I am almost certain the miss alignment is not due to the gantry skewing, mainly because it is in a different axis. If it helps the feet of the gantry are 450mm long with fancy carriages at each end. Thanks Aaron > ----- Original Message ----- > From: "Kenneth Lerman" <[EMAIL PROTECTED]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: Re: [Emc-users] Micro stepper driver MSD542 / KL-5042 cont > Date: Wed, 21 May 2008 16:56:59 -0400 > > It appears from previous posts, that the gantry is about 1.5 meters long > and rides on rails. What is the support/bearing mechanism for the gantry > to ride on the rails? In particular, if there are two or more supports > for each side of the gantry, how far apart are the furthest supports on > each side? > > One of the problems with a gantry style machine is that unless you are > careful, the gantry will skew with respect to the other axis. Skewing > can cause uneven motion and/or distorted motion. There are a variety of > ways to prevent that. > > For example, if the bearing supports for the gantry are as far apart as > the width of the gantry, the forces causing the gantry to skew are > resisted. > > Another technique is to use a motor on each side of the gantry so that > the two sides are driven in tandem. > > A third technique is to use a rack and pinion drive with a rack and > pinion on each side and a shaft connecting the two pinions. Then a > single motor can drive both sides at once. > > There are engineering solutions to these engineering problems. A good > reference is some of Slocum's books/papers. You can google for them -- I > don't have a handy reference. > > Ken > > > aaron Moore wrote: > > One stepper per axis > > Gantry runs on X axis rails and weighs about 90kg - 100kg > > Y axis weighs about 20 -30 kg > > And the spindle and mount 10-20kg > > > > All axis run directly from trapezoidal screws 16mm dia, 4mm pitch > > with brass nuts. > > At present it is set for 16 microsteps. > > Not sure if this answers the last question > > > > The motors are actually FL86STH156-4208 > > Voltage: 5.25V > > Current (phase): 4.2A Resistance (Phase): 1.25Ohm > > Inductance (Phase): 8mH > > Holding Torque: 11.96Nm > > Length: 156mm > > > > Thanks > > > > Aaron > > > > > >> ----- Original Message ----- > >> From: "Dave Engvall" <[EMAIL PROTECTED]> > >> To: "Enhanced Machine Controller (EMC)" <[email protected]> > >> Subject: [Emc-users] Micro stepper driver MSD542 / KL-5042 cont > >> Date: Wed, 21 May 2008 13:26:15 -0700 > >> > >> > >> Aaron, > >> > >> Other responders have indicated they needed more infomation. > >> If you can fill in the blanks and confirm or correct assumptions > >> then someone has a real chance of providing > >> concrete help. It won't be me as I'm a servo person. Sorry. > >> > >> OK, lets gather some more information here: > >> > >> Stated or implied. 1.5m x 1.5 m gantry. One stepper motor per axis. > >> I assume the gantry is the X axis and the Y which lags is mounted on the X. > >> How much weight are you driving per axis? > >> How do you drive the axes; eg. gears, timing belts, etc and what > >> are the ratios? > >> Another way to put this is one step moves you how far? > >> Step rate under normal conditions. > >> > >> > >> > >> This info is for the stepper experts. :-) > >> Copied off a vendor site. > >> > >> Stepper motor: > >> > >> The FL60STH86-3008BF is a High Torque three stack Nema 23, 1.8 > >> degree hybrid stepper motor with a holding torque of 3Nm (425 > >> Oz-in) > >> > >> Driver: > >> > >> Supply voltage up to +50VDC, current output > >> up to 4.2A peak > >> Optically isolated input signals, pulse > >> frequency up to 400 KHz > >> Automatic idle-current reduction > >> 3-state current control for less motor heating > >> 15 selectable resolutions in decimal and > >> binary > >> Suitable for 4,6,8 lead motors > >> Stepping on upward or downward pulse edge > >> (selectable) > >> DIP switch current settingvalue > >> > >> > >> 4.1 Connector P1 configuration > >> Signal Functions > >> PUL+(+5V) > >> PUL- (PUL) > >> Pulse signal: in single pulse(pulse/direction) mode, this input > >> represents pulse signal, > >> effective for each upward – rising edge; in double pulse mode > >> (pulse/ pulse) this input > >> represents clockwise(CW)pulse. For reliable response, pulse > >> width should be longer > >> than 1.5μs. > >> DIR+ (+5V) > >> > >> DIR- (DIR) > >> Direction signal: in single-pulse mode, this signal has low/high > >> voltage levels, > >> representing two directions of motor rotation; in double-pulse > >> mode (set by inside > >> jumper JMP1), this signal is counter-clock (CCW) pulse, > >> effective on each rising edge. > >> For reliable motion response, direction signal should be sent to > >> driver 2μs before the > >> first pulse in the reverse motion direction. > >> ENA+ (+5V) > >> ENA- (ENA) Enable signal: this signal is used for > >> enable/disable, high level for enabling driver and low level > >> for disabling driver. Usually left unconnected(enabled). > >> > >> HTH > >> > >> Dave > >> > >> ------------------------------------------------------------------------- > >> This SF.net email is sponsored by: Microsoft > >> Defy all challenges. Microsoft(R) Visual Studio 2008. > >> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > >> > >> _______________________________________________ > >> Emc-users mailing list > >> [email protected] > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > -- > Kenneth Lerman > Mark Kenny Products Company, LLC > 55 Main Street > Newtown, CT 06470 > 888-ISO-SEVO > 203-426-7166 > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users
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