Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

John We used to measure the acceleration rather than calculate it. We loaded the axis with whatever tooling and 'normal' work piece, then,  in open loop, we applied a voltage that would achieve the max velocity, very briefly. just a bit longer than necc to get to the max velocity ( some hund

Re: [Emc-users] wondering what the status is on S curve jerk control getting added into linuxcnc

A couple of sources: http://www.mesanet.com/pdf/motion/softdmc.pdf  50 us cycle -:) Some years ago a masters candidate in ME at UBC did her thesis on motion control with jerk limiting and sine wave accel. I used to have a copy of it but cannot find it. IIRC is would be post 2005 and author'

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Hi Chris, > -Original Message- > From: Chris Albertson [mailto:albertson.ch...@gmail.com] > > Why on Earth do people still use US units? OK if your final result must > be expressed that way, but do the math in metric then convert at the end. > > I taught high school science for a whil

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Why on Earth do people still use US units? OK if your final result must be expressed that way, but do the math in metric then convert at the end. Using US units is like doing long division in Roman numerals. It can be done but is way-hard so is it far easier to convert to Arabic number do the d

Re: [Emc-users] wondering what the status is on S curve jerk control getting added into linuxcnc

Yes I'm not worried about servo following error spikes. But I'm shaking my whole machine to death. As the acceleration is instantly on. In contrast a friend's okuma can go at 40m/min without shaking. Which is amazing to watch. They are both similar size On Thu, Jul 23, 2020, 9:42 AM Nicklas S

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

I've asked a retired physics professor friend for some enlightenment. Jon Elson has stated that with T = r x Fsin(theta) and F=ma that the acceleration is Gravity because it's equivalent to dropping the X axis table and letting the earth accelerate it. But F=mg is the force due to gravity.

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Yes! Thank you. > On Jul 22, 2020, at 11:07 PM, John Dammeyer wrote: > >  >> -Original Message- >> From: Thaddeus Waldner [mailto:thadw...@gmail.com] >> Sent: July-22-20 8:43 PM >> To: Enhanced Machine Controller (EMC) >> Subject: Re: [Emc-users] Calculating table acceleration. Was:

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

BTW, it looks like the numbers that Jon came up with match with this site. I've used their motors. Nice stuff. https://www.kollmorgen.com/en-us/developer-network/calculating-linear-force-and-torque-ballscrew/ Using the F2 = T x 2 x PI / L I get the exact same value in oz-in and when converted

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

On 7/22/20 11:04 PM, Bruce Layne wrote: On 7/22/20 11:43 PM, Thaddeus Waldner wrote: 1g = roughly 32in/s^2 1 g is 32 ft/sec^2 Feet, not inches. Comparing Standard Gravity to Other Acceleration Units Standard Gravity    1 G's Meters per Second per Second    9.81 Feet per Second per Second

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

> -Original Message- > From: Thaddeus Waldner [mailto:thadw...@gmail.com] > Sent: July-22-20 8:43 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Calculating table acceleration. Was: Need help with > Bostomatic BD18-2 to linuxcnc > > Start with a 226 oz in > > / 1

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

On 7/22/20 11:43 PM, Thaddeus Waldner wrote: > 1g = roughly 32in/s^2 1 g is 32 ft/sec^2 Feet, not inches. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Ah yes In lb is radius, so the ballscrew factor is 2pi*threads per inch Which would double the acceleration from my earlier numbers. > On Jul 22, 2020, at 10:43 PM, Thaddeus Waldner wrote: > >  > > > Start with a 226 oz in > > / 16 = 14.125 lb in > > 5 threads per inch is the same as a b

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Start with a 226 oz in / 16 = 14.125 lb in 5 threads per inch is the same as a belt pulley with a circumference of 0.2 inches since our unit is in lb in, we need to go from a pulley with diameter of Pi, to diameter of .2 thus our final force is 14.125 * (pi/0.2) = 221.875 pounds (poundal?) forc

[Emc-users] Little gear I'm cutting. Thought it may interest people.

Hey everyone just a quick video here. Might interest people. https://youtu.be/3u1bZxd-KCk Regards Andrew ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Problem with Rigid Tapping on USC Equipped Bridgeport

On 07/22/2020 08:51 PM, Matthew Herd wrote: Upon testing, I found that rigid tapping worked as intended, Excellent. Glad Robert Ellenberg is watching here, as most of us had no idea the trajectory planner had this behavior. I love rigid tapping, and have made two fixture plates with a 1" g

Re: [Emc-users] Problem with Rigid Tapping on USC Equipped Bridgeport

I got the braking resistor installed, fiddled with all the DC injection braking and dynamic braking parameters on the machine, then started turning down the deceleration time. It looks like I only tuned the acceleration time when I originally installed the VFD because it was set to the default

Re: [Emc-users] Just took the first flexgear off the printer

On Wednesday 22 July 2020 19:04:00 Chris Albertson wrote: > There are 100 tricks. One is to "cut" the part with a flat plane. > Then print the two halves cut-side down with no support then glue them > together. If you think, sometimes you can find a good place to cut > that actually makes the

Re: [Emc-users] Just took the first flexgear off the printer

There are 100 tricks. One is to "cut" the part with a flat plane. Then print the two halves cut-side down with no support then glue them together. If you think, sometimes you can find a good place to cut that actually makes the part stronger because the joined halves have a double-thick interna

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

On Wed, 22 Jul 2020 11:29:36 -0700 Chris Albertson wrote: > I don't see any relation between max acceleration and max speed. > Acceleration is determined by (1) the mass of the table and (2) the > torque the motor can produce while speed is determined by the max RPM > of the motor. Mostly agree

Re: [Emc-users] wondering what the status is on S curve jerk control getting added into linuxcnc

> hey guys > > I have a relatively high speed machine (3kw motors 16mm pitch ballscrews) > 35mm linear rails, and weights 5.8 ton. I think it used to go 20m/min > with the heidenhain control. I have been noticing a bit of jumping around > when doing parallel finishing 3d passed on it at high sp

[Emc-users] wondering what the status is on S curve jerk control getting added into linuxcnc

hey guys I have a relatively high speed machine (3kw motors 16mm pitch ballscrews) 35mm linear rails, and weights 5.8 ton. I think it used to go 20m/min with the heidenhain control. I have been noticing a bit of jumping around when doing parallel finishing 3d passed on it at high speed. and ta

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

I have to get back to other projects for a while. I've disabled the metric checkbox and made it invisible since the conversion to metric and back isn't complete yet. And since the value to use for MAX_ACCELERATION in the INI file is suspect perhaps the whole project is a joke. I've attached t

Re: [Emc-users] mailing list for ender 3 pro owners?

I pretty much get the same results with my Anet A6. (the A6 id actually a step up from the A8) The ender is different from the A6/A8 in the Ender uses a bowden tube rather then a direct feed. Ender gains print speed with the lighter head but looses fine control of the plastic feed. But this is

Re: [Emc-users] need a logic bit mux.

On Wednesday 22 July 2020 10:55:47 Jon Elson wrote: > On 07/22/2020 01:17 AM, Gene Heskett wrote: > > Greetings all; > > > > The launch of linuxcnc on the pi is without any motor power until > > the F2 button is pushed. So at launch time I get messages about the > > z drive being tripped. > > > >

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

> -Original Message- > From: andy pugh [mailto:bodge...@gmail.com] > > On Wed, 22 Jul 2020 at 19:33, Chris Albertson < > albertson.ch...@gmail.com> wrote: > > > That said acceleration is related to speed. (acceleration) x (time) = > > (speed) > > exa

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Hi Sam, > From: Sam Sokolik [mailto:samco...@gmail.com] > Is this stepper torque? The peak torque is only at 0 rpm and drops off > substantially as you increase rpm. You would need to look a the torque > curve of the stepper and decide what top rpm you are looking for and > calculate accordingly

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

On Wed, 22 Jul 2020, John Dammeyer wrote: Date: Wed, 22 Jul 2020 09:06:38 -0700 From: John Dammeyer Reply-To: "Enhanced Machine Controller (EMC)" To: "'Enhanced Machine Controller (EMC)'" Subject: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to lin

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Yup, speed is distance/time, as long as a constant velocity is held. Speed is constantly increasing as long as your acceleration is constant. Changing accelerations are a bit more complicated to deal with. Mark On Wed, Jul 22, 2020 at 3:13 PM Chris Albertson wrote: > Yes, you technically corre

[Emc-users] Mesa 7i48 (and 7i71) needed

Hello! I am in need of Mesa 7i48 board, preferably also 7i71 as well. I need to retrofit Biesse CNC machine for a client and since I already have done another Biesse machine for them previously, they would like to make both setups identical just in case. I got all the necessary boards from eusurpl

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Yes, you technically correct. I should have written ...acceleration is related to speed. (acceleration) x (time) = (change in speed) On Wed, Jul 22, 2020 at 12:05 PM Mark Wendt wrote: > > On Wed, Jul 22, 2020 at 2:33 PM Chris Albertson > wrote: > > > > > That said acceleration is related t

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

> Also bear in mind that speed x acceleration x mass = power That is actually informative here. It shows that after you have guessed and bought some motor that has some given power like say 1/2 HP or 400W or whatever, the power is now fixed. Also, the mass of the table is fixed. So by the abov

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

On Wed, Jul 22, 2020 at 2:33 PM Chris Albertson wrote: > > That said acceleration is related to speed. (acceleration) x (time) = > (speed) > example: (10 inch per second squared) x ( 0.5 seconds) = (5 inches per > second) > That's true only if your initial velocity is zero. Mark ___

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

On Wed, 22 Jul 2020 at 19:33, Chris Albertson wrote: > That said acceleration is related to speed. (acceleration) x (time) = > (speed) > example: (10 inch per second squared) x ( 0.5 seconds) = (5 inches per > second) Also bear in mind that speed x acceleration x mass = power -- atp "A mo

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

I don't see any relation between max acceleration and max speed. Acceleration is determined by (1) the mass of the table and (2) the torque the motor can produce while speed is determined by the max RPM of the motor. It is very easy to buy a tiny motor with low torque that spins very fast. Or you

Re: [Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Is this stepper torque? The peak torque is only at 0 rpm and drops off substantially as you increase rpm. You would need to look a the torque curve of the stepper and decide what top rpm you are looking for and calculate accordingly.. On Wed, Jul 22, 2020, 11:09 AM John Dammeyer wrote: > Ho J

[Emc-users] Calculating table acceleration. Was: Need help with Bostomatic BD18-2 to linuxcnc

Ho Jon, I've changed the subject line to be more relevant and corrected the gravity value. Now we have 1703 In/Sec^2 for maximum possible acceleration given the load and torque ratings. On my system in imperial units I have 2.5 inches/second and I randomly picked the accel as 3x that. Doe

Re: [Emc-users] need a logic bit mux.

> > > > But I used external hardware to do the time delays to make sure things > > started up the way I wanted. You might also use time delay relays. > > But they aren't cheap. Ultimately an Arduino ends up being an easy > > solution. > > > > John Dammeyer > > Why should I use any external hardw

Re: [Emc-users] need a logic bit mux.

On 07/22/2020 01:17 AM, Gene Heskett wrote: Greetings all; The launch of linuxcnc on the pi is without any motor power until the F2 button is pushed. So at launch time I get messages about the z drive being tripped. So I need a 1 or 2 second delay before that bit is sent on thru, but instant t

Re: [Emc-users] need a logic bit mux.

On Wednesday 22 July 2020 08:03:48 andy pugh wrote: > On Wed, 22 Jul 2020 at 12:12, Gene Heskett wrote: > > > It isn't clear what signal you want to block, or under what > > > circumstances you want to have the delay. > > > > Only long enough for the driver to stabilize after power up. One or >

Re: [Emc-users] need a logic bit mux.

On Wed, 22 Jul 2020 at 12:12, Gene Heskett wrote: > > It isn't clear what signal you want to block, or under what > > circumstances you want to have the delay. > > Only long enough for the driver to stabilize after power up. One or 2 > seconds perhaps I wasn't asking how long. I was asking what

Re: [Emc-users] Just took the first flexgear off the printer

On Wednesday 22 July 2020 04:29:41 andy pugh wrote: > On Wed, 22 Jul 2020 at 06:17, Gene Heskett wrote: > > And had a hell of a time removing the internal supports, which > > probably out-weigh the gear > > Perhaps you would have been better printing it the other way round? > In retrospect, I th

Re: [Emc-users] need a logic bit mux.

On Wednesday 22 July 2020 03:51:34 andy pugh wrote: > On Wed, 22 Jul 2020 at 07:20, Gene Heskett wrote: > > So I need a 1 or 2 second delay before that bit is sent on thru, but > > instant transmission once timed out, giving the driver a chance to > > get all its stuff in one sock from the power

Re: [Emc-users] Just took the first flexgear off the printer

On Wednesday 22 July 2020 03:39:02 Gregg Eshelman via Emc-users wrote: > Design a sacrificial piece that fits closely but not too closely to > the inside area that needs supported. There are plenty of models to > download that have support structures as part of the design, with just > the right ga

Re: [Emc-users] Just took the first flexgear off the printer

On Wednesday 22 July 2020 03:34:01 Chris Albertson wrote: > Gene, > > There about many settings in Cura for supports. You can waste tons of > time and plastic experimenting or just use a pair of needle-nose > pliers and pull it off as you did. Except I don't own any needle-nosed pliers. I was in

Re: [Emc-users] need a logic bit mux.

On Wednesday 22 July 2020 02:45:48 John Dammeyer wrote: > > The launch of linuxcnc on the pi is without any motor power until > > the F2 button is pushed. So at launch time I get messages about the > > z drive being tripped. > > > > So I need a 1 or 2 second delay before that bit is sent on thru,

Re: [Emc-users] Just took the first flexgear off the printer

> But is there a support removal tool that isn't radioactive? Nope. The secret is to design your parts so you don't need support. Unless you have a dual head extruder, then you can use a different material as the support material. ___ Emc-users ma

Re: [Emc-users] @Andrew Beck, how did you get qtpyvcp working?

hey did you get this working? i just saw this sorry On Sun, Jun 7, 2020 at 1:32 AM Valerio Bellizzomi wrote: > Hi, I would like to use qtpyvcp instead of gmoccapy, can you help me? > How did you get qtpyvcp on LinuxCNC? > and how did you configure it? > > Regards > > > > >

Re: [Emc-users] Just took the first flexgear off the printer

On Wed, 22 Jul 2020 at 06:17, Gene Heskett wrote: > And had a hell of a time removing the internal supports, which probably > out-weigh the gear Perhaps you would have been better printing it the other way round? I think I recall seeing someone use pause-at-height to apply an anti-adhesion mate

Re: [Emc-users] need a logic bit mux.

On Wed, 22 Jul 2020 at 07:20, Gene Heskett wrote: > So I need a 1 or 2 second delay before that bit is sent on thru, but > instant transmission once timed out, giving the driver a chance to get > all its stuff in one sock from the powerup enabled by the F2 key. I want > to block any noise during

Re: [Emc-users] Just took the first flexgear off the printer

Design a sacrificial piece that fits closely but not too closely to the inside area that needs supported. There are plenty of models to download that have support structures as part of the design, with just the right gap between their top surface and the underside of what they're supporting so t

Re: [Emc-users] Just took the first flexgear off the printer

Gene, There about many settings in Cura for supports. You can waste tons of time and plastic experimenting or just use a pair of needle-nose pliers and pull it off as you did. The best fix is to get a second extruder on the printer and load it with water-soluble filament and print support with t