Hi Michal . Your application is really impressive !!! Are you using open o closed loop , stepper or servo motors ? For the program did you develop or use a sort of CAD/CAM to design the pattern ? How do you synchronized the needle movement with the X-Y axis ? As I understood the needle movement is used as a "spindle" , isn't it ? Or it's an axis ? What kind of electronic are you using to control the motor drives ? Thank you for any detail you can share.
Regards Alex On Wed, Aug 27, 2014 at 8:23 PM, Michał Geszkiewicz <[email protected]> wrote: > Hi Alex, > > I've done few retrofits of simillar machines, video below. > Originally spindle speed was fully synced with xy velocity but was > disabled due to mechanical problems (it won't saw on lower speeds). > http://www.youtube.com/watch?v=aopjsU7Q5V8 > > regards, > Michael > > W dniu 27.08.2014 19:44, alex chiosso pisze: > > Hi Philipp . > > You point to the right direction. > > I need a full control over the needle movement because I have to start > the > > X-Y movement before the needle is at top position . > > This is mainly related to the speed needed for the sewing cycle . > > As early the enable for X-Y movement is triggered as fast the machine can > > work. > > The worst case is if the X-Y movement is not at target position before > the > > needle is starting to touch the fabric. > > So in the current application I made , the position controller that > manage > > the needle (Z axis), raise a digital output starting from a position > > related to the position of the needle outside the fabric when the stitch > is > > made till the needle position close to the next stitch entering point. > > If the X-Y axis are still moving when the needle is close to touch the > > fabric , the machine stops. > > So the limit is also the maximum stitch length related to the needle > speed. > > And also the needle make a number of rotations as the number of stitches > > that have to be made. > > The needle finish is cycle always on top position (same position that > > starts the cycle). > > I hop I'm clear enough. > > The best solution should be to have the X-Y axis geared in electronic cam > > (with adjustable ratio for the stitch length) with the needle (Z axis) to > > be close as possible as the mechanical traditional machine. > > In this case there is no problem with the working speed (stitches per > > minute). > > > > > > > > On Wed, Aug 27, 2014 at 7:14 PM, Philipp Burch <[email protected]> wrote: > > > >> Hi Alex! > >> > >> Sounds like an interesting thing to do :) > >> Do you need full control over the needle (i.e. coordinated moves), or do > >> you want to let the needle be driven by a single motor in continuous > >> motion and synchronize the X/Y movements to it? In the latter case, you > >> would only need position feedback from the needle, which could be as > >> simple as a single switch telling you when the needle is up and the X/Y > >> can move. > >> With LinuxCNC, you could then hook that switch signal to the adaptive > >> feed input, so that the position is freezed whenever a stitch is being > >> made. If you then connect the velocity command for the needle motor to > >> the spindle control, you could really write a program just like for a > >> mill (except no Z of course). So you'd use G0 to rapid to the starting > >> point of the sew, then set the desired spindle speed using S, start the > >> "spindle" and program your path using G1/2/3. The combination of > >> spindle/needle speed and feed rate would give you the stitch length. > >> > >> Oh, and I'd go for motors with position feedback if possible. Open-loop > >> driven steppers may seem easier to handle as usually no loop tuning is > >> required, but then you need to test veeery carefully how fast you can go > >> without losing steps. Especially if you want to move really fast and > >> have a variable load. > >> > >> Just a few thoughts. > >> > >> Regards, > >> Philipp > >> > >> On 27.08.2014 18:55, alex chiosso wrote: > >>> Bari , thank you for your reply. > >>> How is working a sewing machine for me it is clear (I really did the > >>> application I described). > >>> I read into a Brother industrial sewing machine user/maintenance manual > >> and > >>> their electronic control manage encoders > >>> for the motors. > >>> > >>> > >>> On Wed, Aug 27, 2014 at 6:42 PM, Bari <[email protected]> wrote: > >>> > >>>> Alex, > >>>> > >>>> We started using Linuxcnc to control all sorts automation in the lab. > >>>> > >>>> Breaking down the steps to stitch: > >>>> > >>>> Move X,Y to start of the stitch (with Z at max height) > >>>> > >>>> Move Z down to min. (needle to lowest point) > >>>> > >>>> Raise needle > >>>> > >>>> Start Loop (spin looper motor) > >>>> > >>>> Finish Loop > >>>> > >>>> Needle to max height > >>>> > >>>> Move X and/or Y > >>>> > >>>> > >>>> https://www.youtube.com/watch?v=BAvQBLHMrw4 > >>>> > >>>> On 08/27/2014 10:58 AM, alex chiosso wrote: > >>>>> Hi Bari. > >>>>> Nice to know you. > >>>>> Have you experience with this particular application ? > >>>>> So for you closed loop positioning it's not needed ? > >>>>> > >>>>> > >>>>> On Wed, Aug 27, 2014 at 5:52 PM, Bari <[email protected]> wrote: > >>>>> > >>>>>> Alex, > >>>>>> > >>>>>> I'd use Linuxcnc to build it. > >>>>>> > >>>>>> You can use steppers to control the needle motor and looper in open > >>>>>> loop. Your G-code could be written to just stop X and Y when the > >> needle > >>>>>> is below the surface of the fabric. > >>>>>> > >>>>>> On 08/27/2014 10:21 AM, alex chiosso wrote: > >>>>>>> The application can appear "trivial" but it is not especially > because > >>>> of > >>>>>>> needle speed and sycronization between the needle position and the > >> X-Y > >>>>>>> movement. > >>>>>>> During the sewing the X-Y can move only when the needle it's > outside > >>>> the > >>>>>>> label otherwise the needle can be broken and the clothe/label can > be > >>>>>>> damaged . > >>>>>>> That's why the position feedback is needed. > >>>>>>> Additionally the command for some actuators sycronized to the > sewing > >>>>>> cycle > >>>>>>> + sensors, pushbuttons, button lamps management. > >>>>>>> I would like to discuss with you what do you think about the > >> conversion > >>>>>> to > >>>>>>> LCNC. > >>>>>>> > >>>>>> > >>>>>> > >> > ------------------------------------------------------------------------------ > >>>>>> Slashdot TV. > >>>>>> Video for Nerds. Stuff that matters. > >>>>>> http://tv.slashdot.org/ > >>>>>> _______________________________________________ > >>>>>> Emc-users mailing list > >>>>>> [email protected] > >>>>>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>>>>> > >> > ------------------------------------------------------------------------------ > >>>>> Slashdot TV. > >>>>> Video for Nerds. Stuff that matters. > >>>>> http://tv.slashdot.org/ > >>>>> _______________________________________________ > >>>>> Emc-users mailing list > >>>>> [email protected] > >>>>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>>> > >>>> > >>>> > >> > ------------------------------------------------------------------------------ > >>>> Slashdot TV. > >>>> Video for Nerds. Stuff that matters. > >>>> http://tv.slashdot.org/ > >>>> _______________________________________________ > >>>> Emc-users mailing list > >>>> [email protected] > >>>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>>> > >> > ------------------------------------------------------------------------------ > >>> Slashdot TV. > >>> Video for Nerds. Stuff that matters. > >>> http://tv.slashdot.org/ > >>> _______________________________________________ > >>> Emc-users mailing list > >>> [email protected] > >>> https://lists.sourceforge.net/lists/listinfo/emc-users > >>> > >> > >> > >> > ------------------------------------------------------------------------------ > >> Slashdot TV. > >> Video for Nerds. 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