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print completely detaching

Posted by banthafodder7400 
print completely detaching
April 03, 2012 09:11AM
So I finally got my Prusa2 printing last night. Kinda... I am printing on a heatbed (unknown temp) with a layer of blue painters tape, Hotend about 230, ABS. I am just printing a 20mm cube to make sure that everything is working fine. The corners arent sticking well to the bed, so part of the way up the print you see them pulling up and beng pushed down when the nozzle goes over. Half way up (9-10mm) the cube comes completely detached and gets dragged around.

On my site below I have a video of the my print after it got started. The video kinda records random things at times since I was trying to watch the print not the camera. Near the end of the video you can see the front left corner pulling up. How does the speed of the printer look? How do I even change speed? Any ideas for why its coming unbonded from the surface completely(not in video)?

PS the wife hates the smell of it smiling smiley

Prusa2, Pronterface, Sprinter, Gen6, Skeinforge


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 03, 2012 09:23AM
Print PLA, it smells like popcorn and going to the movies! grinning smiley


Bob Morrison
W├Ârth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
Re: print completely detaching
April 03, 2012 09:56AM
If you print ABS, don't use blue tape. It only works for PLA (and even with a cold bed).

Use kapton or glass instead.


Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.
Re: print completely detaching
April 03, 2012 10:00AM
Quote

printing on a heatbed (unknown temp)

That would worry me, a lot! I've not printed with ABS, so can't really help, but I would try and find out what temp the bed is - perhaps that's too low?


------------------------------------------
garyhodgson.com/reprap | reprap.development-tracker.info | thingtracker.net
Re: print completely detaching
April 03, 2012 10:48AM
With a small print like a 20mm cube you'll want to lower the temperature as much as you dare (I've heard people dropping to 150C (I think it was 150C) with pla for small gears).
You'll also want to lower the speed also, as the layers won't have time to set before the next layer is applied causing issues. This is done in Skeinforge (ps Slic3r is much easier for a beginner).


My Reprap blog

jds-reprap.blogspot.com
Re: print completely detaching
April 03, 2012 10:31PM
Well I bought a piece of replacement glass for an 8x10 photo frame at the home depot for 1.98... clamped it to the heat bed and it worked like a charm.

Now my issue is the layers shifted twice during the build. I have a feeling I know what it is, but I didnt pay attention to which direction they shifted! I will troubleshoot this tomorrow to see if my hunch is right smiling smiley Thanks for the help!

Also I might switch to PLA eventually. And I want to add a way to monitor my heatbed temp and to set it. Can this be done with gen 6 electronics (I thought I read I couldnt do that)? And I might switch to slic3r cause I want something easier for now for sure!


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 03, 2012 10:57PM
Check this thread:

[forums.reprap.org]

I built a temperature controller like what you describe last month as I'm on Gen6 as well. You can do it for about $40 if you want an LCD screen and a stock arduino. Or you can cheap out like me and build it from scratch for about half that.

And do switch to slic3r, it'll make your life easier.

-akhlut


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: print completely detaching
April 05, 2012 08:40AM
The glass did work with when doing a 20mm cube. With the 20mm cube my layers shift a few times towards y-home. Not sure why, the axis is nice and tight and doesnt slip during the print.

I dropped to a 15mm cube to save on material while working on the shifting problem but that doesnt stick. Is it too small to bond well to the glass? should I have a fan cooling it as it prints? Whats the smallest print you have succesfully printed?

I switched to Slic3r as it is much easier already!


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 05, 2012 12:09PM
I had the exact same problem. Have you adjusted the trimpots on the gen6 board yet? My y axis was losing steps and my cube looked more like a set of stairs. How tight is your y-belt?

- akhlut
Re: print completely detaching
April 05, 2012 12:47PM
I think its pretty tight, my trimpots are at what they sent to me as... horizontal (parallel to long sides of board). Should they be adjusted?


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 05, 2012 01:16PM
Absolutely. You bought from makerfarm? I did, and mine needed to be adjusted.

1. grab a small flathead screwdriver (tiny)
2. turn all your trimpots down (counterclockwise), don't accidentally touch the board - you could fry something!
2. send pronterface a long move command for the axis you're adjusting
3. slowly turn up the trimpot until the stepper starts to move. Add
4. repeat for the other axes, including the extruder.

If you turn the trimpots up too much that's a problem too. It's finding the sweet spot where the steppers move but don't get too hot running them. this is a process that may take a while. You won't know if your trimpots are too high until you've got your motors running a while.

Good luck!

-akhlut
Re: print completely detaching
April 06, 2012 09:12AM
Thanks for the help Akhlut! It fixed my print from shifting.

Now Im back to my original problem of prints not sticking. If you look at my post for 4/5 on my site you will see that my print quality has improved significantly. The problem? The bottom of my parts are terrible. The first layer doesnt stick, and sometimes doesnt even extrude the right amount. Once the first layer is competed I use tweezers to pull it off and let the second layer go. This second layer (now the first with other removed) just kinda gets layed down and is not pretty but it allows subsequent layers to bond to it. I have tried glass, kapton tape, kapton tape on glass, all results the same. Ive tried adjusting the z optostop, the z offset in slic3r, and still nothing good.

I cant seem to get that good squished out first layer. Is my bed to hot (i dont even have a way to measure temp on it) or is my print to hot? I upped the temp to 240 in slic3r, and set all print speeds to 25mm/s which my prints look better and actually complete themselves. Is the first layer supposed to print faster/slower warmer/cooler? What about proper Z height? Any input that might help that first layer will be appreciated.


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 06, 2012 10:35AM
I'm glad the advice worked. The quality of your prints has really improved!

After looking at your blog I think you have some issues you need to address (I had some of the same problems).

Do you have kapton tape? Try printing on that. You can get some pretty cheap from amazon - it's not really kapton though. If not there is an alternative that people have tried and seems to work. You'll need some acetone, a jar and some scrap ABS. Take about 100mL of acetone and 10 cm of ABS and toss it in the jar. Lid it and let the ABS dissolve. Once it's in suspension shake and apply to your glass with a lint free cloth. Your print should stick to that pretty well. The thread discussing ABS juice is here: [forums.reprap.org]

An alternative that I've been trying out is mirror tile that's been sanded down with an orbital sander with 80 grit paper, giving it a frosted appearance. I read about using sandblasted glass at [jonaskuehling.de] and it seemed like an inspired idea - increasing surface area to give the first layer of printed parts a better grip. If you've got a spare piece of glass I'd highly reccomend trying it. Still need ABS juice on it to print ABS - PLA will stick to the sanded mirror cold (It stuck so well last night that it chipped the mirror when I removed the part! I attached a photo...).

The other issue I see is that you're using standoffs and have no insulation between the HBP and the build stage. I've seen fiberglass insulation used, but I took adhesive duct wrap and stuck it directly to the bottom of my HBP. Right now you're losing a massive amount of heat - you need to trap it and if possible reflect it up to your build surface. Not only will it get hotter but it will be more efficient as well.

Good luck!

- akhlut


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Attachments:
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Re: print completely detaching
April 06, 2012 11:18AM
If I understand correctly... My heatbed is raised off the acrylic by little nylon spacers, and I have glass directly ontop of the heatbed... So there is a gap directly under the red heatbed. You are saying to add some kind of insulation below the heatbed, so between the board and the acrylic right? Or is your duct wrap between the glass and the heatbed? I think your saying under the bed, just clarifying. I will try it tonight or tomorrow.


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 06, 2012 11:45AM
Yeah, some sort of insulation between the acrylic and the heatbed. I wouldn't reccomend getting the heatbed too close to that acrylic - it'll warp eventually.

Do you have some fiberglass insulation lying around? Try that first before you go out and spend some $$$.

So, to clarify: acrylic - insulator of some kind - heatbed - glass

Also, how are you you leveling your platform? What size nozzle are you using? The smaller the nozzle the tighter the tolerance on the initial leveling.


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: print completely detaching
April 06, 2012 12:07PM
Im leveling it by going to the corners of the print area and putting a gage block between the nozzle and the glass (I have access to gage blocks from 0.100" to 7.000" in .0001" increments). So I set the z height at one corner so that the gage block just slides under it. Go to the next corner and do not touch the z but adjust the bed until the same condition, then I check a few other locations. It is pretty level to a good tolerance. As far as height off the heatbed to set Z=0 I have just been tinkering with the opto switch trying to get the first layer to stick.

My nozzle is a .5mm


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 06, 2012 12:12PM
That's how I've been doing it, but with metric feeler gauges.

What layer height are you using?


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: print completely detaching
April 06, 2012 12:26PM
.35 or .4 I think, I dont rememeber what I set it to. I will have to check it when I get home later . Either tonight or tomorrow morning.


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
Re: print completely detaching
April 06, 2012 12:36PM
They seem reasonable. Try a feeler gauge of around 0.01" or 0.012" for .35 layer height. This will squash the first layer a bit, giving you more contact with the glass.


- akhlut

Just remember - Iterate, Iterate, Iterate!

[myhomelessmind.blogspot.com]
Re: print completely detaching
April 07, 2012 08:30PM
So after some playing around, i discovered my z height was definitely an issue. I couldnt even slide a piece of paper under the nozzle in home position. I upped it to around .01" and its sticking (80% of the time) Will try ABS juice sometime, but definitely can say this problem is pretty much solved! Other issues I have I will save for other topics.

Thanks for the help!


Ryan
Quality Engineer & Hobbyist
thingsandtrains.blogspot.com
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