Designing the coreXY with linear guides and extrusions tell me that you are interested in quality. Please let me give you the hint to support your pulleys from top, otherwise they will tend to bend.by JoergS5 - Mechanics
Hello, I am interested in wire solutions also ... If you take a 8 mm shaft for wiring you have a perimeter of about 24 mm, so with a 0.2 mm wire you need at a 300 mm printer about 14 rounds and need 3 mm for the line moving, this should be small enough to build into your printer.by JoergS5 - Mechanics
gives good tutorials to start with. So please don't give up, but take your time.by JoergS5 - General
QuoteBanana_Luke I have active cooling and heatsinks on the Chip. Just a comment, you may know it: the heatsink must be installed at the opposite side of the circuit board, not on the chip. I bought TMC2130 from FYSETC, they have some disadvantes. One is that the place where the heatsink shall be installed, there is no heat conduction, because they coated lacquer over the heat conduction pins.by JoergS5 - Stepper Motors, Servo Motors, DC Motors
The results of some research so far: - parallel scara is more precise than serial scara and I expect it to be more stable also (serial scara in videos are often shaking). I will concentrate on parallel. Harmonic drive is too expensive for me, I will decide between planetary or cycloid drive, 3d printed if it's good enough. - one problem is that firmware does not support parallel scara yet. I'llby JoergS5 - Polar Machines, SCARA, Robot Arms
I only know Gates GT2 as the Gates Poly Chain GT2. It is different from the commonly used GT2 belt. Teeth of Gates GT2 are 8 or 14 mm distance. Other names for this belt is PC2 8 MGT and PC2 14MGT.by JoergS5 - Mechanics
First I thought about whether Harmonic Drive or cycloidal drive is exact enough for 3D printing. The commercial harmonic drive solutions have a repeatable resolution of 1 arcmin (those drives are very expensive btw). If I calculated correctly: harmonic drive radius 35 mm, perimeter 219 mm, precision 219/360/60 = 10 micrometer For a SCARA arm of 300 mm this is about 0,1 mm precision. With two arby JoergS5 - Polar Machines, SCARA, Robot Arms
I search a solution where you can hide the mechanics for the z-axis totally invisible under the bed. But I have no solution yet. One reason is, I want to have access from all sides to the bed. Another reason is, I want to build the printer as modular as possible to be able to replace the parts for comparing different technology. If a construction needs double space under the bed, this would be nby JoergS5 - Mechanics
Hello, I search for methods to speed up 3D printing and had the following idea. Please tell me your thoughts about it. Speeding up a 3D print could be done by multiple hotends working at the same time. So why not build a 3D printer with the printbed in the middle and at each side one or two SCARA printers (so 4 or 8 in total), printing at the same time. The printbed is moved as Z axis. Advantaby JoergS5 - Polar Machines, SCARA, Robot Arms
@warbunniex do you have a proposal how to construct a one lead screw bed? My fear is that the bed will tilt to one side if it is not fixed in at least two places. I thought about fixing the screw and shaft centrally under the bed, but then you need a lot of space under the bed and must stabilize the shaft carefully.by JoergS5 - Mechanics
Thanks for the hints, I'll wind them on the shaft first, it's 8 mm diameter. I want to see the resulting quality first, speed is not important. I'll try FireLine 0,1 mm first.by JoergS5 - Mechanics
I will try your solution for the Y-axis: a double shaft stepper in the middle, connected by two shafts to the side, then ... ok, I made a "professional" picture.by JoergS5 - Mechanics
You can correct the error directly in software. You know where the position is, so you know the error at this time. The error is nonlinear, so it may be worth to precalculate a lookup table for the positions and corresponding errors to ease calculations for the processor. The error is linear, so it's easy to correct by a stepper correction factor.by JoergS5 - Mechanics
Thanks Mark. Every time I read your comments or blogs, you give me new construction ideas!! Your Z construction is what I plan roughly (with double shaft Stepper, but without gearbox) for my Y Axis in a dualwire-gantry printer. But using it for Z is a great idea also.by JoergS5 - Mechanics
In one thread I read,it's very important that the grooves are very exact. Otherwise you will directly see it in the 3d print. I think about using two short parts of a 20x2 trapezoid spindle as pulleys.by JoergS5 - Mechanics
I meant, the tension will be expanded to the whole wire. If you have a CoreXY with 2 m wire and you stretch your pulleys by 1 mm with 2 loops, you strech the whole line by 2 mm / 2000 mm, by one promille. The stretching between the pulley will be leveled with the rest of the line after a few rotations. (the line tension will have an effect on the tension on the wired line and so on, until the whoby JoergS5 - Mechanics
I think I get it now: every single turn every line is rewinded by the double angle between the two pulleys. Tension works against this because the shortest distance would be without an angle and the line tries to take the shortest distance, so grooves are necessary to take the "angle-route". You could also use a ball bearing or rotating pins pushing the line down (every single line). Result is,by JoergS5 - Mechanics
Maybe the second pulley, which is not driven by the stepper, shall increase the tension and as an effect the friction. But I'm not sure. Edit: no, I think it's not the reason, because the tension should diminish and balance out with the rest.by JoergS5 - Mechanics
Maybe you can help me understanding: in an old thread (https://reprap.org/forum/read.php?2,151871,186357) there was a construction If I use one pulley instead and take 5 windings, the result should be the same with regard to friction or even higher because the whole pulley is used. What is the advantage of the 2 pulley solution?by JoergS5 - Mechanics
I connected my extruders with inner angles now and it was not stable enough. I have extrusions which are exactly cut, so I connected them without space. This helped, but there is still some movement. I use 45x45 with long parts. I remembered my experience with woodworking: if you are machining workpieces, you should fix them with two points, for example clamps. The reason is, you want to preventby JoergS5 - Extruded Aluminum Frames
Thanks for sharing the details, Viktor. @o_lampe: First I mixed my docu, it was not Sli3dr, but a project from The reason for the high tension was, he wanted to reduce stretching of Spectra line. I am thinking about using steel again. A high 20-40 mm diameter makes sense to not destroy the wire.by JoergS5 - Mechanics
For big printers you will need thicker wires, e.g. the Sli3dr creator will switch to wire for a tension of 60 kg. In my calculation this means FireLine above 0,5 mm diameter. I plan to use wire for a small printer (MGN07 linear guides and Bowden) and will try FireLine 0,1 mm, where angles and tensions should not be a problem if the stepper pulley is large enough.by JoergS5 - Mechanics
One Aspect I thought about is: every mechanic has its tolerances and imperfection. As an example, the 3D printed pulley will have different diameters. How is the relation of this tolerance in respect to the angle imperfection or the other backlash/angle/... problems. Or as another example, the stretching effects of the wire between the pulley or when you wind it, length of the wire will be differby JoergS5 - Mechanics
If you have a small diameter of the wire or a big distance, the angle will be low and you may not need the construction. You will have a bit of backlash at the pivot points (ball bearings?). You can use something like that: turned, so the ball moves up and down, but it will have backlash also.by JoergS5 - Mechanics
I admit, I saw your picture only. Your video was very interesting. Your point of axial forces was interesting: if axial forces are high enough, they will pretect against the lines getting stapled. If there are less then say 10 lines, there will be no need for moving the z axis, I expect. Next I will compare FileLine with Kevlar and a steel line. Bearpaw 452 is very expensive, I am still thinkinby JoergS5 - Mechanics
For cutting with a hacksaw: mark the cutting line by holding your carpenter's angle and mark the lines with a sharp knife: on top and at the side visible to you. Saw without force and slowly at the beginning, as long as you dont't have resistance from the aluminium. You can support the saw with the nail of your thumb (but don't cut into the thumb...) You will get experience in which direction yby JoergS5 - Extruded Aluminum Frames
My opinion is, it is only necessary that they are roughly square. (about 1 mm) Squareness of the connection is what matters, so you connect them by an inner or outer angle. If you want, you can strengthen it by a metal sheet at the outside connecting two extrusions. What is important: don't connect the extrusions extactly but leave a space of 1-2 mm, so the connector defines the squareness, notby JoergS5 - Extruded Aluminum Frames
Interesting idea. You can additinally fix the line in the middle of the spoolers, so there is no spinning. If you don't fix the line, you can you your construction is a closed belt system, if you need that. (hmm maybe not fully, the direction of the wire changes in the middle). I thought about how to move the spooling. One possibilitiy is to use the stepper which moves one axis: if you connectby JoergS5 - Mechanics
Ich stimme Dir zu. Wobei ich noch ein kleines Gehäuse um den Schleifblock bauen würde, das verhindert, dass der Staub gleich wegfliegt. Das Gehäuse kann dann gleich den Adapter für den Schlauch enthalten. Wäre ein lohnenswertes weiteres Thing (Schlauchdurchmesser parametrisiert)!by JoergS5 - Druck- und Heizbetten
If the line is not straight on the shaft, the line is in an oval form. So the line is a bit longer. But this longer line is no problem, because it can be corrected by software. But it should be the same factor constantly, which means same angle and the shaft should have a precise surface. Crossing the line results in in a longer line also (and can also be corrected by software), but has the advby JoergS5 - Mechanics