Ghosting problems

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over-$-pent
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Joined: Thu Apr 10, 2014 11:11 pm

Ghosting problems

Post by over-$-pent » Tue May 06, 2014 3:09 am

Hello Maker Gear Forum members,
Though I have been browsing the forum since I purchased my M2 a month ago, this is my first post for some help. I have noticed ghosting issues on the surface of parts when creating fonts or holes. Is there anyway to reduce or eliminate this without slowing the printing speed down? I am using S3d and have tried default settings and tweaking from there, but no changes in ghosting. I know on my cnc machine I can specify a corner rounding and default smoothness so the machine slows down when needed to increase accuracy and surface finish. This would be a great feature to have.

Thanks for the help,

Dave

jsc
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Joined: Thu Apr 10, 2014 4:00 am

Re: Ghosting problems

Post by jsc » Tue May 06, 2014 3:24 am

Turn down X/Y accelerations in your startup gcode: M201 X1000 Y1000.

More info here: https://groups.google.com/d/msg/makerge ... Xl8lE3yqgJ (it goes on and on).

over-$-pent
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Joined: Thu Apr 10, 2014 11:11 pm

Re: Ghosting problems

Post by over-$-pent » Tue May 06, 2014 4:01 am

Thanks for the advice, I will give it a try now. Is this modal and will stay active or does the machine reset to standard acceleration settings? What is the default acceleration setting?

Thanks again!

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jimc
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Re: Ghosting problems

Post by jimc » Tue May 06, 2014 4:07 am

default acceleration is 3000. 1000-1500 is a pretty good setting and doesnt increase print time too bad. once you send the m201 command like jin said it will stay active until the printer resets. anytime you change any firmware settings they are temporary until you send M500 to the printer. this will store it permanently. it can always be changed again though by simply sending another M201 then if you like it send M500 again.

over-$-pent
Posts: 27
Joined: Thu Apr 10, 2014 11:11 pm

Re: Ghosting problems

Post by over-$-pent » Tue May 06, 2014 5:16 am

OK, with just the addition of the M201 X1000 Y1000, the surface finish is better with reduced ghosting, but it is still noticeable. I noticed the jerk settings in the post you had me look at. Will any adjustments to these help?

My current S3D settings are:

3600 mm/min, 50% outline under speed, .15 layer height, 90% infill, with 2 outline / perimeter shells. Using Taulman 618 nylon. I will try to post some pics once I have a part to compare.

thanks again for the help, as we are moving in the right direction.

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jimc
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Re: Ghosting problems

Post by jimc » Tue May 06, 2014 5:27 am

your not going to get it 100% gone. the jerk settings dont do much. on most models you really dont see it too much. its only on certain things like lettering or some type of feature in the middle of a flat surface. the m2 is a style of printer where the bed moves back and forth. it is what it is and is probably the only shortcoming of the m2. it can be made better though through the firmware and going over a few things. another thing you want to be sure of is that you have the bed leveling screws tightened all the way, unscrew 1 turn then level the bed. you basically want the springs compressed as much as possible while being able to level the bed. be sure everything that has to do with the bed is tight and secure.

jsc
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Re: Ghosting problems

Post by jsc » Tue May 06, 2014 5:43 am

I think the result of the massive test from that thread was that reductions down to 800 are noticeable and then there are rapidly diminishing returns. And as jimc said, jerk didn't seem to make much difference. His point on bed screws is also good. I like to just ram mine all the way home, then only ever bring the low side up by loosening the appropriate screw. Keep in mind: loosening the screw -> bed goes up. See my "M2 tips" thread in the tips forum for more useful hints.

over-$-pent
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Joined: Thu Apr 10, 2014 11:11 pm

Re: Ghosting problems

Post by over-$-pent » Tue May 06, 2014 5:57 am

Great point about the bed. Do you think we get any of the ghosting problems from the rubber pads allowing the bed to move / bounce? I have seen corner clips to make this a more rigid connection and thought about trying it. It sure would be nice to be able to change acceleration on the outer perimeter to minimize ghosting, but still maintain max acceleration during infill.

jsc
Posts: 1864
Joined: Thu Apr 10, 2014 4:00 am

Re: Ghosting problems

Post by jsc » Tue May 06, 2014 6:07 am

If you are handy, you may want to take a gander at these upgrades from Ed Nisley:

http://softsolder.com/2013/05/31/makerg ... ilization/
http://softsolder.com/2013/07/16/makerg ... ort-balls/
http://softsolder.com/2013/07/17/makerg ... ner-clips/
http://softsolder.com/2013/07/18/makerg ... ner-clips/

(I am not handy.)

Oh, and slic3r allows you to specify context dependent accelerations, which is nice. Slic3r sucks in many ways, but also has some very useful features not present in SImplify3D, so it is good to learn it.

over-$-pent
Posts: 27
Joined: Thu Apr 10, 2014 11:11 pm

Re: Ghosting problems

Post by over-$-pent » Tue May 06, 2014 5:33 pm

So I did one more test this morning. I went back to default acceleration values, but limited outline under speed to 34% which would be 20mm/sec. This gave me the best surface finish with the least amount of ghosting. I believe there might be more I can gain with making the bed a more solid connection to minimize bounce / movement when the machine changes direction rapidly. I will add some better bed retention and do some more tests as time allows. If this helps, then I could gain back the speed I lost due to under speed, but still get the least amount of ghosting. Keep your fingers crossed.

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