The Stupidly Tall-merod

Most of the parts have arrived for my tall-merod and I've built the frame. In a moment of recklessness I went for 550mm parts for the Y axis and 1000mm for Z. The bed I've ordered is only 300mm x 200mm but that leaves me room for future upgrades, plus as long as the object's footprint is within that size I can theoretically print up to 400mm wide!

I'm still using the 200x200 bed for now as I'm waiting to buy a pillar drill so I can do a decent job of extending the bed support, and I haven't bought a 24V power supply yet either. The pillar drill will also be used to drill out a heater block to fit a 6mm 24V heater cartridge. Thanks to dc42 and DaveK for all the advice on that front.

I expected to have to print some kind of wall bracket to clamp round the top of this beast. Now I've built it it's surprisingly sturdy, but there is still some inevitable wobble. First print will be said bracket.

Frame assembled, stepper motors reattached (note the most important bit, snazzy new colour scheme!):


Y belt attached and tensioned, extended ribbon cable crimped and attached, X arm put back on:


Finally, cables chopped in half and spliced with 750mm of extra wire:


Fired her up and everything seemed to function. Almost... I was a bit worried about the potential voltage drop with all the extra resistance introduced, but as I didn't measure it beforehand I can't compare. I found the Duet wiring diagram in the instructions pages and wired it up perfectly, then sat there scratching my head for 10 minutes wondering why my Z probe didn't work. Crossed wires when splicing? Too much extra cable, not enough of 3.3V getting to the IR sensor? Then I read the text highlighted in bright red above the diagram explaining that it was for 0.78 firmware and the probe pin has moved, my printer is still on 0.59-dc42. Doh! Once I verify it can still print I'll set about upgrading to 0.78.

I'm also going to have to turn the accelerations down a bit I think, especially when I attempt tall prints!

I'll keep the updates coming when I get around to testing.

Gonna have to load that beast with 5kg reels of filament

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Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

Hi static65

!! Well done, that's taller than any other I've seen so far!

Ian
RepRapPro tech support

How long will it take you to lower the X axis to the bed?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
static65

I'm also going to have to turn the accelerations down a bit I think, especially when I attempt tall prints!

I'll keep the updates coming when I get around to testing.

You only need to worry about the Y acceleration - the others are not affected by the height of the print
Greg

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Ormerod #17

The Y acceleration may have to be turned down to prevent the print wobbling. The X acceleration may have to be turned down because the reaction when the print head accelerates will put additional bending forces on the Z extrusion.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42
How long will it take you to lower the X axis to the bed?

AGES What's the maximum recommended speed so that the Z probe works reliably? Or is it more a limitation of the threaded rod design. I've upped the speed from 200 to 400.

I've got a couple of microswitches, just haven't bothered to look at fettling my g-code to work with them yet. I'm assuming I could bring Z down much quicker if it was microswitch triggered?

Cheers,

Watch the speed on that Z-rod, too fast and with the nut at the bottom position, it could start whipping and bend.

---

Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

Quote
Davek0974
Watch the speed on that Z-rod, too fast and with the nut at the bottom position, it could start whipping and bend.

An excellent point. Even the static load might encourage it to bend when the carriage is high up. Best to use a thicker one I think.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I would lightly restrain the top of the Z rod. Not in a bearing, but possible in a printed part that allows it to wobble a bit if it wants to. I haven't needed to do it with mine, but it's only half a meter long! A thicker, heavier rod may cause more problems, I would have thought. Making sure the rod is straight would be a better bet.

Ian
RepRapPro tech support

Hi,

wow, thats a big Thing.




I will also upgrade my ormerod. But only the Z Axis to a 450mm print height. I will upgarde to a 600mm size of the hole Z-axis

Ah good points, I'll keep the speed on the low end of the spectrum.

Unfortunately the M5 rod wasn't sent in a cardboard tube or anything particularly protective and arrived looking rather curved. It was the cheapest one on ebay, get what you pay for. I've done my best to straighten it out but there's still some minor inconsistencies. I've already restrained the top of the M5 rod with this design found on thingiverse (probably made by someone on this very forum): Z axis top mount. It's restrained but with a few mm clearance around the bar top to allow for some wiggle. You should be able to make it out in the third picture.

I'm also using iamburny's Z and extruder drive gears, MasonStonehenge's spring-loaded extruder block, and Form232-tek's cooling ducts. Plus aluminium x-arm and bed support parts provided by Davek. When I get round to it/remember I'll print an extended Z-nut holder (jstck's design?)

My weekend has officially begun, time to get testing and see if I can print a ridiculously tall vase before Monday!

I would be more concerned with it flexing when the whole thing is at high Z (a long segment of rod between the gears and the z-carriage, and the weight of the whole thing on it). It should not be too much work to replace it with a thicker rod (at least, less than what you have gone through already). I'd go with M8 or maybe even a "real" leadscrew.

So here is my Tall-merod.... whole Z-axis is about 600mm

for comparsion with the original axis on the side.




now i have to extend the wiring....

Nice! Is that an Iron Man arc reactor I see next to it?

Printing a 750mm vase now. It took me three attempts to find a scad script that didn't crash when I tried to generate a vase that high! Then I had issues with spiral vase mode in slic3r randomly missing one of the corners every now and then, which is a shame as it was really quick! It's now printing minus spiral vase mode. 3125 layers! Estimated 4 or 5 hours to completion. If it all works beautifully - perfect, but I'm more interested in seeing what can and maybe will go wrong at that height.

Quote
static65
Nice! Is that an Iron Man arc reactor I see next to it?

Printing a 750mm vase now. It took me three attempts to find a scad script that didn't crash when I tried to generate a vase that high! Then I had issues with spiral vase mode in slic3r randomly missing one of the corners every now and then, which is a shame as it was really quick! It's now printing minus spiral vase mode. 3125 layers! Estimated 4 or 5 hours to completion. If it all works beautifully - perfect, but I'm more interested in seeing what can and maybe will go wrong at that height.

hi,

yes, it is an arc reactor for neopixel rings (found on thiniverse)

Success! 8 hour print. I removed all the custom max speeds and accelerations I had set in my config.g, so this was done at whatever the default is for 0.59. There's a pretty unsightly seam working its way up around the whole thing at the layer change, and it's entirely not watertight but it's consistent quality all the way to the top.

There's no apparent flexing in Z, and to the naked eye there's no visible evidence of a twist or squished layers. Didn't even need a wall bracket it seems, though this is only the first tall print... more tests required. One of the main drivers behind the axis extensions was to print this Halo rifle prop so it'll be interesting to see how it handles a lot more weight moving around at height.

Wow

nice job

Nice!

One other thing to look out for when you start tweaking speeds is the y axis acceleration, too much and with a tall print on the be, inertia could break the joint at the bed level and it'll fall over.

Interesting stuff.

---

Another RS Ormerod Mk1 meets the world

Retired now but I used to make....
CNC Machined Mk1 aluminium bed support plates for the Ormerod
CNC machined X-plates and ribs for Mk1 & Mk2 Ormerods
CNC machined bed support arms for the Mk2 Ormerod.
Dual Hot-End heatsink blocks.

Looking good!

Can you share you design for the filament spool holder? I could use one of those.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
Davek0974
One other thing to look out for when you start tweaking speeds is the y axis acceleration, too much and with a tall print on the be, inertia could break the joint at the bed level and it'll fall over.

Yeah cheers that's my main concern with a heavier print. I don't normally need to use a brim unless the object footprint is really small but I may use one for big prints to give it a wider hold, just in case my acceleration is a bit high on some moves.

The spool holder is here, it's just an extended version of that chap's design.

top job!

Ian
RepRapPro tech support

Cheers!

Does anybody have a supplier for large volume filament reels? I can only find one UK supplier doing 2.3kg reels and they're in the region of £75, no thanks. I'd pay that for 5kg though.

And to answer an earlier question properly: homing Z from 750mm took a full 13 minutes and 48 seconds How do I up the homing speed? It seems to be encapsulated in a G30 command, but I'm sure there's an M value i can change somewhere... I reckon I should be able to double it without issue.

Quote
static65
And to answer an earlier question properly: homing Z from 750mm took a full 13 minutes and 48 seconds How do I up the homing speed? It seems to be encapsulated in a G30 command, but I'm sure there's an M value i can change somewhere... I reckon I should be able to double it without issue.

My 0.78d-dc42 firmware does Z homing and bed probing in 2 stages if you are using a Z probe. A fast stage takes the Z probe reading to 90% of target, then a slow stage to 100%. So I have increased the default homing speed of the fast stage to 100mm/min. You could increase it even further, but RRP's standard config file for 0.78 limits the Z axis speed to 100mm/min anyway - which sounds much nicer than the 180mm/min that they used to use.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

You can run the Z axis on it's own at about 5mm/s (300mm/min) before it starts skipping. However, I think there is still a bug in the firmware if you move it at this speed with any other axis (ie, with compensation on), it skips, which is why it is limited to 100mm/min in the config.g.

I tend to move the Z axis down to within 50mm of home before homing on my Tallmerod, as it does take a while! If you happen to have turned off the printer with the Z high, when you turn it on, send G92 Z[roughly how high Z is], then send M203 Z300 (to increase maximum speed), then G1 Z50 F300 to get it to come down at a reasonable speed. Set the maximum Z speed back to 100 with M203 Z100.

Ian
RepRapPro tech support

If you are moving the Z axis down with the intent of homing it once you get there, it wouldn't matter too much if it is skipping anyway.

Even if I just have the regular 200mm Z-axis, Z homing can still take a while if you are high up. I also usually send it down "fast" to Z=10 or so after printing to save some time (and to lower Z while the firmware still knows the current coordinates).
dc, Would it be possible/reasonable to add another stage to the Z homing? Something like moving at "maximum speed" until there is any signal whatsoever, then "normal speed" up to 90%, and "slow" to the last 100%.

Perhaps there is a case for supporting a higher Z axis speed when falling than when rising?

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Using 078d-dc42 firmware has made a fair few improvements over 0.59 (obviously). Homing speed is decent now, but as many have suggested I've been bringing it down manually before homing anyway. If I ever do fit a microswitch I'll up the speed to 300. Eager to get some new tools and a 24V power supply and get the larger bed fitted now

Static65, you can try sending M210 Z300 and M203 Z300 with 0.59-dc42 firmware. Using a microswitch will make things worse because then you lose the fast/slow homing behaviour.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Ah but as long as the microswitch is set correctly would this be a problem? It would home the same way as the Y-axis: fast until triggering the microswitch, then slow until triggering it again. Would the initial fast homing be too inaccurate and end up in a bed collision? I wouldn't have thought this would be problem given that there is a few mm play before the x-carriage hits the x-arm.