THE Bipolar Stepper Driver. Have you seen it?

[NorDevX]

Hi there : )

Thought I'de show you our new creation! Based on the A3977 ic. There are a couple available right now if you go to the link here https://www.nordevx.com/content/bipolar-stepper-driver otherwise they will be available in a couple of weeks. Also there's a distribution board available soon to go with it. This would probably only be used for smaller cncs/diy types or 3d printing : ) However we will be making more industrial motion control which will be more pertinent to the cnc/machining community. If you have any questions or comments let me know.

https://www.nordevx.com/images/front-page/the-stepper-driver-frnt.jpg
https://www.nordevx.com/images/front-page/4-axis-stepper-distribution.jpg

[Jonathan]

$32, that's about £20 plus shipping for a 35V 2.5A stepper driver. You can get 50V, 4.2A stepper drivers for about £25 including shipping, less if you buy a few at a time. I'd spend the extra £5.

Also, I find it worrying that the voltage and current ratings you specified are simply the 'absolute maximum' ratings taken from the datasheet. The absolute maximum ratings are just that, they're not the parameters you should be running the device at. In reality the voltage rating should be lowered to account for back emf from the stepper motors, and the current rating will be less then 2.5A since you don't appear to have any heatsinks on the driver ICs.

[NorDevX]

Can you give me a link to the 50V 4.2A stepper driver? The price is always difficult to set but I thought I set the price lower than any other A3977 based stepper driver I could find...in the U.S. at least. Also yes those are absolute maximum values straight from the datasheet, and that's a great idea I'll add recommended voltages and currents. The heatsinks I talk about on the front of NorDevX.com which I'm going to do some tests with. Without a heatsink you really shouldn't go over 1A at the moment.

[Jonathan]

One of these:
A943A TO REPLACE M542 CNC 1 Axis 4.2A DC24 50V Stepping Stepper Motor Drive-in Motor Driver from Industry & Business on Aliexpress.com (http://www.aliexpress.com/item/A943A-TO-REPLACE-M542-CNC-1-Axis-4-2A-DC24-50V-Stepping-Stepper-Motor-Drive/1092795489.html)
Or many of these:
Wholesale m542 stepper driver - Buy Low Price m542 stepper driver Lots on Aliexpress.com (http://www.aliexpress.com/wholesale/wholesale-m542-stepper-driver.html?SearchText=m542%2Bstepper%2Bdriver&CatId=0&initiative_id=SB_20130919122227&SortType=price_asc&filterCat=100006838,100006835,100006839&groupsort=1)
Or if you're after a driver similar to yours:
57,42 stepper motor driver 3A DC12 32V, CNC stepper driver board,8 microstep,free shipping Wholesale price-in Motor Driver from Industry & Business on Aliexpress.com (http://www.aliexpress.com/item/57-42-stepper-motor-driver-3A-DC12-32V-CNC-stepper-driver-board-8-microstep-free-shipping/606135797.html)

Fair enough I didn't spot that you'd mentioned 1 amp without the heatsink. I take it you're planning on supplying heatsinks as an optional extra?

[NorDevX]

Ahhh yes of course the chinese ones you can get very cheap in fact if you go on ebay you can find them for even cheaper around 5-10 dollars. I've never looked inside them so I can't say anything about them. Another thing that seperates us is the smaller form factor as these are rather tiny. Also these will be opensource. And yes most likely heatsinks will have to be added...not sure if it should be extra or not I will probably just throw them in.

[John S]

Not your fault but the biggest problem with buying your drives is that EVERYTHING from the US gets hit this end for VAT at 20% plus a handling charge put on by the post office so in your case the user will have to pay £10 to £12 extra per drive.

These drives, which BTW are very good, not blown one yet, come in at £25 for 3 post paid from China but always come in under the radar.

New TB6560 DC Stepper Motor Driver Board 3A Controller TB6560 Driver Board | eBay (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=121167286322)

Ower Gert just bought some small hinges from the States without asking me. cost £40 plus £14 postage and got hit for £16 duty.

I could have got the same items from China for £9 all in.

I can understand trying to buy home grown but both China and the US are imports so you buy accordingly.

[John S]

Forgot to add being smaller does nothing for me, it's not like we have to cram it in a tiny box.
On machines space isn't a problem and going tiny just means more heat in a smaller area.

Can't see what the obsession with tiny is. Seen more than enough blown Gecko drives with tiny power traces on the board supposedly rated for 7 amps when the Leadshine ones use the hard shoulder south of Milton Keynes and never blow a trace.

[jcb121]

One of these:
A943A TO REPLACE M542 CNC 1 Axis 4.2A DC24 50V Stepping Stepper Motor Drive-in Motor Driver from Industry & Business on Aliexpress.com (http://www.aliexpress.com/item/A943A-TO-REPLACE-M542-CNC-1-Axis-4-2A-DC24-50V-Stepping-Stepper-Motor-Drive/1092795489.html)
Or many of these:
Wholesale m542 stepper driver - Buy Low Price m542 stepper driver Lots on Aliexpress.com (http://www.aliexpress.com/wholesale/wholesale-m542-stepper-driver.html?SearchText=m542%2Bstepper%2Bdriver&CatId=0&initiative_id=SB_20130919122227&SortType=price_asc&filterCat=100006838,100006835,100006839&groupsort=1)
Or if you're after a driver similar to yours:
57,42 stepper motor driver 3A DC12 32V, CNC stepper driver board,8 microstep,free shipping Wholesale price-in Motor Driver from Industry & Business on Aliexpress.com (http://www.aliexpress.com/item/57-42-stepper-motor-driver-3A-DC12-32V-CNC-stepper-driver-board-8-microstep-free-shipping/606135797.html)

Fair enough I didn't spot that you'd mentioned 1 amp without the heatsink. I take it you're planning on supplying heatsinks as an optional extra?



What's the difference between the M542 and the A943A.

is one a "digital" stepper drive? (seen digital drives on zapp)

is one better then the other?

[NorDevX]

One day maybey we'll be big enough to have a location up there so shipping isn't an issue : ) It's form is tiny because it's efficient, not everyone will need that and it's totally understandable. For instance DIYers might prefer larger components to hand solder...although I have to say one stereo microscope and you can have a lot of fun with smd components as a DIYer. It is not however so tiny that it can't perform at its maximum.

[irving2008]

I'd like to see your thermal calcs, test data and pcb layout. The 28degC/W junc-ambient rating is based on the JEDEC51-7 standard board of 114*76mm (with vias to JEDEC51-5). Yours is only 14% of that area so your thermal resistance is much much higher (its proportional to area), probably at least 170degC/W allowing for all the other components on the PCB. With a total Rds of 0.8ohm you risk random thermal shutdown at 1A especially on the inner units on that distribution board. I'd certainly not consider using this product.

Adding a heatsink to the package will have some but relatively minimal effect, the thermal path is to the PCB.

I recommend you move to the A3979 chip. Its pin compatible, has an Rds of 0.5ohm and gives a higher microstep setting. The 3977 is an old design and due to be deprecated soon anyway.

[NorDevX]

All the testing info will be available soon. If you check out the front of NorDevX.com I'll be updating about its progress also I'll post it here for people interested. I don't understand what your talking about with the JEDEC standards.

I looked at the A3979 and I finally chose the A3977 simply because it stopped at 1/8th step as I feel like 1/16th step is way overkill. As you would need a machine that was very precisely made for it to be worth it. I however didn't check out the Rds on...that does make its mosfets more efficient I'll have to think about that one.

[irving2008]

... I don't understand what your talking about with the JEDEC standards.

Thats exactly my point... the TISSOP package heatsinking needs are very critical and the 28degC/W thermal rating is measured under strict conditions, one being the area of copper ground plane used as a heatsink and the number of vias that act as heatpipes from the contact pad to the ground plane. By shrinking the board size you've compromised your heatsink performance dramatically.


I looked at the A3979 and I finally chose the A3977 simply because it stopped at 1/8th step as I feel like 1/16th step is way overkill. As you would need a machine that was very precisely made for it to be worth it. Disagree, depends on desired resolution and screws used, nothing (directly) to do with how well machine constructed.


I however didn't check out the Rds on...that does make its mosfets more efficient I'll have to think about that one.Rds is your enemy, minimising it is always a good strategy, Esp on the brushless motor controller I'm designing at the mo for 250A continuous, 300A peak! The MOSFETs for that are 0.02ohm and I'll still need 10 or more per channel if the heatsink is going to be
smaller than a football pitch :biggrin:

[~andy]

This will be of more interest to the 3D printer market I think.

It's worth sticking some optocouplers on that breakout board to cover your arse.

[Jonathan]

the brushless motor controller I'm designing at the mo for 250A continuous, 300A peak! The MOSFETs for that are 0.02ohm and I'll still need 10 or more per channel if the heatsink is going to be
smaller than a football pitch :biggrin:

You're not the only one. What's that for? I'm guessing electric car, or reasonably high power mobility scooter?

[JAZZCNC]

You're not the only one. What's that for? I'm guessing electric car, or reasonably high power mobility scooter?

. . . I'm guessing a very fast Kettle. .. :stupid:

[irving2008]

You're not the only one. What's that for? I'm guessing electric car, or reasonably high power mobility scooter?

Let's call it a mobility aid... Scooters can't take rehab seating, go off-road and have 4 wheels...:biggrin:

What's yours for and would you be interested in collaborating or at least sharing ideas?

[Jonathan]

What's yours for

Hard to say, it keeps changing.


would you be interested in collaborating or at least sharing ideas?

Certainly..

[NorDevX]

Wow 250A sounds like a fun project! I'de like to change your mind about needing 1/16microstep for a cnc or similar machine.

Lets pretend I have a screw that takes 10 revolutions to complete 1inch. A stepper motor that takes 200 full steps to complete one revolution.

If I use 1/16th step it will take 200(steps)x16x10=32000steps to complete 10 revolutions and go an inch. Now you just take 1/32000 =.000031inches which is your resolution. Lol that's a really high resolution. Even at full step resolution is good at .0005 inches...this will vary with your threads per inch/meter. Microstepping is definitly needed though as it makes everything much smoother and you have control over your resolution but I see no reason to go super high with microstepping. Unless you have 2tpi and want .0001 then it is very usefull...now I'm curious what microstep are all of you using on your machines right now?

[Jonathan]

Whilst I agree that the higher resolution microstepping being available with the newer IC is not much especially useful, that statement is largely irrelevant - the lower Rds alone is the reason to use the A3979, especially when you're trying to make this compact. Lower Rds means lower heat dissipation, which means less space is needed to extract the heat, i.e. the heatsink is smaller.


Unless you have 2tpi and want .0001 then it is very usefull...now I'm curious what microstep are all of you using on your machines right now?

Not really, as if you really need extra resolution you'd change the drive ratio between the screw and the motor as the accuracy of micro-stepping is limited. A lot of people here use 10mm pitch screws driven 1:1, so that's effectively 2.54tpi...but the main factors in choosing the microstepping valua are the maximum frequency your controller can output, the maximum feedrate you require and the value which causes the least resonance in the machine.

[John S]

Every time you microstep you loose torque.
So by the time you drop down to 1/16th and need to overcome stiction it will miss steps unit it has enough to make a sudden move so basically anything over 8 is a waste of time.

Also remember systems can't remember microsteps so a shut down and start up will go to the nearest full step regardless of where it was.