Is Nema17 1.2A too weak for 3d printing?

Quote
VDX

Quote
realthor

Quote
VDX
... I've powered my first heated bed simply with a bare 12VAC@8A transformator (which gives roughly 16 to 14 Volts AC depending on load) and switched the current with an AC-SSR.

This can be done with any available transformator (found several from 5VAC@60A to 14000VAC@1mA in my scrapery), but for heated beds I'll avoid output powers above 50 Volts and currents greater than 20 Amps for safety reasons (and it's hard to find proper connectors).

You know what you're talking about, I couldn't understand half of it . I would venture in electronics but I don't know if it's smart to do that as a beginner. I think I'm going with an ATX power source (I have one around) and see from there. I believe there are good tutorials around the web how to use that (i've seen a good one but I can't seem to find it).

Here's the ATX one I can use:

[attachment 78241 IMG_20160517_122534.jpg]

... here's a sketch to show the driving of a heated bed with a transformer and switching it with an AC-SSR (solid-state-relay):

[attachment 78242 HB-Test.png]

Indeed a safer approach than a hotbed powered from the main supply. To make it even safer, don't you use a thermal fuse ?

... I have several comercial heaters and different cooling and heating modules with and without extra safety sensors - the sketched circuit was only a test for a simple heated bed many years ago

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote
MKSA

Quote
realthor
@MKSA you're not helping and this type of attitude is only perpetuating a tensed environment. What about some common sense in these forums ...

Tensed ? No, just funny ! Common sense ? Not very common, reading your non sense !
I am just wondering, do you know nothing about everything or everything about nothing ?

I'm glad you enjoy being a troll.
You're wasting your precious time on a thread you feel is nonsense. It's not nonsense to me and I don't need your kin to come tell me what/how you feel. Nobody cares.

Edited 1 time(s). Last edit at 05/18/2016 06:22AM by realthor.

---

RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Quote
cozmicray
ikcl There you go again

i've sent you a private message, cozmicray.

Quote

What are timing belt issues doing in a topic about NEMA 17 current draw?

BTW the more contact (wrap) of a belt on a pulley is better for power transmission
keeping in mind that the belt has to be able to withstand a sharp bend by a small diameter pulley.

... and that the load on the belt is distributed across less teeth if it is a smaller diameter pulley, resulting in more (localised) stress on it. also, the higher the angle the belt turns through, the larger the inertia of the actual belt's material to contend with as it is "flung" round the belt. at low speeds this effect will not be such a problem, but at higher speeds it will be. also, belts on smaller gears will have each tooth on the belt being bent through a sharper angle. at some point, that bend isn't going to be a bend, it's going to be resistance. that will result in both vibration of the belt as well as stretch it in irregular ways in proportion to how engaged one tooth is as it comes on (and off) the belt. if this isn't clear, take it to the extreme and imagine what would happen if there were only 5 teeth (or even 4) on the belt. the belt would be a "square wheel" in effect, and if you saw what they did with mythbusters when they made square wheels for a car, they had to get it up to speed and *rely* on vibration to smooth out the motion of the car... but it was still a hell of a rough ride. and a very funny episode.

anyway, so there are a heck of a lot of good reasons why you should think twice about using small gears and angles approaching 180 degrees. but, y'know what? if it works, it works.

Edited 1 time(s). Last edit at 05/18/2016 05:45AM by lkcl.

Quote
MKSA

I know who is who !
I worked in a nut case asylum and I can identify the real Washingtons from the fake ones !

MKSA, i recall that you were rude earlier, and didn't apologise for doing so. what that - and these comments - tell me is that you are the type of person who, at school, would laugh harshly at another child's distress. it tells me that you are the type of person who feels vindicated and happier if other people are unhappy. whilst you are clearly intelligent, it tells me that you are egoistic and, whilst not a bully because you don't go out of your way to *deliberately* harm other people, i don't think you're actively conscious of what you're doing.

i give you this advice because i trust that you will listen to it, understand that your words are not really appropriate on a technical *public* forum which is searchable forever and thus may affect your future job and career prospects, and, after taking these things into consideration, you will become a much more mature and useful contributor to this community as a result.

Quote
lkcl

Quote
cozmicray
ikcl There you go again

i've sent you a private message, cozmicray.

Quote

What are timing belt issues doing in a topic about NEMA 17 current draw?

BTW the more contact (wrap) of a belt on a pulley is better for power transmission
keeping in mind that the belt has to be able to withstand a sharp bend by a small diameter pulley.

... and that the load on the belt is distributed across less teeth if it is a smaller diameter pulley, resulting in more (localised) stress on it. also, the higher the angle the belt turns through, the larger the inertia of the actual belt's material to contend with as it is "flung" round the belt. at low speeds this effect will not be such a problem, but at higher speeds it will be. also, belts on smaller gears will have each tooth on the belt being bent through a sharper angle. at some point, that bend isn't going to be a bend, it's going to be resistance. that will result in both vibration of the belt as well as stretch it in irregular ways in proportion to how engaged one tooth is as it comes on (and off) the belt. if this isn't clear, take it to the extreme and imagine what would happen if there were only 5 teeth (or even 4) on the belt. the belt would be a "square wheel" in effect, and if you saw what they did with mythbusters when they made square wheels for a car, they had to get it up to speed and *rely* on vibration to smooth out the motion of the car... but it was still a hell of a rough ride. and a very funny episode.

anyway, so there are a heck of a lot of good reasons why you should think twice about using small gears and angles approaching 180 degrees. but, y'know what? if it works, it works.

It's almost like they wrote a document, to which you keep referring but refuse to read. In that document they call out a minimum recommended pulley size for GT2 pulleys, and surprise it happens to be 16t. Same document talks about speed as well. It's on the website (www.sdp-si.com), and available freely. Perhaps you might consider reading it before dispensing theory.

Quote
MKSA
I am just wondering, do you know nothing about everything or everything about nothing ?

MKSA - taunting others and trying to goad them to get a reaction out of them is very immature, and is not appropriate for a public technical forum where the archives will affect your future career prospects. there is a specific word used to cover the type of behaviour that you're engaging in, it's defined as the word "Troll". you may also be breaking the terms and conditions of use of this web site.

so please for your own sake have some respect for other people and for yourself.

Quote
Koko76

It's almost like they wrote a document, to which you keep referring but refuse to read. In that document they call out a minimum recommended pulley size for GT2 pulleys, and surprise it happens to be 16t. Same document talks about speed as well. It's on the website (www.sdp-si.com), and available freely. Perhaps you might consider reading it before dispensing theory.

ok so that's great! thank you for bringing to my attention important information that i can use to improve my own printer as well as pass that knowledge on to others in this quite small and exclusive community, in the future.

now, why did you have to bring that knowledge to our attention in a way that made yourself look better than anyone else? is it *absolutely* necessary for you to be sarcastic at other people's expense, denigrating to others, and to place yourself as being better than other people *at the same time* as providing really, really useful information and corrections to other people's lack of knowledge?

does doing that make you feel like you are a better person? what, specifically, do you gain from such clear demonstrations of anger and resentment? and why would you expect us to have to work harder than it should be, to filter out the noise that you are making in order to find the valuable information that you've provided?

Quote
lkcl

Quote
Koko76

It's almost like they wrote a document, to which you keep referring but refuse to read. In that document they call out a minimum recommended pulley size for GT2 pulleys, and surprise it happens to be 16t. Same document talks about speed as well. It's on the website (www.sdp-si.com), and available freely. Perhaps you might consider reading it before dispensing theory.

ok so that's great! thank you for bringing to my attention important information that i can use to improve my own printer as well as pass that knowledge on to others in this quite small and exclusive community, in the future.

now, why did you have to bring that knowledge to our attention in a way that made yourself look better than anyone else? is it *absolutely* necessary for you to be sarcastic at other people's expense, denigrating to others, and to place yourself as being better than other people *at the same time* as providing really, really useful information and corrections to other people's lack of knowledge?

does doing that make you feel like you are a better person? what, specifically, do you gain from such clear demonstrations of anger and resentment? and why would you expect us to have to work harder than it should be, to filter out the noise that you are making in order to find the valuable information that you've provided?

I find a lot of noise is generated by people who talk without knowledge. I don't make recommendations without a foundation of knowledge. I'm sorry if you take it personal that you get called out for not knowing what you are talking about. I would advise that you refrain from uneducated comments, and then your problem will be resolved.
Again, this is freely available stuff that can be found (as I did when I looked for it many years ago) online. Instead of writing a multi page report on what you think is right try searching for already done work. You are adding noise on already settled subjects. Most of the things discussed here are settled science. Despite people's ego most if my everything discussed on these forums are rehashes of decades old tech, much of it documented if you can be bothered to research it.

Quote
Koko76

Quote
lkcl

Quote
Koko76

It's almost like they wrote a document, to which you keep referring but refuse to read. In that document they call out a minimum recommended pulley size for GT2 pulleys, and surprise it happens to be 16t. Same document talks about speed as well. It's on the website (www.sdp-si.com), and available freely. Perhaps you might consider reading it before dispensing theory.

ok so that's great! thank you for bringing to my attention important information that i can use to improve my own printer as well as pass that knowledge on to others in this quite small and exclusive community, in the future.

now, why did you have to bring that knowledge to our attention in a way that made yourself look better than anyone else? is it *absolutely* necessary for you to be sarcastic at other people's expense, denigrating to others, and to place yourself as being better than other people *at the same time* as providing really, really useful information and corrections to other people's lack of knowledge?

does doing that make you feel like you are a better person? what, specifically, do you gain from such clear demonstrations of anger and resentment? and why would you expect us to have to work harder than it should be, to filter out the noise that you are making in order to find the valuable information that you've provided?

I find a lot of noise is generated by people who talk without knowledge. I don't make recommendations without a foundation of knowledge. I'm sorry if you take it personal that you get called out for not knowing what you are talking about. I would advise that you refrain from uneducated comments, and then your problem will be resolved.
Again, this is freely available stuff that can be found (as I did when I looked for it many years ago) online. Instead of writing a multi page report on what you think is right try searching for already done work. You are adding noise on already settled subjects. Most of the things discussed here are settled science. Despite people's ego most if my everything discussed on these forums are rehashes of decades old tech, much of it documented if you can be bothered to research it.

Quote
lkcl
ok so that's great! thank you for bringing to my attention important information that i can use to improve my own printer as well as pass that knowledge on to others in this quite small and exclusive community, in the future.

now, why did you have to bring that knowledge to our attention in a way that made yourself look better than anyone else? is it *absolutely* necessary for you to be sarcastic at other people's expense, denigrating to others, and to place yourself as being better than other people *at the same time* as providing really, really useful information and corrections to other people's lack of knowledge?

does doing that make you feel like you are a better person? what, specifically, do you gain from such clear demonstrations of anger and resentment? and why would you expect us to have to work harder than it should be, to filter out the noise that you are making in order to find the valuable information that you've provided?

I would ask why would you make such a definitive statement as:

Quote

watch out for that, though: *don't* wrap the corexy belt through 180 degrees round GT2-16t's. put an idler bearing in (or two) so that the belt loops back on itself through 90 degrees instead.

If you didn't actually know? THAT is actual noise, because it's, well, wrong. And fairly easy to check. Without someone contradicting you, that incorrect statement might be read by someone who doesn't know any better, who found the post via a google search, and winds up seriously over-complicating their printer design because of incorrect information.

As others pointed out, 16T GT2 pulleys with 180 bends are very common (usually 2 on each axis) in Delta style printers. As table 8 on [sdp-si.com] points out, minimum radius for 3mm GT2 belt is 16T, with a maximum RPM of 1600 (at 200 steps / revolution on most 1.8 degree steppers, that's around 5333 steps/second, which on a delta would mean the carriage is travelling at 667 mm / second-- do your own calculation on your steps/mm for your X/Y axis. If you need more RPM, up your tooth count, but you aren't going to melt plastic that fast anyhow, so why bother?

You made an incorrect statement, and got defensive when you were challenged on it. Sarcasm was to be expected at that point, really.

Looks like ickl doesn't believe in using www.sdp-si.com
or other industry standards.

They do know how to use timing (Power Transmission) belts
His one or two printer designs are his knowledge base.

Show me your mechanical engineering degree and design articles in
industry documents that you are indeed an expert to make comments.

and I will stop telling you to stop spewing manure.

I think everyone here knows to ignore you
I hope your foldable Rube Goldberg printer works great and gets adopted by Epson.

BTW --- The ultimate use of timing (Power Transmission) belts --- dragster blower drive
perhaps 300 - 500 HP to drive blower off crankshaft -- 6 inch wide belt 1 inch pitch
2 > 180 degree belt contact with outside idler. Usually use them for 1 run.
Specifically designed for power transmission -- many times very few teeth left
Been there at timing belt tests with an expert (my father) Dragster -- rock crusher
selectronic typewriter, timing and power transmission on news print machines

I will try to refrain from giving timing belt comments -- I just here flushing sound!

Thank you

When is it enough for you guys? I think we all have to learn something by being here but sometimes a "lesson learned" doesn't need so much insisting and bragging and showing how's got muscles and where does he come from. Intelligence and expertise is not all that matters in these type of communities, social skills are too, any some of us need too to take that as a "lesson learned" if they are as smart as they want to believe. But ego will prevent it by the way many of you talk. And even if you usually give good advice and have the experience and expertise your way of delivering it is just ...welll... you get it.

This thread should be erased by the moderators... it just proves what a community we are. I will unsubscribe from my own (nonsense) thread because I don't want to get alerts with updates about a war going on here who is better and who should be disciplined and who's background makes him more glorious. I will actually refrain from posting too much in the forums, because this seems to be a forum for the smartest guys, not for people who need advice, want to learn and make mistakes.

---

RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

This thread is funny and sad at the same time...

"Is Nema17 1.2A too weak for 3d printing?"
Why use this motor in the first place? In the corexy the x, y, z motors do not move. simply use mena17 1.5A motors, there are almost the same price.
If your making this question because you already have the motors, them try.. They probably work fine, all depends the firmware/steppers configuration you use.

Is there moderator intervention on any of the topics?

I guess freedom of speech wins

There are many topics that are stolen by other issues.

good talk buried under wrong title?