New TAZ 5 Adhesion Issue

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dowlf
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Joined: Fri Apr 03, 2015 2:15 pm

New TAZ 5 Adhesion Issue

Post by dowlf » Sun Apr 26, 2015 1:45 pm

I have had my TAZ 5 for several weeks now. I seem to have the bed leveled reasonably well, and small prints come out just fine. Whenever I try to do anything bigger than about 3 inches across, or parts with thin sections, they come loose during printing. Items with sharp angles almost always come loose in the corners. I thought that maybe it had something to do with the filament I am using, HIPS from Lulzbot, so I have now tried ABS and PLA, also from Lulzbot, but they come up just the same as the HIPS. I have been cleaning the PEI surface with isopropyl alcohol between printings. I have tried printing parts on different areas of the bed. I have experimented with many different temperatures. But it is always the same.

I understand that building an enclosure might help, but is there perhaps something else I am doing wrong?

Should it be necessary to use some other material like glue or lulzjuice to get prints to stick to PEI?

I do plan to get some sort of enclosure put up, but this case seems extreme. Any advice would be appreciated.

Thanks

nbmoretto
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Re: New TAZ 5 Adhesion Issue

Post by nbmoretto » Sun Apr 26, 2015 2:03 pm

you can try moving the nozzle slightly closer to the bed, slower speed for first layer, higher bed temperature, also using a raft or brim may help as well

dowlf
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Joined: Fri Apr 03, 2015 2:15 pm

Re: New TAZ 5 Adhesion Issue

Post by dowlf » Sun Apr 26, 2015 7:11 pm

Thanks for the advice.

I read in the manual about using some 2000-2500 grit sandpaper on the PEI surface. Luckily I found a piece of 2000 in my collection. I am going to give it a light sanding to see if that helps too.

tmorris9
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Re: New TAZ 5 Adhesion Issue

Post by tmorris9 » Sun Apr 26, 2015 10:19 pm

with a PEI bed getting the bed perfectly level is key. Reasonably level won't cut it.

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edlink
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Re: New TAZ 5 Adhesion Issue

Post by edlink » Mon Apr 27, 2015 4:45 am

First thing to try is surely adding a brim feature. I almost always add a 5mm brim feature to everything I print.

Also - what are your first layer settings?
Is your fan off when printing? Especially for first layers?

kcchen_00
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Re: New TAZ 5 Adhesion Issue

Post by kcchen_00 » Mon Apr 27, 2015 12:16 pm

Adjusting nozzle height and brim are both good starts... I've heard of sanding the PEI, but only to remove gloss on DIY sheets or removing gouges. Sanding is a one way street, can't get back the PEI material you remove.

Get the nozzle closer to the print bed. Use the Z-end stop knob to get the initial setting (business card should pass between nozzle and bed with a little friction), then tweak by .1-.2 through the Z-offset in gcode... for projects with large surface areas on the bed usually. Or if need more adhesion use negative values.

Raise the temp of your bed. For ABS, try 110C for the first layer then dropping to 80-100C later in the project.

Brim helps to keep the air from seeping in under the project... 8-10mm brim is what I like.

For really stubborn warp issues, breaking up the airflow or blocking airflow at corners help. Hard to describe... but after the brim is printed and a few layers of the actual project, take a Post-it note or blue painters tape and fashion a temporary wall to block the air in the Y-axis. I put the tape on the brim and bend up to form the "wall" at about 10-15mm away from the actual print... make sure it doesn't block the nozzle & fan.

BaltimoreBully
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Re: New TAZ 5 Adhesion Issue

Post by BaltimoreBully » Mon Apr 27, 2015 7:08 pm

Like everyone else has said, brim is your friend. I don't even try to do long prints without a brim. On general if it's over an hour long print, I use a brim. I have had my printer for a little over 2 months now and I have only printed with the lulzbot brand hips (esun). I keep the bed temp at 110 but on long prints it's just too much cooling going on, on the bottom layers. Without the brim my two front corners always curl ( I don't have an enclosure). With the brim I can pull off 6 hour prints with minimum curling on the ends.

dowlf
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Joined: Fri Apr 03, 2015 2:15 pm

Re: New TAZ 5 Adhesion Issue

Post by dowlf » Wed Apr 29, 2015 4:13 pm

Thanks to everyone for the advice. I did not end up using the sand paper. I have tried to get the bed as level as I can, spent many hours at it, but I can't declare it "perfectly" level by any means. My human senses and a piece of paper prevent perfection. I have been having better luck using a brim. I have had parts stay successfully stuck to the bed throughout the printing process that previously came loose.

I will continue to read as much as I can, experiment, and enjoy this printer. I have not been board for one second since it arrived.

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edlink
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Re: New TAZ 5 Adhesion Issue

Post by edlink » Wed Apr 29, 2015 6:13 pm

We've all over-stressed about the bed level thing.

Honestly, I don't think it's that important. Get it close, but don't think you have to be perfect.

I printed a dial gage holder and I only check level when I swap out PET sheets. We've been printing for over a month on same PET sheet and haven't checked for bed level after the PET install.

Get the four corners close, then really pay attention to the z height adjustment in the center of the table.

Happy Printing.

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piercet
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Re: New TAZ 5 Adhesion Issue

Post by piercet » Thu Apr 30, 2015 1:50 pm

A thicker starting layer for PEI is a good place to start too. You basically want as thick a first level as your nozzle will support. You can also try bumping the bed temperature up a little bit.

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