Ryan Hulsker wrote: > Good to hear that foam cutting is being added, i will check out the > current CVS and try it out once i get the machine complete (should be > this weekend). > > The filament winding applications I am looking at are for winding > fiberglass and carbon fiber tubes. There are basically 3 different > windings I am looking at. > > 1. Regular round tubing. > Fibers will be laid in layers of 90 degrees to the axis of the tube (or > as close as possible to it) to provide crush resistance. Then > lengthwise down the tube (as close to 0 degrees as possible) to provide > lengthwise stiffness. Then +-45 degrees to provide torsional rigidity > and a nice finish. These seem pretty easy because the winding angle and > pitch is constant down the whole length of the tube. Having extra > material bunch up at the end of the tube is no problem, we can just make > the mandrel longer than required and chop the ends of afterwords. > > 2. Axis symmetric tapered or contoured tubes. > These would basically be round sections that are either evenly tapered > or multiple sections that are of different tapers. ie tube diameter is > 6" at the base, 6" at the half way point, and then tapered evenly down > to 3" at the tip. > > The tricky part here would be calculating the decreasing velocity of the > winding head in relation to the spindle speed as the diameter (and thus > the surface speed) of the mandrel changes. But i assume I would just > divide the length of the tapered section into multiple Gcode statements > as the "pitch" is going to be changing constantly as the diameter of the > mandrel changes in order to keep the same winding angle. > > I guess the key is that I want the angle to be maintained even as the > diameter of the tube (and thus the pitch required) is changing. > > And in some cases we want a tapered tube, where the winding angle is > varied down the length of the tube. ie fibers running near parallel to > the axis of the tube at the base to make it stiff, and having the angle > slowly change towards the tip of the tube to make it more bendy. > > 3. Axis asymmetric straight tubes. > Basically this would be a straight tube with an elliptical or rounded > foil section, with the base and tip being the same section. The winding > head would have to speed up as the filament is being laid on the flatter > part of the ellipse, and slow down as the filament is being laid on the > more curved part of the ellipse to keep the same fiber angle. This > would have to happen with each rotation of the mandrel. > > As for the basic winding procedure, the "tow" would be a ribbon of > fiberglass or carbon fibers that is soaked in resin in the feed head, > and then wrapped on the mandrel. > (snip my g-code for winding straight tubes with high angle fibers)
> Seems like this would work for symmetrical tubes, but how about tapered > tubes and non symmetrical sections like ellipses? > > Ryan It sounds to me like this will require some very tricky g-coding. One possibility to consider is using a rotary axis instead of a spindle. Then you can program any head-vs-mandrel pattern you want, including zero-degree, 90-degree, etc. Clearly the CAM requirements for fiber winding are a lot different than those for milling or lathe work. Figuring out the toolpath is the hard part - controlling motors to follow that path (what EMC does) is easy by comparison. If g-code doesn't lend itself to describing the paths you need, there are other ways. Can you can write a program that prints the desired mandrel angle, feed head axial position, and feed head radial positions, at some relatively small time interval? (Like 0.01 second or so.) If so, it isn't hard to feed that stream of positions to motors. (See the man page for hal_streamer). It's an interesting application - please keep us informed. Regards, John Kasunich ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
