First print :-)

Discussions about firmware/slicing software, tweaks and settings
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daveinhull
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Joined: Fri Jan 11, 2013 2:31 am

Re: First print :-)

Post by daveinhull »

Hi,

Just an update on some more adjustments now that I'm home.

I undid everything to do with the z-axis, stepper bolts to part, part to frame, z-axis slider to frame and removed the top bearing.

Then I let the stepper move up and down to find its own natural position and locked everything back up - seemed to improve the wobble and certainly removed the grinding sound :o However, I had to leave the stepper bolts to the part loose to allow for a little wobble.

I also realised that the y-axis part which attaches to the z-axis slider was not as tight as it should be, but I note Kenny's comments above.

My conclusions for the z-axis is:
1. No need for the top double nuts above the top bearing - they don't do anything and can just cause problems with locked in the wrong position - just a nice plastic cap might do - might print one.
2. Need something much better for the connection between the z-axis bolt and the z-axis stepper - the machines aluminium part doesn't work well - everything rotates without wobble when not connected together but connect it together and it wobbles.
3. Need a better arrangement/design for the connection between the y-axis holder and the z-axis slider. As Kenny points out if you tighten the bolt it grabs the slider and won't move - there must be a very fine line between too tight and too loose.

So, now got the new Repetier software and have actually managed to get a reasonable print, but still a few slicer adjustments needed - I need to learn a bit more about the effects of nozzle heat, bed heat, etc.

Dave

daveinhull
Posts: 66
Joined: Fri Jan 11, 2013 2:31 am

Post by daveinhull »

Hi,

I can now print routinely with the SFACT (thanks Guillaume for the new Repetier download - files ended up all over the place in Win7, but it works).

I can get some reasonably good prints - good enough for me anyway, but the last big problem is the warping from the heated bed. Kjetilei has given me some ideas and I think the Scotch Blue painters tape suggestion is the next to try as I can't seem to get them not to warp using the Kapton tape no matter what temp the bed is at or how much I clean it....

Dave
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gfeliksdal
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Post by gfeliksdal »

Hi Dave,

What temp are you using for your heated bed? And have you properly degreased it? Are you using PLA from felixprinters? The z-wobble is pretty well noticable in your prints. Have you followed the tips in the tips and tricks thread, to eliminate/reduce it?

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gfeliksdal
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Post by gfeliksdal »

daveinhull wrote:Hi,

My conclusions for the z-axis is:
1. No need for the top double nuts above the top bearing - they don't do anything and can just cause problems with locked in the wrong position - just a nice plastic cap might do - might print one.
2. Need something much better for the connection between the z-axis bolt and the z-axis stepper - the machines aluminium part doesn't work well - everything rotates without wobble when not connected together but connect it together and it wobbles.
3. Need a better arrangement/design for the connection between the y-axis holder and the z-axis slider. As Kenny points out if you tighten the bolt it grabs the slider and won't move - there must be a very fine line between too tight and too loose.

Dave
1 and 2). In theory you are right, the z-axis assembly is overdefined, because there are two mounting points above and below which carry forces. But if you only have the lower bracket carry the weight it will probably deform over time and also when carrying the printer it might break from impact forces when you put the printer down. I removed the top bracket once and it didn't significantly reduced the z-wobble. I normally mount it in this order to prevent/minimize wobble.
- Make the z-axis rail is parrallel with the vertical beam of the frame and also the rod is not bend.
- loosen the set-screw of the z-axis coupling.
- Make sure the top bracket is mounted firmly and perpendicular. Any minor deformation from this part is directly visable on the height of the table.
-Make sure the z-axis coupling is not screwed on the z-axis rod completely, loosen it one turn. (There is sideways play between the m8 thread of the z-axis coupling and the z-axis rod. So when fixing the coupling with the m8 nut you could mount it slightly out of centre.).
- Fix the z-axis coupling onto the rod lightly with the m8 nut, don't forget the curved washer.
- turn the coupling by hand a couple of turns and see if there is some wiggling of the motor. If there is, push it against the wiggle and turn it some more. Repeat this untill there is almost no wiggling of the motor. Then fix the m8 nut more without pushing the parts out of line, and also not too firm that the curved washer is completely compressed.
- now fix the setscrew.

I know it is tricky to get it optimal, but this is how I do it at the moment.

3.) I guess all the tolerances of the parts are not in your favor for the bolt to tough the rail. If you add an extra washer it should be ok.

daveinhull
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Post by daveinhull »

Hi Guillaume,

Thanks for the reply. To your first post:
gfeliksdal wrote: What temp are you using for your heated bed? And have you properly degreased it? Are you using PLA from felixprinters? The z-wobble is pretty well noticable in your prints. Have you followed the tips in the tips and tricks thread, to eliminate/reduce it?
I've tried bed temperatures between 55 and 70, yes I think I have degreased it using surgical spirit and yes PLA from felixprinters. I didn't actually think there was much z-wobble given previous attempts these are good to me ;)

Your second post,
gfeliksdal wrote: 1 and 2). In theory you are right, the z-axis assembly is overdefined, because there are two mounting points above and below which carry forces. But if you only have the lower bracket carry the weight it will probably deform over time and also when carrying the printer it might break from impact forces when you put the printer down. I removed the top bracket once and it didn't significantly reduced the z-wobble. I normally mount it in this order to prevent/minimize wobble.
Ok, I'll add the top two bolts back on but could really do with some more crinkled washers, if you remember my printer shipped with too few.

I spent a fair bit of time yesterday trying to align everything to remove the wobble and the grinding of the y-axis part on the z-axis bolt - the z-axis stepper doesn't move much at all now although I've left the four screws loose. I certainly can't see any wobble in the bed as it moves, not like previously anyway where there was a really noticeable wobble.

I did leave the bottom bolt loose (near the coupling) but it would actually unscrew itself as the bed went up (clearly a problem with the alignment which I think I've fixed) so I had to tighten the nut and in doing so have 'flattened' the crinkle washers - hence would appreciate a few more if you get chance.
gfeliksdal wrote: 3.) I guess all the tolerances of the parts are not in your favor for the bolt to tough the rail. If you add an extra washer it should be ok.
Ok, will add a few washers.

Thanks
Dave

daveinhull
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Joined: Fri Jan 11, 2013 2:31 am

Post by daveinhull »

Hi all,

Well it’s been a little while since I post last but have been having some success after a few mods, changes, improvements etc.:
  • I've replaced the z-axis bold and bottom coupler with a new one from Felix
  • I've replaced the kapton tape with Scotch painters blue tape
  • I've dropped the hotend temperature to 185 and raised the print bed to 70 (appeared to be needed with the Scotch tape)
  • I'm using the production profile
Prints so far are looking good, well good enough to use on my projects.

The only thing I noticed that when I put the scotch tape on the print bed it was perfectly aligned but after the first 'heat' there are now gaps (about 1 mm) between the strips of tape - should I have put the tape on while the bed was hot?

Dave

alexandrestcyr
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Post by alexandrestcyr »

heres my first print after 10 hour of assembly!!! So happy

Hugues
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Post by Hugues »

alexandrestcyr wrote:heres my first print after 10 hour of assembly!!! So happy
so happy that you forgot to attach the picture ? :lol:
Hugues
Regards from Switzerland

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