23, 2011 10:20AM |
Registered: 16 years ago Posts: 818 |
nophead Wrote:
-------------------------------------------------------
> How do you keep it flat without the glass? Mine
> bows upwards in the middle so has to be held down
> from above.
I had exactly the opposite issue, my middle sunk down until I added an M3 nut taped to the underside, it's now completely flat and stays level.
> Kapton on top of PET?
The PET was originally just to protect the Heater PCB as it's nice and thick and levels out the tracking on the PCB (used upside-down), but PLA seems to stick better to Kapton, so I covered the PET in Kapton and found both PLA and ABS seemed to stick better that way, now I just change the Kapton every few months, easy to remove from the PET tape.
> Yes come to think of it I did have to raise my
> temperatures when I started getting ABS from
> reprapsource.com. And I think PET needs a higher
> fist layer temperature than Kapton.
My Pink and Yellow ABS from Reprapsource needs +20 degrees Higher than natural ABS for the same print speed.
[richrap.blogspot.com]
-------------------------------------------------------
> How do you keep it flat without the glass? Mine
> bows upwards in the middle so has to be held down
> from above.
I had exactly the opposite issue, my middle sunk down until I added an M3 nut taped to the underside, it's now completely flat and stays level.
> Kapton on top of PET?
The PET was originally just to protect the Heater PCB as it's nice and thick and levels out the tracking on the PCB (used upside-down), but PLA seems to stick better to Kapton, so I covered the PET in Kapton and found both PLA and ABS seemed to stick better that way, now I just change the Kapton every few months, easy to remove from the PET tape.
> Yes come to think of it I did have to raise my
> temperatures when I started getting ABS from
> reprapsource.com. And I think PET needs a higher
> fist layer temperature than Kapton.
My Pink and Yellow ABS from Reprapsource needs +20 degrees Higher than natural ABS for the same print speed.
[richrap.blogspot.com]
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Re: Sanding Pyrex for better adhesion? November 23, 2011 11:24AM |
Admin Registered: 19 years ago Posts: 7,883 |
> I had exactly the opposite issue, my middle sunk
> down until I added an M3 nut taped to the
> underside, it's now completely flat and stays
> level.
>
Ah yes. That is because you have it upside down. The solid copper side expands more than the side with the tracks so that side becomes convex.
[www.hydraraptor.blogspot.com]
> down until I added an M3 nut taped to the
> underside, it's now completely flat and stays
> level.
>
Ah yes. That is because you have it upside down. The solid copper side expands more than the side with the tracks so that side becomes convex.
[www.hydraraptor.blogspot.com]
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Re: Sanding Pyrex for better adhesion? November 23, 2011 04:18PM |
Registered: 16 years ago Posts: 126 |
I've been using PET on glass at 110C, and I've printed large parts with no problems, no curling at all. I haven't tried a full bed of parts yet, the most I've done is 4 larger parts (Wade's big gears). That however doesn't print anything near the edge of the bed and I can tell just by touch that the edges of the bed are cooler than the center. I tried using Kapton, but it seemed to wear out too quickly. The only time I've had to replace my PET is when I accidentally crashed the nozzle into it and tore it.
I have noticed that for small parts I need to have the first layer be closer to the bed so it mashes down, or else it sometimes detaches later in the print, while for large parts with infill I need it to be as close to a single layer height as possible or else the first layer infill lines get pulled up by the nozzle.
For PLA I use bare glass, and have a separate pane that I swap out. For both I wipe once with acetone to get plastic residue and then with isopropyl to get finger oils and anything dissolved in the acetone.
My heating element is nichrome on aluminum. I've thought of counteracting the edge cooling issue by running the nichrome primarily along the outside of the panel with the thermistor in the center. The aluminum should be sufficiently heat conductive to get the center. I'm not sure if it'd cause any difference.
I have noticed that for small parts I need to have the first layer be closer to the bed so it mashes down, or else it sometimes detaches later in the print, while for large parts with infill I need it to be as close to a single layer height as possible or else the first layer infill lines get pulled up by the nozzle.
For PLA I use bare glass, and have a separate pane that I swap out. For both I wipe once with acetone to get plastic residue and then with isopropyl to get finger oils and anything dissolved in the acetone.
My heating element is nichrome on aluminum. I've thought of counteracting the edge cooling issue by running the nichrome primarily along the outside of the panel with the thermistor in the center. The aluminum should be sufficiently heat conductive to get the center. I'm not sure if it'd cause any difference.
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Re: Sanding Pyrex for better adhesion? November 23, 2011 05:43PM |
Registered: 14 years ago Posts: 10 |
Is anyone currently printing with ABS (Black) from Ultimachine since that is what I am using. I have not had the time to
clean the sanded pyrex side with pure acetone this time to see if the adhesion will improve. I have ordered some PET tape
from Dealextreme to see if that works as well....if you don't try you don't know! The one problem I still have is that I cannot get
the pcb above 110 Celcius. I am going to look into a power supply with a higher voltage so I can play around with the temperatures a bit.
Another question: is anyone using a medium to improve the transfer of heat from a pcb to pyrex or glass? If the PCB has a slight warp to it
there will be areas where the glass is not fully touching the pcb. That could be a possible cause for discrepancies in temperature of the glass.
clean the sanded pyrex side with pure acetone this time to see if the adhesion will improve. I have ordered some PET tape
from Dealextreme to see if that works as well....if you don't try you don't know! The one problem I still have is that I cannot get
the pcb above 110 Celcius. I am going to look into a power supply with a higher voltage so I can play around with the temperatures a bit.
Another question: is anyone using a medium to improve the transfer of heat from a pcb to pyrex or glass? If the PCB has a slight warp to it
there will be areas where the glass is not fully touching the pcb. That could be a possible cause for discrepancies in temperature of the glass.
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Re: Sanding Pyrex for better adhesion? November 23, 2011 06:15PM |
Registered: 14 years ago Posts: 15 |
-fittoextrude
I've heard that pp3dp's up! uses a paint on their bed which I can only imagine is some type of liquid ABS paint described on Makerbot (#14). I printed a whole set of Prusa parts in ABS with a bed at 105-110, but cranking it up to 125 helped a lot.
What type of power supply are you using right now? Almost every power supply recommendation I've seen has been to increase the current rather than the voltage (12V 20A vs 12V 5A). If you keep 12V you can run your steppers and bed off the same supply. Good luck.
Chris Sketch
Ann Arbor, MI
blog.chrissketch.com
We’re here to put a dent in the universe. Otherwise why else even be here?
—Steve Jobs
I've heard that pp3dp's up! uses a paint on their bed which I can only imagine is some type of liquid ABS paint described on Makerbot (#14). I printed a whole set of Prusa parts in ABS with a bed at 105-110, but cranking it up to 125 helped a lot.
What type of power supply are you using right now? Almost every power supply recommendation I've seen has been to increase the current rather than the voltage (12V 20A vs 12V 5A). If you keep 12V you can run your steppers and bed off the same supply. Good luck.
Chris Sketch
Ann Arbor, MI
blog.chrissketch.com
We’re here to put a dent in the universe. Otherwise why else even be here?
—Steve Jobs
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Re: Sanding Pyrex for better adhesion? November 26, 2011 09:37PM |
Registered: 16 years ago Posts: 126 |
In terms of increasing heat transfer from the heater to the bed, I'm not sure if this would work with a PCB heater but it helped a lot with my nichrome on aluminum heater. My Al sheet warped a bit and so wasn't making great contact with the glass like you mentioned. So I just threw a sheet of aluminum foil on top of it and didn't bother to flatten it out particularly well. When the glass is secured down the foil bunches so that parts are in contact with the glass and parts are in contact with the heater. It made the glass heat up much faster. The only issue is with a PCB heater it'd probably short the traces.
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