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Inq
 Inq
(@inq)
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For instance is...    

  1. 59.9625°
  2. 59.99765625°

... good enough?

These are easy to achieve.  After this, things get more difficult.

VBR,

Inq

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, Access Point Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
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Inq
 Inq
(@inq)
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If you want a theoretical exact through mechanical means, use a gear a reduction.  Again, backlash will have error.

Ratio of 3:10  

Tell stepper to move 200 steps * 3/10 = 60.0000000000000000000000°

 

VBR,

Inq

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, Access Point Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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olddude
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@inq Sorry for the slow response.  I was in town on a business issue. 

I have a stepperonline nema 17 CE ROHS   17HS19-2004S1


   
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olddude
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@inq Wow that is pretty close.  I have to work out what would happen in an 8 hour day.  Thank you.


   
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olddude
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@inq yes even with that high of a percentage it wouldn't hold up.  I run at 4,000 rph.

in an 8 hour day 32,000 revs.  That equates to a rather large number.


   
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olddude
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@inq Yes, i just got back from the machine shop to do that very thing.  They are working on getting the gears needed to solve my problem.  I am still unsure of my stepper as to be able to do the job I need done.  Torque for sure, I have 3 gates that will open and close so time will tell especially with the gear reduction and revolutions.  Thank you again for all your help.  Olddude


   
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Inq
 Inq
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Posted by: @olddude

I have a stepperonline nema 17 CE ROHS   17HS19-2004S1

With the 3:10 ratio, it'll multiply the torque.  You profile doesn't mention where you are, so I'll use Imperial.  I have a set of those stepper motors and they're pretty stout.  

Torque goes up:  84 oz-in * 10/3 = 280 oz-in

Speed of motor goes up: 4000 rph * 10/3/60 => 222 rpm.

That should be OK, but you might have to accelerate the stepper up to that speed by using code.  It'll depend on how much torque you're using.  

Posted by: @olddude

yes even with that high of a percentage it wouldn't hold up.  I run at 4,000 rph.

in an 8 hour day 32,000 revs.  That equates to a rather large number.

Not that it matters if you're using the 3:10 gearing, but it isn't cumulative if you use the direct method (no gears).  

  1. 60° => 59.99765625°
  2. 120° => 120.00234375°
  3. 180° => 180.00000000°
  4. 240° => 239.99765625°
  5. 300° => 300.00234375°
  6. 360° => 360.00000000°

I really can't imagine anything mechanical that could tell the difference.  Angle error is only 0.004%.  I doubt any machinist will claim that kind of accuracy. 😉 

Good luck.

VBR,

Inq

 

 

 

 

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, Access Point Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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Inq
 Inq
(@inq)
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Curious what gear set you decided.  6:20 or 9:30... etc.

image

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, Access Point Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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olddude
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@inq Thank you so much.  I really appreciate your input.  Regards,  Jim


   
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olddude
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@inq In what you are suggesting is it something unique that I have to do to achieve that accuracy or is it inherent?


   
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Inq
 Inq
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If you're prototyping, gears can easily be 3D printed.  In Nylon they're tremendously strong.  Many 3D printers use 3D printed gears and run for years successfully.  The second image is the same stepper you're using.

image
image

VBR,

Inq

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, Access Point Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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Inq
 Inq
(@inq)
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Posted by: @olddude

@inq In what you are suggesting is it something unique that I have to do to achieve that accuracy or is it inherent?

It depends on what you're using to drive the stepper motors.  You do have to do something explicit, but its very common in 3D printer usage.  The keyword you'd need to look-up is "Micro-stepping".  Using the dirt-cheap A4988 drivers (~$1.20), they can be set to do 1/16 micro-stepping.  Thus... each step pulse you send them actually moves the only 1/16th of a full step.  So... there are 200 * 16 steps/rev = 3200 steps / rev.

The high-accuracy, second set of numbers I show is using another, more expensive driver that can handle more current and has 1/256 micro-stepping => 200 * 256 = 51,200 steps / rev.

Again... it is not cumulative.  Coming out exact at 180.000000 and 360.00000 degrees at 25,600 steps and 51,200 steps respectively.

Just something in you back pocket if the gears don't work out for you.

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, Access Point Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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olddude
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@inq Believe me I will avoid gears if there is any alternative.  I will follow your info and obtain these drivers.  Again, thank you.  NOGEARS


   
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olddude
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@inq Can you give me the part number for the second driver?


   
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olddude
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@inq Yes the gears you show are exactly what we discussed.


   
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