Test Equipment Anonymous (TEA) group therapy thread

[xrunner]

The Good, The Bad, and The Ugly

I was using this coax for some testing and noticed it seemed to be a little intermittent, so I had put it aside a few weeks ago. I don't remember where or when I got it but I've had it a long time. This evening I decided to cut it open and see what the deal was (I expected shoddy workmanship).

My prediction was rewarded (yay me!). The bad crimp is shown at the top, and a proper unused new crimp connector at the bottom. After I trimmed into the plastic glob holding it all together - the cable pulled right out of the crimped connector as if no pressure at all was holding it - either the inner conductor crimp or the outer.

So what do we see here? Oh yes - we have the shield crappily folded over and crimped not to an inner metal sleeve (as can be seen in the new crimp connector) - but to the plastic jacket!

So beware all ye who buy cheap materials - you get what you pay for.

Note: Check the label on the cable. 

[mnementh]

From Radidio Shank? Shocking, I tells ya!!! 

mnem
*BEEEEEEEP! goes the microwave* Get the 'ell outta muh way. Please.

[beanflying]

Parts ordered back on Oct 18 for my test-lead fabbing venture have FINALLY arrived; as usual with Bang-em-Good, a mixed bag. Aside from the abysmal delivery time (Seriously USPS - 18 days from Rochester NY to Houston? What did I do to piss you off?), and the fact the stuff was shipped in a freaking poly film bag.... amazingly, it all arrived intact. 

The leadscrews are one of the last bits I'm pulling together to do a 1:4 layer height/dual Z mod on my Tevo Tornado; 600mm x 2mm pitch leadscrews to replace the single 550mm x 8mm pitch lead that came stock. Zero-Lash rod nuts, G2 sprockets and self-centering couplers arrived a couple weeks ago; now all I have to do is fab up bearings/mounts and the modding can begin.

The leadscrews are actually pretty amazing quality, especially for $10 each; stainless steel with decent finish and somehow they actually arrived still straight, and very smooth with very little backlash in the included nuts. I'm not even sure I'll need the zero-lash nuts, especially for the amount of gravity preload in this application.

Gravity is your backlash nut on Z for a 3D printer unless your squishing to much plastic on the first layer or two. Still good practice to minimise it however.

Packaging - dumbasses are out there all over the world and seem top specialize in using an inverse law of protection to fragile or damageable contents. That rule doesn't apply to Mouser they are just excessive always, last 20 component shipment was about the size of a shoe box the bits with padding would have fitted into a cigarette packet. 

[mnementh]

Yeah, I know... in theory. But the 1:4 part of this mod will make a 50 micron printer into a 10 micron printer; possibly less once I learn enough to really dial it in. That is small enough that the BLTouch will be pretty much useless, so iterative accuracy will be paramount.

We'll see if the wider and genuine Vee-groove Y-axis rail cures the accuracy issues that plagued the Tarantula; so far the Tornado seems better in all respects by about a factor of 10. Otherwise I may wind up rebuilding with dual linear sliders.

mnem
*Print-ily*

[bd139]

The Good, The Bad, and The Ugly

I was using this coax for some testing and noticed it seemed to be a little intermittent, so I had put it aside a few weeks ago. I don't remember where or when I got it but I've had it a long time. This evening I decided to cut it open and see what the deal was (I expected shoddy workmanship).

My prediction was rewarded (yay me!). The bad crimp is shown at the top, and a proper unused  new crimp connector at the bottom. After I trimmed into the plastic glob holding it all together - the cable pulled right out of the crimped connector as if no pressure at all was holding it - either the inner conductor crimp or the outer.

So what do we see here? Oh yes - we have the shield crappily folded over and crimped not to an inner metal sleeve (as can be seen in the new crimp connector) - but to the plastic jacket!

So beware all ye who buy cheap materials - you get what you pay for.

Note: Check the label on the cable. 

Gah been there. I’ve only just got myself sorted on the cable front. Found this is the route to happiness:

1. Buy the coax separately so you can see what’s in it. I’ve had stuff that has as little copper as they could get away with hiding inside ready made leads. Seems to be that “military spec” (probably isn’t but looks like it might be) RG58U is about as good as it gets without costing you £300 a reel. Think I paid £25 for 20m of it.
2. Twist on connectors are the least shit. As long as you solder the center conductor. Crimps are just trouble and require more tools.
3. Amphenol at both ends. The shit plugs fall to bits.
4. Double heat shrink the end.
5. If it’s outside wrap it in plumbers tape and then go over that with liquid tape. My antenna has been ravaged by storms three times now but the feed and balun are still rock solid.

[beanflying]

I am unlikely to change any of mine to a BL touch or similar at 0.1 layers as I suspect they will already start having consistency issues. At 0.1 I run a decent brim and manually tweak the bed by eye looking at layer squish and consistancy around the loop after leveling it first. At 0.2 I don't always bother checking the bed for level between prints (because I am lazy) as I don't think they move as much as people assume. Different if I used a scraper or force to remove prints but I generally don't need to.

The roller wheel style bed on my CR10 is the weakest point IMO of the mechanics at 40mm width rail with a 300mm bed the Ender Pros running the same rail at 220 beds 'seem' ok.

Building an Enclosure for the CR-10 today partly for keeping it clean but it should get better prints.

[mnementh]

@bd -    I've been using Silicone Self-fusing Tape to seal up outdoor connections for decades; ever since my teenage years doing DirecTV/Hughes satellite TV installs. Stuff is effing magic for sealing against weather, though the claims of it holding against pressure are greatly exaggerated.

mnem
*Tool-Dwagon-ily*

[mnementh]

@bean -    Yeah, I got the BLTouch because it was all the thing when I first started... found it did work, but mostly because of variations in the bed itself. Since I did the 12" x 12" mirror tile mod, it's so flat, so repeatable (even after swapping tiles) that I just tweak as it's printing the brim myself. Still getting the hang of that... and of getting a level coat of hairspray.   

Great thing with the mirror tiles is they come 6/$10, so you can just take a tile with a project off, set it aside, and move onto the next print with a new tile. Uniformity of the glass is actually pretty amazing... you can swap in a new tile and just tweak without releveling. While you're printing the next item, the last one separates by itself from the glass as it cools.

I usually don't relevel unless the printer's been still for a few days; of course, that's probably a bad habit I'll get out of as I get to be less of a noob. I still forget to put the filament away in a dessicant bag when I'm not printing sometimes. Okay, a lot of the time. Like right now. 

So far I don't regret not splurging on one of those expensive full-bed glass build sheets. We'll see how that works out in the future.

mnem
*Silicone Gel-ly*

[Specmaster]

@bd -    I've been using Silicone Self-fusing Tape to seal up outdoor connections for decades; ever since my teenage years doing DirecTV/Hughes satellite TV installs. Stuff is effing magic for sealing against weather, though the claims of it holding against pressure are greatly exaggerated.

mnem
*Tool-Dwagon-ily*

Yes that tape is really something else I have used it before  Those 4mm banana plugs are just awful however, I too got some of these with the decent turned metalwork on but the plastic sleeve is sheer shit, they just do not hold at all. The only way I could get them to sort of stay on was to use some PTFE take on the thread of the plug but even then the plastic is dire that it will often just stretch or split as you screw it on. 

[Neomys Sapiens]

Do I need help?

Depends. Do you have a matching arbitrary generator?

[mnementh]

@Specmaster - I noticed on mine that the threads in the sleeves don't start until ~2-3mm of the way up; I toyed with the idea of trimming some away, but I think unless I make some kind of jig, it'll be impossible to do so without making it look shite as the profile of the whole thing is tapered. Maybe I can find a drill bit just the right size to jam up its butt and be able to spin-file it on my drill so it shaves down squarely.

mnem
Oh, yeah. Some kind of jig... 

[mnementh]

Do I need help?

Depends. Do you have a matching arbitrary generator?

That's all the help he needs, I think. 

mnem
"Oh, The Wheel in the Sky keeps on turnin'..."

[beanflying]

Still getting the hang of that... and of getting a level coat of hairspray.   

If you are only doing PLA dump any and all glue or interface layer and just use the glass or mirror surface! Clean glass then a wipe with IPA prior to each job and print at circa 50C on the bed.  Uber slick finish 

For PETG I use Bostik Glustick applied as evenly as I can, not ideal but it sticks well and releases consistently. The brand of Hairspray I got was a fail.

[mnementh]

I tried exactly that and had poor results couldn't get jack-sh** to stick, though it might have been bed temp. I discovered later that unless I'm printing for over an hour with lots of coverage to retain heat, according to my IR thermo-tormentor the mirror runs about 10° C cooler than bare, at least compared with the Tevo clone-buildTak print surface. A lot of folks say to peel it off and just print on the bare ceramic plate underneath, but I like the convenience of the tile; thus far the Tevo-Tak hasn't bubbled up, so I prefer to keep it to cushion the glass.

One thing I have to admit... the 120V bed heater is effing FAST, and it regulates very well. Because it doesn't rob current from the hotend, the printhead heats up faster and regulates better on a PSU half the size of the Tarantula.   That and the numerous reports that Tevo had "stepped up their game²" were what sold me on the Tornado over the CR10. Well, that and the fact I had enough BG points to get it for $260. 

mnem
"Poit!"

[beanflying]

I have checked my glass against the shown temperature and there is good correlation and consistency across the entire surface. The mirror could be giving you emissivity issues with the IR gun for example mine hates Chrome or Polished surfaces and isn't reliable even on Milk but works great otherwise. Break out a thermocouple and some thermal paste to test or even use your hand

[mnementh]

I double-checked by shooting at a 2" square of 0.012" aluminum laid on both surfaces. I turned bed temp up 10° and it seems to be working well. And I keep getting better with the hairspray, which I like the finish. Only problem is if I lay it on too thick it has the opposite effect. Obviously this isn't going to be workable with hotter filament without destroying the Tevo-Tak, but I'm going to have to invest time and money in ventilation before I or my family can tolerate ABS or TPE. Folks tell me PETG is strong as ABS and doesn't stink, but I haven't had a chance to validate those claims. I suppose I can always put a spool of clear PETG in my cart next time I'm shopping Amazon...

mnem
Stop making me THINK!!!

[beanflying]

PETG is well worth adding to your stash. Suffers from more stringing and oozing so crank the retraction a touch but layer bonding and toughness are great (not as rigid as PLA). I am taking one of my Ender Pro's back to glass as while the magnetic bed and build surface is 'easy' the finish isn't as good and the temperature limit is an issue for some of what I want to play with.

There is a whole lot of old wives tales out there online about 3D printing that keep getting repeated as gospel on farcebook etc. Some very good youtube accounts in Tom Sanladerer, CNC Kitchen, Makers Muse but also a lot of absolute dribble accounts 'look at the free awesome printer/accessory/filament gearbest/bangood sent me'.

Thinking is good too

As is the 15-20kg of filament I have dropped through the printers in the last few months. 

[mnementh]

Yeah, it's just like flying... the way you learn is just plain old stick time. Same with this stuff; the way you learn is by getting a machine that works, and using it til you figure out how to make it print BETTER.

I already ran into that whole "old wives' tales" thing in a really disturbing way when I was shopping CR10 vs Tornado and saw a number of talking heads out there... respected "names"... trying to NOT praise the Tornado in comparison with the CR10, and coming up with all sorts of "I think" and "What-if" conjecture but not a single solid argument aside from the fact Tevo has a history of making cheap shit. It was painful to watch.   

You could see them wanting to call the Tornado a C10 clone, except Tevo did this geometry first, years ago with the Tarantula. In truth, that may have been what pushed me over as much as the $$$.

mnem
"Unbiased" my hindscales.

[mnementh]

[" were they THINKING?!?" Mode]



I just now took this out of a tire gauge on my bench. The whole universe of cool ideas for product names to pick from, and they choose to register THIS as a trademark?!?

[/" were they THINKING?!?" Mode]

mnem
"What was your second choice? Scrotum Hat?" ~Rocket Raccoon

[Mr. Scram]

Possibly an obtuse question, but a PTC heater should have the same temperature regardless of the environment right? Providing the environment's temperature is lower. Any environmental difference should just contribute to getting to temperature quicker.

[beanflying]

Currently due to a rash of clones of clones there is to many brands making minor variations on the same basic layout. There is still within them mechanically piss poor rubbish being produced. Simple, Strong, Square and Straight is a good start.

Creality has had that right for a while and Tevo has gotten better but some of their early attempts were not so good. Electrically and with Firmware Tevo was lagging/dangerous but once again getting better recently. Fairly typically second and third generation production in a market area out of China starts to rival worlds best but for less $$ and they seem to get it eventually the West want's stuff that works properly out of the box . Win for the consumers loss for the Western manufacturers unless they stay ahead technically.

All of mine have come direct from Creality via their Aliexpress or Evilbay accounts backup has been excellent when needed. One of their 30+ year old female support staff was I think shopping for a husband and was getting very friendly via personal email (I ran away)  saved the TEA budget.

[beanflying]

Possibly an obtuse question, but a PTC heater should have the same temperature regardless of the environment right? Providing the environment's temperature is lower. Any environmental difference should just contribute to getting to temperature quicker.

Controlled by what if anything exactly?

If it is just connected to a fixed source it will provide X additional watts of heat energy to the environment or area. So higher ambient with X watts additional will yield a higher resulting temperature.

[Mr. Scram]

Controlled by what if anything exactly?

If it is just connected to a fixed source it will provide X additional watts of heat energy to the environment or area. So higher ambient with X watts additional will yield a higher resulting temperature.

Are you sure? A PTC heater is supposed to have a resistance which increases exponentially with temperature. This way they self regulate to a supposedly fixed temperature. Considering the temperature is the variable controlling the resistance, having a higher environmental temperature shouldn't really influence much. I'm not sure how that works out practically, though.

[beanflying]

They are supposed to be intrinsically safe against getting to hot and catching fire or melting depending on how they are made or surrounded by. In effect they are just a resistor with VERY positive temperature coefficient. I would call it a safety and not a set temperature.

Try this spec sheet. Wattage dropping off with increasing temperature also a curve of increasing inlet temp over outlet temps. http://www.spxtransformersolutions.com/wp-content/uploads/2017/11/PTC2-1.pdf

[Mr. Scram]

They are supposed to be intrinsically safe against getting to hot and catching fire or melting depending on how they are made or surrounded by. In effect they are just a resistor with VERY positive temperature coefficient. I would call it a safety and not a set temperature.

Try this spec sheet. Wattage dropping off with increasing temperature also a curve of increasing inlet temp over outlet temps. http://www.spxtransformersolutions.com/wp-content/uploads/2017/11/PTC2-1.pdf

That's what I figured. Thanks for the data sheet, I was looking for something like that. That fairly clearly confirms it.