DemonDeltaTube - A delta inside an acrylic tube... Build

DemonDeltaTube - A delta inside an acrylic tube... Build So this was not my idea but I did like it the original idea was presented here http://forums.reprap.org/read.php?178,785395,785395#msg-785395 The idea is to build a delta printer inside a PVC or acrylic tube, the tube will act as both the frame and an enclosure. The first issue is not how to mount things to the inside of a tube, this is an issue, but it is getting hold of a suitable tube. My options were PVC sewer pipe or some sort of display case-type acrylic tubing. PVC sewer pipe is available in 8-foot lengths in 300mm diameter or thereabouts, and its expensive. Offcuts would be great but I have no source for them, I've tried local scrap stores, junk shops etc.. Building sites might also be worth a look but nothing came up. So I looked into ready-made acrylic tubing but a 300mm diameter x 600mm high tube in 4mm acrylic costs around £160. So how about a fishtank? I came across this one called a [url=https://www.google.co.uk/search?q=biube+fishtank&hl=en&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiHwr6b96_YAhWRF8AKHUpfDGsQsAQIQQ&biw=2327&bih=1214]Biube[/url] eBay provided me with one second hand (no fish included) for £30. Its a 300mm diameter, transparent tube. It is certainly preferable to do this with a transparent tube, delta printers look amazing in function and not being able to see inside would be quite unfortunate. So fishtank arrived, acrylic could use a polish but its quite serviceable. 4mm thick walls. [attachment 100972 20171229_190504.jpg] First snag the diameter at the top and the diameter at the bottom are not the same, it is essentially a plastic cup, not a cylinder. The difference in radius is 11mm over 435mm. My plan is to use linear rails, I have used rollers on extrusions once before on a kossel mini, it worked pretty well, but my other two deltas use rails, and they work better. I have got 3x "chi-win" MGN9H rails from ebay for around £15 each. How to drill the holes? Since precision is required and with a smooth "cylinder" (I will refer to the fishtank as a cylinder from here on in as "frustum of a cone" is not particularly eloquent) there is nothing to align the rails on, unlike a hexagonal or triangular framed conventional delta design - there appear to be 4 methods that I can determine. 1) use paper circles possibly with appropriate markings printed onto them at 0, 120 and 240 degrees, to make marks on the cylinder at the top and the bottom, and draw a line with a straight edge. - Would work but seems a little imprecise. 2) make a large paper template that I can wrap around the cylinder with the hole markings printed onto it after drawing it in a 2D design package. - needs a large paper printer to work, my cylinder is not actually cylindrical, and I have no expertise with 2D drawing packages. 3) Get someone to mount the cylinder in a 5 axis cnc and precision cut the holes. Probably the best idea, but I don't know anyone offhand, or how easy this would be to do. 4) Make a template using my existing Kossel XL printer to place inside the cylinder to mark the axis along which to drill the holes. So given that 4 is more fun, I designed a scaffold in Tinkercad, after modelling the cylinder and determining where 0, 120 and 240 degrees were. The idea being I would insert this into the cylinder and use the vertices to mark the axis where the rails would be mounted. [attachment 100973 scaffold.png] Now to print it. This would be by far the largest object I have printed, at 300mm width and 386mm tall. PLA was chosen, I don't need any warping. Several attempts were made, I needed to remove bed clamps, move fans, and generally squeeze every last mm of xy space out of my kossel XL. There was one slight layer shift on one "leg" from curling overhangs, and it stopped with a heater fault with around 50mm to go. My heater wires has come loose. Luckily I'm using RRF on duetwifi and the power_resume feature came to my recuse. Only the hotend heater was disabled, I rebooted the printer, making sure to immediately return the bed set temp to 75 so as not to lose adhesion on the part, then fixed the heater wiring, and sent M916, whereby it resumed printing where it left off. After a total of 17 hours it finished. [attachment 100980 20171229_134046.jpg] Now to mark the lines where the rails should be: [attachment 100981 20171229_160318.jpg][attachment 100982 20171229_160323.jpg] These lines are vertical measured using a square and a digital angle finder. I will need to offset the rails at the bottom by whatever distance is required by simple Pythagorean geometry to ensure they are vertical in and X and Y. Now since this machine is going to be quite experimental I am going to try to use leadscrews. I looked into ballscrews versus leadscrews, and whilst ballscrews are more efficient, they don't offer any passive holding when motors are powered-off so I don't want my effector dropping to the bed after a print finishes. Leadscrews at 8mm lead should be 400 steps/mm for 1.8 deg motors. This should offer sufficient resolution 0.0025mm, and speed (using 24v low inductance motors). I designed an axis which might allow me to attach the motors and leadscrews to the rails. I intend to print all parts in something like Ngen from Colorfabb. [attachment 100983 axis.png] Controller will be duetwifi and intend to use sensor less homing for endstops, and a Precision Piezo sensor in the hotend, which will be a raised hotend design. I have an e3d gold v6 hotend on order. One thing that will also make this printer unusual is that it will essentially have an open base. So it could be placed onto a variety of surfaces to print on, using the fast delta calibration on RRF. The intention currently is to get a tooling plate bed with silicone heater as the default printing surface, and that the printer would be lifted off the bed to free the parts when finished. This will probably prove impractical so a door might have to be made in the cylinder. https://reprap.org/forum/read.php?178,802910,802910#msg-802910 Mon, 07 Sep 2026 23:28:07 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?178,802910,830753#msg-830753 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,830753#msg-830753
The main issue was that the acrylic cylinder did not tolerate being heat cycled from ambient to 55 deg repeatedly and developed major cracking, it looked like it was about to fall apart.

Parts are on ebay [www.ebay.co.uk] as well as some other stuff, some of it 3d printing related.]]> DjDemonD Delta Machines Thu, 09 Aug 2018 19:13:20 -0400 https://reprap.org/forum/read.php?178,802910,813561#msg-813561 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,813561#msg-813561
I'd suggest that a transparent cylinder like a fishtank would make a very good delta enclosure placed over a more conventional frame, but using it as a frame makes for a tricky build. Although the next step if I was going to make more would be figuring out how to make assembly easier.]]> DjDemonD Delta Machines Fri, 09 Mar 2018 02:20:37 -0500 https://reprap.org/forum/read.php?178,802910,813543#msg-813543 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,813543#msg-813543
[www.eplastics.com]

The tolerances should be very good, and the cast tubes are much better than their extruded counterparts.]]> klcjr89 Delta Machines Thu, 08 Mar 2018 23:21:40 -0500 https://reprap.org/forum/read.php?178,802910,813539#msg-813539 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,813539#msg-813539
[attachment 103204 20180308_231722.jpg]

However in terms of real world results I just printed this Marvin:

[attachment 103205 20180309_003301.jpg][attachment 103206 20180309_004313.jpg]

and the layer registration issues seen in the previous cubes seem to have vanished, in fact, he has visible facets (Nebbian's test of quality - where is he these days?)
So a couple of things I've learned:
-Use anti backlash nuts for leadscrews especially on any axis which is prone to rapid changes of direction - so less necessary with a heavy z axis, more so for X, Y or on deltas.
-Don't use Ngen for structural parts I have had several snap, I might be flamed for this, but it's overrated, its quite brittle and very stringy even when you are trying hard to tune the stringiness out.
-For printer parts consider using carbon fibre filled PETG (I am using Technology Outlet) this stuff prints well, hides the layer lines and seems very stiff and certainly stronger than unfilled PETG.
-I don't think I've said this enough - Don't build a delta printer in an acrylic tube.]]> DjDemonD Delta Machines Thu, 08 Mar 2018 19:53:05 -0500 https://reprap.org/forum/read.php?178,802910,812721#msg-812721 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812721#msg-812721 DjDemonD Delta Machines Sat, 03 Mar 2018 03:05:46 -0500 https://reprap.org/forum/read.php?178,802910,812720#msg-812720 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812720#msg-812720

Quote

I might build a slightly more conventional frame

In the U.S. they have these huge water bottles. Is that conventional enough? ;)]]> o_lampe Delta Machines Sat, 03 Mar 2018 03:02:40 -0500 https://reprap.org/forum/read.php?178,802910,812711#msg-812711 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812711#msg-812711 DjDemonD Delta Machines Sat, 03 Mar 2018 00:36:10 -0500 https://reprap.org/forum/read.php?178,802910,812710#msg-812710 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812710#msg-812710 Cobalt Griffon Delta Machines Fri, 02 Mar 2018 22:37:22 -0500 https://reprap.org/forum/read.php?178,802910,812697#msg-812697 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812697#msg-812697 DjDemonD Delta Machines Fri, 02 Mar 2018 15:48:52 -0500 https://reprap.org/forum/read.php?178,802910,812696#msg-812696 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812696#msg-812696 [www.obxstore.com]]]> MKSA Delta Machines Fri, 02 Mar 2018 15:47:54 -0500 https://reprap.org/forum/read.php?178,802910,812692#msg-812692 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812692#msg-812692 o_lampe Delta Machines Fri, 02 Mar 2018 15:26:21 -0500 https://reprap.org/forum/read.php?178,802910,812674#msg-812674 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812674#msg-812674 DjDemonD Delta Machines Fri, 02 Mar 2018 14:08:54 -0500 https://reprap.org/forum/read.php?178,802910,812672#msg-812672 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812672#msg-812672 Just my $0.02]]> Cobalt Griffon Delta Machines Fri, 02 Mar 2018 13:57:28 -0500 https://reprap.org/forum/read.php?178,802910,812657#msg-812657 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,812657#msg-812657 DjDemonD Delta Machines Fri, 02 Mar 2018 11:50:32 -0500 https://reprap.org/forum/read.php?178,802910,811992#msg-811992 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811992#msg-811992 DjDemonD Delta Machines Sun, 25 Feb 2018 16:30:05 -0500 https://reprap.org/forum/read.php?178,802910,811984#msg-811984 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811984#msg-811984 Cobalt Griffon Delta Machines Sun, 25 Feb 2018 15:24:49 -0500 https://reprap.org/forum/read.php?178,802910,811975#msg-811975 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811975#msg-811975
Here the first in PLA, with woefully inadequate cooling:

[attachment 102904 20180225_191738.jpg]

The second, same PLA but with twin fans, nozzle jammed:

[attachment 102905 20180225_191745.jpg]

The third in ABS (my preferred material by far):

[attachment 102906 20180225_191755.jpg]

Now its not perfect, fans could be ducted to provide better cooling, especially as the machine is an always enclosed machine by it's nature. I currently have not done any pressure advance tuning, to make the seams neater. But I think its okay for its 5th print, and given that its not a precise delta frame but a used fishtank.]]> DjDemonD Delta Machines Sun, 25 Feb 2018 14:25:15 -0500 https://reprap.org/forum/read.php?178,802910,811893#msg-811893 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811893#msg-811893
So will unjam and switch to abs. Might have to drill a hole to fit a vent fan to allow the inside to be cool when printing pla.]]> DjDemonD Delta Machines Sun, 25 Feb 2018 05:43:14 -0500 https://reprap.org/forum/read.php?178,802910,811882#msg-811882 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811882#msg-811882 Even worth: by using them the screw can now wobble freely.
You'd have to design something similar for the anti-backlash nut.]]> o_lampe Delta Machines Sun, 25 Feb 2018 03:48:14 -0500 https://reprap.org/forum/read.php?178,802910,811846#msg-811846 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811846#msg-811846
[www.thingiverse.com]]]> DjDemonD Delta Machines Sat, 24 Feb 2018 18:04:20 -0500 https://reprap.org/forum/read.php?178,802910,811810#msg-811810 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811810#msg-811810 klcjr89 Delta Machines Sat, 24 Feb 2018 13:30:22 -0500 https://reprap.org/forum/read.php?178,802910,811731#msg-811731 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811731#msg-811731

Quote
Myself, on page two
There are couplers with an "X" in the middle, they allow radial misalignment without lateral movement. If you have flexible filament for the "X", you could make them yourself smiling smiley

I mentioned those couplings earlier, but not knowing the name of them....
You could print them in one piece with a TPU segment in the middle.]]> o_lampe Delta Machines Sat, 24 Feb 2018 03:57:15 -0500 https://reprap.org/forum/read.php?178,802910,811688#msg-811688 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811688#msg-811688 DjDemonD Delta Machines Fri, 23 Feb 2018 18:36:14 -0500 https://reprap.org/forum/read.php?178,802910,811686#msg-811686 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811686#msg-811686
You need to get these, proper Oldham couplings.]]> klcjr89 Delta Machines Fri, 23 Feb 2018 18:28:49 -0500 https://reprap.org/forum/read.php?178,802910,811640#msg-811640 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811640#msg-811640
Just also want to say the sensorless homing is working perfectly as long as you remember to calibrate after homing. Otherwise there is enough inaccuracy to cause a head crash. This is worse now with the flexible couplers as they stretch when the carriages hit the motor brackets before the stall detection kicks in and stops the motors.]]> DjDemonD Delta Machines Fri, 23 Feb 2018 14:12:02 -0500 https://reprap.org/forum/read.php?178,802910,811602#msg-811602 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811602#msg-811602 firefly555 Delta Machines Fri, 23 Feb 2018 10:27:13 -0500 https://reprap.org/forum/read.php?178,802910,811461#msg-811461 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811461#msg-811461
[attachment 102821 20180222_192000.jpg]

What I've done is to fit flex couplers at each motor. I did not have any suitable ball bearings but found some small plastic fittings which are inside the couplers, the couplers are then stretched and tightened, to prevent any Z movement during reverses in motor direction (thanks to Olampe for this idea). Removed all three axes and reassembled them. Returned the lower bearings. Now nothing wobbles around as it moves.

So whilst by no means perfect, quite a big improvement on before. Now waiting on the anti-backlash nuts.
Use flex couplers, with leadscrews unless they are extremely precisely mounted, if anyone needs 3 rigid couplers (5mm ot 8mm) in fetching anodised blue, let me know.

It calibrates to 0.25mm deviation, which is a far cry from my XL which calibrates over the central 200mm of the bed to 0.004mm, but its made from a fish tank!

Maybe now to print something a little more useful as a test like a benchy.]]> DjDemonD Delta Machines Thu, 22 Feb 2018 14:23:09 -0500 https://reprap.org/forum/read.php?178,802910,811290#msg-811290 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,811290#msg-811290 DjDemonD Delta Machines Wed, 21 Feb 2018 08:21:43 -0500 https://reprap.org/forum/read.php?178,802910,810972#msg-810972 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,810972#msg-810972 DjDemonD Delta Machines Mon, 19 Feb 2018 08:56:16 -0500 https://reprap.org/forum/read.php?178,802910,810967#msg-810967 Re: DemonDeltaTube - A delta inside an acrylic tube... Build https://reprap.org/forum/read.php?178,802910,810967#msg-810967

Quote

Also, it might be worth trying to retain the leadscrew nuts to the carriages in such a way that they are unconstrained laterally

How come, nobody has invented an anti-wobble bearing? It's like a thrust bearing, but the balls can roll around laterally too.]]> o_lampe Delta Machines Mon, 19 Feb 2018 08:42:36 -0500