I do have some Scottish in my blood I believe... I had red hair at one time lol.
With no limits or home switches I would configure the axes as follows: Axis MIN_LIMIT MAX_LIMIT X 0 - 550 (if that is the X travel) Y 0 - 400 Z 0 - 60 I would move the axes to the following positions then home each axis: X left most position (of the tool, you might have to move the table to the right to move the tool to the left) Y rear most position (of the tool) Z fully up Now your machine limits match your machine. You still have to touch off the work piece to machine a part but you will not run past the physical limits even if the program tries too. When you press the + key for an axis the tool should move in the following directions: X Right Y Away Z Up JT On 10/15/2013 12:13 AM, Richard Thornton wrote: > Thanks Andy and John, very helpful. > > John, cool tutorial, I'm a Scotsman living in Australia now :) > > Let's say you had just bought a chinese 6040 bridge gantry CNC (work > area is roughly 550 x 400 x 60mm), of course you are going to use it > with linuxcnc, it doesn't have any limits, how would you configure: > > X axis table travel and home > Y axis table travel and home > Z axis table travel and home > MAX_LIMIT > MIN_LIMIT > NO_FORCE_HOMING > > Thanks again. > > Richard > >> John Thornton wrote: >> >> Typically a mill like machine has the machine home up for Z. This means >> that Z travel goes from 0 to -something. Standing in front of the >> machine with the X axis perpendicular to you positive movement on the X >> moves the "tool" to the right and positive movement on the Y moves the >> "tool" away from you and positive movement on the Z moves the "tool" up. >> The reference to the "tool" is because some machines move the table and >> some move the spindle. Table to the left moves the "tool" to the right etc. >> >> If you don't have home switches make a match mark for each axis and jog >> to that point and press the home button when that axis is selected. This >> will make your limits functional. Typically you move to the zero >> position of the part and touch off the tool to establish the part >> position. Once you touch off if the part is within the limits you can run. >> >> Some good reading here: >> http://gnipsel.com/linuxcnc/g-code/index.html >> >> Are you by any chance from North Carolina? >> >> JT >> >> Andy Pugh wrote: >> >> The problem is that the machine thinks that the G-code lies outside >> its limits. If you look in the graphical preview you will see a red >> box, this is where the machine thinks that its limits are. >> You need to ensure that its view of the situation is accurate. >> >> There are two stages to go through here. One of them is normally >> automatic, and happens during the homing sequence, the second is part >> of setting up for the current job. >> >> The first thing you need to do is home the machine. As you don't have >> home switches you need to jog the machine to the specified home >> position (275,200,5) and then home each axis via the GUI. This tells >> the controller where the machine is on each physical axis. ("Homing" >> basically means telling the machine that the current axis physical >> location matches the "HOME" location in the INI file. You can use >> labels on the axes, or pointers. scribed marks or a datum block or >> anything for this part. >> LinuxCNC now knows where the ends of travel of the physical axes are, >> and can avoid running in to them. >> >> There is an alternative to this. You can set the NO_FORCE_HOMING >> option in the INI file. If you do this then the machine will assume >> that wherever it is can be called machine-coordinate home. In this >> case you probably want to make the axis limits at least twice as large >> as the physical limits. (to account for the machine being powered up >> anywhere in the work envelope, and still being able to reach anywhere >> else. >> If there is any danger at all of your machine hurting itself against >> the end stops I would discourage the NO_FORCE_HOMING option. >> >> Once the machine is homed you then need to tell it where the workpiece >> is. This is the "touch off" stage. If you are using the Axis GUI then >> you will see an XYZ triad on the display, this shows the (0,0,0) >> location that the G-code is referenced to. This is almost never the >> same as the machine (0,0,0) You should jog the (possibly imaginary) >> cutter to a point on the (possibly imaginary) workpiece that matches >> the origin of the G-code and use the "Touch off" button to set the >> axis positions, >> >> For more accuracy you can follow this process. Jog the cutter close to >> the work in the axis being set. Hold a dowel (I use a broken 6mm >> milling cutter) against the side of the tool, then slowly jog away >> until the dowel slides underneath. Then touch-off and type the dowel >> diameter in the box. >> > On 10/9/2013 5:00 AM, Richard Thornton wrote: >> Thanks Dave and Marius! >> >> Dave so this is different than table travel from stepconf axis config?: >> >> MIN_LIMIT = -1000 - The minimum limit (soft limit) for axis motion, in >> machine units. When this limit is exceeded, the controller aborts axis >> motion. >> >> MAX_LIMIT = 1000 - The maximum limit (soft limit) for axis motion, in >> machine units. When this limit is exceeded, the controller aborts axis >> motion. >> >> Marius so I will set home back to 0 for xyz in stepconf axis config. >> >> So if I have: >> >> X axis table travel 0 to 550 home 0 >> Y axis table travel 0 to 400 home 0 >> Z axis table travel 0 to 60 home 0 >> >> Does that seem correct? >> >> Where would the negative values I have seen in example screenshots be >> relevant to table travel? >> >> If the above values are correct what would my values be for MIN_LIMIT >> MAX_LIMIT, I am also confused about the use of negative values, the >> MIN_LIMIT example above is -1000? >> >> Thanks again. >> >> Richard >> >> Message: 6 >> Date: Wed, 9 Oct 2013 08:36:44 +0100 >> From: Dave Caroline <dave.thearchiv...@gmail.com> >> Subject: Re: [Emc-users] Extremely confused about axis and home, >> please help... >> To: "Enhanced Machine Controller (EMC)" >> <emc-users@lists.sourceforge.net> >> Message-ID: >> >> <CALfYgt=rkGV8wdbmR9PRU90nDYfD=v85TWr=W=qgxwukrgq...@mail.gmail.com> >> Content-Type: text/plain; charset=ISO-8859-1 >> >> On Wed, Oct 9, 2013 at 6:40 AM, Richard Thornton >> <richie.thorn...@gmail.com> wrote: >>> Hi, >>> >>> So I have one of the Chinese 6040 gantry CNC routers, like this, I >>> have setup the axis as I have indicated in the image: >>> >>> https://www.dropbox.com/s/ochmutxnacs4fo6/6040.JPG >>> >>> The 6040 does not have any limit/home switches yet. >>> >>> Now under stepconf, using mm, I have setup: >>> >>> X 0-550 home 275 >>> Y 0-400 home 200 >>> Z 0-60 home 5 >>> >>> Putting home in the centre of xy to keep it simple right now >>> >>> All of the axis move OK, so my next step way to get it to go through >>> some gcode without any tool, I get various error but they are all of >>> the same flavour: >>> >>> Program exceeds machine minimum on axis x >>> Program exceeds machine minimum on axis y >>> Program exceeds machine minimum on axis z >> Make sure you edit your axis limits (MIN_LIMIT,MAX_LIMIT) to match. >> >> in the relevant axis section >> see >> http://www.linuxcnc.org/docs/devel/html/config/ini_config.html#_axis_lt_num_gt_section_a_id_sub_axis_section_a >> >> Dave Caroline >> >>> Linear move on line 7 would exceed joint 0's negative limit >>> >>> I also get errors about it not being homed, then under "Manual >>> Control" I select each axis and click "Home", I think this is wrong. >>> >>> I tried the LinuxCNC logo gcode that loads as default and created my >>> own 50x50 text in Cut2D both give similar errors to the ones above. >>> >>> https://www.dropbox.com/s/n803ycbfmkm3u8g/Quick%20Engrave%201.ngc >>> >>> I think I am doing something fundamentally wrong here, please help. >>> >>> Thanks for looking. >>> >>> Cheers >>> Richard > ------------------------------------------------------------------------------ > October Webinars: Code for Performance > Free Intel webinars can help you accelerate application performance. > Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from > the latest Intel processors and coprocessors. See abstracts and register > > http://pubads.g.doubleclick.net/gampad/clk?id=60135031&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60135031&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
