Dermot's RMv2 Build

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dlbyers
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Re: Dermot's RMv2 Build

Post by dlbyers »

guanu wrote:Gene, the blue wire was used for literally one day when we ran out of white and werent going to keep from shipping because of that.. no big deal, we got the white the next day so only a dozen or so kits have the blue instead of white. We did not change that on you, promise lol


Cool! I've got a limited-edition blue-wire machine. Prints are coming out absolutely amazing. I DON'T miss using my cranky cartesian!

TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

I will say, I don't believe I've ever met a small company with a better handle on customer support.

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Post by TheIrishScion »

Question;

I notice, having mounted the carriages and adjusted the tension on the belts (yay! progress!), that one of my servos has a slight 'tight spot' in rotation. It's subtle, and with the belt tensioned up correctly it's not obvious (much more apparent with a loose belt), but if I articulate that axis at speed I can feel pulsed resistance at exactly the frequency of one revolution of the servo.

I haven't torn the motor off yet to examine it, I suppose it's equally _possible_ that there's actually an issue with the toothed pulley. However, the pulley doesn't appear to have any rotational or tilt runout to indicate an out of round condition or bad mounting to the shaft and I'd prefer not to break the loctite if I don't have to. With that said, I am using the brand name rubbery dampers on the steppers so the pulleys aren't mounted as far onto the shaft as factory spec. They are spaced correctly though, according to some quality time spent with Mr. Mitutoyo. The belts all seem to be aligned well (though another one pulley, not on the binding axis, likes to walk its belt slightly left and right, depending on the direction of belt travel, I'm not entirely sure why yet. Realigning the idler doesn't appear to help and I'd expect it to consistently move towards the short side if it was tilted)) and I don't get the impression that there's a lot of lateral force on the idlers (though I don't much like the slightly rough finish from turning on the black plastic slip-on bearing idlers, I suspect that may accelerate belt wear) and the pulse definitely corresponds to one turn of the stepper, not one turn of an idler. The tight spot is only maybe 30 to 50 degrees of actual rotation (as best I can tell with my finely calibrated fingers/eyes, so take that for what it's worth)

So; I ask you, the Best and the Brightest, do these teeny steppers need time to bed in? Are they sometimes a little bind-y early on? Do some of them tend to bind a tiny bit magnetically but work just fine under drive current their whole lives? Thinking about the actual workings of a stepper it's not immediately obvious to me what _could_ be slightly binding, except perhaps a high spot on the rotor coming close to a low spot on the stator, but not actually touching. Or something? Baby non-pneumatic, non-servo actuators are slightly alien territory for me.

I don't get the impression that this slight binding presents any real risk of stopping the printer from working, drive current will massively overwhelm it, but I'm hoping to be able to print out very fine pieces, very accurately once the printer is properly dialled in and I'm trying to catch any stupid assembly errors or parts flaws as I build rather than after it's all buttoned up. I'm also seeing if I can break JJ's record for most whinge-y parts request emails in a single build.

///d

TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Right, the sticky stepper will have to wait. EzStrudel is assembled with replacement part, everything looks good. Everything but the discovery that I installed the damned top plate upside down. Intentionally. As in I looked at the laser engraved letters and thought 'hmm, they must go on the bottom so they're visible when the machine is assembled'

I looked back over the instructions and they are clear. However, may I make a slightly serious plea to have "Bottom sheet of the top assembly. This side up" written on that side of the sheet in the next revision.

TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Right, mistake corrected. That only took about two hours :-/

Over-torqued my EzStrudel a bit putting it back on and split the melamine around the nut (sigh) but it's still holding so we'll hope for the best. So far the captive nuts in the melamine is my very least favorite bit of the kit.

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barry99705
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Re: Dermot's RMv2 Build

Post by barry99705 »

TheIrishScion wrote:Right, mistake corrected. That only took about two hours :-/

Over-torqued my EzStrudel a bit putting it back on and split the melamine around the nut (sigh) but it's still holding so we'll hope for the best. So far the captive nuts in the melamine is my very least favorite bit of the kit.


Saturate the split with superglue. Should help keep it from spreading.
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Re: Dermot's RMv2 Build

Post by geneb »

...and then print yourself a new mount. :D

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TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

barry99705 wrote:Saturate the split with superglue. Should help keep it from spreading.


Actually that's a bloody excellent idea! Disassemble the mount, saturate the buggered spot in a suitably watery adhesive, cover with plastic and wood on either side and clamp like a MoFo in a vise to flatten it out as it sets. I might do that once I have everything together. First things first though, finish getting it all together.

I don't know _why_ I'm doing it exactly but something in _my_ calibration keeps making me over-torque the captive nuts. I think I spent so many years torquing to a specific end 'feel', and the natural give of the melamine never quite reaches that positive end point. As crazy/OCD as it sounds, part of me wants to buy another set of melamine sheets, tear the whole thing down and try again. Though I think actually what I'll end up doing is finishing this up as is and playing with it hard to get up to speed until the V3 comes out. If that looks good, that'll be xmas or wedding anniversary or something this year, if not I can look into 6-million-dollar-man-ing the v2. (Where do I sign up to be an early adopter? :-) )

I wonder how the whole kit would work using really high quality hardwood plywood instead of melamine. Has that been tried? Smells like an excellent extra-cost upgrade. Are the cut files available if I wanted to pay someone to cut me a kit out of the fancy European birch? So many questions...

Also, why on _earth_ isn't there a supplemental melamine kit that extends the bottom and top plates and adds verticals to build an enclosure with? That would be _soooo_ easy to do for SeeMeCNC and _such_ a pain in the arse for us to do on our own. Again, extra-cost addon for the base kit. I'd cheerfully spend a couple hundred to avoid having to engineer my own enclosure.

geneb wrote:...and then print yourself a new mount. :D

Now that's just crazy talk.

TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

A serious suggestion; cut a couple of test/education/calibration melamine pieces into the unused parts of the sheets and then, in the instructions, encourage first-time builders to experiment with them first to get a feel for how hard to tighten and when damage is likely to start taking place. Might cut down on support requests and replacement parts costs. I've found SeeMeCNC to be very generous with the replacements, but every support transaction carries real costs, the cost of another few seconds on the laser table and a couple of extra nuts and machine screws would likely be absorbed by those reduced costs and increased customer satisfaction at the end of the process.

Dammit all, CMeC needs to hire me immediately, I'm just _full_ of fatuous unsolicited advice! :-P

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Re: Dermot's RMv2 Build

Post by Xenocrates »

The files are available. I happen to have both a laser cutter (I am told by my brother, who talked with SeemeCNC about it, that it's almost precisely the one they use) and 1/4 inch baltic birch. There have been other people who have done it. But really, the Melamine is a better material in ways other than hardness (it is more stable and consistent, mostly, and it warps less) If you don't want to engineer an enclosure, some of us have gone ahead and done that already (A reason to not have SeemeCNC do it is that each extra option turns into more stock, more packing complexity, more engineering complexity when they have to do updates, and other overhead costs)

Enclosure designs:
http://repables.com/r/447/ Jfettig's

http://repables.com/r/719/ Mine (Based off Raymond Ma's)

http://repables.com/r/176/ Bubbasnow's
Machines:
Rostock Max V2, Duet .8.5, PT100 enabled E3D V6 and volcano, Raymond style enclosure
Automation Technology 60W laser cutter/engraver
1m X-carve router

Sic Transit Gloria Mundi
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TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

You guys (and gals doubtless) are all just great. In an attempt not to drown out the board with inanity I'm going quiet until I have some _actual_ _progress_ to report :-/

Meeting my biological imperative, while rewarding in many many ways, has been hard on my discretionary time.

TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Right. The guinea pig butt-warmer build is complete;
IMG_5327.JPG

Seems a bit over-engineered to me but they're pleased with it.

The rest of the assembly went smoothly. My label maker got a proper workout. The commissioning of the software went very smoothly (though MatterControl seems to be buggy as all _getout_ on both PC and Mac) with one notable exception; PID loop tuning would _not_ give consistent results. We'll revisit this later.

Printed out my PEEK fan shroud like a frickin' HERO. I get the impression that I could take an empty cornflakes box, write "Fancy Three Dee Printer" on it, copy the fan shroud onto an SD card and drop that, along with a couple meters of ABS, into my new 'printer' and it would still successfully produce a fan shroud.
IMG_5322.JPG

IMG_5333.JPG


I installed the TrickLaser LED ring at build time so I knew the layer fan part wouldn't fit, but I printed it anyway as a matter of principle. Came out pretty much flawless. Does anybody have a conveniently modified version of the layer fan shroud that _doesn't_ interfere with the LED ring that I can use until my 3d modelling chops are up to doing it myself? Ideally one that mounts to the same tabs and uses the same little squirrel cage fan (of which I own three)?

So I meant to write this post and ask these questions this morning but instead I got carried away printing gear bearings (multiple) and nautilus-shaped gear sculptures and Marvins and my kid's names and their teachers names and and and. I'm particularly impressed with how the geared bearings turned out. Video below;
https://www.youtube.com/watch?v=6M2I3jFBr9w

Also amazed at how _fast_ the thing is.
https://www.youtube.com/watch?v=kwA7KR0RQN4

I've completely fallen in love with it already, and i'm only 63.5M of filiment in :-)
I am going to need to buy shares in the glue stick people though, didn't realize how much of that I'd be going through.

However (and there is a slight however) there's _something_ not quite right about my thermistor behavior.
I've got jumpy readings from both probes, even down around room temperature, consistent with each other, but not all the time.
Story;
Sunday afternoon, immediately following the completion of the build and initial power up was the worst thermistor behavior, reported temperatures jumping around all over the place (+/- 3 degrees at ~24 degrees) for both the bed and the extruder. Calibration was impossible, I got figures like the following (sorry, don't think I can make tables in this BBS software);
Run Kp Ki Kd
1 29.77 7.94 37.13
1 20.48 1.71 61.27
1 29.1 7.76 27.29
2 27.14 2.9 63.53
2 37.37 9.96 35.04
2 31.92 3.55 71.73
3 30.25 8.01 28.58
3 15.93 1.07 59.08
3 25.78 6.87 24.18
4 21.37 1.92 59.51
4 26.94 7.16 25.34
4 14.19 0.81 62.44
What appeared to be happening was that the temperature reading was so unstable, the reported temperature effectively jumped above 200, then back below, then back above, all in a matter of a second or two, and not in a true response to the heater, thereby greatly confusing the calibration routine which was trying to cross the 200 degree threshold in a nice controlled fashion. In the end I averaged the numbers from Gene's example screenshot in the instructions and used that, which worked well enough. When I tried running _my_ calculated values (even averaging out all 12 entries the 4 complete runs above) yielded a printer with at +/- 8 degree temperature swing (220-236*) at ABS temperatures.

Cut to Monday morning, after a night of being turned off, I turn the machine on and both bed and extruder temperatures are dead stable, varying +/- 0.1 degrees at room temperature. 'Whoopee!' sez I, 'it's fixed itself!' (though I was deeply suspicious) and I set about running the calibration procedure again. This time it worked flawlessly, here's two runs worth of data from that;
Run Kp Ki Kd
1 14.78 0.88 62.2
1 15.59 0.94 64.31
1 15.17 0.92 62.6
2 15.31 0.93 63
2 15.59 0.95 64.1
2 15.59 0.95 64.03
I ran it a third time but the numbers were near as dammit identical so I didn't bother recording them.

I averaged and plugged those numbers in and got printing. Initially it seemed to be flawless, maintaining target temperature to within small fractions of a degree. But after a few minutes of printing it seemed to lose accuracy again and the swings started to creep back in. But I wasn't having serious print quality problems so I kept going until Monday night when I just re-ran the calibration routine a couple of times and am getting much the same nonsense results I was on Sunday, and the ambient temperature swing has returned as well, though not as pronounced, about a degree total variance at room temp, though _occasionally_ 2 degrees. See video;
https://www.youtube.com/watch?v=cTNuTY4c41k

So, I don't have an o-scope to hand, I'll have to borrow one from a mate, but based on the behavior I'm seeing I have to suspect that there's either a problem with the ADC resistance measurement circuitry on the RAMBo, or the nifty new industrial-style PSU is feeding me dirty dirty current and throwing everything else off. Or possible something else that I haven't considered. The fact that both thermistors are experiencing the same behavior suggests it's not a wiring issue, nor cross-talk in the columns, but that doesn't get me much close to knowing what it _is_.

To, Brain Trust, a penny for your thoughts? How did I manage to screw this up? What's considered the 'normal' thermistor jitter? Clue me in!

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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Powered up again this morning from cold hoping for a repeat of Monday morning's stable readings. Sadly no such luck, still looking jumpy, still won't give rational calibration numbers :-/

Folks with RAMBo 1.3 machines, can you tell me how stable your thermistor readings are at room temperature? I could use a base line.

Also, should I move this question to Troubleshooting perhaps?

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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Right, I'm going to move this to Troubleshooting where it belongs.

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Re: Dermot's RMv2 Build

Post by Eaglezsoar »

I love your guinea pig butt-warmer, they seem to be comfortable and it certainly made me smile! :)
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Finally got around to knocking out a quick & dirty time lapse;


*Edit to the edit* Doh! Silly me, https is far too advanced for BBCode... ;-)
*Edit* youtube support turned off? Hmm.

https://www.youtube.com/watch?v=HTBnNNSUR9k
See if this works.
Last edited by TheIrishScion on Sat May 14, 2016 3:36 am, edited 1 time in total.

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Eaglezsoar
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Re: Dermot's RMv2 Build

Post by Eaglezsoar »

That is one high speed build! A very good job. Did you figure out what was happening to your thermistors?
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barry99705
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Re: Dermot's RMv2 Build

Post by barry99705 »

TheIrishScion wrote:Finally got around to knocking out a quick & dirty time lapse;

[youtube]HTBnNNSUR9k[/youtube]
*Edit* youtube support turned off? Hmm.


See if this works.


Remove the s in the https and use the full video link. ;)
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TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

barry99705 wrote:
TheIrishScion wrote:Finally got around to knocking out a quick & dirty time lapse;
Remove the s in the https and use the full video link. ;)


Hmm, produces a white box instead of a working embed, but maybe my browser has lost its mind. Either way, links's still there.

TheIrishScion
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Re: Dermot's RMv2 Build

Post by TheIrishScion »

Eaglezsoar wrote:That is one high speed build! A very good job. Did you figure out what was happening to your thermistors?


Cheers, it's actually spread out over several weeks. I think my shirt changes about 6 times. Also, who knew I was so fat? Wow.

The thermistor issue has been <cough> not the top of my priority list. I've had a borrowed 'scope sitting on the healing bench for about a month now, and not a single constructive thing has been done with it. However, I have been printing out a frankly redonkulous amount (Well, maybe not quite that much, but about 2km of filament by the internal counter) of cool stuff, so evidently jumpy thermistor readings and slightly approximate hot end temperature regulation are only a slight impediment.

Actually what I _really_ need to do in the worst kind of way is find a modified fan shroud design for the factory squirrel cage fan that will clear the TrickLaser LED light ring. I haven't yet even tried printing PLA because I have no way to selectively cool it, and I feel sure I'm missing out. Also I have a metric ass-tonne of PLA I was given for my birthday just sitting in a box slowly humidifying.

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