Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 01:36AM |
Registered: 11 years ago Posts: 5,780 |
Quote
thetazzbot
so what i have is one static screw with a spacer in one corner, and three adjusters in the remaining corners.
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 02:23AM |
Registered: 11 years ago Posts: 1,277 |
I said two I meant three or more specifically that plane geometry states "Any three noncollinear points can define a plane (that is if ALL three points TOGETHER are noncollinear)".Quote
the_digital_dentist
I challenge you to draw two points such that I cannot draw a straight line between them.
Quote
A plane can be defined by four different methods:
A line and a point not on the line
Three non-collinear points (three points not on a line)
A point and a normal vector
Two intersecting lines
Two parallel and non-coincident lines
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 02:29AM |
Registered: 11 years ago Posts: 1,277 |
Agreed, but I still do not get how my bed can be almost dead flat (within a few microns up against a speed square, a composite square, and a laser/digital level flat part) but that one corner droops when on the bed. Take it off and it is flat with the rest of the corners. With four screws I can see what I was doing because I saw that in the home position and made it level but the opposing side would then droop and when I raised that up it made my bed all sorts of warpped. With three screws I do not have that problem but that home position, being in free space, is left there drooping with no way to level it it up. I wonder why it is drooping when only on the bed? My boro glass, over just the MK2B, did the same exact thing. So, even with a 6mm hunk of metal on top it is still going to droop I think.Quote
the_digital_dentist
Quote
thetazzbot
so what i have is one static screw with a spacer in one corner, and three adjusters in the remaining corners.
When you adjust the screw diagonally opposite the spacer, what do you think the bed is going to do? If the corner with the spacer were free to move, the bed plate would pivot about the other diagonal. Since you have fixed the corner with a spacer, instead of pivoting about the other diagonal, the plate will bend about that diagonal. How can you level the bed by bending it? This is why using four screws to level the bed is a bad idea- it makes no sense and it requires a lot of screwing around to make it only sort-of work.
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 03:46AM |
Registered: 10 years ago Posts: 175 |
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 04:35AM |
Registered: 11 years ago Posts: 1,277 |
Nice, but not revelant to this discussion though.Quote
chriske
Hi,
Don't read the whole post(sorry)
We just started building our 18the printer(most of them for friends). Almost all are i2 models. Almost all of them use a glass surface(4mm) on top of the heatbed.
Don't know about other countries, but our glass is pretty flat. (Belgium, glass is from Saint-Gobin, France)
The only thing we do is clean and degrease the glass surface using glasscleaner(I'll take it off the printer of course), sticks like hell. I myself use multiple glass sheets because it takes to long for the parts to come of the glass. So while it's cooling, next part is already printing. After about 15 to 20 minutes parts just pop off the glass.
And BTW our printers work just fine, gives good quality prints, no warping at all(even large prints) and cost about 400€ to build.
My very first i2 was assembled exactly 2 years ago, prints every single day, still doing it's job, no changes have been made, nor replacements were needed.
Chris
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 06:58AM |
Registered: 10 years ago Posts: 175 |
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 07:05AM |
Registered: 11 years ago Posts: 1,277 |
Well, it pertains but didn't say how you managed it. I have an I3 Rework from hell as not a soul can figure out wth is wrong with it so I can't even make it flat with 3 screws instead of 4. It isn't the boro glass nor the heat spreader it is something weird. [edit: So, in my case it would be Voodoo to make it flat as it is already cursed.]Quote
chriske
Oops...!
I thought it was all about hotbed flatness..?
Hmm.. I should have posted just the first three lines.
Chris
Re: Hotbed flatness, voodoo or scientific method? July 02, 2015 09:39AM |
Registered: 9 years ago Posts: 396 |
Re: Hotbed flatness, voodoo or scientific method? July 03, 2015 02:25AM |
Registered: 11 years ago Posts: 1,277 |
Re: Hotbed flatness, voodoo or scientific method? July 03, 2015 09:59AM |
Registered: 11 years ago Posts: 5,780 |
Quote
thetazzbot
It is not illogical to have four leveling screws vs three. Although it is agreed that three give a finer adjustment.
Re: Hotbed flatness, voodoo or scientific method? July 03, 2015 04:05PM |
Registered: 9 years ago Posts: 396 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 01:01PM |
Registered: 11 years ago Posts: 1,277 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 02:06PM |
Registered: 11 years ago Posts: 5,780 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 02:24PM |
Registered: 11 years ago Posts: 1,277 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:06PM |
Registered: 9 years ago Posts: 396 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:09PM |
Registered: 9 years ago Posts: 396 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:14PM |
Registered: 9 years ago Posts: 1,873 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:17PM |
Registered: 9 years ago Posts: 396 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:27PM |
Registered: 11 years ago Posts: 1,277 |
If I could plus one you I would.Quote
thetazzbot
But i have to tell ya im so fed up with this i3 im about to dismantle it coompletely. Start over with something that delivers more prints than headaches.
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:29PM |
Registered: 11 years ago Posts: 1,277 |
I am not understanding what you mean.Quote
JamesK
From what you describe it sounds like your smooth rods are not parallel. If you measure directly over one of the rods do you find a much smaller difference?
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:38PM |
Registered: 9 years ago Posts: 1,873 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:43PM |
Registered: 11 years ago Posts: 1,277 |
How do I position the print head/nozzle above one of the two smooth rods? in case you do not know this is an I3 Rework that I have so a variant of the I3.Quote
JamesK
Try doing the same test of setting Z0 at the front of the bed and then comparing with the back, but position the print head directly above one of the two smooth rods instead of out at the corner. If there is minimal difference between front/back when over the rod, and a greater difference when measuring away from the rod it will confirm that the problem is with the geometry of the rods, with the bed rotating and twisting as it moves front to back. I'm guessing you went for three bearings instead of four? A four bearing arrangement would be more likely to bind in this scenario, but a three bearing setup could have enough play to twist. Of course I may have just misunderstood what you are measuring, in which case some annotated photos might help clarify things.
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:47PM |
Registered: 9 years ago Posts: 1,873 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 03:58PM |
Registered: 11 years ago Posts: 1,277 |
Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 04:06PM |
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Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 04:09PM |
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Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 09:20PM |
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Re: Hotbed flatness, voodoo or scientific method? July 14, 2015 10:06PM |
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Re: Hotbed flatness, voodoo or scientific method? July 15, 2015 03:33PM |
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Re: Hotbed flatness, voodoo or scientific method? July 15, 2015 09:03PM |
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