printer settings

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Tygrik
Posts: 38
Joined: Tue Jun 19, 2012 12:17 pm

printer settings

Post by Tygrik »

Hello,

I have a problem with the printing of round things. I attach a photo for info. Printhead not be copied circle, but prints as if in an "irregular" square. Someone help me?
Attachments
IMG_1811.JPG
IMG_1797b.jpg
IMG_1806a.jpg

Kjetilei
Posts: 334
Joined: Fri Mar 16, 2012 8:26 pm
Location: Stavanger, Norway

Post by Kjetilei »

Hi Tygrik,

Your printing problems are due to backlash on one or both of your axes (x,y).

I had the same problem and got it fixed (but due to "laziness" on my behalf I still have a little bit too much backlash left).

Backlash is caused by slop in the setup. You should try to tighten the belts a little bit more to see if that helps. If not I believe it could be caused by slop in the y-axis sliding bearing. Guillaume has a nice tutorial about optimizing the sliding bearings (check first post in the Common problems/Tips and tricks thread). He most likely knows much more about removing backlash than I do.

As a matter of fact I believe it would be a good thing if Guillaume added a section about backlash in the Common problems/Tips and tricks thread.

To better study your backlash problems you can use the Concentric circle test on Thingiverse. Download and use the gecode version.

Best of luck and please report back on your progress :)

mcole254
Posts: 18
Joined: Sat Jun 02, 2012 12:42 am

Post by mcole254 »

Try tightening your x and y axis belts

Tygrik
Posts: 38
Joined: Tue Jun 19, 2012 12:17 pm

Post by Tygrik »

Hello,

I cleanse and lubricate the bearings with WD40.
Printing result is now fine, but X sliding bearing is a weakness of this amazing printer. Sliding bearing trouble doing lateral load, which the heavy stepper motor for the extruder.

There are two solutions.

1) remake direct extruder to the bowden extruder and mount the stepper motor to the printer frame.

http://www.thingiverse.com/thing:22426

2) change sliding bearing to the "linear rail" ..... price is not small (approx. 78 EUR), but will be guaranteed resistance to lateral load at ultimate accuracy.

http://hiwin.com/html/linear% 20guideways/mg.html


test print after maintenance on the X and Y axis
Attachments
IMG_1846.JPG

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gfeliksdal
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Post by gfeliksdal »

Hi Tygrik,

Your print results can be significantly better...

My experience with WD40 is that it only works temporary. After a while the lubricant will catch dust and becomes more sticky and friction will increase even more than before. Best and only working lubricant is PTFE/teflon spray as far as I know. It is commonly used for bicycle chains.

Indeed the friction increases when lateral force is exerted on the bearing, but during printing this force should be very low and also constant over the whole stroke. I had a customer once who experienced a very high increase in friction of the rail at a certain range in the motion. After searching it appeared to be the belt rubbing the washers next to the bearing of the of the belt-mount part. The solution was to add an extra small washer next to the bearings to give the belt more room to move. So maybe you could check if that's not the case.

Have you tried to loosen the belt and try to move the x-axis slider with extruder mounted along the rail? You should feel no increase in friction over the whole range and it should move smoothly.

Also increasing belt tension can reduce the backlash, but too much will increase the friction.
1) remake direct extruder to the bowden extruder and mount the stepper motor to the printer frame.
http://www.thingiverse.com/thing:22426
I'm not convinced that the bowden extruder type will benefit in the printer concept. The benefit is less moving mass in x-direction, but adds more complexity with the bowden construction. Also printing with rubber filament will be difficult. Another thing is that the limiting factor is the moving table, which is still heavier than the x-axis.
2) change sliding bearing to the "linear rail" ..... price is not small (approx. 78 EUR), but will be guaranteed resistance to lateral load at ultimate accuracy.
http://hiwin.com/html/linear% 20guideways/mg.html
This can indeed benefit print quality, but comes with a relatively big price. Currently testing with linear guides and must say I'm impressed with the results so far. Only downside is that the construction becomes so stiff that you get other vibrations, which appear on the printed object. The sliding bearings damp vibrations which gives a nice finish on the object. Anyways, if I can get a good deal from some supplier, these kind of bearings are the way to go.

Kind regards,

Guillaume.

Tygrik
Posts: 38
Joined: Tue Jun 19, 2012 12:17 pm

Post by Tygrik »

Today I'm going to print E upgrade and so will the opportunity to clean the printer and use recommended lubricant.

In the Czech Republic is one vendor for linear guides and so thinking about it to try to buy one. Offer sadly only one model and MGN12C Z1 H for rail MGNR12.

Lioric
Posts: 116
Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

How about the MakerSlide ? its around $10 to $20 per meter. That is the "linear rail" that is used in the ORD Bot 3d printer

MakerSlide ks page and video:
http://www.kickstarter.com/projects/938 ... ing-system

ORD bot 3d Printer video:
http://www.youtube.com/watch?v=JEJL_6TL_Q0

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