Hey Alex Joni and all: If two Alex Joni tripods are placed on their sides three or more feet apart with a hotwire connected to the center washers you would have a cnc foamcutter.
There are articles about constraining cable crafters or cable robots. A triangle the most stable structural form. If a tripod and three more cables and three more motors always maintaining tension would make your device most stable. Cables in tension are stronger than compression members. Alex if you don't mind me asking, how much did your prototype cost. Could you give me the particulars and specification of making your prototype. I think my first step is to make two tripods to do foam cutting. Then to make modifications for a inverted tetrahedron tripod using gravity for tension. Later using six motors for constant tension to maintain stability. I think that tensegrity structures although light can be very robust. Geodesic domes and geometric structures are a hobby of mine. I think that triangular cables can make cnc structures inexpensive. Your particular prototype would be good for use as a rapid prototyping framework for reprap if you have a method for obtaining a z axis. Best regards, Andrew ----- Original Message ----- From: "Alex Joni" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, October 03, 2007 3:30 AM Subject: Re: [Emc-users] Robocrane > Hi there, > > I don't think it would be stiff enough to do that. > You need the extra 3 wires for stability (even if you still do only XYZ > work). > I intended to use the 3-wire version for plasma cutting, where you don't > have any forces besides the weight of the plasma torch. > > Best regards, > Alex Joni > > ----- Original Message ----- > From: <[EMAIL PROTECTED]> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Sent: Wednesday, October 03, 2007 1:06 AM > Subject: Re: [Emc-users] Robocrane > > >> Dear Kirk and all: >> >> Thank you for supplying me with relevant information. I think that Alex >> Joni's toy would give me needed information >> to implement a step in the right direction. I wonder if a tripod made >> more >> robust could do milling and routing. >> >> Best regards, >> >> Andrew >> >> ----- Original Message ----- >> From: "Kirk Wallace" <[EMAIL PROTECTED]> >> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> >> Sent: Tuesday, October 02, 2007 3:30 PM >> Subject: Re: [Emc-users] Robocrane >> >> >>> Hello Andrew, >>> >>> I just looked at the NIST site. The Robocrane is quite a complex >>> project. I suspect that EMC should be able to serve as the foundation >>> for your project since you can plug in your own kinematics and EMC is >>> highly configurable hardware interface wise. I suspect the Robocrane is >>> a step further in the hexapod evolution, so you should maybe study a >>> search on "hexapod" at linuxcnc.org. Check these: >>> >>> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Alex_Joni's_Toy >>> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Koppi's_Toy >>> http://cvs.linuxcnc.org/lxr/source/configs/hexapod-sim/ >>> >>> Be prepared to create your own C code. >>> >>> If you haven't already done so, you might want to study the basics by >>> getting a demo CD working: >>> >>> http://www.linuxcnc.org/content/view/21/4/lang,en/ >>> >>> Then interface an encoder to your parallel port using the etch-servo >>> configuration (in Sample Configurations, study etch.ini and etch.hal for >>> connection information) and a NetMOS parallel port card ("lspci -v" will >>> come in handy). >>> >>> Then maybe drive a stepper or DC servo motor like this setup: >>> >>> http://emergent.unpy.net/projects/01142347802 >>> >>> I found a good motor and encoder in a junk Epson C-80 printer (sure >>> hated to see that printer go). >>> >>> Good luck. I'll try to help, if I can. Others here are better at the >>> nitty-gritty stuff. >>> >>> Kirk Wallace >>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> On Mon, 2007-10-01 at 16:29 -0400, [EMAIL PROTECTED] wrote: >>>> Dear enc-users: >>>> >>>> Hello my name is Andrew I am new to this list. I want to make a cable >>>> robot milling machine similar to the >>>> NIST 1meter robocrane milling machine. Any help would be appreciated. >>>> If this list is not relevant >>>> to obtain this kind of information, please direct me to where I can >>>> obtain it. I am starting from scratch. >>>> I want to obtain all relevant information before I start. Are there >>>> any simulations software that can be run on >>>> a PC. >>>> >>>> Thank you for your help, >>>> >>>> Andrew >>> >>> >>> >>> ------------------------------------------------------------------------- >>> This SF.net email is sponsored by: Microsoft >>> Defy all challenges. Microsoft(R) Visual Studio 2005. >>> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> >>> >>> -- >>> No virus found in this incoming message. >>> Checked by AVG Free Edition. >>> Version: 7.5.488 / Virus Database: 269.13.39/1044 - Release Date: >>> 10/2/2007 11:10 AM >>>. >> >> >> ------------------------------------------------------------------------- >> This SF.net email is sponsored by: Microsoft >> Defy all challenges. Microsoft(R) Visual Studio 2005. >> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> >> -- >> No virus found in this incoming message. >> Checked by AVG Free Edition. >> Version: 7.5.488 / Virus Database: 269.13.37/1042 - Release Date: >> 10/1/2007 6:59 PM >> >> > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. 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