Hypercube xy distortion Hello, I have notice a weird distortion, and I'm struggling to understand why it iexists. The attached image show a 100mm x 100mm square. What you will notice is a slight curving towards the bottom right. It's about 102 on the bottom and right hand side. Can anyone suggest what might be causing that? Regards Matt https://reprap.org/forum/read.php?397,770438,770438#msg-770438 Mon, 09 Mar 2026 01:49:54 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?397,770438,893927#msg-893927 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,893927#msg-893927 julidondero CoreXY Machines Fri, 15 Dec 2023 08:42:39 -0500 https://reprap.org/forum/read.php?397,770438,773189#msg-773189 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773189#msg-773189 tgmorris99 CoreXY Machines Tue, 13 Jun 2017 10:44:15 -0400 https://reprap.org/forum/read.php?397,770438,773174#msg-773174 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773174#msg-773174 All I had was 8mm smooth rods, I had use use someone else's 8mm xy joiner.

....nope, looking at the two STL files, the distance from the base of the xy joiner to the centre of the xy idler is the same.
So it's not that.

Both sides have the same problem.]]> mjoyce CoreXY Machines Tue, 13 Jun 2017 09:40:32 -0400 https://reprap.org/forum/read.php?397,770438,773171#msg-773171 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773171#msg-773171
Belt misalignment seems to be a very common problem among coreXY printer builders.]]> the_digital_dentist CoreXY Machines Tue, 13 Jun 2017 09:22:06 -0400 https://reprap.org/forum/read.php?397,770438,773167#msg-773167 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773167#msg-773167 Anyway, I had misunderstood, and did calculate the alignment from the motors to the rear idler.

Looking down at the motor, with the x gantry at it's most forward position, I can see the XY joiner idler is misaligned.
Picture attached.

So now I need to have a think to understand why....]]> mjoyce CoreXY Machines Tue, 13 Jun 2017 08:57:09 -0400 https://reprap.org/forum/read.php?397,770438,773158#msg-773158 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773158#msg-773158
Quote
the_digital_dentist
"Well, to be fair, I'm just using the design from here : [www.thingiverse.com]
Some of your points have been raised in that community and the consensus is, it's fine."

Well, you wouldn't want to go against something that "the community" has decided is OK, would you?

When you start digging into machine design and performance you'll find that what "the community" considers acceptable is often terrible, and even dead wrong. Look at the four screw bed leveling error that has been around for years and shows no signs of ever going away. Any idiot who didn't sleep through the first week of highschool geometry can tell you that 3 points define a plane, not 4. So why are there 4 screws? "Duh, I dunno... the bed has 4 corners?"

If "the community" says the belts don't need to be parallel to the guides rails, "the community" is wrong. It isn't difficult to find HUGE examples of how wrong communities can be. Turn on the news- at any given moment the top story is liable to be an example of how wrong "the community" (a different one) has been. Unfortunately for those of us who are able to learn from our own and others' mistakes, "the community" that can't seems to get larger every day.

OK, you make some valid points. Thank you.
I guess my point was that I felt that if the design was so fundamentally flawed, that someone would have noticed and pointed it out before me.
Seems more likely that I have constructed it wrong.]]> mjoyce CoreXY Machines Tue, 13 Jun 2017 07:54:44 -0400 https://reprap.org/forum/read.php?397,770438,773149#msg-773149 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773149#msg-773149 tgmorris99 CoreXY Machines Tue, 13 Jun 2017 06:52:33 -0400 https://reprap.org/forum/read.php?397,770438,773107#msg-773107 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773107#msg-773107
[attachment 95273 HyperCubeBeltPath.JPG]]]> lkcl CoreXY Machines Mon, 12 Jun 2017 23:03:17 -0400 https://reprap.org/forum/read.php?397,770438,773100#msg-773100 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773100#msg-773100
Quote
tgmorris99
As an exercise I lined up the various parts (motor mount, idler, XY Joiner, belt, pulleys) for the left motor in 123D and the belt path at the XY joiner *should* be well under 1mm tolerance. Assuming I lined everything up correctly the belt path from the motor pulley to the idler pulley looks to be out by 1mm or so.

.... which would be about the right amount given that the belts comprise a part which holds the fibres and another part which has the teeth.

hmmm, so the OP appears to have either modified the design or mis-assembled it. hmm...]]> lkcl CoreXY Machines Mon, 12 Jun 2017 22:39:53 -0400 https://reprap.org/forum/read.php?397,770438,773041#msg-773041 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773041#msg-773041
The drive pulley assumes a 12.7mm belt pitch and the belt segments as drawn are 1.38mm. The idler pulleys are 10mm in diameter.]]> tgmorris99 CoreXY Machines Mon, 12 Jun 2017 13:03:11 -0400 https://reprap.org/forum/read.php?397,770438,773023#msg-773023 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773023#msg-773023

]]> the_digital_dentist CoreXY Machines Mon, 12 Jun 2017 10:59:30 -0400 https://reprap.org/forum/read.php?397,770438,773017#msg-773017 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773017#msg-773017 "the community" reminds me a bit of my favourite game in the '80: The lemmings...

]]> o_lampe CoreXY Machines Mon, 12 Jun 2017 10:40:16 -0400 https://reprap.org/forum/read.php?397,770438,773013#msg-773013 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,773013#msg-773013
Quote
the_digital_dentist
If "the community" says the belts don't need to be parallel to the guides rails, "the community" is wrong. It isn't difficult to find HUGE examples of how wrong communities can be. Turn on the news- at any given moment the top story is liable to be an example of how wrong "the community" has been. Unfortunately for those of us who are able to learn from our own and others' mistakes, "the community" that can't seems to get larger every day.

baaaaa

[attachment 95262 99caf0b0ddf86dc9fd1673fee8f0b536.jpg]]]> lkcl CoreXY Machines Mon, 12 Jun 2017 10:17:46 -0400 https://reprap.org/forum/read.php?397,770438,772985#msg-772985 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772985#msg-772985 Some of your points have been raised in that community and the consensus is, it's fine."

Well, you wouldn't want to go against something that "the community" has decided is OK, would you?

When you start digging into machine design and performance you'll find that what "the community" considers acceptable is often terrible, and even dead wrong. Look at the four screw bed leveling error that has been around for years and shows no signs of ever going away. Any idiot who didn't sleep through the first week of highschool geometry can tell you that 3 points define a plane, not 4. So why are there 4 screws? "Duh, I dunno... the bed has 4 corners?"

If "the community" says the belts don't need to be parallel to the guides rails, "the community" is wrong. It isn't difficult to find HUGE examples of how wrong communities can be. Turn on the news- at any given moment the top story is liable to be an example of how wrong "the community" (a different one) has been. Unfortunately for those of us who are able to learn from our own and others' mistakes, "the community" that can't seems to get larger every day.]]> the_digital_dentist CoreXY Machines Mon, 12 Jun 2017 07:37:29 -0400 https://reprap.org/forum/read.php?397,770438,772982#msg-772982 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772982#msg-772982
Quote
mjoyce
Quote
lkcl

yes. okay, this is a classic mistake. here's highlighted in red where you'll need to ensure that the belts come off the idlers exactly at right-angles (at all four locations). the right-hand motor looks to be just about ok (but might not be - you'll have to check it carefully, it could be out by as little as 1mm), but the left one is out by a whopping 10mm at least (yellow arrow).

I think the angle of the photo, has altered the perspective, the left side is not 10mm out.

Looking at the STL files, and taking some measurements.
The idler centre is 11.25mm from the square post.
The bearing used in the ilder are 10mm, so the belt would be 11.25-5= 6.25mm from the post.

The centre of the motor spindle is 12.5mm from the post, the gear diameter is 12mm.
So the belt at the front is 7.5mm from the post

Seems all I need to do is change the idler bracket to shift in 1.25mm.

ok can you confirm: for that left motor you're measuring the *inner* part of the belt (right-most) *NOT* the outer part that is currently covered by the red line? it's the *inner* part, as it comes off the left idler, that needs to be at right-angles and down to the *inside* (right side) of the motor gear.

the reason i ask is that according to the photo the left motor is so far out that you may be misunderstanding and believing that because the red line covers the OUTER part of the belt, that you must align that part only by adjusting it 1.25mm to the... *thinks*.... right.

whereas in fact you may need to adjust the motor something like 12-1.25mm to the LEFT.

this is why i said that it's important to take another photo, moving the x-gantry down to the front part of the printbed.

to confirm that perspective is not interfering, take the photo directly above the left motor's spindle, stand much further back (above), and use the "zoom" function on the camera.

Quote

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lkcl
now, the other thing: i notice you've copied a cantilevered bed design. those look like 8mm rods, which you should be aware are hopelessly inadequate for the job of supporting a 250mm span. you can check this easily by grabbing the front of the printbed and pushing it up and down. it should be possible to apply a tiny amount of pressure to achieve an alarming amount of "travel". also, you only have a single z lead screw, and you're using plastic pieces to hold the linear bearings. the combination of these two things means that the entire printbed will wobble about. for more details about this see [reprap.org]

Well, to be fair, I'm just using the design from here : [www.thingiverse.com]
Some of your points have been raised in that community and the consensus is, it's fine.

then.. please assume that i am speaking diplomatically: that community has unfortunately arrived at a consensus of collective engineering ignorance. it is quite frustrating to see people continually copying and propagating basic engineering design flaws, and, worse, being reluctant to perform the necessary tests to confirm that their faith in their lack of knowledge is flawed. this is in direct violation of basic scientific enquiry / methodology.

*sigh*.

anyway take a look at the ultimaker-2: you will see that it uses 10mm rods. this is the absolute bare minimum that's needed for a cantilevered 200mm printbed. 12mm is better, and 12mm is essental for a 300mm cantilevered design. again: review those printbed examples at the mechanical rigidity page i wrote.


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lkcl
one other important thing to check: the belt parts that i've marked in red MUST be all at the exact same height. the other parts (not marked) are not so critical but you really should do an "offset" design (like the Fusebox - the belt arrangement in the Fusebox is its one really really good design aspect). on the right-hand belt i can see that the inner part of the belt is not straight: it "coils" so that about half-way along it faces UPWARDS. this tells me that there is the strong possibility that the right-hand motor's height is not properly alighned: either it is at an angle (not properly vertical) or the belt is not properly horizontal. a photo from the right side would confirm this suspicion.

Thank you for sharing FuseBox, the xyjoiner on that design looks really elegant.

yeah it is... but please do bear in mind that the belt layout really is the only part of that design which is good. everything else, it is a classic example of what not to do. i outline a full list of the fusebox design flaws on its own page here [reprap.org]

there's a _lot_ :)

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Quote
lkcl
also: the 20x20 corner-pieces are hopelessly inadequate. you should source at least some 50x50 metal triangles (don't laugh: i use sheet steel 1.5mm corners that were designed for wood-working: they're cheap and amazingly strong). you'll also need to stiffen up all the other five faces: do not be tempted to miss one of them out. think of a cardboard box with its lid open: it's hopelessly structurally unsound. close the lid and it becomes amazingly strong. for more on this (including some video demonstrations) see [reprap.org]

All faces have 4 corner brackets. They are metal, and as you correctly identified, 20mm. It seem pretty solid to me, but I can see how bigger brackets would be better, but perhaps not noticeably in this situation.

ok i made that mistake as well, by buying a taobao $150 clone which had those 20mm corner brackets. i too genuinely believed that they would be adequate, and was dismayed to find that, on proper testing, they were utterly, utterly useless. you can easily test this for yourself by "twisting" (or unscrewing, like a bottle-top) the frame. tape a piece of paper to the printbed, and securely fasten a pen or pencil to the carriage. then, putting the printer on the floor (even just moving it from the table to the floor is itself a good test), hold the base between your feet and hold the top with your hands. put a SMALL amount of pressure on the top, moving it sideways and back and forth. then, do a "twist" test as well - make sure that at all times the base is firmly held between your feet.

once you've done that, check what the pen has drawn. if it's a "dot" then you have a great design, and there is absolutely nothing to fix.

if on the other hand you have a series of squiggles, you'll know that you're copying and propagating "collective ignorance". i know that you'll be absolutely shocked at how much the pen tells you that the carriage is moving about. with those 20mm corner pieces you should easily have around 2mm of "squiggle" - much more than that if you were confident to try pressing quite hard.

now, if you believe that it doesn't matter, i can tell you that it definitely does. as the printhead goes into corners, the weight of the assembly causes the *entire frame* to judder, and on the "exit" from the corner you get a "wave" pattern for several mm. to stop that from happening you not only need to limit the max speed to under 50mm/sec but also the acceleration to well under 500mm/sec^2. which, if you're using marlin, runs you smack into several design flaws in the marlin firmware itself (i've tried).


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lkcl
so... sorry to be the bearer of bad news! you have a lot of redesign work ahead of you. but... it's not all bad: sometimes you have to try things without consulting people first, in order to value their input and to know what they're talking about. if you hadn't started at all you would not have the experience to know what corrections needed to be made. you'll do ok :)

Not at all, you're clearly knowledgeable about these things, and you've taken the time to share information and concepts.
I did not have a proper understanding about the mechanics, and frankly it seems a bit obvious not that you point out the relationship between the belts and the y axis.

thank you

no problem - we'll get you sorted :) but do those photos ok! they're important to double-check before you go ahead, make sure we're absolutely talking about the same thing(s).

btw i'm on to i think it's my 6th printer, now. from my experience with software libre project management i know to listen to the people who can clearly demonstrate an ability to logically explain their particular area of expertise: dc42, digital_dentist, and several others on here. but i then *write it down* on a wiki page (because otherwise i forget). one of the mistakes that's made by most people who use forums is that they forget that forums are near-impossible to find anything. there was a guy 18 months ago who made a fantastic cantilevered printbed design. can i remember his username? of course not. can i use the search function to narrow down where to find his design? of course not, because there have been tens of thousands of posts on here, since. that's just *one* example of some valuable engineering knowledge that's been totally swamped.

my point is: what you call expertise is just total frustration at wasting my own time and money in the past :) if i document things, that stops *me* from forgetting. it also means that other people benefit, and that in turn helps me.]]> lkcl CoreXY Machines Mon, 12 Jun 2017 06:43:17 -0400 https://reprap.org/forum/read.php?397,770438,772950#msg-772950 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772950#msg-772950
Quote
lkcl

yes. okay, this is a classic mistake. here's highlighted in red where you'll need to ensure that the belts come off the idlers exactly at right-angles (at all four locations). the right-hand motor looks to be just about ok (but might not be - you'll have to check it carefully, it could be out by as little as 1mm), but the left one is out by a whopping 10mm at least (yellow arrow).

I think the angle of the photo, has altered the perspective, the left side is not 10mm out.

Looking at the STL files, and taking some measurements.
The idler centre is 11.25mm from the square post.
The bearing used in the ilder are 10mm, so the belt would be 11.25-5= 6.25mm from the post.

The centre of the motor spindle is 12.5mm from the post, the gear diameter is 12mm.
So the belt at the front is 7.5mm from the post

Seems all I need to do is change the idler bracket to shift in 1.25mm.


Quote
lkcl
now, the other thing: i notice you've copied a cantilevered bed design. those look like 8mm rods, which you should be aware are hopelessly inadequate for the job of supporting a 250mm span. you can check this easily by grabbing the front of the printbed and pushing it up and down. it should be possible to apply a tiny amount of pressure to achieve an alarming amount of "travel". also, you only have a single z lead screw, and you're using plastic pieces to hold the linear bearings. the combination of these two things means that the entire printbed will wobble about. for more details about this see [reprap.org]

Well, to be fair, I'm just using the design from here : [www.thingiverse.com]
Some of your points have been raised in that community and the consensus is, it's fine.


Quote
lkcl
one other important thing to check: the belt parts that i've marked in red MUST be all at the exact same height. the other parts (not marked) are not so critical but you really should do an "offset" design (like the Fusebox - the belt arrangement in the Fusebox is its one really really good design aspect). on the right-hand belt i can see that the inner part of the belt is not straight: it "coils" so that about half-way along it faces UPWARDS. this tells me that there is the strong possibility that the right-hand motor's height is not properly alighned: either it is at an angle (not properly vertical) or the belt is not properly horizontal. a photo from the right side would confirm this suspicion.

Thank you for sharing FuseBox, the xyjoiner on that design looks really elegant.


Quote
lkcl
also: the 20x20 corner-pieces are hopelessly inadequate. you should source at least some 50x50 metal triangles (don't laugh: i use sheet steel 1.5mm corners that were designed for wood-working: they're cheap and amazingly strong). you'll also need to stiffen up all the other five faces: do not be tempted to miss one of them out. think of a cardboard box with its lid open: it's hopelessly structurally unsound. close the lid and it becomes amazingly strong. for more on this (including some video demonstrations) see [reprap.org]

All faces have 4 corner brackets. They are metal, and as you correctly identified, 20mm. It seem pretty solid to me, but I can see how bigger brackets would be better, but perhaps not noticeably in this situation.


Quote
lkcl
so... sorry to be the bearer of bad news! you have a lot of redesign work ahead of you. but... it's not all bad: sometimes you have to try things without consulting people first, in order to value their input and to know what they're talking about. if you hadn't started at all you would not have the experience to know what corrections needed to be made. you'll do ok :)

Not at all, you're clearly knowledgeable about these things, and you've taken the time to share information and concepts.
I did not have a proper understanding about the mechanics, and frankly it seems a bit obvious not that you point out the relationship between the belts and the y axis.

thank you]]> mjoyce CoreXY Machines Sun, 11 Jun 2017 23:43:20 -0400 https://reprap.org/forum/read.php?397,770438,772947#msg-772947 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772947#msg-772947 Your image did attach, just didn't show for me.]]> mjoyce CoreXY Machines Sun, 11 Jun 2017 21:11:27 -0400 https://reprap.org/forum/read.php?397,770438,772906#msg-772906 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772906#msg-772906
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mjoyce
Could you attached the image you marked-up, I can't see it.

that's odd. it's stored on the server, the link is here [forums.reprap.org] - if you examine the source of the forum page it can also be obtained that way.

Quote

Thanks for the detailed reply, I'll, respond more fully tomorrow.

no problem. remember: move the horizontal x-gantry further down the printer (towards the front), take another photo. also take a photo from the right-hand side, make sure to put the camera *absolutely* dead-level with the belts. we need to check that the required belt-sections are absolutely dead horizontal.]]> lkcl CoreXY Machines Sun, 11 Jun 2017 14:04:55 -0400 https://reprap.org/forum/read.php?397,770438,772904#msg-772904 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772904#msg-772904
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mjoyce
Funny you mention the belts, they all I had and yes they are reinforced.
Switched to black rubber. will try a print tomorrow.

don't do it: save the black rubber for when you've corrected the design flaws. only print at the top part of the printbed until then.]]> lkcl CoreXY Machines Sun, 11 Jun 2017 14:00:13 -0400 https://reprap.org/forum/read.php?397,770438,772882#msg-772882 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772882#msg-772882 Thanks for the detailed reply, I'll, respond more fully tomorrow.]]> mjoyce CoreXY Machines Sun, 11 Jun 2017 10:19:33 -0400 https://reprap.org/forum/read.php?397,770438,772880#msg-772880 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772880#msg-772880 Switched to black rubber. will try a print tomorrow.]]> mjoyce CoreXY Machines Sun, 11 Jun 2017 10:14:33 -0400 https://reprap.org/forum/read.php?397,770438,772739#msg-772739 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772739#msg-772739
Quote
mjoyce
Hello,

Sorry for the delay in responding, it's been a hectic week.
I really appreciate the comments and responses.

I have attached a top down picture of my printer, I hope it's useful.
The bottom of the photo, is the front of the printer, where the xy motors are.
That's where the distortion is.

Regards

Matt

yes. okay, this is a classic mistake. here's highlighted in red where you'll need to ensure that the belts come off the idlers exactly at right-angles (at all four locations). the right-hand motor looks to be just about ok (but might not be - you'll have to check it carefully, it could be out by as little as 1mm), but the left one is out by a whopping 10mm at least (yellow arrow).

the way to check (and to emphasise the problem really *really* clearly) is: move the horizontal x-gantry down as far as it will go. the angle of those two lower belt parts coming off the motor gears will change MASSIVELY. in the case of the left one it should change to something like almost 30 degrees. don't leave it there very long because it will stretch (and damage) the belt. as a result you should be looking to order a replacement, ready for when you've fixed the design flaws. (edit: dd is correct: the tension should not change. "pungg" the outer part of the belt with your finger - or any part that does not change length. if the note changes when you move the horizontal part of the "H" then you have this classic and very common design flaw).

now, the only major problem that i can see is that moving the left motor over means that it's going to hit the left y-rod. do NOT be tempted to put the motor lower down in order to "fix" this problem because you will simply be exchanging left-right incorrect alignment for up-down incorrect alignment...

if that's the case, what you'd need to do instead is redesign the white parts for the x-y gantry, moving the idlers on it slightly inwards, thus allowing you to move the y-rods OUTWARDS a sufficient amount to accommodate the amount by which the motor(s) need to be shifted over. or... don't move them: you will just have to tolerate a reduction in print area.

you _should_ be able to print things along the top (back) edge of the printer in order to minimise distortion.

now, the other thing: i notice you've copied a cantilevered bed design. those look like 8mm rods, which you should be aware are hopelessly inadequate for the job of supporting a 250mm span. you can check this easily by grabbing the front of the printbed and pushing it up and down. it should be possible to apply a tiny amount of pressure to achieve an alarming amount of "travel". also, you only have a single z lead screw, and you're using plastic pieces to hold the linear bearings. the combination of these two things means that the entire printbed will wobble about. for more details about this see [reprap.org]

one other important thing to check: the belt parts that i've marked in red MUST be all at the exact same height. the other parts (not marked) are not so critical but you really should do an "offset" design (like the Fusebox - the belt arrangement in the Fusebox is its one really really good design aspect). on the right-hand belt i can see that the inner part of the belt is not straight: it "coils" so that about half-way along it faces UPWARDS. this tells me that there is the strong possibility that the right-hand motor's height is not properly alighned: either it is at an angle (not properly vertical) or the belt is not properly horizontal. a photo from the right side would confirm this suspicion.

also: the 20x20 corner-pieces are hopelessly inadequate. you should source at least some 50x50 metal triangles (don't laugh: i use sheet steel 1.5mm corners that were designed for wood-working: they're cheap and amazingly strong). you'll also need to stiffen up all the other five faces: do not be tempted to miss one of them out. think of a cardboard box with its lid open: it's hopelessly structurally unsound. close the lid and it becomes amazingly strong. for more on this (including some video demonstrations) see [reprap.org]

so... sorry to be the bearer of bad news! you have a lot of redesign work ahead of you. but... it's not all bad: sometimes you have to try things without consulting people first, in order to value their input and to know what they're talking about. if you hadn't started at all you would not have the experience to know what corrections needed to be made. you'll do ok :)

[attachment 95197 CoreXY_top.png]]]> lkcl CoreXY Machines Sat, 10 Jun 2017 03:08:55 -0400 https://reprap.org/forum/read.php?397,770438,772733#msg-772733 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772733#msg-772733 o_lampe CoreXY Machines Sat, 10 Jun 2017 01:37:19 -0400 https://reprap.org/forum/read.php?397,770438,772715#msg-772715 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772715#msg-772715 the_digital_dentist CoreXY Machines Fri, 09 Jun 2017 20:54:50 -0400 https://reprap.org/forum/read.php?397,770438,772709#msg-772709 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772709#msg-772709
Sorry for the delay in responding, it's been a hectic week.
I really appreciate the comments and responses.

I have attached a top down picture of my printer, I hope it's useful.
The bottom of the photo, is the front of the printer, where the xy motors are.
That's where the distortion is.

Regards

Matt]]> mjoyce CoreXY Machines Fri, 09 Jun 2017 20:10:57 -0400 https://reprap.org/forum/read.php?397,770438,772678#msg-772678 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772678#msg-772678
Quote
sigxcpu
I really don't understand what you don't understand.

the relevance to the discussion, which is rapidly veering away from the OP's question. i'm noticing a pattern emerging, which is that you don't answer questions which contradict what appears to be a desire to be "right", even at the expense of people's time and effort. i've encountered this behaviour before, and have learned that by engaging in any way with such behaviour simply increases the noise-to-signal ratio. so, very regrettably, for the sake of the forum and to improve the quality of discussions here it is with much asdness that i have to tell you that i'll not engage with you further, sigxcpu, on this topic.]]> lkcl CoreXY Machines Fri, 09 Jun 2017 15:13:08 -0400 https://reprap.org/forum/read.php?397,770438,772676#msg-772676 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772676#msg-772676
A delta printer has no "right angle" requirements, but it has "parallel" axis belt to axis guid requirements. OP issue is elongation at the edge of the printed model, caused by belt not being parallel to the guide.
"Right angle" is a specific case for a squared AB axes (XY, XZ or YZ) in some specific printer configurations (cartesian, H-Bot, CoreXY), it is not the generic requirement.

In a linear motion system the "force" direction vector needs to be parallel to the "guide" direction vector (sorry for my English, I don't know the exact words). In a H-bot or CoreXY configuration the "right angle" is a side-effect of XY being at "right angle".

Is it more clear now?]]> sigxcpu CoreXY Machines Fri, 09 Jun 2017 14:58:06 -0400 https://reprap.org/forum/read.php?397,770438,772658#msg-772658 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772658#msg-772658 Qdeathstar CoreXY Machines Fri, 09 Jun 2017 12:36:18 -0400 https://reprap.org/forum/read.php?397,770438,772656#msg-772656 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772656#msg-772656
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dc42
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lkcl
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sigxcpu
The unsquare XY was a forced hypotetical drawing (although perfectly working) to prove that the constraint is parallelism, not squareness. Squareness is the most used, but optional.

can you please point me to any existing off-the-shelf firmware for a CoreXY 3D printer which supports the hypothetical arrangement that you've described?

RepRapFirmware should be able to, if you configure it for a normal CoreXY printer and then enable orthogonal axis compensation.

allo dc42, nice to hear from you.

[reprappro.com]

jaezuss, i am kinda surprised that such adjustments actually exist - i wasn't actually expecting anyone to say "sure, you can" :) but in reading what they're for, it makes sense: basically the documentation there says, not in so many words, "you really should have assembled your printer correctly but if you haven't and for whatever reason you really can't face properly aligning and calibrating it, here's the extraordinarily-complex and convoluted process for calculating the necessary adjustments you'll need to correct the mis-assembly".

so if anyone *really wanted* to make a CoreXY printer where huge amounts of materials and space were wasted because the printer's frame was a parallelogram not a cube, and they *really wanted* to waste significant amounts of time on calibration which would otherwise be completely unnecessary if they simply followed everyone else's designs kept everything orthogonal.... they could.

dang.]]> lkcl CoreXY Machines Fri, 09 Jun 2017 11:54:35 -0400 https://reprap.org/forum/read.php?397,770438,772653#msg-772653 Re: Hypercube xy distortion https://reprap.org/forum/read.php?397,770438,772653#msg-772653
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o_lampe
I have only one comment for this discussion ;)

[attachment 95177 SteveWozniak_nerds.mp4]

:)]]> lkcl CoreXY Machines Fri, 09 Jun 2017 11:44:29 -0400