Level and thickness?

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aadamson
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Joined: Wed Jun 05, 2013 2:53 pm

Level and thickness?

Post by aadamson » Sat Oct 12, 2013 9:55 am

Why is that there are 20 different descriptions of both leveling and setting first layer thickness???

I can get the bed perfectly level (of course, any temperature change and that changes :().... But I'm sorry the description of how to set the first layer thickness is just all over the map.

The manuals says to do it such that you have a well formed *round* with a slight flat on the bottom where it's adhering. Other people say do it with a piece of paper - yeah right, did that, first layer comes out *FLAT*.

So I decide to stay with the paper and I wanted to print a small round cylinder with a hole in the middle of it.

I *ALWAYS* get a distinctive ridge around the first layer that is wider than what is being printed, because the layer is too thin and squeezed out. - and this from the paper setup.

BTW, if I setup for as the manual describes round with a slight flat where it adheres. There is enough variance in the bed temperature from point a to point b that the highs and low of the bed will pull the filament loose in spots and screw up the print...

And no a RAFT isn't the answer.

Either you all will accept the first layer being something you have to *clean* up every time and can have no detail, or I'm just doing something wrong... But I'm tired of it and on a hunt for how to do it correct such that you can have detail if you want on your first layer...

So, I'm open to suggestions and with pictures if you don't mind as all these words don't seem to be read the same by any two people??

Anyone got what they think is a best practices for 1 layer setup? Level I can handle :)

Thanks,
Alan

p.s. yes, I'm using Lutz juice too btw

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Gemini64
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Location: Québec City, Canada

Re: Level and thickness?

Post by Gemini64 » Sun Oct 13, 2013 7:51 pm

I've been wondering more or less the same thing. What I ve doing on some of the parts I model is to add a small bevel (0.5mm) on all the edges of the base, so the first layer is smaller than the others, and when it gets squished it does not exceed too much.

I think the best way to get a perfect first layer is with a perfectly level bed. Have you seen 1013's work on a automatic bed probing and compensation? Very impressive, and he posted pictures of before/after that show a huge difference. http://forum.lulzbot.com/viewtopic.php?f=16&t=166

Unfortunately I don't think I have the technical know-how to adapt this to my AO-100. In any case, I've been procrastinating on doing much simpler upgrades... :roll:

P.S. I was sure 1013 posted pictures of the same part with and without automatic bed leveling, and I can't find them.

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piercet
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Re: Level and thickness?

Post by piercet » Sun Oct 13, 2013 8:23 pm

Gemini64 wrote: Unfortunately I don't think I have the technical know-how to adapt this to my AO-100..
I'm planning on seeing if I can make that work in a future project. I need to get the y-rail mod in place and working well first, but once that is done, the auto bed leveling probe is one of the next ones on the wish list now that the taz style x ends are working well. The tricky part is going to be designing a sldier that will fit the carriage, probably mounting off the belt clamps, and then figuring out a target for it to hit on either side. I don't know that its going to fit well on the ao-100 without widening it slightly though. I'm thinking instead of a bumper sysytem like 1013 used, maybe radio controll airplane pushrods. I haven't got very far with it though.

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Gemini64
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Location: Québec City, Canada

Re: Level and thickness?

Post by Gemini64 » Sun Oct 13, 2013 8:38 pm

On the other hand, it seems that Marlin has new bed leveling features, and someone over on the 3D Printing Google+ community posted his implementation. It looked a lot simpler than 1013's, using only the Z endstop relocated to the x carriage as probe.

I'm too lazy to find the link right now... :oops:

1013
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Joined: Thu May 23, 2013 9:56 am

Re: Level and thickness?

Post by 1013 » Tue Oct 15, 2013 7:14 pm

Gemini64 wrote:...
P.S. I was sure 1013 posted pictures of the same part with and without automatic bed leveling, and I can't find them.
That picture can be found here: http://forum.lulzbot.com/viewtopic.php? ... t=30#p1056

One simple thing you can do is add this code into your G-code (or your Slicer G-code configuration so it always shows up)

Code: Select all

M206 X0.0 Y0.0 Z0.0; offset home position for fine tuning
and then instead of trying to fine tune the Z-height by adjusting the red knob. Just change that Z0.0 to z0.2 or something. This would mean printing the first layer or two, and then stopping the print, cleaning the plate and then re-starting the print....but it's about the best you can do.

Also make sure you set your Z-height with the nozzle and bed at temperature, and also with the nozzle positioned about where the center of your print will be.

aadamson
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Joined: Wed Jun 05, 2013 2:53 pm

Re: Level and thickness?

Post by aadamson » Tue Oct 15, 2013 8:53 pm

So what I've been experimenting with is something similar to what 1013 posted above.

I would start my print, let the 2 lines of perimeter print and the first layer start... if I was getting a squished layer, I would stop it, adjust the stop knob to raise the platform, re-home and repeater until I had it at a layer thickness that looked good.

My last 2 prints doing that turned out amazingly good... Also adding the linear bearings helped greatly. I'm still getting a little bit of what I think it *melt* on the first layer... even with it adjusted as above, where the first layer is just barely sticking, after a full print is finished, I still get a bit of an edge on that first layer. I'm printing at 230 on the nozzle and 85 on the bed in abs... maybe those need to be dropped down a bit?

I just printed a fan mount so I'm going to be adding that as well... I need to remember to get some connectors for it...

It's coming together, but this again proves that there is NO default setup that will work for this. Each location on the bed is at a very different temperature and so there is NO way you can have one adjustment that will work for the entire bed.

I'm also thinking that there is some hysteresis on the Z axis that I need to resolve. I've got most of 1013's modifications printed, I need to check a few things and get those installed and see if I can't resolve that area of weakness.

Alan

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