A Hack to Bring Print Diameter Nearer to Spec

[HumanLiberty]

Context: I bought/built the Rostock Max v2 for one purpose: to print a prototype around the edges (a circle 10.7" diameter x ~4" high) that was in April, about 4 months ago. It feels like 4 years.

I have come to realize that, either due to a glaring error or willful deception, it is physically impossible for the out-of-the-box Rostock Max V2 to print an 11" circle as the specs claim. The real spec is perhaps 10.6"

This is due to two limiting factors/design flaws, of which photographic proof shall follow.

1) With the nozzle opposite its tower, no Cheapskate can proceed low enough relative to the print bed to position its Delta Arms horizontally to maximize their reach.

2) Even if they could, the DAs are simply not long enough to extend the nozzle all the way out to the 11" circle line.

I imagine this all could be solved with longer Delta Arms. The Cheapskates don't like taking the DAs horizontal anyway, so this would be the best option, and I for one don't need so much Z room. Anyone know a source for those out of the box?

Meantime, of necessity, I have found a way to address issue #1 by raising the Build Plate
onto 2" circuitboard spacers. That gets the nozzle at least far enough out for my purposes.

Check it out:

Note the horizontal Delta Arm. If you try this with your on-base bed, you will see it cannot be done (I'm not going to paste a pic of that after all, cause they're in my other computer.)

http://forum.seemecnc.com/download/file ... w&id=10079

http://forum.seemecnc.com/download/file ... w&id=10080\n

Now see here how the nozzle is still significantly within the 11" line?
No, because it's a shitty picture?

Ok here's a closeup with the line visible - better?

http://forum.seemecnc.com/download/file ... w&id=10081

It's not all the way to 11", but significantly closer - enough for my purposes at least.

Also, I removed the Layer Fan to avoid interference with the towers/belts, and brought in my skirt from 3mm to 1mm from the object.

So problem solved right?

Wrong.

Turns out printing way over here requires super-human calibration precision.

So now I'm dead in the water as RollyRowland progresses in his Herculean endeavor to
make auto-calibration a feasible reality. See here for that awesomeness:
http://forum.seemecnc.com/viewtopic.php?f=36&t=8698

626Pilot has also kicked ass on that front, though his solution seems beyond my level/appetite for punishment - but you can see his progress here:
http://www.thingiverse.com/thing:161753/#instructions
and here:
http://forum.seemecnc.com/viewtopic.php?f=82&t=7640
and here:
http://forum.seemecnc.com/viewtopic.php ... 5&start=50

And here's some more relevant stuff for edge-printers
http://forum.seemecnc.com/viewtopic.php?f=37&t=8368

Meantime I'm gonna get me some Motorcycle Feeler Gauges and see if I can do that super-human calibration manually. I'll let you know how that goes, if you like.

[ramai]

Just out of curiosity I pushed my printer to the edge manually, and it does not quite make it to the white line. I suppose that would be disappointing if you bought the printer to specifically hit that maximum diameter. However, good luck finding any other printer near the build volume of the rmx for anywhere around $1k.

[DGBK]

I haven't quite gotten my printer calibration up to snuff to print that far out, but I've been working with the Rowlie's algorithm without a gauge. I seem to be almost there. It takes quite a bit longer than 10 minutes, but it is doable if you have patience.

It might be much easier for most people to mount their hot end beneath the effector plate. That's where I currently have mine mounted, and it will reach the outer most parts of my build plate.

[Jimustanguitar]

I drew this up in CAD once... With 3 towers in a triangle centered on a 200mm radius, 269mm arms, and the carriage and effector offsets, my drawing had the maximum reach of the stock setup at 274mm (10.787"). Assuming that you can reach that point without crashing the carriages into the base.

[HumanLiberty]

Just out of curiosity I pushed my printer to the edge manually, and it does not quite make it to the white line. I suppose that would be disappointing if you bought the printer to specifically hit that maximum diameter. However, good luck finding any other printer near the build volume of the rmx for anywhere around $1k.

Yeah, I hear you - that price/area ratio was primarily what led me to get one, and maybe it was the right decision after-all. Or maybe it would have been better to spend 2-3x but actually have a couple of working prototypes 2-3 months ago. I dunno - what was that they say about the greener grass and the fence...?

Between the raised bed and/or longer arms, and/or KAS's solution of mounting the nozzle under the effector,
and Rolly's calibration work, this may all end up a non-issue soon - trying to dissolve the frustration as it arrises...
AUMmmm....

[HumanLiberty]

I haven't quite gotten my printer calibration up to snuff to print that far out, but I've been working with the Rowlie's algorithm without a gauge. I seem to be almost there. It takes quite a bit longer than 10 minutes, but it is doable if you have patience.

It might be much easier for most people to mount their hot end beneath the effector plate. That's where I currently have mine mounted, and it will reach the outer most parts of my build plate.

Wish I'd known about that before I improvised this approach, but glad to know you guys are having trouble with the peripheral calibration too, and it's not just a byproduct of the stilt-mount - that would have been exasperating.

How do you mount under the effector?

[ramai]

I'm mounted under the effector as well. It's what all the cool kids are doing, we like to drop it low. You lose a little z-height but as 626pilot says, it's nice to see the hot end.
Simply removing the stand-offs will allow it to slide down. You could get shorter bolts or just let them be long on top if you are lazy.

[HumanLiberty]

I'm mounted under the effector as well. It's what all the cool kids are doing, we like to drop it low. You lose a little z-height but as 626pilot says, it's nice to see the hot end.
Simply removing the stand-offs will allow it to slide down. You could get shorter bolts or just let them be long on top if you are lazy.

"Ooh! Ooh! I wanna be a cool kid!" said the uncool kid, thus forever disqualifying himself from coolness...

But seriously, though; I do. Would you mind posting a pic or two of this set-up? Hard to visualize.

[HumanLiberty]

"2) Even if they could, the Delta Arms are simply not long enough to extend the nozzle all the way out to the 11" circle line."



I just found out the standard delta arm length is officially 269mm.
So how could there ever have been any illusion that they could've reached across a 280mm diameter build area?
It's strange this issue wasn't noticed and corrected before the v2 was ever released. Must have been a mass brainfart at Rostock - let's hope they take ownership of it and just increase the stock arm length to like 300MM, and send replacements to those of us who want them - seems like a quick/easy fix to me...

[KAS]

You need to account for the carriage offset as-well. Not saying that 11" is feasible, just that I'm sure they rounded up as 10.5 is definitely doable.

[geneb]

There's probably somewhere close to 10,000 Rostock MAX printers out in the wild right now. Out of that pretty large number of printers, a tiny, TINY, number of people (like *5*. MAYBE) are getting all spun up about about .40". Do you honestly think they should spend thousands of dollars to design a new injection mold, manufacture it and then spend even more to manufacture and send out 60,000+ new arms? Over essentially a half-inch of marketing fluff? Seriously?

If it was ME, I'd contact Brian over at Trick-Laser and see if he'd be interested in making me a set of 300mm carbon fiber arms.

Please understand that I don't speak for SeeMeCNC - I'm just the angry old man that writes their documentation. I suspect they keep me around because I'm amusing when wound up.

g.

[Eaglezsoar]

There's probably somewhere close to 10,000 Rostock MAX printers out in the wild right now. Out of that pretty large number of printers, a tiny, TINY, number of people (like *5*. MAYBE) are getting all spun up about about .40". Do you honestly think they should spend thousands of dollars to design a new injection mold, manufacture it and then spend even more to manufacture and send out 60,000+ new arms? Over essentially a half-inch of marketing fluff? Seriously?

If it was ME, I'd contact Brian over at Trick-Laser and see if he'd be interested in making me a set of 300mm carbon fiber arms.

Please understand that I don't speak for SeeMeCNC - I'm just the angry old man that writes their documentation. I suspect they keep me around because I'm amusing when wound up.

g.

You are amusing when you are not wound up!

[ramai]

To the gentleman wondering about how to mount your hot end under the effector, here is a photo. You just remove the standoffs and slide it on down.

[bvandiepenbos]

Longer arms is something that has been on my to do list for quite some time, not so much for larger build area, but possible benefit for calibration in the problem areas between towers.
Anybody have ideas what length would be good?
Does any certain length make more sense mathematically?
I will have to modify our build jig, so I would like to determine a "extended" length arm to standardize on.
Up to 290 mm will still be OK for good raw material yield.

[stonewater]

I would order 300 mm ones..... even if that costs extra because you have to waste a piece of tubing.

Tom C

[Jimustanguitar]

300mm is the length I want for my next build too.

[bvandiepenbos]

Why 300 ?

[stonewater]

at 300 mm the arms will not go completely horizontal when reaching the edge of the bed, there will be a decent angle on them, to keep the steppers from going postal. I am also thinking of moving the top carriage mount for the arms to the bottom of the carriage plate..... would this allow a bit more clearance at the tower locations to increase diameter a bit more? careful layout should keep the holes in the right spots.

Tom C

[ramai]

lets be honest here, 300 is rooooooooooouuuuuunnnnnndddd. Mmmmm mmmm. Yummy!

[Jimustanguitar]

Why 300 ?

For some reason, probably placebo, it just sounds right to have the arms match the bed diameter.
Plus, it's close to a 10% increase in length, which would make a change in positioning accuracy more pronounced and easier to detect.

[bvandiepenbos]

at 300 mm the arms will not go completely horizontal when reaching the edge of the bed, there will be a decent angle on them, to keep the steppers from going postal. I am also thinking of moving the top carriage mount for the arms to the bottom of the carriage plate..... would this allow a bit more clearance at the tower locations to increase diameter a bit more? careful layout should keep the holes in the right spots.

Tom C

Just turn the carriages 180 degrees to put mount point lower. That would increase build diameter only if carriages are hitting machine base.
You will lose build height.
You will also need longer endstop screws.

[bvandiepenbos]

I just did some checking, it works out material wise to go up to 332 mm without wasting to much CF tube.

NOW what length would you all want?
I am thinking longer than 300 could be even better.

[ramai]

I haven't hit my height cap yet, but I've been slowly turning in my z-height for other things. Is there any other benefit to longer arms than simply eeking out that last .5" on the build plate?

[ZakRabbit]

I just did some checking, it works out material wise to go up to 332 mm without wasting to much CF tube.

NOW what length would you all want?
I am thinking longer than 300 could be even better.

Heck, with that, I'd vote 325mm, just because the further away from horizontal, the better.

[HumanLiberty]

There's probably somewhere close to 10,000 Rostock MAX printers out in the wild right now. Out of that pretty large number of printers, a tiny, TINY, number of people (like *5*. MAYBE) are getting all spun up about about .40". Do you honestly think they should spend thousands of dollars to design a new injection mold, manufacture it and then spend even more to manufacture and send out 60,000+ new arms? Over essentially a half-inch of marketing fluff? Seriously?

If it was ME, I'd contact Brian over at Trick-Laser and see if he'd be interested in making me a set of 300mm carbon fiber arms.

Please understand that I don't speak for SeeMeCNC - I'm just the angry old man that writes their documentation. I suspect they keep me around because I'm amusing when wound up.

g.

That was indeed amusing, and I appreciate your putting this issue in larger perspective, as I've had pretty much none. I've been just about 100% focused on my own frustration and disappointment over it, and glad to find a little tribe of others in the same/similar boat. But I do think it was a bad idea to be imprecise on this point; isn't the whole running Dilbert joke (or a main one anyway) about engineers, that they're overly precise? I wish that were true in this case. Also, in defense of we 5/10,000; that .5" is trivial if you don't need it; it's not trivial if you do - especially so if you only bought this particular printer because of it. I do think it's unjust that anyone should have to spend $.01 extra to bring this printer, or any product, up to the standards the manufacturer claimed for it as standard. Also, before buying I specifically checked with Customer Service to ensure the full 11" was printable. I made it clear this was a key criterion, and was assured 11" was a legit spec. So yes, maybe they shouldn't bother making moulds and 60k new arms etc, but they definitely should buy the upgraded arms for the ±5 of us who care. Can I get an Amen?! (BTW, thanks also for mentioning Tricklaser - I didn't know about them.)