Corexy issues advice needed June 13, 2016 04:36AM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 13, 2016 06:46AM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 13, 2016 07:29AM |
Registered: 9 years ago Posts: 93 |
Quote
filipeCampos
The problem you have is not a problem of the extruder. From the image i can see layers put with lack of precision, the cause can be many things...
You need to check the obvious: possible rigidity problem of the bed, carriage and main structure. Check the belt tension too.
Re: Corexy issues advice needed June 13, 2016 08:03AM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 13, 2016 08:10AM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 13, 2016 08:17AM |
Registered: 9 years ago Posts: 93 |
Quote
filipeCampos
the printer looks like to have a very strong main frame.
I only have some information and the photos, is pretty difficult to pinpoint the problem. I will suggest some action you can do, but not sure if it will help you.
Some of my conclusions:
From the image of the print is easy to see the hotend do not have the same position on all the layers. but is not a missing steps problems.
I think the problem was nothing to do with software or configuration, like the print speed.
It appears to be some type of problem related with the lack of rigidity or something not correctly installed that provoke this lack of precision of the hotend.
I will suggest to check the next items:
-check if the hotend is well secure in the carriage.
-check if the carriage move freely and not allow sides movements.
-The mk2 bed looks to be at a very high point in relation to the wood plate, I will suggest to screw more the bed, Try to put the metal mk2 at half the distant is actually is know.
My bet is the problem is related with the bed structure.
-check if the bed arms was a good rigidity and lot allow side movements. From the image it appears you are using two printed arms, this can be the cause.
Re: Corexy issues advice needed June 13, 2016 11:09AM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 13, 2016 11:49AM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 13, 2016 02:49PM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 13, 2016 04:25PM |
Registered: 11 years ago Posts: 12 |
Re: Corexy issues advice needed June 13, 2016 05:29PM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 13, 2016 05:39PM |
Registered: 11 years ago Posts: 12 |
Re: Corexy issues advice needed June 13, 2016 05:44PM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 13, 2016 06:43PM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 13, 2016 07:14PM |
Registered: 12 years ago Posts: 5,794 |
Re: Corexy issues advice needed June 14, 2016 07:54AM |
Registered: 9 years ago Posts: 93 |
Quote
the_digital_dentist
The belt on the left side deflects laterally each time the motor reverses direction, and the belt on the right does the same to a lesser extent. That indicates an alignment problem. The belts should not deflect at all.
Re: Corexy issues advice needed June 14, 2016 08:03AM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 14, 2016 08:05AM |
Registered: 12 years ago Posts: 5,794 |
Re: Corexy issues advice needed June 14, 2016 08:51AM |
Registered: 9 years ago Posts: 93 |
Quote
LarsK
I agree with The Digital Dentist that your belts are flexing - But I don't think it is belt tension.
I think it is the idler posts. When the printer changes direction the load on the idlers (marked with read below) changes and the idler posts flexes slightly. If this is true it should be visible if you feel with your finger on the screw that secures the idler while it is running
To fix this is not entirely trivial as you will need to redesign the support for the idlers to be stronger.
Quote
the_digital_dentist
Measure the height of the pulley edges relative to the printer's frame. For each belt the pulleys should be at the same height. The belt should not be rubbing hard on the flanges of the pulleys. If the motor and pulleys' axes are not parallel it will cause the belt to ride against the flanges on the pulleys.
Doh! LarsK beat me to it.
That's the problem with cantilevered bearing posts, and especially if they are screwed to printed plastic mounts. Under belt tension the mounts will flex. If you're going to use printed plastic mounts for the pulleys, they should support the bearing axle at the top and the bottom. Likewise, plastic motor mounts. The left motor pulley looks like it is pulled up on the shaft away from the motor body. That makes a long lever with which to flex the motor mount. Keep the pulleys close to the motor body to minimize flex in the mount.
Re: Corexy issues advice needed June 14, 2016 09:31AM |
Registered: 12 years ago Posts: 5,794 |
Re: Corexy issues advice needed June 14, 2016 10:19AM |
Registered: 9 years ago Posts: 93 |
Quote
the_digital_dentist
Are the black pulleys 3D printed? I would not trust 3D printed pulleys to be perfectly round. If they are out of round at all the belt tension and extruder carriage position will keep changing because the belt path length will be changing as the pulleys rotate. You'll never get two print layers to match up...
Re: Corexy issues advice needed June 14, 2016 10:33AM |
Registered: 12 years ago Posts: 5,794 |
Re: Corexy issues advice needed June 14, 2016 10:46AM |
Registered: 9 years ago Posts: 93 |
Quote
the_digital_dentist
Use flanged ball bearings (F608zz, F625zz, or similar), or use properly made, flanged, toothed pulleys (http://www.ebay.com/itm/5pcs-GT2-20-16-Tooth-Gear-3mm-5mm-Idler-Pulley-Aluminum-2GT-for-3D-Printer-/201584674855?var=&hash=item2eef620827:m:mIY9J8L1M_sWNwPpl2DToNw)
Re: Corexy issues advice needed June 14, 2016 01:47PM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 15, 2016 06:05AM |
Registered: 9 years ago Posts: 93 |
Re: Corexy issues advice needed June 15, 2016 07:46AM |
Registered: 9 years ago Posts: 346 |
Re: Corexy issues advice needed June 15, 2016 08:14AM |
Registered: 12 years ago Posts: 5,794 |
Re: Corexy issues advice needed June 15, 2016 08:19AM |
Registered: 9 years ago Posts: 93 |
Quote
LarsK
Just for clarification, it is not play we are looking for. Play means when the idlers can move because a hole is too big or something like that. What I was looking for, was if the belt under load forces the idlers to bend in a direction. Maybe that is what you did, but just to clarify in case.
Nobody seemed to want to post a belt video, so here is one I shot from the printer I am currently working on: [goo.gl]
You see how the belt moves up and down the pulley? That is not supposed to happen - But you also see how my belt does not "relax" when going in the opposite direction, this is the important thing.
And here is the 3d benchy I was printing yesterday: [goo.gl]
I recommend you do test printing of the 3dBenchy ( [www.thingiverse.com] & [www.3dbenchy.com] ). Benchy is really a good "standardized" challenge with many dimensions to check and pictures on the internet to compare.
Last night I was test printing the Benchy before I move on to replacing the bed on the printer, this way I can do before and after comparison.
Re: Corexy issues advice needed June 27, 2016 03:50AM |
Registered: 9 years ago Posts: 93 |