Dermot's RMv2 Build

[TheIrishScion]

Right, I've received my RMv2 kit, a day ahead of schedule at that. Popped the box open to make sure everything is in one piece, and it is. Very cleverly and efficiently packaged into minimal space with ample protection. Well done to whomever is in charge of boxing.

Box arrived unmolested

My planned build weekend is Feb 4th, 5th, 6th, and 7th. I know it's a cliche but I aim to video the whole thing and knock up a time lapse if I can.

I'm not terribly concerned about building the kit, in a former life I earned my crust doing prototyping and manufacturing small-run industrial automation robotics. The calibration and actual printing itself are another matter entirely, one I have only the haziest notions about, so expect a lot of comical stumbling once I get to that point.

As for what I'm building, there's the BOM as it currently stands;

• RMv2 Kit (X1) (Glorious White Melamine Master Race!)
• Raspberry Pi Wifi Kit (X1)
• SNANSHI 5V 2A 10W regulated (allegedly) industrial style PSU for RasPi build-in (X1) (I want a non-switched, or possibly separately switched, 5V going to the print server to reduce probability of Linux filesystem corruption)
• MicroSDHC Card, 32GB, Sandisk (X1)
• SDHC Card, 32GB, Sandisk (X1)
• Spare SMT Fuses (X2)
• Spare .35mm, .5mm and .7mm nozzles
• Spare heater resistors
• Spare thermistor
• Spare glass build plate
• Tiny squirrel cage fans (X2) for possible additional PLA cooling
• XT60 High current connectors (X3)(quick disconnects for platform)
• JST Low current connectors (Silicone insulated) (X10)(quick disconnects for platform)
• Name brand rubber mounts for steppers (X3)
• Cork mount for possible future damping of cold end stepper (x1)(Probably impossible, I now realize)
• TrickLaser aluminium heat spreader (X1)
• TrickLaser LED light ring (X1) (mostly so my kids can see what it's doing)
• 2.5" Blue painter's tape (X1)
• Purple disappearing glue stick (X6)
• Kapton Tape (X1)
• PermaTex Ultra Copper (X1)
• 1KG PLA
• 1KG ABS (probably more of both by build time)
• Stanley 014725 25-Removable Compartment Professional Organizer (X4) (For parts organization/storage)
• 1 QT Acetone
• 1 QT Zinnser Clear Shellac (for melamine sheet edges. with assorted brushes and rollers)
• Loctite Blue (X1)
• Assorted heat shrink tubing
• Assorted cable ties
• 1/2 a kilo of desiccant in 50 little bags to help keep the filament dry.

I believe I have all the required tools, though I am using this as an excellent excuse/opportunity to freshen up my solder station (Hakko 888, where have you been all my life?) and vernier (Mitutoyo 500-196-30, the very best there is. When you absolutely, positively, got to measure every m***********r in the room, accept no substitutes)

I'm obviously not making any significant mods at this stage of the game, and that's by design. I want to get the base kit up, running and dialed in well before I start trying to do fancy things to impress the older boys.

With all of that said, I know just enough to know how very little I actually know, and as such I'm absolutely open to suggestions;

What have I forgotten?

Dermot.

[ccavanaugh]

XT30 connectors are now available instead of the XT60. The size is a bit more suitable and still good for 30 amps and helps reduce the bulk around the platform.

[Xenocrates]

If you plan on using the stock hotend long term, I suggest a set of M3 taps, (taper, plug and bottom), a properly sized drill for same, an M3 screw in thermistor, and a heater cartridge with grub screw to hold it. If not, an E3D or Prometheus hotend might be a good idea. RTV and resistors are less than ideal.

[TheIrishScion]

XT30 connectors are now available instead of the XT60. The size is a bit more suitable and still good for 30 amps and helps reduce the bulk around the platform.

They're a third the weight, which is appealing, though past experience makes me very leery of running anywhere near spec current through Good Enough connectors, especially considering the environment they're going to be exposed to. If I start having platform mass issues I will certainly take a closer look.

If you plan on using the stock hotend long term, I suggest a set of M3 taps, (taper, plug and bottom), a properly sized drill for same, an M3 screw in thermistor, and a heater cartridge with grub screw to hold it. If not, an E3D or Prometheus hotend might be a good idea. RTV and resistors are less than ideal.

I plan on keeping the stock hotend for a while (probably 6 months or more, depending on when the new self-calibrating retrofit hot end kit comes out and gets stable) though not indefinitely. As such I'm not inclined to launch into modifying it much (and again, job 1; get everything working well in stock configuration, I don't want to launch into the process of finding out subtle differences between the glass bead thermistor and the screw-in while I'm trying to print a usable PEEK fan shroud.)

What is the primary concern around the stock bead thermistor? Failure from work-hardening of the leads/poor strain-relief? RTV failure? (I've found RTV to be remarkably tenacious stuff when applied correctly) Laggy measurement/poor hysteresis? I'm slightly surprised that SeeMeCNC continue to supply them if they're that problematic, though I did pick up a spare in case of fat-fingered assembly on my part.

On the same topic, I won't be using anything with a heater cartridge until I have adequate fire suppression/monitoring set up (bitter experience sadly) so that won't be an option for a while. The equipment will be operated in my house, which also happens to be where I keep my wife, small children, mother in law, dogs, cats, fish, guinea pigs and Other Cool Stuff so safety of semi-unattended printing is paramount.

Your point is very well taken though, the stock hot end is necessarily a compromise and is likely the most limiting component in the whole device. Thank you both for your input. I _almost_ sprang for a E3D V6 when I initially ordered but erred against mostly on grounds of safety and not wanting to change too many system variables at once. I do want to be able to reliably print nylon and other exotics down the road so I will have to upgrade at some point, but right now I feel that better equipment would largely be pearls before swine.

[Xenocrates]

Pull out and creep given the small pocket size is the main concern, which is alleviated by kapton wrapping the hotend.another concern is that rtv is messy and slow to change if you have issues. As far as the heater cartridge goes, they have a lower wattage than the power resistors, if you get a small one such as E3D now packs in. You could also follow the lead of one person here, and get a temperature fuse from a copier (which will still allow the peek to melt in most cases, but will prevent fires)

[Windshadow]

I keep an old-fashioned CO2 extinguisher right next to my printer as well as in the kitchen and machine shop. I once had to use a drychem extinguisher on a boat fire and what the fire did not wreck the fused dry chem destroyed... I have an old Halon extinguisher in my car and i know the limitations of CO2 in the 10 lb size that i use around the house but for the sort of thing where they might be used while the fire department is on the way for me they are the best fit.

and I think for unattended operation I would set it up to run in a basically fireproof section of my barn.

[TheIrishScion]

Pull out and creep given the small pocket size is the main concern, which is alleviated by kapton wrapping the hotend.another concern is that rtv is messy and slow to change if you have issues. As far as the heater cartridge goes, they have a lower wattage than the power resistors, if you get a small one such as E3D now packs in. You could also follow the lead of one person here, and get a temperature fuse from a copier (which will still allow the peek to melt in most cases, but will prevent fires)

That's kind of what I figured. I actually suspect that a properly installed and relieved bead thermistor/RTV combo should be fundamentally more robust than any of the screw-in versions that I've seen (nasty sharp cable bend liable to occur immediately out of the housing, hard to screw in without potential for damage to conductors, hard to do strain relief because of heat, etc). I plan on using a little extra RTV as structural routing/strain relief in concert with the PTFE sleeve. I'm not expecting thermistor failure without something else going fairly catastrophically wrong with the head (though I may be wrong about that). I did toy with the idea of using thermal epoxy but decided against as sod's law dictates that spontaneous thermistor failure will occur immediately after curing if I do.

All of which sounds very opinionated for someone who's never built a 3d printer. In my defense, cabling, wiring, connectors, and strain relief used to be a big part of my job. When a fixture is expected to articulate 4-10 times a minute, 16 hours/day for a design life of 5 years, you get really interested in the topic

Regardless of wattage, heater cartridges are designed to be able to attain dramatically higher temperatures than a regular old wire-wound power resistor (which isn't designed to get any hotter than it has to, and should fail fairly gracefully before setting anything around it on fire) though someone may be manufacturing industrial heaters which fail at lower temperature these days, and if not they certainly should be. Untapped market here I think.

And yes, a single-shot thermal fuse will almost certainly figure prominently in my future plans, as perhaps will flame and smoke sensors feeding an external SCRAM setup. Also possibly an automatic discharge extinguisher. All still very much in the planning stages though. I want to ultimately be able to leave the thing running unattended without undue concern.

[TheIrishScion]

I keep an old-fashioned CO2 extinguisher right next to my printer as well as in the kitchen and machine shop. I once had to use a drychem extinguisher on a boat fire and what the fire did not wreck the fused dry chem destroyed... I have an old Halon extinguisher in my car and i know the limitations of CO2 in the 10 lb size that i use around the house but for the sort of thing where they might be used while the fire department is on the way for me they are the best fit.

and I think for unattended operation I would set it up to run in a basically fireproof section of my barn.

I don't particularly mind destroying the printer in case of real fire, they're very cheap to replace in the great big scheme of things. Something along these lines might be an idea; http://www.amazon.com/Sun-System-Flame- ... B0030KM0V4" onclick="window.open(this.href);return false;
Halon systems are available as well, though they're a lot more spendy.

[TheIrishScion]

First problem (with solution);

The wages of buying cheap-o (~$10) off-brand power supplies from Amazon is apparently very marginal quality control (which is I suppose better than death, so I've got that going for me);

They did _just_ enough quality control to catch that the board was dead, and reworked the board _just_ enough to get it working. Note the bottom of the big solder rectangle in the 2nd image, that's immediately under the high end of the tilted IC. It's been kissed _just_ enough to get it making contact. They didn't bother actually reflowing the IC properly flat. So while it did supply 5.2xx volts when plugged in, I was deeply suspicious. Suspicions confirmed when I tried to trim it down a little to hit 5v even. Nope. Second the output dropped under 5.2v it lost its tiny little mind, voltage jumping around all over the place. Regulated my arse.

Usual solution; throw money at the problem till it goes away. $37 to digikey later and we have a 5v version of what I should have bought in the first place winging its way.
http://www.cui.com/product/resource/vsk-s10-t.pdf" onclick="window.open(this.href);return false;

[TheIrishScion]

Well heck. We've hit a snag.

The first 15 hours of the build have gone very well (and been great fun), albeit rather more slowly than you'd expect. I elected to apply two coats of shellac as a moisture barrier which took 3-4 hours on its own. Add to that some friends swinging by to say hi and hang out while I worked and you don't have a recipe for terribly efficient assembly.

Up to this point I've only had three hiccoughs of any note;

1. There is a discrepancy between the build instructions and the BOM in the wiring bag (which claims to have 12 gauge wire pairs for both PSU and heated bed) that led to me initially using 12 gauge wire for the bed instead of 18. Easily fixed but the BOM should probably revised. Loosing an inch off the 12 gauge won't make it too short to reach the RAMBo in any case.

2. The supplied nylock nuts are a bit cheap-o and inclined to bind, leading to three of the 4 long screws affixing the cabinet exhaust fan to fail during assembly (torqued apart mid-length). The final one went on after the judicious application of a little olive oil to the threads. Easy Home Depot fix, just a hassle having to go buy more hardware.

3. There was surprisingly little correlation between the supplied wires and the instructions. All the correct gauges and lengths seem to be present (albeit in different colors and bundled differently) and I've wired the extrusions now, but there was an hour of cursing and head-scratching with a calipers as I tried to make sense of what I had versus what was called for.

Unfortunately I've hit a roadblock that I can't do much about. One of my cheapskates looks like it got bound up at the edges of the mold while the center ejector pins hit it hard. It's significantly distorted and not possible to mate up against the opposing half.

The rest of them _seem_ fairly ok though I don't have a good set to compare them against, they will mate up with each other with a small amount of BF&I. I don't know whether there was a bad batch or this was a one-off. They all have more of the white stress telltales than I normally like to see though.

So I guess I shall be giving the famous SeeMeCNC customer service machine a whirl!

I will say, this whole process so far has been the most satisfying thing I've done in _years_. I almost don't care whether it works at the end, building it has been a hoot!

///d

[Eaglezsoar]

Great job up to this point and I am enjoying reading your build. Thanks for posting it.

[TheIrishScion]

Actually, one other the other ones is definitely slightly off as well. A bad batch I suspect.

[geneb]

What's the version # of the manual you're using? If possible, grab the latest (4.18) and let me know if the issues you've encountered have been resolved.

tnx!

g.

[TheIrishScion]

I'm working off a version dated Feb 4th.

[TheIrishScion]

Ok, yes, confirmed, I've been working 4.18. The heated plate wiring SNAFU was me reading the bag-BOM rather than focusing on your instructions. When it became clear that the heated bed _used_ to take 12 gauge and there used to be two batches supplied for that purpose (hence the huge solder pads, BOM etc) but now didn't, it became clear what I did wrong and I focused back on the written instructions.

The issue with the supplied wires was just a combination of pictures of specific bundles and colors and lengths of wires in the instructions that were not reflected in the reality of what I got in my kit and how it was bundled, intersecting with the old 'did you get the A kit or the B kit' uncertainty. Like I say, ultimately all the required wire _was_ in there, it just needed to be kind of puzzled out. The inconsistency of colors was what particularly got me. I spent quite a while hunting for a white 26 gauge spool that simply wasn't there, it was a blue wire wound up with the red and black 26 gauges. Going forward it might be worth marking the shipping box with a clear A or B revision so that folks can definitively tell what they should be dealing with. Actually, ideally SeeMeCNC would get a wire winder and just knock off the correct lengths in the correct colors and bag 'em up like that rather than relying on disassembling multi-core cables and things. I'm not sure what the financial impact of that would be though.

On the whole though, I'm finding the instructions to be great, and delightfully written. I will try to write up my notes on them when I'm done with the build and send them to you (I've produced and consumed more technical documentation that I care to admit over the years so I'm even _more_ neurotic about docs than I am about everything else, don't take me whinging about a small part of the build doc as a suggestion that it's not very good, rather that I am an arse'ole who's never entirely happy with anything, least of all himself)

[TheIrishScion]

Wow, SeeMeCNC support really is fast. I was provided a human-authored response and resolution before I'd even woken up this morning. Kudos to JJ.

[geneb]

I though the blue 26ga wire was someone winding me up. Something tells me the JJ Bus tires need snow studs added. *ahem*

g.

[guanu]

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

[geneb]

Yeah I know. I talked to JJ about it today.

g.

[TheIrishScion]

Ooh, you malingering runts! Well that explains a lot.

So, when I get my replacement cheapskates and eventually finish my build, and get around to uploading the time lapse, and you watch it so you can make fun of my dreadful process, and about two thirds of the way through you'd swear you saw a couple of frames of me flipping the camera the bird?

That's for stealing 40 minutes of my life.

While it might feel a bit Treachery Of Images-y, next time you might consider affixing a note to the blue wire saying "This is white 26gauge wire"

Just a thought

[Xenocrates]

Perhaps a note, preferably humorous, with any temporary or unplanned substitutions. Just take a spare post it note (or write on the thermistor one, since Gene has us doing hotends first)? Course, that takes a minute or two per kit, so it might not be ideal, depending on just how busy you folks are shipping these out.

[barry99705]

Ooh, you malingering runts! Well that explains a lot.

So, when I get my replacement cheapskates and eventually finish my build, and get around to uploading the time lapse, and you watch it so you can make fun of my dreadful process, and about two thirds of the way through you'd swear you saw a couple of frames of me flipping the camera the bird?

That's for stealing 40 minutes of my life.

While it might feel a bit Treachery Of Images-y, next time you might consider affixing a note to the blue wire saying "This is white 26gauge wire"

Just a thought

White balance must have been off....
[img]http://s3.amazonaws.com/media.wbur.org/ ... dress2.png[/img]

[TheIrishScion]

White balance must have been off....

Hah!

Right, the replacement trucks are in, all three straight as a die. Now just have to carve out another 10 hours to finish the job!

[TheIrishScion]

Hmm. I must have done something to peeve the injection molding gods.

My EZ-struder looks to have been either mis-molded or misassembled;

It came in the baggie with the clear cover screw tightened down but the cover itself rotated slightly so it was clamped on top of the locating pegs.

I loosened it off and located it correctly but the clear cover seems to have taken a set with the bend in the middle

This wouldn't bother me except that the clear cover looks like it's designed to control lateral movement of the sprung idler bearing arm, which I've read is liable to slide off the filament if not fairly accurately aligned with the hobbed portion of the capstan. If I hold the parts flush together the idler has very little play, but if I don't it can move around more than I like relative to the capstan. And I'm concerned that when the whole assembly is hot, any play I'm seeing cold is likely to be magnified. And I don't want to loctite everything together until I'm fairly confident I've got the capstan aligned correctly.

So, back to support we go

///d

[jjjohnson]

Sorry about that. I have a new part shipping today.