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Hi there, I've built a printer few months ago and I've been experiencing problems non-stop. Nonetheless my machine does decent printing with a bit z wobble. I use 2 parallel rods for every axis. But angles of my frame aren't perpandicular in every connection due to poor cutting of the aluminium. Is it absolutely necessary to remove all my profiles and replace them ? what potential problems might they be causing me

Non orthogonality between x and y will skew prints, so squares will be parallelograms. Assuming x and y are square but not square with z then first layers won't print evenly, compressed on one side often to the point of not extruding at all, and high above the bed on the other side so won't adhere at all, or a less extreme version of this.

In an ideal world your axes are orthogonal in all regards. This is however difficult to achieve without a fair degree of effort, precision and a little experience in achieving it. Having some means of adjusting your frame such as diagonal braces with turnbuckles can square a slightly less square frame. My kossel Xl frame 1m x 0.35m X0.35m size is accurate to 0.1mm difference between the tower spacing measured top and bottom. Achieved with lots of measuring, building on a really flat surface, and loosening screws tweaking and tightening. About 5 hours construction and truing it up until I was happy with it.

My corexy made from 2020 extrusions, supposedly "cut to length precisely" were very much not the same length. Having no precision cutting gear, I clamped them all into a vice so that all the ends were level at one end, and went through 15 sanding discs with an orbital sander making the other ends all the same length and 90 degrees to the extrusions. Then just bolt them together, they should make a square frame.

However in the real world this isn't always achievable. So for z alignment issues software compensation is now common and called bed levelling which can be pure software height compensation either approximating a plane or using a grid to map the bed height at a (often large) number of points. To use this well you need accurate probes, see my signature if you want to make one or buy one.

You can also use probes to measure and then actually level using firmware that supports it like RRF on duet boards which can control 2,3 or 4 motors supporting the bed to actually level it. Again precise probe needed or you won't get close.

Software can now compensate all three axes, prusa are doing it automatically to some extent with the i3 mk2 / mk3 and duet/RRF can do it if you manually work out the angle difference between axes.

You'll find a split between those here who have no time for software compensation and believe you build it right in the first place and the rest who are happy to use compensation where it helps. I'm on the fence, if you can build it right do so, using a probe to check perhaps or calibrate in the case of a delta as it saves a lot of time. If you don't manage to build it right, use compensation and try again next time.

Edited 3 time(s). Last edit at 10/04/2017 02:35PM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

think it like a limping table, 1 of the feet is not touching the ground while other 3 are, so I support one feet with few papers underneath, [i.hizliresim.com] [i.hizliresim.com] [i.hizliresim.com] [i.hizliresim.com] the bluesword)
these are some of the prints I had with threaded rods, so I don't think my printer is dramatically askew. Do you still think my problem may be caused by the unequal feet

There's nothing wrong with those prints that I can see (I'm on a phone) unless their dimensions are off? A bit of z wobble banding but that's common with threaded rods which are rarely straight.

Try printing an orthogonality test object like this [www.thingiverse.com] make sure the angles are 90 degrees?

You mention a problem but not what your problem is?

Edited 2 time(s). Last edit at 10/04/2017 03:50PM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

dimensions were okay, angles are 90 degrees too, that little wobble drove me crazy cuz I wanted to proceed to 100 micron prints and didn't want to see wobble on my prints so I replaced threaded rods with leadscrews. Screws turn superbly but when they are about to reach z0 the rod on heavier side starts acting weird, skipping turns etc.

Edited 1 time(s). Last edit at 10/04/2017 09:10PM by lyro.

I think we're talking about leadscrews in another thread. Threaded rod is slightly forgiving but less accurate. Leadscrews need precise alignment but are much more accurate.

Edited 1 time(s). Last edit at 10/05/2017 01:39PM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

well I'm thinking about replacing my profiles too but then again, that's gonna be building the printer all over again, do you have any alternatives to aluminium sigma profiles ?

What style of printer is it?

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

[i.hizliresim.com] that is the printer we talk about

I'm not sure you have to replace them, just take it apart and make sure the ends are 90 degrees to the profiles, so when assembled everything is square.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

problem is from what I observed, the cuts arent made straight, so the edges that come together arent perpandicular

Sure so take them apart and make the edges perpendicular.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions