Always Change As Many Variables At One Time As Possible

 Mmm, yes, that's a good idea! >_>

 Depending on what my back lets me do, I might replace the Y-axis belt tensioner today.
[later: nope, cry, hurts]

 Once that is done (meaning, belt re-tensioned using both calculated audio & belt tuning app and investigating if they don't match)...

 I plan to try a print with:

• Flexible PLA
• a 0.8mm nozzle
• a 0.3mm - 0.6mm layer height {to be reviewed; I want thin, flat, slow layers}

- all for the first time of course.  <_<

[later: ah-heh, maybe another week. Owwww.]

 I think the reason I am like this is that life has always thrown me into the deep end of everything, all the time, so I'm just used to it.

meh

 Back pain continues to make doing anything interesting difficult as hell. 

When it stops, I feel certain I'll have more to say.

grumpy old man doesn't understand world he lives in, "film at eleven"

 So I bought a replacement Y-axis belt tensioner.  It is made of aluminum and weighs sixty grams.  I don't think the extra mass - presumed extra mass, I gotta take the old one off to weigh it - will be sufficient to cause problems.

 It hasn't been installed yet because of ongoing severe back pain which has kept me immobilized for several days.  For under ten smackeroos I couldn't be arsed to make it from scratch.

 In the mean time, I've been shopping around for filament dryers since the filament I've had sitting around for five years is now showing signs of humidity absorption, and I was hoping that post-holiday prices would drop.

 I had half-settled on one, and even had it in my Amazon wish list, but then the price bounced up and I decided to see if it was just that vendor or everybody.  It was just that vendor, so all well and good, but then I found the ringers which really prompted this post.

 So the unit I'm looking at typically sells for ≈ $160 US.  You can get it as low as $102 direct from Aliexpress, or a bit higher if you choose Amazon.

 But two vendors want more.  Much more!  One eBay seller wants $700+ and another $900+.  I thought maybe they were selling four or five units, or throwing in a free printer, but they are not.

 It's not the first time I've seen this.  Can anyone explain what's going on?  The high flyers are usually on eBay, not always.  Shoppers are not stupid, they aren't going to buy that when the same unit normally sells for 1/4 of that.  Unless it's a money laundering scheme?  My dumb ass is not very good at thinking up successful criminal enterprises, or I'd be a lot wealthier.  IDGI.

because life would be boring without a few setbacks... now and then... right?

Uh, is that a crack? It looks like a crack.

 I do not believe this belt tensioner is supposed to be at an angle with respect to the rest of the arm:

um, those are new since yesterday

Uh-oh, that doesn't look right!

 If only I had some device, machine, or tool that can make complex plastic parts easily... d'oh!

 The best part is, I ran another test print without realizing this was busted, and the print completed.  Was run at 125% speed too, just for yucks.  I'm not saying it was pretty... O_O

 I can probably buy another one or someone's claimed unbreakable upgrade (which will be glass-  or carbon-filled, but printed, and therefore quite breakable) or I could machine one from aluminum.  I guess there's other materials I could use, but out of everything I have on hand, aluminum seems like the best choice.

 The next issue is that aluminum is heavier than whatever unfilled garbage resin Creality™ used for this part.  It's a stressed part; why was it not glass-filled nylon?  And that matters because of how this printer's Z axis works; from one end only.  The design works best if the wheels never wear at all, and the far end weighs nothing at all.  Um... <_<

 I was so naive, thinking I was nearly ready - with just some tuning and probably a bunch of filament-drying - to start printing for real.  Silly old man.  Silly, SILLY old man.

PS: machine has not been moved in years.  Belt was not over-tightened.  Well now, it's probably a tad under-tightened.  I'm frelling grumpy about this, TBH.  I think I need a break again, I feel like I'm constantly being sabotaged by invisible fairies and ninjas.  Ninja fairies, even!

UPDATE: I ordered a metal upgrade unit.  For $11, I couldn't be arsed to make one.

 This also leaves me with a spare bearing and pulley for what should be a high-wear area... if I were printing a lot. 

The blue knob is trash.  I have enough bakelite knobs, I certainly don't need any crappy PVC knobs.

 Belt tensioning is done sonically with a belt-tensioning phone app (easiest) or by calculation and any free audio measurement app.

buy the heavier one

  The basin wrench:

Fiddly to use, but no one (not even Ridgid), has come up with a better design.

 The first one I bought - with a different house, in a different wife - was some random inexpensive store brand.  It broke after maybe a dozen uses; the handle tore out of its holes.  I was also young and dumber; I may have used a bit of cheater pipe instead of heat to get antique fittings apart.  Ahem.

 So I asked around my circles, "what do pipe fitters and plumbers* use?"  Mostly, I got one word: Ridgid.
So I bought the Ridgid.  I believe Ridgid expects users to abuse the tool because the handle torque is applied to the hollow shaft not through its holes, which are slightly oversized to prevent it, but via a solid piece of square stock nestled inside the shaft, to wit:

 I've been wrestling with another very old (probably installed in the 1950s) enameled cast iron sink in my shop bathroom, replacing a supply line.  I put, oh, however much my weak-ass biceps are good for... let's say 45 lbs... onto a foot-long adjustable wrench onto the hollow shaft, and while the fitting did not come off (I'll use the torch today), that wrench was nice and stiff.  And did not slip off the fitting either. 

 Not a commercial, just a reminder that you get what you pay for:

made in USA - I checked

Tools For Christmas?

 If you're a regular reader of this blog, I hope you received at least one tool for Christmas, and I don't mean that one asshole relative coming over for dinner.  I suppose even a software tool would count.  So would a 3D printer, or just a hammer if it's a hammer you need and appreciate.

 Santa brought me two things I needed/wanted, both PPE; a pair of MIG welding gloves to replace the ones I wore *, and a pair of leather welding spats to cover boots and lower pants legs.  I really need those when I'm welding at higher currents.  Sometimes the spatter seems as bad as welding stick. :)

 So those were welcome indeed.  Also welcome was a high grade (Tripp Lite), steel cased, isolated outlet, RFI filtered, surge arresting, outlet box.  ie; ISO-BAR 6.  These units are very nice indeed, and this one  will go straight into the 3D printing lab/bench.

 And I got another present which I shant detail, because it's prurient / naughty and thus not suited for this blog.  So there.  Yes I know I frequently curse in my "family-safe" blog.  Shaddup. ;P

 Might not seem like much, but we're kinda broke.  The good news is, we're not really into the crass commercialism of the season.  We prefer giving things which are thoughtful and appropriate to the person, not expensive.

 Merry Christmas, and new tool wishes to all of you.
___________________________________________
* pro tip: MIG welding gloves at the welding store are fifty bucks.
   The EXACT SAME gloves are sold in gardening shops as "rose
   gauntlets" for twenty-five bucks.  I like the "MUD" brand.
   You're welcome. ^_^

Merry Christmas

 I have two gifts for you (if you're a 3DP person, that is):

1. This online database of filament material properties

2. This offline database (a different one) of filament properties

 From us to you, our wishes that your holiday is warm, safe and pleasant -
and spent with people you actually like. ;)

now let's talk about print quality... *sigh* the number one bugaboo of 3D printing

 "PRINT QUALITY"?? 
Hey isn't that where we left off eighteen months ago? 
(yeah, pretty much, before the upgrades and modifications, the extended cable
drama, the broken camera ribbon cable socket, the camera noise problem,
printer firmware updoot, controller updoot...)

Ahem.  Finally we return to working on the printer's actual purpose, printing.  I was pretty proud of the big owl I printed a year or two ago until I noticed the overhang problems.  Granted, printing overhangs without a support is a recipe for trouble, and I was using a comparitively primitive Cura Utilimaker to slice then.  I am now using PrusaSlicer, and if I do it again, there will be a mess of supports, probably.  The whole breast of the owl?  Couldn't we uh, just make it print overhangs somehow?  Mostly no, AFAIK, but a lot has happened in the last eighteen months, and gho knows what new cleverness has been released since then.  edit, later: I think the solution for that owl is to print it upside down.  I'm serious.

 Amusingly, as soon as I loaded good old Benchy into Prusa, it complained about the model, saying it might not be stable, there might not be sufficient bed adhesion, I should consider supports and a brim. 

Well, Benchy isn't supposed to be easy to print beautifully, it is supposed to be hard to print beautifully.  That's why and how it is a benchmark.  I also use CHEPs cube and anything else someone can show has merit.  The thing about Benchy is that everyone uses it and there's a lot of information about it, charts featuring it, etc.  Great for the beginner like me.

 But as for the low bed adhesion warning (which it bases on the base minimum width vs. the model's maximumn height) well, I could be a spokesmodel (can you see me in a bikini? Egad, best not.) for that Layerneer bed glue. It's a routine part of my flow now.  Granted, sometimes I just re-wet the existing and smear it around again.

 I think it is an Amazon stealth brand, TBH.  Got bed adhesion problems?  Stop!   Before you start messing with rafts, brims, and supports, and assuming you have a sane bed temperature profile, try somebody's, anybody's bed adhesive.

 I only have experience with this Layerneer stuff, which came to me as part of an Amazon starter package (I swear to Ghu, it was the exact thing I needed, in that moment).  Maybe I'd use it up faster if I printed more (I took more than a year off, whaddya want)  Since I began using it, I've only had a model break loose once, and that was because it was a max-volum model with many supports, and when the bed was allowed to cool off as "normal", the model broke loose.  A solution I haven't tried yet (because the print quality was ass too) is to leave the bed hot for the whole print.  Next time.

 

 Here's a test print I did with a small kodama ornament; you can see it's got serious issues.

 The tiny blebs are mostly due to the filament having sat unused and forgotten, on the printer, inside the tent... for the last eighteen months.  💦

 The only reason this prints at all is that the tent was closed up and it has a lot of silica gel socks lying around the bottom of it.  This is why filament dryers are useful, and why good dry storage is mandatory.

 Aside from the blebs, you can see that the first layer -  in fact all the layers - look a little bit high, and should be smooshed flat against the bed just a little more (for good bed adhesion).

 A taller layer height also makes for more pronounced layers and a less-smooth print.  Okay, so layer height needs to be tweaked in the slicer, right?  Ah, but reducing layer height strongly increases the number of layers and thus the print time. 

 I'll worry about that stuff when I'm satisfied with the bed leveling, which is taking me some time because I am being anal about it, and because there is no screw in the center of the bed and it seems as if there needs to be one. >_<

 And an afterthought: I've got some soft PLA I haven't tried.  It's yuge, as in 1.75mm, and I haven't any nozzles big enough - maybe.  Some say a standard 0.4mm can be used but most do not recommend the usual, saying 0.6mm is the absolute minimum. 

 The fancy "splitter" nozzles (see right) look like a good idea for such large filament because thick filament is harder to heat through if the filament is moving fast - plastics are lousy conductors of heat.  So Bondtech CHT and imitators have a design that splits the incoming cold filament into three separate channels, significantly increasing surface area, and reducing the "heat-through" cross section greatly.

 Unfortunately I'm not feeling generous right now and they want too much coin for just one nozzle.  There are "clones" but most I've looked into seem like very bad fakes, not clones.

 In fact, I'm thinking of drilling out a spare nozzle and trying it... getting the nozzle smooth around the hole >_> might be tricky.  Not sure how I'd drill it either, given that the lathe is currently in several pieces.

"I see no purple light crashing out of you (so just walk on in!)" -- The Sisters of Mercy

 Notice anything different?

 It turned out as I suspected: there was one crucial place in the complex chain which, if I choked it, would block most of the noice from entering either the camera or the camera port in the Pi.  This is a lot easier to apply than adding components inside the TCS, but that still needs to happen since it is the source of the problem.

 But in the mean time, I got lucky: one common-mode choke (mystery ferrite, probably mix 31 based on how well it works) with two turns on the core.  I'd have done three but I couldn't get the connector through again.

 EDIT LATER: when I posted this, there was supposed to be a video clip showing the printer running via the R-pi cam, but without the purple flashes.  So here is that:

 This outcome confirms my suspicion that the EMI was A) conducted not radiated and B) common-mode in nature.  And those suspicions were just based on experience, I'm afraid.  I am startled to have found a critical spot on the first try.  Back when I was getting paid to do EMI suppression for "EMC Acceptance Testing" it was rarely this simple to solve a noise problem, I can assure you!  (fortunately, I had very smart and experienced help)

 At some point, I will install both common and differential mode filters, plus small capacitances (handwave let's say at the relay and at the outlet (forming a pi network I guess).

 One has to be careful specifying and selecting such caps to be used across the power line, especially if they're expected to survive surges and spikes...

 On a 120VAC circuit, a capacitor with a 300VAC rating would be a minimum for the supply voltage alone, and normal best practices suggest 600VAC rating.  From my own reading and experience, and given that there are no other transient voltage surge suppression devices in this box, these devices should be able to survive a 3kV spike if you're being lazy, and a 6kV spike if not.  Good thing these are very small value (.001uF/1000pF should do it, and the reactance is so low their current draw may be ignored) capacitors.  Some likely suspects are the self-healing metalized plastic units on DigiKey rated for 6kVDC, whose longest dimension is 1.2in - they should do nicely.  The ferrites will be somewhat larger.

The printer-shaped-object is a real printer again! (and I have proof)

 Check it:

gosh darn Blogger - here is a backup link in case below video vanishes or malfunctions.

Blogger is being weird (for me), so I can only fullscreen the video sometimes. (WTH)
If the same is true for you, hit the link above if you want a larger / clearer version.
And anyway you're not missing anything special, it's just the printer, printing. ;)

(if you use the link to the Google Drive file, be sure to change the res from 360 to 720)

 
 So anyway, yes, it's a printer once again, finally, and last night it managed to spit out a recognizable Kodama with no great effort from me, which I took as a sign that I may once again be in favor with the gods.

 I had already grid-leveled the bed (software cancelation of bed height variations using BLtouch - I gotta take a picture of the results, it's fabulous) a week ago, so all the printer had to do last night was find home and double check that the center height is where it thinks it should be, which requires just one 'dip' and happens on every print.  I could make it so it doesn't.  I might, when I 'get gud'.  If I ever need to print lots of something, I would want to disable that.

 These "kodama xmas tree ornaments" are a good test for getting (re)started because frankly, they're not as challenging as Benchy.  And this first Kodama has plenty of problems showing.  I think most of that is about the slicer, not the printer settings.  TBD of course.

 Also, at least one maybe two of the steppers on this printer seem to run HOT AS HELL, so that will be investigated and I will report back when I am smarter.  Not sure how I will investigate this since it comes down to "how hot is too hot" and I haven't got a good... ohh, heh-heh-heh well now, that was gonna be a lie.  I have a perfectly good thermocouple plugged into a 'perfectly good' (chinesium) PID controller, which should tell me what time it is.

 Operating temps of steppers routinely reach 70ºC  - 80ºC, so I just need to stick my thermocouple on there.  I am not using the temp control system, and won't really need it except for certain high temperature filaments I'm not ready for and don't even own yet.

 It could be that I'm just not used to working with steppers (true statement) or it could be that the drive voltage needs to be backed off a bit.  There is a lot of mechanical resistance in these inexpensive printers, and maxing-out the driver voltage means maximizing the pole/step hold strength as well as step torque, both of which help overcome that resistance.

 I'd like to believe that is as easy as turning a tiny trim pot on the driver board inside the printer.
I'd rather find out it isn't necessary and that I worry too much.

 Currently I am on hold because my other half is asleep.  The printer is in the basement, the work area is not far from the bedroom above, and the creaky basement stairs pass under the bedroom too.  "St. Jude" has a sleep-in day today, and I would not take that away from her. ;)

 BTW, I crashed the printer near the end of the first kodama print because I was experimenting with the Temperature Control System (TCS, okay? sheesh) which, while not in use, was still causing camera interference. When I unplugged the circulation fan, the printer crashed.

"In my house there's this light switch that doesn't do anything.
Every so often I would flick it on and off just to check.
Yesterday, I got a call from a woman in Madagascar.
She said, 'Cut it out.'"

 Sigh, okay, another useful disapoint, I mean datapoint.  I am gathering the feroids while I may, and when I have enough different sorts and sizes and quantities, I'll start applying them to various cords and seeing what if anything helps.  I'm also probably going to put a small HV cap across the SSR in the TCS box.  A cap across it and a series toroid, or a common-mode choke inside the box, will go further than filters at the victim hardware end.  The TCS box is all metal.  It should be possible to stop the RFI cold before it leaves that box on the cords.  It cannot radiate (much - be reasonable) from the grounded box.

 I also suspect polling from the PID controller could be making noise (WTH?!?) onaccountabecuz there is camera interference even when the SSR is not being commanded on or off, or even when its heater load is unplugged.

 I am aware this sad little Pinocchio SSR is not a real SSR because I've had it apart; oh yes, it comes right apart, nothing is potted inside, and there is a thermopad like device inside, held down to the heatsink plate by a single screw and no evidence of heat sink grease or silpad.  And the screw projected past the heat sink, rendering it unuseable.  I wet-sanded it flat, then half-ass lapped it a little.

 I've no idea what happened to my small collection of SSRs, but they are gone now, apparently.  A real one from a name brand is $100 and up.  So for now, I'm stuck with what I have, whether or not its counterfeit construction contributes to interference.

 This was cheap chinesiunm; the entire kit, including PID controller, SSR, and heatsink for SSR, was $99.  In the western world, you'd do well to be able to buy the heat sink for that.  If you plan on spending $250 - $300 for your own kit using high quality parts from the usual suspects, you'd be in the right ballpark.

 If only there were some instrument which allows one to see a line voltage event with respect to time. <_<

 Again with the measurements this guy... *sigh* okay, where's my ground lift?  (techie joke)
I got 99 problems, but a scope capable of looking at line voltage safely* isn't one. 
Hey, that could totally be a line in a rap song.
 

 Thank the gods the printer and my o-scope are right next to each other because neither is portable at all!  I mean, the o-scope is on a wheeled cart because it weighs right at fifty pounds with four plugins installed.

 Blah blah old guy but at least I never have to hunt through menus, AND there's no one-shot sample rate limit all the way to its 500MHz BW, because it doesn't use sampling to store a signal.  No dots, ever, unless they're part of the signal.  So there.

___
* if you do this, make sure you never connect a probe's ground lead to live power circuits!

 The best practice is to use the signal side of two channels and invert one of them.  Just
take the ground clips off the probes and stow them, for safety.  Also for safety, don't use
"ground lifts" aka "3 prong adapters" to remove the ground reference connection of the
scope.  This is hazardous to both instrument and operator - you could die, so don't do it.