stepper motor bulk purchase

check is in the mail, I expect you should have by Monday (mailed from Austin).

quick update:

i got the check, am depositing it today, and will order the stepper motors shortly. i'm going to be ordering 48 motors which is 16 sets of motors.

once i sell through those, i'll order more... the idea here is to keep those motors in stock at the store at all times.

heck yeah!

update: i mailed a check to Keling for an order of 48 motors. they'll be up on the RRRF store for $25 each here in a week or 2 when i get the motors in.

yay!

great! put me down for 3 :-)

yeah, so these keling motors don't change the design at all?

---

Jay

My understanding is that the software has parameters that allow some variation.

which Design? I think Zach is making the new Arduino interface even more flexible in terms of interface.

yes, these motors dont change the design at all.

* darwin requires a dual shafted NEMA 23 motors - which these motors are, so they will work well.

* they can be wired in a variety of ways: unipolar, bipolar-serial, bipolar-parallel and will work with all the stepper driver boards we have

basically, they are awesome steppers.

I don't think these motors will work with the non Arduino electronics without using a series resistor to get the coil resistance to minimum 6 ohms so in bipolar-series you would need a 2.4ohm add-on minimum 20 Watt I would suggest.

With the Arduino electronics as Zach said they will be sweet.

---

Ian
[www.bitsfrombytes.com]

I have been using them with Rev 1 Electronics and they are working fine I do have a big heat sink nothing monstrous the heat sink does heat up a little.

but the l297 is able to be pushed a little... and it has been holding up for 2 months now of use..

Bruce

UPDATE: the stepper motors have arrived. i got 48 of them, or 16 sets of 3 total. you can get them here: [store.rrrf.org]

only $25 each!

Sorry - Zach only has 45 available because I just ordered my 3.

---

Bob Teeter
"What Box?"

Subtract 3 more for me

Just ordered my 3, looking forward to play with them! i have everything else for a mcwire complete. I have smaller steppers currently, but they arent big enough to move the platform

yayay!

Just a thought for these new motors.

I haven't done much research into it (yet), but it seems the universal controller boards have all of the necessary circuitry for PWM. I realize it might require some patch wires and firmware changes, but couldn't you use the power transistor usually reserved for the extruder heater to effectively mimic any voltage as the supply for the 298? Then you could drive many different steppers without series resistors.

Scott McClure

Scott: technically yes. Actually I believe thats what the 'power' setting for the steppers (in the host software) does, is drive them via pwm instead of a direct on/off signal. However it still causes huge spikes which is why you'll still want series resistors.

Of course there is always the 'chopper method' which the arduino stepper boards use that monitors the current and cuts power when it hits the predefined limit. That ensures no matter what stepper you use, it always gets the right amount of power.

I hope everyone notices that the 48 stepper motors (16 sets) lasted all of 4 days. They probably lasted that long only because most people did not know that Zack had them in the store. O well. I will have to wait to order another set when he gets more in.

---

Bob Teeter
"What Box?"

Zach, exactly what motor did you buy - from where - and what was your cost broken down by product, shipping, tax.

Does anyone have identifying information that is printed on the motor itself? Part numbers, etc.

Thank you.

Edited 1 time(s). Last edit at 01/18/2008 11:31AM by RoundSparrow.

Here is the data right off the RRRF site.

This is a "KL23H251-24-8B" 8-wire NEMA 23 stepper motor with dual output shafts from Keling Technology, Inc. It can be wired in unipolar, bipolar-serial, or bipolar-parallel modes. It is compatible with both generation 1 and generation 2 stepper driver boards.

You can view the datasheet here, and the torque/speed curve here.

You will need 3 (three) of these to drive a full RepRap machine, one for each axis.

I hope that this helps.

Zach sells these for $25.00 more than that I don't think we need to know. This should give you enough information if you wish not to purchase from RRRF to find your own source of supply.

Disclaimer: I am a very happy customer of RRRF.....

---

Bob Teeter
"What Box?"

its exactly as Robert Teeter says. i'm all for transparency of the RRRF, but at this point in time i dont have time to put all this information out there. its pretty well documented in this thread exactly which motors we bought, how much they cost, etc.

i hope you dont think the RRRF is trying to rip anyone off. yes, its true the RRRF marks up the prices slightly, but you have to keep in mind that it needs to a) cover expenses such as rent and b) needs to earn money in order to expand and be able to provide more services. its a balancing act, and i think that all the prices on the website are very fair.

finally: ordering the motors singly:

keling: $29.00 ea.
RRRF: $25 ea.

Cheers,
Zach

> Zach sells these for $25.00 more than that I
> don't think we need to know.

Ok, so again Robert Teeter has taken upon himself to follow me around on this forum and tell me what I need to know or otherwise discuss.

It is clear to me that price and availability of motors in the USA is a significant factor in keeping people from building RepRap's. But Hey, Robert Tweeter will probably tell me ideas are inappropriate for this forum and haven't researched that enough.

In November 2007 it took me 4 weeks to get my motors from England. And others put the problem on the table... that price was a factor (I did not start this thread).

It is my understanding that the first batch of RRRF motors sold out very quickly and there was demand for a second batch. And I can speculate that it might be more demand beyond another 16 sets.

Is it beyond imagination that some people out here might actually believe in the goals of the project and *gasp* be willing to donate time, travel, and do other things at a loss?

I just asked a straight-forward question on what price to aim for on a bulk purchase - to be sure I'm getting the right motors at a good price. You know, sharing information that might help the project either move quicker or help others build a RepRap.

I don't really have anything to say about the motors, but stop the bickering in the forums. If you want to bicker, than send a PM, but it is a waste of space in th forums and nobody wants to read this junk.

---

Jay

redskinsjbs Wrote:
-------------------------------------------------------
> I don't really have anything to say about the
> motors, but stop the bickering in the forums. If
> you want to bicker, than send a PM, but it is a
> waste of space in th forums and nobody wants to
> read this junk.


If you don't have anything to say about motors, then why the heck did you post in this thread? How about YOU send a PM.

I'm trying to ask what price was paid for a bulk motor purchase that impacts the RepRap community. And I am the one who financed that purchase. And this is the thread where that very purchase was organized.

Where is the second set of motors that Zach purchased? Are they in yet? It was December 19 when I witnessed the first batch come in. As was pointed out in this thread, they sold out in 4 days. It has been another 30 days. And I am waiting to order more myself... is the vendor giving Zach trouble?

My agenda is to get problems on the table and SOLVE THEM. Money seemed to be the issue, so I provided money. First batch was done in less than 3 weeks. Things are slowing down, so maybe the time is to step forward and help out more on the labor side. I know Zach is very busy. I'm asking questions so I can decide if it makes sense to help out by starting a second source here in the USA for some of these parts.

And in case not clear: these questions are directly related to motors for building a RepRap.

Edited 3 time(s). Last edit at 01/19/2008 11:58AM by RoundSparrow.

I checked the site Tuesday and the new stepper motor order was in and online. I ordered 6 and Zach shipped them yesterday.

---

Bob Teeter
"What Box?"

bobt Wrote:
-------------------------------------------------------
> I checked the site Tuesday and the new stepper
> motor order was in and online. I ordered 6 and
> Zach shipped them yesterday.

Thank you for sharing that.

I was not aware of this. As this thread was was the place all this started (fully documented in the messages). And I had asked Zach to let me know when they were in so I can order 3 for myself.

Good to hear.

Sorry. I had a blog post typed up about the new motors, but it got eaten by my browser. The new steppers are in (48). I figured a blog post would be overkill, since my supplier has to re-order more steppers in china (~2 months til next set.)

If you have to know, 48 motors cost $1138 including shipping. You wont be able to order any, because the supplier is temporarily out of stock. He's reordering more and my plan is to keep ordering to perpetually keep the RRRF in stock. He's 100% interested in working with us and we even chatted on the phone.

ZachHoeken Wrote:
-------------------------------------------------------
> Sorry. I had a blog post typed up about the new
> motors, but it got eaten by my browser. The new
> steppers are in (48). I figured a blog post would
> be overkill

No need to apologize. I just assumed you were too busy, my mistake for underestimating you.

> since my supplier has to re-order
> more steppers in china (~2 months til next set.)

Well, ok. But 16 sets doesn't seem much to me for 2 months, as the feedback on the motors seemed great (I got to see one in action in Houston on Sunday myself). At least I hope we run out. So did we come up with any useful alternates when we found this source Is Keller the direct mfg on these, I can't find that part # anywhere else.


> If you have to know, 48 motors cost $1138
> including shipping.

It seems odd to me that this information isn't open shared. It isn't personal finances we are talking here. You are charging great prices. Maybe I'm out of line on expectations for open source. It isn't like you don't have to deal with returns and other overhead... so gross cost isn't expected to equal net cost.

> You wont be able to order
> any, because the supplier is temporarily out of
> stock. He's reordering more and my plan is to
> keep ordering to perpetually keep the RRRF in
> stock.

We in the USA seem to get favorable pricing from China. That may only be a short-term opportunity (next 6 months) as the Chinese are turning up the heat on the currency imbalance. Part of the reason I expect high demand for motors is I expect even with shipping that overseas demand will be there at USD$25.

Plus one thing that I'm not sure we can really solve (or should try): There clearly is a lot of open source activity out there related to stepper motors - and RepRap project is going to draw attention for people wanting to share technology. This can lead to 16 sets being sold out in 1 day once another project finds out about it Always a reasonable chance of this.

I entirely admit my need for help in finding the correct compatible motors. Please post any leads.

Started chasing stepper motors - Nema 23 156 oz-in 1/4" shaft

Webtronic - $24.95 qty 1 Spec sheet:
[lib.store.yahoo.net]

Circuit Specialist - $24.95 qty 1 Spec Sheet:
[www.circuitspecialists.com]

I just chased google for : nema 23 stepper motor

---

Bob Teeter
"What Box?"

Nice. If those alternate parts could be validated, I would certainly order.

As an engineer for a large disk/data storage company, I can tell you that it is always best to source from multiple vendors. We could then share our experience with the others as 'mods' that are within spec.

Both those motors are 12V 0.4A motors these probably won't give good performance if driven from 12V. They are also 56mm long not 51mm as standard RepRap. They will fit but are not exactly true spec (you pays your money and takes your choice!).

---

Ian
[www.bitsfrombytes.com]