Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
So my question still stands. Now we have 1703 In/Sec^2. MAX_VELOCITY = 2.5 MAX_ACCELERATION = 7.5 So could I use that value? What I'm trying to do with this tool is to take out some of the guesswork or the accident.tal divide instead of multiply. > -Original Message- > From: Bruce Layne [mailto:linux...@thinkingdevices.com] > Sent: July-21-20 7:57 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc > > > > On 7/21/20 10:09 PM, John Dammeyer wrote: > > If Gravity is 32 ft/sec^2 then it's also 2.7 in/sec^2. > > Only if there are 12 feet in an inch, but there are 12 inches in a foot, > so one g is 384 in/sec^2. > > > > > ___ > Emc-users mailing list > <mailto:Emc-users@lists.sourceforge.net> Emc-users@lists.sourceforge.net > <https://lists.sourceforge.net/lists/listinfo/emc-users> > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
Crap. Went the wrong way... > -Original Message- > From: Bruce Layne [mailto:linux...@thinkingdevices.com] > Sent: July-21-20 7:57 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc > > > > On 7/21/20 10:09 PM, John Dammeyer wrote: > > If Gravity is 32 ft/sec^2 then it's also 2.7 in/sec^2. > > Only if there are 12 feet in an inch, but there are 12 inches in a foot, > so one g is 384 in/sec^2. > > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 7/21/20 10:09 PM, John Dammeyer wrote: > If Gravity is 32 ft/sec^2 then it's also 2.7 in/sec^2. Only if there are 12 feet in an inch, but there are 12 inches in a foot, so one g is 384 in/sec^2. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
I started pulling stuff apart on the bostomatic today found out some information on the encoders and spindles. The encoder is a encoder products company 755a it is 5000 cycles per revolution. Quadrature A channel with index. Line driver output, max frequency 200 kHz <= 3000 cycles per revolution. There are 2 spindles on the machine. Main spindle is uaaska-04D looks like its 1500/8000 rpm rated Secondary spindle is the precise corporation sc82. Spindle is 1-4 rpm rated. There are linear rails on all 3 axis. A 15 position tool changer for the main spindle. I think the machine should be really nice if i can get it running. Also if anyone has ever heard of or knows Barry Tognazzi or Gary Wells both from Massachusetts I'm trying to get in touch with them. They were part of a company that specifically retrofit Bostomatic machines that was dissolved in 2018. I hope to get some better info if i can get in touch with either of them. Any suggestions on best way forward is appreciated. Trying to retrofit the machine on a fairly tight budget. Thomas From: andy pugh Sent: Monday, July 20, 2020 2:49 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc On Mon, 20 Jul 2020 at 02:44, Tom Smart wrote: > The motor is this glentek GM4040-41 180vdc, 9.1A. I decoded the serial number > it has no brake, no tachometer, a special encoder, no resolver. Just how special is the encoder? Everything else sounds like a simple retrofit, DC servos are relatively easy. Do you have the power supply? If so, what is the actual output voltage? The Pico servo amps are close: http://www.pico-systems.com/pwmservo.html but may come up a little short if the actual power supply voltage is 180V. The 7i29 from Mesa http://store.mesanet.com/index.php?route=product/product=83_90_id=141 also comes in a little low on voltage. (Note that you can run two motors from each 7i29) If you don't have the DC power supply then perhaps you could look at AC input drives, https://www.a-m-c.com/product/ab30a200ac/ might be an option. But AMC make so many drives it's probably best to actually talk to them. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
Hi Jon, You're right. That's fixed now. As is the Peak Torque value too. My INI file for Y axis which uses a KL34-180-90 DC servo (226 oz-in, 3000 RPM) has to move the X table and Y plus rotary section in between which I'd guess at 400 lbs so... http://www.autoartisans.com/milton.htm The same as the Grizzly G3616. The X pivots for Horizontal Milling and helical gear cutting. Except I don't have the horizontal mill feature. That was the G3617. MAX_VELOCITY = 2.5 MAX_ACCELERATION = 7.5 If Gravity is 32 ft/sec^2 then it's also 2.7 in/sec^2. So if we multiply the G value by that now taking into account the Reduction ratio I get 11.83 in/sec^2 Does that mean the MAX_ACCELERATION value can actually be set to 11.83? And since the Peak Force is 4x that assuming I can draw 40A then the backlash value (2x MAX_ACCELERATION) STEPGEN_MAXACCEL = 15.0 could also be larger. A reasonable assumption is that the power supply will be at least capable of suppling the continuous motor torque value. Otherwise we'd have to add Continuous Current, Power Supply Current and Peak Current values and then scale the Cont. Torque by that value. It's a bit harder to calculate peak current. My linear toroid based supply is up in the 26A range well above the 7.8A continuous. What else would you like on this form? Have I missed anything else? Cheers, John Dammeyer > -Original Message- > From: Jon Elson [mailto:el...@pico-systems.com] > Sent: July-21-20 6:19 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc > > On 07/21/2020 06:53 PM, John Dammeyer wrote: > > Jon, > > Here's a screen shot (assuming it makes it through). I used your 100 oz-in > > motor and 0.2" pitch screw. I set the RPM to 3000 but > with a 3:1 reduction. Not sure If it would be better to just add two boxes > for the reduction so that 0.25 is really 4:1 in two boxes. > > > You had a 4:1 reduction, but that doesn't seem to show in > the linear force number. > > Jon > > > ___ > Emc-users mailing list > <mailto:Emc-users@lists.sourceforge.net> Emc-users@lists.sourceforge.net > <https://lists.sourceforge.net/lists/listinfo/emc-users> > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 07/21/2020 06:53 PM, John Dammeyer wrote: Jon, Here's a screen shot (assuming it makes it through). I used your 100 oz-in motor and 0.2" pitch screw. I set the RPM to 3000 but with a 3:1 reduction. Not sure If it would be better to just add two boxes for the reduction so that 0.25 is really 4:1 in two boxes. You had a 4:1 reduction, but that doesn't seem to show in the linear force number. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
Jon, Here's a screen shot (assuming it makes it through). I used your 100 oz-in motor and 0.2" pitch screw. I set the RPM to 3000 but with a 3:1 reduction. Not sure If it would be better to just add two boxes for the reduction so that 0.25 is really 4:1 in two boxes. Using your table weight of 200 lbs and the resulting Continuous Linear force of almost 200 I get approximately 1 G as expected. Now the ideal would be that the last box there would tell us what acceleration value we want to enter into the INI file. So would you multiply the 0.98G by 32 Ft/Sec/Sec to get 31.36 or turn it into inches 376 Inch/sec/sec but since our table speed is in inches per minute divide by 60 or by 3600? For inch/min/min? Oh and of course the checkmark will convert the numbers and units indication to N.m etc. Doesn't yet but that's just a bit of math and text output. John Dammeyer > -Original Message- > From: Jon Elson [mailto:el...@pico-systems.com] > Sent: July-21-20 1:52 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc > > On 07/21/2020 02:54 PM, John Dammeyer wrote: > > Hi Jon, > > How did you come up with the constant 0.0318? > Long story. There's complicated formula to compute it from > the helix angle of the screw. > Too much fiddling around. So, if you had a drum with a > string wrapped around it that advanced the > axis as much as the leadscrew, it should be equivalent > (ignoring friction and diameter of the string). So, how big > would such a drum be? The circumference should be equal to > the pitch of the screw, in this case 0.2". So, what is the > radius of a circle with a 0.2" circumference? 2 Pi R = > Circumf. so > R = circumf./2 Pi so, 0.2 / (2 Pi) = 0.0318 > > Now, if you apply 10 in-Lb torque to a 5 TPI leadscrew, you > get 10 / 0.0318 = 314 pounds force. > > > > " So, that 100 oz-in motor (0.52 lb-ft) would > > produce 0.52/0.0318 = 16.35 lbs of linear force (neglecting > > friction)." > And, this was wrong due to a inch/foot mixup! > > 0.52 lb-ft is 6.24 in-Lb, and the linear force would be 196 Lbs. > > And how did you work out the 5G? > > > > "So, if your machine has a 200 Lb table, and the leadscrew > > were to produce 1000 Lbs linear force, > > it would accelerate at 5 G? > > > If you dropped the table on your toe (don't do this at home, > kids!) it would accelerate at 1 G. > if you push on the table with a force equal to 5 times it's > weight, that will accelerate at 5 G. > > Jon > > > ___ > Emc-users mailing list > <mailto:Emc-users@lists.sourceforge.net> Emc-users@lists.sourceforge.net > <https://lists.sourceforge.net/lists/listinfo/emc-users> > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On Tue, 21 Jul 2020 at 21:54, Jon Elson wrote: > > How did you come up with the constant 0.0318? > Long story. There's complicated formula to compute it from > the helix angle of the screw. Or a very simple formula based on a unit circle and the lead, simply comparing two distances. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
Thanks. I'll whip up a quick app for this. Nothing special. Could be done in as spreadsheet but where's the fun in that? John > -Original Message- > From: Jon Elson [mailto:el...@pico-systems.com] > Sent: July-21-20 1:52 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc > > On 07/21/2020 02:54 PM, John Dammeyer wrote: > > Hi Jon, > > How did you come up with the constant 0.0318? > Long story. There's complicated formula to compute it from > the helix angle of the screw. > Too much fiddling around. So, if you had a drum with a > string wrapped around it that advanced the > axis as much as the leadscrew, it should be equivalent > (ignoring friction and diameter of the string). So, how big > would such a drum be? The circumference should be equal to > the pitch of the screw, in this case 0.2". So, what is the > radius of a circle with a 0.2" circumference? 2 Pi R = > Circumf. so > R = circumf./2 Pi so, 0.2 / (2 Pi) = 0.0318 > > Now, if you apply 10 in-Lb torque to a 5 TPI leadscrew, you > get 10 / 0.0318 = 314 pounds force. > > > > " So, that 100 oz-in motor (0.52 lb-ft) would > > produce 0.52/0.0318 = 16.35 lbs of linear force (neglecting > > friction)." > And, this was wrong due to a inch/foot mixup! > > 0.52 lb-ft is 6.24 in-Lb, and the linear force would be 196 Lbs. > > And how did you work out the 5G? > > > > "So, if your machine has a 200 Lb table, and the leadscrew > > were to produce 1000 Lbs linear force, > > it would accelerate at 5 G? > > > If you dropped the table on your toe (don't do this at home, > kids!) it would accelerate at 1 G. > if you push on the table with a force equal to 5 times it's > weight, that will accelerate at 5 G. > > Jon > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 07/21/2020 02:54 PM, John Dammeyer wrote: Hi Jon, How did you come up with the constant 0.0318? Long story. There's complicated formula to compute it from the helix angle of the screw. Too much fiddling around. So, if you had a drum with a string wrapped around it that advanced the axis as much as the leadscrew, it should be equivalent (ignoring friction and diameter of the string). So, how big would such a drum be? The circumference should be equal to the pitch of the screw, in this case 0.2". So, what is the radius of a circle with a 0.2" circumference? 2 Pi R = Circumf. so R = circumf./2 Pi so, 0.2 / (2 Pi) = 0.0318 Now, if you apply 10 in-Lb torque to a 5 TPI leadscrew, you get 10 / 0.0318 = 314 pounds force. " So, that 100 oz-in motor (0.52 lb-ft) would produce 0.52/0.0318 = 16.35 lbs of linear force (neglecting friction)." And, this was wrong due to a inch/foot mixup! 0.52 lb-ft is 6.24 in-Lb, and the linear force would be 196 Lbs. And how did you work out the 5G? "So, if your machine has a 200 Lb table, and the leadscrew were to produce 1000 Lbs linear force, it would accelerate at 5 G? If you dropped the table on your toe (don't do this at home, kids!) it would accelerate at 1 G. if you push on the table with a force equal to 5 times it's weight, that will accelerate at 5 G. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
Hi Jon, How did you come up with the constant 0.0318? " So, that 100 oz-in motor (0.52 lb-ft) would produce 0.52/0.0318 = 16.35 lbs of linear force (neglecting friction)." And how did you work out the 5G? "So, if your machine has a 200 Lb table, and the leadscrew were to produce 1000 Lbs linear force, it would accelerate at 5 G? It would be handy to have a spreadsheet where once can key in motor in oz-in or Nm, max RPM, reduction ratio, and table weight. Maybe even in addition to screw pitch and an acme or ball tweak factor. Heck I'll whip up a Lazarus Free Pascal program with all the entry fields for this. It would run on Linux, PCs, MACs, Beagles and Pi computers. I just need a bit more of the math/constants behind it. John Dammeyer > -Original Message- > From: Jon Elson [mailto:el...@pico-systems.com] > Sent: July-21-20 7:31 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc > > On 07/20/2020 11:49 PM, Tom Smart wrote: > > So my 3500 rpm rated motor at 180vdc would be 2916 rpm at 150 vdc and 2333 > > rpm at 120vdc? > Yes, exactly. > > If my ballscrew is 5tpi then at rated voltage i would get 700 ipm at 150vdc > > 583 ipm and at 120vdc 466ipm feeds? > Yes. > > If i keep the amps at the rating of 9.1 I should keep my 31.3 IN-LBS or 2.6 > > FT-LBS? > > > > So 2.6 / .0813 would be 81.76 lbs of linear force? > That denominator s .0318 but your result is correct. > > So if my table weighs 200lbs my acceleration would be .41 G? > > > > I'm wondering if I've done a calculation wrong or is this a good setup? > > > Well, 81 Lbs sounds pretty weak for a milling machine. Is > the motor directly driving the leadscrew or is there a belt > reduction? My Bridgeport setup is kind of anemic, but it > has a 2.5:1 belt reduction on the motor. That gets me to 23 > In-Lb at the leadscrew, for 700 Lbs of linear force. > > Now, the 9.1 A rating of the motor, is that a continuous > (stall) rating or a peak rating? If that is stall, then the > motor can handle more current during acceleration peaks, at > least twice, possibly 4 X. > That will help. > > Jon > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 07/21/2020 08:33 AM, Andrew wrote: вт, 21 лип. 2020 о 06:17 Jon Elson пише: So, if your machine has a 200 Lb table, and the leadscrew were to produce 1000 Lbs linear force, it would accelerate at 5 G. This is a simplified calculation, it doesn't account for rotary inertia of ballscrew and other rotary parts. You need to reduce that rotary inertia to a mass and add it to the table mass. And that will be a pretty significant amount, particularly if the ballscrew is long and massive. Yes, quite true. But, in fact, the ballscrew is insignificant compared to the MOTOR mass. But, this was just a ballpark figure. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 07/21/2020 04:07 AM, andy pugh wrote: On Tue, 21 Jul 2020 at 05:52, Tom Smart wrote: If i keep the amps at the rating of 9.1 I should keep my 31.3 IN-LBS or 2.6 FT-LBS? So 2.6 / .0813 would be 81.76 lbs of linear force? So if my table weighs 200lbs my acceleration would be .41 G? I'm wondering if I've done a calculation wrong The way I think about it.[1] Imagine pushing with a force of 1 lb on the end of a 1 foot handle fastened to the end of the screw through one complete turn. That is circle of radius 1 foot and a distance of 2 x pi X 12 = 75 inches and a torque of 1 lb/ft The screw moves 0.2 in The ratio is 75" / .2" = 377:1 So 2.6 lbft on a 5tpi screw is 750lbs. I think there was a feet to inches error in the calculation above. And a shuffling of 0.0138 to 0.0813. OK, I screwed up. I had to do a whole page of calculations to see it. My cheat sheet was in INCH Pounds, not FOOT pounds! So, to start over : 31.3 Inch-Lb / 0.0318 = 985 Lbs linear force. That should be fine. Sorry for the error in my earlier posts. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 07/20/2020 11:49 PM, Tom Smart wrote: So my 3500 rpm rated motor at 180vdc would be 2916 rpm at 150 vdc and 2333 rpm at 120vdc? Yes, exactly. If my ballscrew is 5tpi then at rated voltage i would get 700 ipm at 150vdc 583 ipm and at 120vdc 466ipm feeds? Yes. If i keep the amps at the rating of 9.1 I should keep my 31.3 IN-LBS or 2.6 FT-LBS? So 2.6 / .0813 would be 81.76 lbs of linear force? That denominator s .0318 but your result is correct. So if my table weighs 200lbs my acceleration would be .41 G? I'm wondering if I've done a calculation wrong or is this a good setup? Well, 81 Lbs sounds pretty weak for a milling machine. Is the motor directly driving the leadscrew or is there a belt reduction? My Bridgeport setup is kind of anemic, but it has a 2.5:1 belt reduction on the motor. That gets me to 23 In-Lb at the leadscrew, for 700 Lbs of linear force. Now, the 9.1 A rating of the motor, is that a continuous (stall) rating or a peak rating? If that is stall, then the motor can handle more current during acceleration peaks, at least twice, possibly 4 X. That will help. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
вт, 21 лип. 2020 о 06:17 Jon Elson пише: > So, if your machine has a 200 Lb table, and the leadscrew > were to produce 1000 Lbs linear force, > it would accelerate at 5 G. > This is a simplified calculation, it doesn't account for rotary inertia of ballscrew and other rotary parts. You need to reduce that rotary inertia to a mass and add it to the table mass. And that will be a pretty significant amount, particularly if the ballscrew is long and massive. WBR, Andrew ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On Tue, 21 Jul 2020 at 05:52, Tom Smart wrote: > If i keep the amps at the rating of 9.1 I should keep my 31.3 IN-LBS or 2.6 > FT-LBS? > > So 2.6 / .0813 would be 81.76 lbs of linear force? > > So if my table weighs 200lbs my acceleration would be .41 G? > > I'm wondering if I've done a calculation wrong The way I think about it.[1] Imagine pushing with a force of 1 lb on the end of a 1 foot handle fastened to the end of the screw through one complete turn. That is circle of radius 1 foot and a distance of 2 x pi X 12 = 75 inches and a torque of 1 lb/ft The screw moves 0.2 in The ratio is 75" / .2" = 377:1 So 2.6 lbft on a 5tpi screw is 750lbs. I think there was a feet to inches error in the calculation above. And a shuffling of 0.0138 to 0.0813. [1] Except in metric, generally. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
So my 3500 rpm rated motor at 180vdc would be 2916 rpm at 150 vdc and 2333 rpm at 120vdc? If my ballscrew is 5tpi then at rated voltage i would get 700 ipm at 150vdc 583 ipm and at 120vdc 466ipm feeds? If i keep the amps at the rating of 9.1 I should keep my 31.3 IN-LBS or 2.6 FT-LBS? So 2.6 / .0813 would be 81.76 lbs of linear force? So if my table weighs 200lbs my acceleration would be .41 G? I'm wondering if I've done a calculation wrong or is this a good setup? From: Jon Elson Sent: Monday, July 20, 2020 9:14 PM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc On 07/20/2020 09:00 PM, Tom Smart wrote: > I forgot to ask how would I calculate the loss of abilities of the mill if i > don't drive the servos with their maximum rated power and amps? If I were to > get drives that weren't rated to 180vdc what losses will i have and how do i > calculate the loss? > > First, find the rated speed of the motor. If the motor is rated at 1800 RPM and directly drives a 5 TPI leadscrew, then it will give 360 IPM linear speed at rated voltage. If you then run the servo amps at half the motor's rated voltage, you would get half that speed, or 180 IPM. Then, if the motor has a peak torque rating at some amperage, but your servo amp can only deliver half the rating, you would only get half that torque. if the motor only shows a continuous torque at some current, you can guess the peak rating is 2-4 times higher. I'll use those horrid imperial units, as that's what my cheat sheet was done in. If the motor is rated in oz-in, then you can convert that to lb-ft by dividing by 12*16. So, a 100 Oz-In motor provides 0.52 lb-ft or torque. A 5 TPI leadscrew advances the axis 0.2 inch per turn. This is equivalent to a spool with a radius of 0.0318". So, that 100 oz-in motor (0.52 lb-ft) would produce 0.52/0.0318 = 16.35 lbs of linear force (neglecting friction). You can plug in your own numbers to calculate it for your own motors and servo amps. So, if your machine has a 200 Lb table, and the leadscrew were to produce 1000 Lbs linear force, it would accelerate at 5 G. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On 07/20/2020 09:00 PM, Tom Smart wrote: I forgot to ask how would I calculate the loss of abilities of the mill if i don't drive the servos with their maximum rated power and amps? If I were to get drives that weren't rated to 180vdc what losses will i have and how do i calculate the loss? First, find the rated speed of the motor. If the motor is rated at 1800 RPM and directly drives a 5 TPI leadscrew, then it will give 360 IPM linear speed at rated voltage. If you then run the servo amps at half the motor's rated voltage, you would get half that speed, or 180 IPM. Then, if the motor has a peak torque rating at some amperage, but your servo amp can only deliver half the rating, you would only get half that torque. if the motor only shows a continuous torque at some current, you can guess the peak rating is 2-4 times higher. I'll use those horrid imperial units, as that's what my cheat sheet was done in. If the motor is rated in oz-in, then you can convert that to lb-ft by dividing by 12*16. So, a 100 Oz-In motor provides 0.52 lb-ft or torque. A 5 TPI leadscrew advances the axis 0.2 inch per turn. This is equivalent to a spool with a radius of 0.0318". So, that 100 oz-in motor (0.52 lb-ft) would produce 0.52/0.0318 = 16.35 lbs of linear force (neglecting friction). You can plug in your own numbers to calculate it for your own motors and servo amps. So, if your machine has a 200 Lb table, and the leadscrew were to produce 1000 Lbs linear force, it would accelerate at 5 G. Jon ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
I forgot to ask how would I calculate the loss of abilities of the mill if i don't drive the servos with their maximum rated power and amps? If I were to get drives that weren't rated to 180vdc what losses will i have and how do i calculate the loss? Thanks for the assistance, Thomas From: andy pugh Sent: Monday, July 20, 2020 2:49 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc On Mon, 20 Jul 2020 at 02:44, Tom Smart wrote: > The motor is this glentek GM4040-41 180vdc, 9.1A. I decoded the serial number > it has no brake, no tachometer, a special encoder, no resolver. Just how special is the encoder? Everything else sounds like a simple retrofit, DC servos are relatively easy. Do you have the power supply? If so, what is the actual output voltage? The Pico servo amps are close: http://www.pico-systems.com/pwmservo.html but may come up a little short if the actual power supply voltage is 180V. The 7i29 from Mesa http://store.mesanet.com/index.php?route=product/product=83_90_id=141 also comes in a little low on voltage. (Note that you can run two motors from each 7i29) If you don't have the DC power supply then perhaps you could look at AC input drives, https://www.a-m-c.com/product/ab30a200ac/ might be an option. But AMC make so many drives it's probably best to actually talk to them. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
I looked at the machine today and pulled the y-axis servo. Apparently NASA's definition of machine working when taken out of service doesn't consider the fact parts were removed. The y-axis encoder is MIA. I did speak with Glentek today, they let me know the "special" designation was that they didn't include encoders in the servos. I'm going to check the other axis servo tomorrow. I'm uncertain if I have the power supply for the drives or not. I'm leaning towards they were part of the drives that were removed. There is a large capacitor that is labeled Glentek and all 3 drives were wired into it. I have 4 wires on top where the drives were. 1 white, 1 black, 1 red and another black. The white and black go to the servos. The wiring is done incredibly if only i had the road map aka wiring diagrams. Oh I don't see any glass scales and there are wires in the servo where the encoder was likely connected. I will continue pecking away at it trying to figure out what i need to bring it back to life. From: andy pugh Sent: Monday, July 20, 2020 2:49 AM To: Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc On Mon, 20 Jul 2020 at 02:44, Tom Smart wrote: > The motor is this glentek GM4040-41 180vdc, 9.1A. I decoded the serial number > it has no brake, no tachometer, a special encoder, no resolver. Just how special is the encoder? Everything else sounds like a simple retrofit, DC servos are relatively easy. Do you have the power supply? If so, what is the actual output voltage? The Pico servo amps are close: http://www.pico-systems.com/pwmservo.html but may come up a little short if the actual power supply voltage is 180V. The 7i29 from Mesa http://store.mesanet.com/index.php?route=product/product=83_90_id=141 also comes in a little low on voltage. (Note that you can run two motors from each 7i29) If you don't have the DC power supply then perhaps you could look at AC input drives, https://www.a-m-c.com/product/ab30a200ac/ might be an option. But AMC make so many drives it's probably best to actually talk to them. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Need help with Bostomatic BD18-2 to linuxcnc
On Mon, 20 Jul 2020 at 02:44, Tom Smart wrote: > The motor is this glentek GM4040-41 180vdc, 9.1A. I decoded the serial number > it has no brake, no tachometer, a special encoder, no resolver. Just how special is the encoder? Everything else sounds like a simple retrofit, DC servos are relatively easy. Do you have the power supply? If so, what is the actual output voltage? The Pico servo amps are close: http://www.pico-systems.com/pwmservo.html but may come up a little short if the actual power supply voltage is 180V. The 7i29 from Mesa http://store.mesanet.com/index.php?route=product/product=83_90_id=141 also comes in a little low on voltage. (Note that you can run two motors from each 7i29) If you don't have the DC power supply then perhaps you could look at AC input drives, https://www.a-m-c.com/product/ab30a200ac/ might be an option. But AMC make so many drives it's probably best to actually talk to them. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
