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Message |
    
fabrica
Registered
Username: Daya
Post Number: 184
Registered: 10-2006
| | Posted on Tuesday, January 16, 2007 - 06:09 pm: | 
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Gerald, What do they mean by the diametrical pitch and how does it relate to the ditsnace travelled per revolution. My pnion has a diametrical pitch of 20 as per Boston gear specs. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 719
Registered: 11-2005
| | Posted on Tuesday, January 16, 2007 - 06:19 pm: |
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It means that 20 teeth make a precise diameter of 1 inch. I suppose your pinions do have 20 teeth and so you are on the "standard" number of teeth for the 1 inch diameter. The distance travelled will be p times diameter, equals 3.1416 X 1, equals 3.1416 inches (X 25.4 = 79.79645mm)
What is your gearbox ratio? |
Gerald_D
Registered
Username: Gerald_d
Post Number: 720
Registered: 11-2005
| | Posted on Tuesday, January 16, 2007 - 06:38 pm: |
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If you had a 20 tooth DP20 pinion direct to motor with no gearbox, Mach3 will want a "Steps per mm" setting of 2000/79.79645 = 25.06377.
If you have a 3.6 : 1 ratio gearbox with that pinion then Steps per mm becomes 90.22957
Etc. |
fabrica
Registered
Username: Daya
Post Number: 185
Registered: 10-2006
| | Posted on Wednesday, January 17, 2007 - 06:43 am: |
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Thanks for your explanation. My pinion does have 20teeth as you guessed and the gearing ratio is also 3.6 : 1 and the motor rotates .5 Deg per step. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 721
Registered: 11-2005
| | Posted on Wednesday, January 17, 2007 - 07:19 am: |
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Okay, if you are setting up Mach to work in millimeter, the magic number you need for calibration is 90.22957 steps per mm.
Just to explain a little further....
Most stepper motors have 200 full steps for one revolution (1.8o per step). Your motor has a 3.6 reduction gearbox on it therefore the output shaft is 0.5o per step. In other words, the motor must receive 720 full steps before the shaft will make one turn.
The Gecko driver employs 1/10th micro-stepping....meaning that the Gecko must receive 7200 full steps from the computer before it will produce 720 full steps to the motor, before the shaft (pinion) will make one turn and move the machine 79.79645mm. Divide 7200 by 79.7964 and you get your calibration value. |
Hugo Carradini
Registered
Username: Hugotel
Post Number: 4
Registered: 11-2006
| | Posted on Wednesday, January 17, 2007 - 02:02 pm: |
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Hello Fabrica.
¿What is the difference in performance between using motor direct to the pinion and working with a motor with gearbox?
Thanks for your answer
Hugo Carradini |
fabrica
Registered
Username: Daya
Post Number: 188
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 05:53 am: |
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I think by using a gearbox you get a better torque and also a better finish on the cuts that you make. |
Hugo Carradini
Registered
Username: Hugotel
Post Number: 5
Registered: 11-2006
| | Posted on Thursday, January 18, 2007 - 06:38 pm: |
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Hello fabrica. I understand that but you also reduce speed . ¿Do you have and estimate off the IPM you can archived with your actual configuration and the IPM going direct to the motors? I am getting ready to start buying my stuf and want to have everything clear in my head . Thanks for your time. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 729
Registered: 11-2005
| | Posted on Thursday, January 18, 2007 - 06:42 pm: |
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Hugo, maybe you want to look at this thread |
fabrica
Registered
Username: Daya
Post Number: 194
Registered: 10-2006
| | Posted on Thursday, January 18, 2007 - 07:43 pm: |
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Hugo, With modern software like Mach3 you could increase the RPM of the motors by taking advantage of their in built higher pulsing speeds. These RPM increases of the motor through higher puilsing sppeeds adequetly compnsate for the lost speeds due to gearing. You have a win win situ here. Higher torques at the same cutting or jogging speeds which you had earlier. With higher torques you have better cutting or engraving quality. No lost steps on steppers.
If you need furher info on this issue you could follow the links provided by Gerald. |
Hugo Carradini
Registered
Username: Hugotel
Post Number: 6
Registered: 11-2006
| | Posted on Friday, January 19, 2007 - 03:03 am: |
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Thanks fabrica and Gerald.
I am just getting use to the order of the deferents links. |
reza forushani
Registered
Username: Reza
Post Number: 96
Registered: 01-2007
| | Posted on Tuesday, February 27, 2007 - 04:21 am: |
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As you know, I got movement. Now I am studying the Mach3 and Vcarve. Can somebody help me with numbers to plug in for English system (inch)
Thanks |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1040
Registered: 11-2005
| | Posted on Tuesday, February 27, 2007 - 07:00 am: |
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Reza, I've forgotten the gear ratio of the motors you ordered? are you using 20 teeth pinions? |
reza forushani
Registered
Username: Reza
Post Number: 97
Registered: 01-2007
| | Posted on Tuesday, February 27, 2007 - 07:23 am: |
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3.6 and yes. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1043
Registered: 11-2005
| | Posted on Tuesday, February 27, 2007 - 08:08 am: |
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20 teeth make a precise diameter of 1 inch. One turn of the pinion makes 3.1416 inches of linear movement.
With the 3.6:1 gearbox, 3.6 turns of the motor make 3.1416 inches of linear movement.
The Geckos need 2000 pulses to make one turn of the motor, so you need 7200 pulses to make one turn of the pinion, to make 3.1416 inches of linear movement. That gives a value of 2291.8 pulses per inch to be set in Mach. |
reza forushani
Registered
Username: Reza
Post Number: 98
Registered: 01-2007
| | Posted on Tuesday, February 27, 2007 - 08:19 am: |
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Thanks Gerald. On the Calibration screen, it's asking for other stuff. Where do I plug this number in (2291.9) Thanks again |
Gerald_D
Registered
Username: Gerald_d
Post Number: 1044
Registered: 11-2005
| | Posted on Tuesday, February 27, 2007 - 08:45 am: |
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In Mach, you first do the Config > Select native units, and I am sure you picked inches there.
Then you do Config > Motor Tuning, and at bottom left there is a block "Steps per", it actually means "Steps per selected native input", which in your case is "steps per inch" or "pulses per inch"...
For the rest, you can play with any value on that screen, because you pick the final speed and acceleration values once the whole machine is moving. |
reza forushani
Registered
Username: Reza
Post Number: 99
Registered: 01-2007
| | Posted on Tuesday, February 27, 2007 - 09:23 am: |
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Got it boss. Thanks a million $$$ |
Driving Mechanisms: Rack/pinion, gears, screws & chains