First time buying stepper motors: enough torque? [Question]
June 24, 2015 02:52PM
Hi. I all trying to make a 3D printer on a budget. Therefore I can't really afford 60 euros for stepper motors :/ I have found a deal on ebay for some SONCEBOZ 8110R003 nema 17 type ones but there is virtually no information about them. This is the only document available:
[forums.reprap.org]

I'm not sure of they have enough torque as the are listed as 130 mNm dynamic torque.
If someone who knows about the required torque and what the different values mean in the doc could point me in the right direction I would be very grateful.
Thanks.
P.S: I have attached screenshots of the photos on the ebay listing.
Attachments:
open | download - Screenshot_2015-06-24-20-23-43.png (445.9 KB)
open | download - Screenshot_2015-06-24-20-24-41.png (417.7 KB)
Re: First time buying stepper motors: enough torque? [Question]
June 24, 2015 03:30PM
Sorry, from the data you linked to it appears that those stepper motors have way too much resistance to work with standard drivers.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: First time buying stepper motors: enough torque? [Question]
June 24, 2015 03:47PM
Thanks for the reply. What resistance values should they have? Up to what resistance can the drivers work?
Thanks.

Edit: I found this: [reprap.org]
It indicates that the resistance doesn't matter with modern drivers. I have ordered the A4988 driver.

Edited 1 time(s). Last edit at 06/24/2015 04:05PM by gomme600.
Re: First time buying stepper motors: enough torque? [Question]
June 24, 2015 04:16PM
The steppers we often use are sold with an indicated holding torque of 35-54 N·cm, (or 3.5-5.5kg·cm, 49-76 oz-in...they're all approximately equivalent). The motors you linked to have a holding torque of 50 mN-m, which is equivalent to 5 N-cm. In other words, those are an order of magnitude weaker than what you really need to be looking for.

Unless you get lucky, you're probably going to need to pay 60+€ for five new retail steppers, especially if you can't find any domestically and need to pay VAT for importing them from China or elsewhere.
Re: First time buying stepper motors: enough torque? [Question]
June 24, 2015 04:28PM
Oh dear :/ Excited by the cheap price I made an offer the other day! I now see this was a mistake. It hasen't been accepted yet so I might not need to worry but if it is do you think they are useable or should I explain the situation to the seller?

Edit: I explained the situation and they refused right away. On another note do you have any recommendations for nema 17's for my tight budget please?
Re: First time buying stepper motors: enough torque? [Question]
June 25, 2015 09:23AM
How many do you need and what is your budget? Does saying you can't afford 60€ mean 59€ is ok? Or are you talking more like 50, 40 or 30€? Also from your image I presume you're located in France? Also if 60€ for steppers is too much, what about all the other required parts? Can you maybe skimp in other areas for the time being to upgrade later? Motors are one of the areas where if you skimp, you'll pay in the long run.

Edited 1 time(s). Last edit at 06/25/2015 09:25AM by cdru.
Re: First time buying stepper motors: enough torque? [Question]
June 25, 2015 11:34AM
I know this might sound impossible at first but I am trying to build it for under 100 euros. You see I have a lot of scrap printers I can get 8mm metal rods from and a glass build plate from the scanner part. I have free wood lying around and possibly access to another 3d printer to print parts. So really all I need to buy is the motors, a ramps board+arduino, a hot end, threaded rods to move the z axis and other things I'm probably forgetting here.

Ideally 30euros would be the price I'm looking for but it looks like I will need to pay more.
I was thinking of getting 5 motors but 4 might do if I only use one for the z axis. I might also be able to buy less if I find some good enough ones in the printers
And yes, I am located in France.
Re: First time buying stepper motors: enough torque? [Question]
June 30, 2015 06:56AM
You forgot to mention a power supply, driver chips, end stops, belts, bed heater, fans etc - even the hot-end (if you buy a ready made one) will cost a bit also, and you're trying to build the whole thing for under $100?
Anyway, those motors will be useless for a Reprap. If I was you, I would find some way to finance the project and give it the investment it deserves - 3D printers are wonderful things to have and I'm sure if you build it well with decent components you will not regret the expenditure.


_______________________________________
Waitaki 3D Printer
Re: First time buying stepper motors: enough torque? [Question]
July 02, 2015 05:23AM
I have a psu from an old pc along with some fans. I have already got the ramps board with drivers. I have also dismanteled old printers so I have belts and other little bits. I am going without a heated bed at first and I am bidding on a hotend on ebay. Finally I am going to make the printer out of free wood.
So I have most of what I need and infact since my last post I got some stepper motors out of the printers but I don't think they will be powerful enough. I'm going to try with them anyway as they were free though.
I will post back results when I get all the parts from china. It sounds impossible but I'm hopeful and even if it doesen't I will have most of the parts for when I get more money.
Re: First time buying stepper motors: enough torque? [Question]
September 08, 2015 03:28PM
So how did it went?
Re: First time buying stepper motors: enough torque? [Question]
October 02, 2015 06:42AM
[www.robotdigg.com]
[www.robotdigg.com]

You could take a look at these.


ShapeForger
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