print shifts slightly to the left mid print

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cosi
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print shifts slightly to the left mid print

Post by cosi » Thu May 26, 2016 1:43 pm

I think the title pretty much says it all.
Somehow the model shifts mid print.
Take a look at the image.

Have you guys seen anything like this before. Its not the first time this has happened.

I'm also having adhesion problems and am cycling through the different suggestions so the bottom of the print doesn't warp
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insta
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Re: print shifts slightly to the left mid print

Post by insta » Thu May 26, 2016 3:48 pm

cosi wrote:I think the title pretty much says it all.
Somehow the model shifts mid print.
Take a look at the image.

Have you guys seen anything like this before. Its not the first time this has happened.

I'm also having adhesion problems and am cycling through the different suggestions so the bottom of the print doesn't warp
Enable "Z Retraction Lift" or "Z-Hop" (whatever your slicer calls it), set it to 0.2mm, try again.
Custom 3D printing for you or your business -- quote [at] pingring.org

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Matt_Sharkey
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Re: print shifts slightly to the left mid print

Post by Matt_Sharkey » Thu May 26, 2016 5:22 pm

when that layer shift happened, was the part already curling up? your nozzle may have hit the side of the print and skipped a step.

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Tim
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Re: print shifts slightly to the left mid print

Post by Tim » Fri May 27, 2016 1:56 am

What kind of a motor mount do you have? The alternative to the motor skipping is the motor rotating, which can happen with the plastic motor mount (but not the new metal motor mount). If you have the printed motor mount, check if it is loose, and/or if it has developed a crack. If that happens, you can get a shift in X with only a small bit of resistance against the nozzle, like a part of the print that has detached from the bed (as in your picture). The shift happens because the motor rotates in the mount.

cosi
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Re: print shifts slightly to the left mid print

Post by cosi » Fri May 27, 2016 5:08 am

insta wrote:Enable "Z Retraction Lift" or "Z-Hop" (whatever your slicer calls it), set it to 0.2mm, try again.
I tried that and there is still lifting.
Its always lifting in the same place on the bed.

I am running 60 on the bed and 210 for layer 1 and 215 for layer 2...

I am trying some of the settings from an old post of mine. I have never had a good print yet. I just can't seem to get the settings right.
viewtopic.php?f=7&t=3019

I tried 205 and 55 on glass with hair spray and that didn't stick at all, it was a complete mess.

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ednisley
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Re: print shifts slightly to the left mid print

Post by ednisley » Fri May 27, 2016 1:15 pm

cosi wrote:Its always lifting in the same place on the bed
Adhesion is painfully sensitive to both platform alignment and surface contamination.

If those pucks are aligned as they were built, then platform may be low along the right edge, particularly in the front. Several recent threads have pointed out the hair-fine tolerances required for good results, so go through the entire alignment process again. I build five thinwall boxes in the center & corners of the platform, then measure their height with calipers to verify the alignment.

Make sure the platform surface is absolutely clean before you apply hairspray or another adhesive. If you're wiping with alcohol, make sure it's straight hooch, not rubbing alcohol with soothing lotions & potions. Acetone can be your friend, if you treat it like the enemy.

Also, given the size of those pucks, unless you really really need all that infill, reduce it to the absolute minimum. That will reduce the lifting forces due to contraction of the upper layers.

Good hunting ...

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jimc
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Re: print shifts slightly to the left mid print

Post by jimc » Fri May 27, 2016 1:39 pm

The z lift doesnt have anything tondo with adhesion. It keeps yhe nozzle from knocking into the print when it makes a non printing move. This will help with the shifting lauers BUT you still jeed to get that warping under control. Hairspray works great bit as ed said the gap has to be dead on. If not your not going to stick. Do your first layer at 70 then the rest at 60.

cosi
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Re: print shifts slightly to the left mid print

Post by cosi » Fri May 27, 2016 2:47 pm

Matt_Sharkey wrote:when that layer shift happened, was the part already curling up? your nozzle may have hit the side of the print and skipped a step.
Yes it was already curling up before it shifted. However, the level of the last layer looked dead flat and it was not curling as well.
I should also mention that the models are lifting when they are at about 10mm in height, it doesn't happen right away.
Tim wrote:What kind of a motor mount do you have? The alternative to the motor skipping is the motor rotating, which can happen with the plastic motor mount (but not the new metal motor mount). If you have the printed motor mount, check if it is loose, and/or if it has developed a crack. If that happens, you can get a shift in X with only a small bit of resistance against the nozzle, like a part of the print that has detached from the bed (as in your picture). The shift happens because the motor rotates in the mount.
I am not sure what motor mount I have, it is a stock machine I bought roughly 8 months ago.
ednisley wrote:Adhesion is painfully sensitive to both platform alignment and surface contamination.

If those pucks are aligned as they were built, then platform may be low along the right edge, particularly in the front. Several recent threads have pointed out the hair-fine tolerances required for good results, so go through the entire alignment process again. I build five thinwall boxes in the center & corners of the platform, then measure their height with calipers to verify the alignment.

Make sure the platform surface is absolutely clean before you apply hairspray or another adhesive. If you're wiping with alcohol, make sure it's straight hooch, not rubbing alcohol with soothing lotions & potions. Acetone can be your friend, if you treat it like the enemy.

Also, given the size of those pucks, unless you really really need all that infill, reduce it to the absolute minimum. That will reduce the lifting forces due to contraction of the upper layers.

Good hunting ...
It is always the right edge that's having the issue with lifting. When I flipped the platform around and used the glass only, I have been using the blue painting tape suggestion, I applied the hairspray. I did check the levels again and I used a sheet of paper to slide between the hotend and the bed and all 4 corners seemed to be pretty even. That didn't stick well at all as can be seen in the first picture. I didn't clean the surface at all before applying it. It wasn't sticky to the touch at all before printing.

The infill was set to 5 or 6%. I did that so the holes have support as I need to thread those holes and bolt it to other parts.

Check out the second image and you will see that the middle print is perfectly flat, no lifting at all. All I did was move the job away from the the centre of the bed to the left far corner away from where it always lifts.
jimc wrote:The z lift doesnt have anything tondo with adhesion. It keeps yhe nozzle from knocking into the print when it makes a non printing move. This will help with the shifting lauers BUT you still jeed to get that warping under control. Hairspray works great bit as ed said the gap has to be dead on. If not your not going to stick. Do your first layer at 70 then the rest at 60.
This is a good setting I guess, I am a total noob at 3D printing. I will take note of the temp suggestions for the bed and also cleaning it correctly.


I would like to purchase a dial indicator to ensure the bed level is 100% and would like a suggestion, here is a store near me http://www.machineryhouse.com.au/Indicators
Also, what about printing a holder/clamp for it to secure it to the printer. There are some on thingiverse but not sure which to use, any ideas?
I'm thinking http://www.machineryhouse.com.au/Q213 and http://www.thingiverse.com/thing:70891

When I set the bed to home all, how far away should the hot end be to the bed?
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Matt_Sharkey
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Re: print shifts slightly to the left mid print

Post by Matt_Sharkey » Fri May 27, 2016 3:45 pm

This is what I will be getting into shortly for indicating the bed.

http://www.amazon.com/Surface-Smoothnes ... +indicator

viewtopic.php?f=10&t=2209&start=0

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Jules
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Re: print shifts slightly to the left mid print

Post by Jules » Fri May 27, 2016 3:52 pm

The problems you are showing are caused by BOTH an adhesion issue, and a temperature issue. It's possible that the warping from one side on the print knocked the nozzle out of alignment for your first post, (where you talked about the shifting of the print to the left), but the underlying cause is still that the print is pulling away from the plate as the print proceeds.

Do ALL of these things, in this order:

1. If you insist on using masking tape on the plate - spray a thick layer of hairspray on top of the masking tape, let it dry completely, spray another thick layer of hairspray. If you want to do it in one pass, spray until it puddles on the tape, then spread it around with a finger. Put it on the HBP and turn the bed heat on 50°C until it dries completely. (Speeds up the drying.)

(This is a temporary fix for your adhesion problem - eventually you will want to look into a PEI surface for the plate instead of the masking tape and hairspray. It will mean re-setting the gap if you choose this option, but you will then never have to mess with hairspray or tape again. - Highly recommended.)

2.
I am running 60 on the bed and 210 for layer 1 and 215 for layer 2...
This is backwards. You want to run the first layer temp a little higher, and all subsequent layers lower with PLA. The hotter you print PLA, the more it warps, because the warping only happens while that filament is cooling - if it doesn't have to cool off for as long, it warps less. When it cools off completely, it stops warping.

Use these:

Bed temp: 60°C
First layer temp: 210°C
All other layer temps: 205°C
Full fan after first layer (Additional fan is always a good idea with PLA - removing the fan guard on the bed fan will exponentially increase the cooling power, which you want with PLA.)

Your main problem is adhesion - you still have not gotten a good bond between the plate and the print. PLA wants to warp - you have to make it stick. (Get tough with it!) ;)

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