Newbie question

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Kaspa3
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Newbie question

Post by Kaspa3 » Fri May 29, 2015 12:45 pm

Love my M2!!... Just got it up and running and now trying to figure out the gcode sequences. I have found start routines from a couple of different people. Copy and pasted into my Repetier gcode start routine and end routine(s). The question I have is when i down load a new print from Thingiverse, and load the slicer3 file it creates, do i have to disable some of the start routines it has or do I leave the file as is? I have noticed in some prints the Z is too far off the bed to make contact and the material is extruding in mid air!! Some start routines home the Z to "0" and some to Z 0.5...what is the correct setting and start for the Z axis? Help! Thank you! :D

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Tim
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Re: Newbie question

Post by Tim » Fri May 29, 2015 1:42 pm

I always keep the start routine homing to zero. Slic3r should always create the basic build, with no extras like moving the nozzle off to the side and purging before starting (although it will home the axes; usually the start code homes the axes and the g-code for the print also homes the axes redundantly, just because everybody wants to be sure that they're working with the same point of reference). Just make sure that in Slic3r, the bed size and print center are correct, and the Z offset is zero. You don't want to deal with every tool setting the Z-axis differently, although presumably any Z offset in the start g-code will immediately be overridden by the homing done at the beginning of the print. Since different types of filament (or even different colors of the same type of filament) work best at different first-layer heights (that is, some work best when squashed a lot, and some work best when they're not squashed at all), some people prefer to always level the bed to the same height (using an index card or something to measure the offset) and then adjust the Z-offset in S3D or slic3r to get the best first-layer height for whatever filament they're using.

Hopefully that explanation made sense.

Kaspa3
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Re: Newbie question

Post by Kaspa3 » Fri May 29, 2015 4:03 pm

HI Tim
Thank you for the response! PLA was fine, but it appears most people do not have as much of an issue with PLA. ABS seems to be a little more involved(?) I have switched to ABS (blue) and do see some parts (Simple parts) come out just fine and the nozzle starts near the bed (.3 mm?) when beginning the run. On other parts that are sliced (Slic3r) the Z axis appears to be different from part to part and sometimes when the extrusion starts, there appears to be an offset and the nozzle is higher. Looking at the code G28 should home all to "0"...? I intend to modify the Gcode for that one parameter and see if it makes a difference, but i was curious what others may have found out that have had the instrument for some time.... experience beats experimentation!! So my last question is: why have a separate "start code" if the slic3r creates one as well... ? and can the slic3r undo/affect the custom start code created??
Thank you!!

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ednisley
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Re: Newbie question

Post by ednisley » Fri May 29, 2015 8:24 pm

Kaspa3 wrote: On other parts that are sliced (Slic3r) the Z axis appears to be different from part to part
At least for recent Slic3r versions, there's an option (File -> Preferences) to select "Auto-center parts". If that's checked, Slic3r should center the object in XY and snap the bottom surface to Z=0. If that's not checked, the object can be anywhere and usually is.

I think it should be checked by default, but ya never know...

Kaspa3
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Re: Newbie question

Post by Kaspa3 » Sat May 30, 2015 11:42 am

Thank you Ed!! I will check. But I am using Repetier and do not see that option. Would it be someplace else?

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ednisley
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Re: Newbie question

Post by ednisley » Sat May 30, 2015 12:52 pm

Kaspa3 wrote:But I am using Repetier
The slicing program produces the G-Code that tells the printer when and how to move; the host program passes that text file to the printer firmware.

So, since (you've said) you're using Slic3r to create the G-Code, that's where you should look to make sure it's creating the proper code.

You should also verify the G-Code before printing using a previewer, perhaps http://gcode.ws/, to ensure that nothing bizarre has happened. Current Slic3r versions have a tool path preview, but I prefer an independent verification.

Kaspa3
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Re: Newbie question

Post by Kaspa3 » Sat May 30, 2015 7:08 pm

Hi Ed
I think i figured it out..if you place a start code in the printer settings of the slicer config, that start code will now be placed at the beginning of anything you slice. now that i got that straitened out, i started my first ABS print and all was going great until the edges started to lift...ugh...I have the bed at 110 and the nozzle at 250 and the first 10-15 layers looked great!! after about 50 layers the edges started ti lift. The bed fan is not on. I have read others have had the same problem and have started using abs juice,,a slurry of acetone and abs parts...I intend to see if this will help...do you have any thoughts on this??
thanks for the replys!!

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ednisley
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Re: Newbie question

Post by ednisley » Sat May 30, 2015 7:36 pm

Kaspa3 wrote:do you have any thoughts on this??
Use PETG? [grin]

For large objects containing plenty of plastic, ABS shrinks so much as it cools that it overpowers all practical platform adhesives. Some folks swear by heated chambers, but the consensus seems to be that "big" and "ABS" don't fit together very well at all.

Rummage around the forums for stories from folks using ABS: plug "site:forum.makergear.com abs curl" into Google for plenty of reading and some success stories.

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