A bit 'o speculation is fun right? Well, heres my two cents: a cylindrical positioning system could easily be achieved by building on the darwin system. if we added a turntable module that could be attached to the Z build platform, we could then be able to make things with vertical radial symmetry. basically, we would get really easy cylinders, hopefully better gears, possibly primitive plastic threads, belts? also, its possible that we could also attach some sort of horizontal wire feed and have it do automated wire wrapping. the feed attachment could be pretty simple... just a spindle holder (which would be eminently reprappable...) the wrapping would be around the vertical axis, and the Z motion of the table would control where it wrapped as the turntable spun. being able to produce our own motors would be a huge future step. some day. =) https://reprap.org/forum/read.php?1,1023,1023#msg-1023 Thu, 15 Oct 2026 04:21:26 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,1023,2006#msg-2006 https://reprap.org/forum/read.php?1,1023,2006#msg-2006 Forrest Higgs General Wed, 23 May 2007 00:52:14 -0400 https://reprap.org/forum/read.php?1,1023,2003#msg-2003 https://reprap.org/forum/read.php?1,1023,2003#msg-2003 ZachHoeken General Tue, 22 May 2007 22:01:15 -0400 https://reprap.org/forum/read.php?1,1023,1993#msg-1993 https://reprap.org/forum/read.php?1,1023,1993#msg-1993 LeeB General Tue, 22 May 2007 16:48:29 -0400 https://reprap.org/forum/read.php?1,1023,1990#msg-1990 https://reprap.org/forum/read.php?1,1023,1990#msg-1990 ZachHoeken General Tue, 22 May 2007 16:02:20 -0400 https://reprap.org/forum/read.php?1,1023,1988#msg-1988 https://reprap.org/forum/read.php?1,1023,1988#msg-1988
"You have to remember that while 0.1 positioning accuracy is pretty much what we do, the extruded thread of molten polymer is close to 0.8 mm in diameter."

Ahh, I thought the thread was 0.5 or smaller now. Is that a limitation of the material, or process, or just where reprap is at the moment? I know there was some talk of 0.5mm nozzles, and even down to 0.1mm nozzles, and talk of different materials, etc.]]> LeeB General Tue, 22 May 2007 14:50:31 -0400 https://reprap.org/forum/read.php?1,1023,1984#msg-1984 https://reprap.org/forum/read.php?1,1023,1984#msg-1984
I think that you will find both Zaphod, Tommelise, and, I believe, Darwin use XY and "A" (extruder on/off) with Z being handled as a separate command.

The point of having another motor to allow for radial translation of a printed object is that it would allow for finer detail when producing things radial objects such as gears and the like. You have to remember that while 0.1 positioning accuracy is pretty much what we do, the extruded thread of molten polymer is close to 0.8 mm in diameter. That makes printing features of ~ 1 mm a rather difficult undertaking.]]> Forrest Higgs General Tue, 22 May 2007 14:20:51 -0400 https://reprap.org/forum/read.php?1,1023,1982#msg-1982 https://reprap.org/forum/read.php?1,1023,1982#msg-1982 LeeB General Tue, 22 May 2007 13:35:27 -0400 https://reprap.org/forum/read.php?1,1023,1972#msg-1972 https://reprap.org/forum/read.php?1,1023,1972#msg-1972
Decoding that a circle needs to be drawn would be the big thing, then the existing motors, and control boards, could be coached through drawing it using basic geometry.

What would be more useful, in my humble opinion, would be the ability to tilt the head relative to the working surface, so as to apply to the side.

It wouldn't do much good, at present, but might be a useful feature later. Say, when we want to reprap painted parts.]]> Roach_S General Mon, 21 May 2007 21:09:37 -0400 https://reprap.org/forum/read.php?1,1023,1967#msg-1967 https://reprap.org/forum/read.php?1,1023,1967#msg-1967
If we're talking about adding turntables for flexibility (which I also don't really see a need for, if print/filament/movement resolution is good)... wouldn't it make more sense to have the print head able to rotate around the print "arm"'s position, wherever that is, rather than to have a single, fixed-center turntable?]]> LeeB General Mon, 21 May 2007 16:54:40 -0400 https://reprap.org/forum/read.php?1,1023,1167#msg-1167 https://reprap.org/forum/read.php?1,1023,1167#msg-1167
The opensource robot the size of a room allows parts larger than the standard reprap bed.

Also, the coils of material can be carried like a cartridge on the extrusion head assembly.

But the main flexibility would be loading up several diagrams, then moving from table to table.]]> Homer Hollis General Mon, 16 Apr 2007 14:49:03 -0400 https://reprap.org/forum/read.php?1,1023,1161#msg-1161 https://reprap.org/forum/read.php?1,1023,1161#msg-1161
also, it would be really cool if we had a claw mechanism, then you could play a home version of the game on your reprap machine!!]]> ZachHoeken General Mon, 16 Apr 2007 09:21:33 -0400 https://reprap.org/forum/read.php?1,1023,1159#msg-1159 https://reprap.org/forum/read.php?1,1023,1159#msg-1159
Another thing, since the extruder seems to be nailed down, the transport system (or extrusion bed) seems to be the next "evolution". When I first started reading about this system, I envisioned the same type of system used in the amusment park "claw machine". In theory, this would allow the system to be scaled up to room size. Then the transport head (extruder) could move from table to table, reading a sensor on each one to "zero" the X/Y/Z, and start extruding.

This would allow workers to remove the part, reset the table and move on to the next.]]> Homer Hollis General Mon, 16 Apr 2007 08:30:03 -0400 https://reprap.org/forum/read.php?1,1023,1062#msg-1062 https://reprap.org/forum/read.php?1,1023,1062#msg-1062
like fernando said, the value of an added axis would be able to adapt the technique to the problem at hand. of course you can program a cartesian axis to do circles. we're just saying that the circles produced might be of higher quality with cylindrical.]]> ZachHoeken General Thu, 12 Apr 2007 19:46:06 -0400 https://reprap.org/forum/read.php?1,1023,1057#msg-1057 https://reprap.org/forum/read.php?1,1023,1057#msg-1057 nophead General Thu, 12 Apr 2007 19:04:34 -0400 https://reprap.org/forum/read.php?1,1023,1056#msg-1056 https://reprap.org/forum/read.php?1,1023,1056#msg-1056 Like i mentioned above, error margins will propagate a lot more in each system when you are trying to do something which it's not good at:
Drawing a circle in a cartesian system involves a lot of steps, each step adding up a new error source.
Drawing straight lines in a cylindrical system adds radial errors that can become significant very fast.

What about building the rig in a way that the x,y positioning pane is contained inside a large toothed disc, with the axis of the disc, it's radius=0,alpha=0]]> spota General Thu, 12 Apr 2007 18:22:46 -0400 https://reprap.org/forum/read.php?1,1023,1041#msg-1041 https://reprap.org/forum/read.php?1,1023,1041#msg-1041 Nevertheless, i think the cartesian one with good precision has one advantage that the cylindrical can't beat:

For non circular shapes, given an arbitrary stepper precision, incremental error margins simply add (or substract) up in the cartesian system, whereas in the cylindrical, error margins are proportional to the radius distance between the turntable origin point and the point where you are printing and add up (or substract) proportionally. In other words, having a 0,1]]> spota General Wed, 11 Apr 2007 04:34:00 -0400 https://reprap.org/forum/read.php?1,1023,1040#msg-1040 https://reprap.org/forum/read.php?1,1023,1040#msg-1040 ZachHoeken General Tue, 10 Apr 2007 23:09:45 -0400 https://reprap.org/forum/read.php?1,1023,1034#msg-1034 https://reprap.org/forum/read.php?1,1023,1034#msg-1034
It may be worth adding a curve drawing function to the firmware rather than expressing curves with a large number of straight lines, but I can't see the point of a turntable.

Currently the filament deposition system seems to be the limiting factor when it comes to accuracy and surface smoothness rather than the axes.]]> nophead General Tue, 10 Apr 2007 19:28:22 -0400 https://reprap.org/forum/read.php?1,1023,1032#msg-1032 https://reprap.org/forum/read.php?1,1023,1032#msg-1032
plus, if you want to do normal cartesian print either:

1. dont run the table and print to its build surface
or
2. remove the turntable entirely.

what is better? an XYZ system, or an XYZ + theta system. =)

hell, once you got the rest of the thing setup, you might as well go the whole way!]]> ZachHoeken General Tue, 10 Apr 2007 19:01:23 -0400 https://reprap.org/forum/read.php?1,1023,1030#msg-1030 https://reprap.org/forum/read.php?1,1023,1030#msg-1030 0.1 mm??? that's pretty good!!
Do we really need the turntable? i know that it would make cylindical symetry printing faster, but the precision seems to be OK allready, not?
Switching between cylindrical coordinates and cartesian coordinates could introduce error margins that would make awaye with the advantages of the change in coordinates system, don't you people think?]]> spota General Tue, 10 Apr 2007 18:34:49 -0400 https://reprap.org/forum/read.php?1,1023,1029#msg-1029 https://reprap.org/forum/read.php?1,1023,1029#msg-1029 Only if we design a table that moves in the x,y plane and that carries a rotating disk, able to spin 360]]> spota General Tue, 10 Apr 2007 18:29:40 -0400 https://reprap.org/forum/read.php?1,1023,1028#msg-1028 https://reprap.org/forum/read.php?1,1023,1028#msg-1028
My point was that when making a tube it would be better to lay down a coil rather than a stack or circles, but that does not fit in with slice and dice.]]> nophead General Tue, 10 Apr 2007 18:25:02 -0400 https://reprap.org/forum/read.php?1,1023,1026#msg-1026 https://reprap.org/forum/read.php?1,1023,1026#msg-1026 ZachHoeken General Tue, 10 Apr 2007 17:49:43 -0400 https://reprap.org/forum/read.php?1,1023,1024#msg-1024 https://reprap.org/forum/read.php?1,1023,1024#msg-1024
[builders.reprap.org]]]> Forrest Higgs General Tue, 10 Apr 2007 17:31:52 -0400 https://reprap.org/forum/read.php?1,1023,1023#msg-1023 https://reprap.org/forum/read.php?1,1023,1023#msg-1023
a cylindrical positioning system could easily be achieved by building on the darwin system. if we added a turntable module that could be attached to the Z build platform, we could then be able to make things with vertical radial symmetry.

basically, we would get really easy cylinders, hopefully better gears, possibly primitive plastic threads, belts?

also, its possible that we could also attach some sort of horizontal wire feed and have it do automated wire wrapping. the feed attachment could be pretty simple... just a spindle holder (which would be eminently reprappable...) the wrapping would be around the vertical axis, and the Z motion of the table would control where it wrapped as the turntable spun. being able to produce our own motors would be a huge future step.

some day. =)]]> ZachHoeken General Tue, 10 Apr 2007 17:16:14 -0400