Print not sticking to bed

I've bought a new roll of PLA filament via Amazon, and I'm having trouble getting it sticking to the bed. I clean the bed with isopropanol between prints, and I've tried renewing the Kapton tape too. Is this likely to be due to poor filament quality? Has anyone any tips to make it stick better?

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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].

Can't remember where I read it but someone somewhere used a thin layer of something called plumbers sealant and it solved his problem, the plumber product I know will handle the heat but don't seems to be very sticky

Might be worth experimenting with temperatures (especially warming the bed a bit more), I've swapped from kapton to using a thin film of Marley Solvent Cement (for solvent welding PVC and ABS plumbing) - it spreads easily onto the glass using the provided applicator, it holds PLA very well, and you can patch it up between prints without having to peel it all off. If you have any lying around I suggest you give it a go.

It works ok at a setting of 100 for ABS too, but seems to go a little soft at 110/120 (not sure of the actual tempearatures, but it does hold less at higher temperatures, so I've reverted to Kapton for ABS).

Ray

Thanks, Ray. I find the Kapton difficult to apply without getting bubbles in it anyway. I'll give the PVC solvent cement a go.

I did wonder whether they might have sent me ABS filament by mistake, since it is labelled just "3D printing filament" plus a batch number; but I guess if it were ABS then it wouldn't print at all at 205C.

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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].

Ray, is that the Marley KS10 solvent cement you are using?

Edited 2 time(s). Last edit at 01/06/2014 11:58AM by dc42.

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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].

At first I could not get anything to stick! Played with temperatures but nothing worked, then for me this course of events worked.

Bed levelling/compensation. As it 'looked' OK I had not done this!
But once done as documented this made a huge difference, my extruder nozzle gap to the bed was OK near home, but way out (extra 0.5mm) where my print started.

Posted by Ian, in answer to my same question he supplied this link which was useful
[www.reprappro.com]

reading the above I then lightly sanded to 'rough' (not smooth) the surface of the tape and then cleaned with IPA solvent.

With the initial z clearance set to the thickness of a sheet of printer paper 80g, as suggested by others, such that you feel the paper vibrate as slid under the nozzle.

The above gave me perfect sticking (at least for 4 prints which is all I have done!) without any issues.

As an observation the prints seem to stick more (judged by removing them!) with the number of prints, so I don't know if the printing leaves a fine residue which then helps?
Or I might just be trying to remove the prints in a different way.

@DC42 - yes it is KS10 (contains epoxies, use in a well ventialted area, avoid inhaling etc) -

I've just tried extruding ABS @ 195°C (according to M105 anyhow), and it squirts out fine... if you have some acetone to hand you could try dipping some of the filament in it - if it melts/ goes tacky it won't be PLA, or you could heat some with a lighter - ABS smells rubbery, PLA not so much, ABS burns with yellow sooty flame, PLA bluer with white smoke not black (this may vary depending on fillers/pigments, but on batches I've got it seems to hold true).

I tried the acetone test. The filament doesn't dissolve or go tacky when dunked for a few minutes, however the colour leaches out and it gets stretchy. If I rub a smooth shiny surface from the bottom of a print with acetone, it goes dull quite quickly. The filament supplied with the kit shows the same effects, but to a lesser extent. So I think it's PLA, but not very good PLA.

I just received another batch of PLA filament from a different supplier today, so I'll try that. This one is actually marked PLA and is better sealed.

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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].

@DC42, I found that after raising the bed temperature to 85 degrees the first layer of PLA stuck much better. BTW, the stock 110 degrees value worked well for ABS. Let us know how the other brand works.

Thanks KK, I'll try that.

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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].