Print not stick any more

I print PLA until now not ABS at the moment due to the environment i'm in not quite ventilated.
My printing so far is acceptable on kapton tape. Recently my print was not quite a success
because it will not stick to the bed. I have to change kapton tape and it ok but it was a pain.
Please advice if you have any trick to get pla stick to the kapton tape applied on the glass.
Thanks.

Clean the Kapton tape with some isopropyl alcohol. Works good for me.

Why not try printing on plain glass... I do... I just wash it before every use.
If it won't stick raise the temps by 5' and lower the head a fraction so the plastic gets push on to the glass.
It works for me, but I run a level bed without compensation.

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

I gave up on Kapton tape a while ago because I find it so difficult to apply. I've taken delivery of a roll of 200mm wide Kapton tape that I planned to apply using the wet method, but I haven't used it yet. I use two different techniques:

1. Printing direct on glass. Wash the glass in hot soapy water initially, then before each print, wipe it with a clean tissue moistened in distilled malt vinegar. Avoid finger-marking the glass when removing prints. I find I can do several prints before I need to wash the glass again. I set the bed temperature to 65C, although it may be that 70C is more reliable. When printing direct on glass, do not clean the glass with acetone or isopropanol between prints, use vinegar only. The print is easily removed once the glass has cooled.

2. For prints that have a lot of fine detail on the bottom layer, I have sometimes experienced adhesion problems printing direct on glass - although maybe washing the glass before the print would have fixed that. For those prints, I paint the bed with diluted solvent pipe cement. Solvent pipe cement is available from DIY stores. You can use it neat, but it goes further if you dilute it with several parts acetone. When you remove the print, the thin layer of pipe cement comes off with it. You need to patch up the bed with diluted pipe cement for the next print, but you don't need to replace it all.

Having several glass plates and using quick-release fixings (see [forums.reprap.org] and later posts in that thread) makes for a fast turnaround between prints.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

PVA + water, brushed onto the glass. Put bed up to temp and allow to dry. Reapply mixture a couple of times.

PLA Will stick every time. You need to let it cool right down before trying to remove your print, I was rushing the other day and snapped the original glass in half. Now I use 6mm glass and actually pulled off a small slither of glass the other day.

Quote
PaulHam
PVA + water, brushed onto the glass. Put bed up to temp and allow to dry. Reapply mixture a couple of times.

PLA Will stick every time. You need to let it cool right down before trying to remove your print, I was rushing the other day and snapped the original glass in half. Now I use 6mm glass and actually pulled off a small slither of glass the other day.

Sounds like it sticks too strongly to me :-) I've heard that some people put it in a freezer for a few minutes to get the part to unstick.

I'm starting to get annoyed with the slight doming of the glass on my Ormerod. I've now got a nice sturdy aluminium frame supported bed adjusted to be perfectly level and don't use any bed compensation, but due to the doming the first layer is not completely consistent, though it usually works well enough so long as I zero the Z height at the lowest point (on the furthest outer perimeter). It's time to pay a visit to a glazier for some 6mm float glass, I think!

Dave
(#106)

Quote
dmould
[I'm starting to get annoyed with the slight doming of the glass on my Ormerod. I've now got a nice sturdy aluminium frame supported bed adjusted to be perfectly level and don't use any bed compensation, but due to the doming the first layer is not completely consistent, though it usually works well enough so long as I zero the Z height at the lowest point (on the furthest outer perimeter). It's time to pay a visit to a glazier for some 6mm float glass, I think!

Stiffness (i.e. reciprocal of deflection for constant load) varies as the cube of thickness, so the 4mm float glass that I usually use is 2.37 times as good as 3mm glass, and good enough IMO

Bear in mind that there are other factors at play here. Someone (I forget who) pointed out that if you hang the extruder on the middle slot of the X axis, the Bowden tube exerts a stronger outward (and hence downward) force on the print head at the centre of the X-axis range than near the ends. The amount that the glass domes up in the middle depends on how firmly it is clamped at the corners, which you can adjust.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for all advices. I'll try printing on plain glass, it's seem to take off the pain applying kapton tape away.
Btw. I also wanted to have another printing glass plate
but i can not find any borosilicate glass sheet around my area of living.
Are they any thing that can be use for printing surface apart from the boro glass.

It doesn't need to be borosilicate glass, ordinary 3mm or 4mm float glass will do. Ask the glass merchant to smooth off the edges.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

As I said earlier I use the same method of printing on glass as Dmould, but I've found that to release the print I hold the print and glass under the cold tap, and it floats off on it's own.

I've not tried the PVA method yet, but my thoughts are using a very cheap PVA that isn't water proof, putting the print and glass in to a bowl of hot water should dissolve the PVA and float the print free.... I might try it later today...

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Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Here's another vote for printing on glass... I've been printing a lot lately making and evolving prototypes and even really detailed bottom layered parts have been sticking perfectly - here's my receipe:
1. Let bed heat up to almost 80C using pronterface.
2. Spray on alcohol (I use record cleaner - not certain quite what it is, but basically smells like thin alcohol spray)
3. Rub around with lint free dusting cloth
4. Put a few drops of malt vinegar on cloth and rub on glass.
5. Do setbed etc, load file and print. My sclicer settings are a cooler 70/65C bed temperature, but the initial heat somehow seems to make the cleaning and vinegar go better.

After printing some large prints recently (25MB, 36 hours, 400 grams) with huge first layer surface area, my glass unfortunately cracked. I think it created a tiny kind of vacuum between the plastic and glass as I was trying to get it off when both glass and plastic were cold. My local glass shop cut me a 4mm plate for free, so I'm back up and running again. If I have trouble removing prints again, I think i'll try re-heating the bed then running it under cold water, hoping the thermal shock will release the print.
Squags

Quote
dc42
Stiffness (i.e. reciprocal of deflection for constant load) varies as the cube of thickness, so the 4mm float glass that I usually use is 2.37 times as good as 3mm glass, and good enough IMO

Bear in mind that there are other factors at play here. Someone (I forget who) pointed out that if you hang the extruder on the middle slot of the X axis, the Bowden tube exerts a stronger outward (and hence downward) force on the print head at the centre of the X-axis range than near the ends. The amount that the glass domes up in the middle depends on how firmly it is clamped at the corners, which you can adjust.

Yes, I thought at first that the apparent doming was probably due to X carriage tilt, but I placed a straightedge across the glass and found that it rocks quite a bit, so the glass is definitely domed. I have my extruder in the slot closest to the Z support and a 10mm bearing that's pretty tight to stop downward movement, and cannot see any movement of the hotend as it traverses the X axis.

If the glass were to be clamped so loosely that the edges are not in contact with the heating plate, it could move during a print, so I prefer to keep it clamped tightly. I may get both a 4mm and 6mm plate cut to see whether 4mm is sufficient. Thinner would be better for heat conductivity. Having said that, I've just tried clamping the glass on one corner only and it seems to be held reasonably firmly - it's rear edge is pressed up against the bolt heads which should prevent it swivelling during a print, and so I might try a print like that (after levelling it) to see how it goes. I have no idea how the slight air gap will affect the evenness of the surface temperature.

Dave
(#106)

Quote
dc42
...Bear in mind that there are other factors at play here. Someone (I forget who) pointed out that if you hang the extruder on the middle slot of the X axis, the Bowden tube exerts a stronger outward (and hence downward) force on the print head at the centre of the X-axis range than near the ends.

Was me, here:
[forums.reprap.org]
..and the visual here:
[forums.reprap.org]

Quote

..The amount that the glass domes up in the middle depends on how firmly it is clamped at the corners, which you can adjust.

Depends, if your bed is stable (e.g. use Davek0974's alu bed) and use 3-point adjustment and if the glass (in my case 4mm) rest on the PCB only (no alu heat plate), if you clamp the glass to the PCB only, then the PCB will hang a bit at the middle from the weight of the glass and not effect it at all



..ad to that - if your x-axis is stable (e.g. use Davek0974 alu x-axis) and able to resist the force of the bowden cable and the weight of the hot end and the the extruder, then you will find that your glass is perfectly flat

..and furthermore, if you adjust your y-axis-end-plate and reinforce them will alu support then you can forget all about any setbed.g, and if you took care in assembling the ormerod axis´s with perfect angles then you can forget about axis compensation



So what's left to do before printing?, nothing really, if you installed dc42's perfect probe (I use sub sonic only), just heat up the bed, do a G30 and start printing, easy peacy



..and your cabling will look nice and tidy, what's not to like? - thank you dc42!

and back to topic, when I find the print will not stick to kapton tape I sand it lightly with P320 sandpaper, works every time for me

Erik

Quote
ormerod168

Quote
dc42
...Bear in mind that there are other factors at play here. Someone (I forget who) pointed out that if you hang the extruder on the middle slot of the X axis, the Bowden tube exerts a stronger outward (and hence downward) force on the print head at the centre of the X-axis range than near the ends.

Was me, here:
[forums.reprap.org]
..and the visual here:
[forums.reprap.org]

Quote

..The amount that the glass domes up in the middle depends on how firmly it is clamped at the corners, which you can adjust.

Depends, if your bed is stable (e.g. use Davek0974's alu bed) and use 3-point adjustment and if the glass (in my case 4mm) rest on the PCB only (no alu heat plate), if you clamp the glass to the PCB only, then the PCB will hang a bit at the middle from the weight of the glass and not effect it at all

[attachment 31651 bed.JPG]

..ad to that - if your x-axis is stable (e.g. use Davek0974 alu x-axis) and able to resist the force of the bowden cable and the weight of the hot end and the the extruder, then you will find that your glass is perfectly flat

..and furthermore, if you adjust your y-axis-end-plate and reinforce them will alu support then you can forget all about any setbed.g, and if you took care in assembling the ormerod axis´s with perfect angles then you can forget about axis compensation

[attachment 31652 frankenrod.JPG]

So what's left to do before printing?, nothing really, if you installed dc42's perfect probe (I use sub sonic only), just heat up the bed, do a G30 and start printing, easy peacy

[attachment 31650 dc42probe.JPG]

..and your cabling will look nice and tidy, what's not to like? - thank you dc42!

and back to topic, when I find the print will not stick to kapton tape I sand it lightly with P320 sandpaper, works every time for me

Erik

Thanks Erik, I learn new trick today.
BTW. I google for the solution and found a lot of post mention hair spray but
I still not very convinced to that idea. Anyone have tried it yet? Just curious!!!

Quote
Chaisaeng
Thanks Erik, I learn new trick today.
BTW. I google for the solution and found a lot of post mention hair spray but
I still not very convinced to that idea. Anyone have tried it yet? Just curious!!!

Yes, I've tried hairspray. It works after a fashion, but not nearly as well as solvent cement (or ABS dissolved in acetone), and though it is easy to apply, even the budget brands are darned expensive for the number of applications you'll get from a can!

I may have a look to see whether any of the spray bottles I have lying around would survive being filled with an acetone solution, because spraying the glass would be easier and give better results than brushing it on as I do at present. I suspect however that at least some of the parts of the spray pump are made from ABS.

Dave
(#106)

Quote
zombiepantslol
Clean the Kapton tape with some isopropyl alcohol. Works good for me.

I tried using isopropyl alcohol which I found it lying around in my home a while back.
I used to buy it to clean switches contact and my barcode printer head (which using heat to
applied to the print label). I can confirm that is is really work. I got the print start and the print stick
to the bed very good. Thanks for the very good advice, this solution may be a very cheap one
compare to hair spray if not count print directly on glass.

Would it be fair to say that there is an upper limit to how big (or dense) of an ABS part can be printed on ANY build surface without a heated build chamber? The force just keeps increasing and eventually something's gotta give, right?

That's the conclusion I've come to. Just wondering if anyone agrees...

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Wayne
PRINTinZ.com

Even if there is some upper limit, I don't think it should have to be a practical limitation (at least not in the sizes our printers can manage). If the print sticks well enough, it will be held in place even though there is lots of internal force wanting to have it shrink/warp and snap off. And when the forces increase with the size of the print, so does the area of the print, and it's "adhesive force".

I agree that as the contract area with the bed increases, you can go larger with the print. But i guess my experience has been that even when everything sticks, you will eventually reach a point where the stresses affect the layer bonding and the part is the "something" gives.

I see people trying to build increasing large machines at home, and I just think they are going to hit a wall with ABS with out a heated chamber.

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Wayne
PRINTinZ.com