Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Zero Cool on May 01, 2011, 07:56:21 AM
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When looking at the machine view/table view window in Mach. it always wants to put the design at the bottom and to the left of the work area as shown. My mill is set up so that "home" is back and to the left. this is the way it was built. Is there a way to tell Mach this so that when looking at the table view it starts at the top left??
(I am still weeding through the video tutorials)
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Standard is like a graph, X0Y0 is lower left corner of the paper. If your home switches are at locations other than that position then you can enter a Home Off value in Homing and limits. The value you will enter is equal to the distance your axis is away from the standard machine zero point when you home.
You can of course set things up any way you like and feel comfortable with but it is best to stick with convention in my opinion as it wont cause issues down the road, setting up unconventionally may or may not cause problems but will certainly make things harder if moving to a machine that observes convention.
One last thing is remember that it is the tool position that dictates the XY and Z zeros and not the table movement. On a knee mill it is often confusing for a beginner as they see the table moving left when there is a positive X move and it looks wrong but if they think about the tool in relation to the work they will see it is right.
Oh another "one last thing" ;D you dont have to have the home position as the point you start your work, you can jog wherever you like on the table and zero the axis, that sets up a work offset, the stanndard being the G54 but there are many more you can stor if you wish.
Hood
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it doesn't matter where you home as you'll be machining from work offsets which you can set anywhere on the table. Your plus measurements should be from left to right on the x, from front to back on the y axis, and (for a column mill) from table to uppermost point on the z. These are tool movements.
It's worth having the home so that the tool goes back (table comes forward) on the y axis as you'll have more room to set the job up on the table.
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My mill is a gantry type so the table is fixed. but i get what you are saying. and i have figured out how to do the work offset and get a program to run within the machines limits...so i am learning and getting it slowly figured out.
I have the machine homed in. I move the machine to the point i want to start work at and zero the work offset. then regen the toolpath and it shows the work off the table in the view window. the program runs like this but i cant get the work to be shown ON the table...so i still have something not right.
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I bet I have the Y axis set up wrong. it counts positive when moving forward.
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It sounds like your code may have a start point in it other than the normal XYZ zero. for example your CAM may have chosen (or rather you within your CAM) an origin of some value which is way off your table.
Best to get that sorted in CAM but even then you can get around this by entering suitable values into the DROs to offset rather than just zeroing the DROs.
Hood
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I am very much a beginner. I am no where near being able to use CAM's, or for that matter even know what that is!(I think i know) LOL!
i am learning mach and just trying to get the machine to run the roadrunner test program that comes with mach hahaha!
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Not knowing your bed size, when at home position, wouldn't your home DRO's settings then be something like X 0 Y 48.5 (Left, back corner of table)
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hmm well. i have been able to home the table in...im pretty sure anyway and i have the table size figured out and entered in the home/limits section. so when its back and to the left and the machines home position the DRO's all are set to zero.
When it moves forward it counts from zero to +19" and when it moves right it counts from 0 to +19" but it sounds like i need to set it up so that when it is at home. it is at 0-X and 19-Y and have it count down from +19 to 0 when moving forward.
I have someone that lives in the MN area that is going to give me a hand at some point. I will keep tinkering with it and watch the rest of the videos in the meantime.
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You need to set a Home Off value in Homing and Limits as mentioned above. That will mean when you home the Y axis will have for example 19 in the DRO and Mach will know machine zero is 19inch in the negative direction.
Ad to that it sounds like your Y axis is going the wrong way as the tool coming towards you should be a negative move, you can reverse the direction in Homing and Limits but you will also have to change the Home direction for that axis.
Hood
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Thanks Hood. I will dig into that today!
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I had my Y and Z axis's reversed. one i got that fixed now things work fine. the pattern is just upside down on my mill from whats show on the screen. but the Z-axis moves correctly now. which i didnt know was wrong until i tried to run one of these test programs. and now the gcode pattern is show in the table view correctly etc.
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If the pattern is upside down then you have the Y axis the wrong way.
Hood
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Hmmmmm. if i reverse the Y, then the pattern is shown off the table in the view window...
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Ok so in your vid I am presuming the Y is the axis that is Top/Bottom of the smily face.
If so then I am thinking you are hming to the top left corner of the table, if thats correct then that would mean X fully negative but Y fully positive. What to do in that case is like I said earlier, set a Home Off value in the Y axis (Homing and Limits) which is equal to the amount the Y is away from zero when you home. That way your Y DRO will read the value you set and Mach will consider that the Machine zero is negative from there by that value.
Hood
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Yes you are correct in your assumptions of my axis orientations. thansk for looking at the vids.
That's right i remember you saying that about the home off value. i did play with that a little bit yesterday. but i wasn't sure what i was doing (im not real sure what i am doing most days LOL). Ok i will play with that some more and get that figured out.
THANK YOU for your help!
Dave
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First thing to do is get the Y moving in the correct direction, ie when the tool is close to you and you jog positive your tool should move away and the DRO in Mach should show the Y axis increasing in value
Once thats set then you will need to set the Homing as positive (i presume its negative now) and then enter a Home off value eaual to the table travel.
Hood
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Hmmm This is still now working correctly. I reversed the motor connections to the Y-axis. now when the tool moves away from the from of the machine...away from me, the DRO increases. Ok so that's correct now. which way should the X-axis move then? if it moves right should it increase?
I entered a value in the home off value Y box. as you said equal to the table size.
If i press ref all home, the Z- zeros at the top, the Y-moves back and zeros at the back, the X moves left and zeros there.
If i then press regen tool path. it shows the design off the table, in fact in front of the table on the left.
I played with it in all sorts of ways, but no matter what i do I cannot get the X part of the curser in the tool path window to ever go to the top left of the table view. it always is at the bottom left of the table and then moves off screen when the tool moves towards me...So I have something really goofed up.
I wonder if part of the problem is that my home/limit switches are at the back and to the left. there are no switches in front or to the right.
I am half inclined to just put it back the way it was and deal with it working upside down.
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Maybe I should move the Y-axis home switch to the front of the table...
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X should increase in value as you move from Left to Right, Y should increase in value as you move from you to away and Z should be Sero when fully up and move negative when going down.
Can you attach your xml as it may make the issue easier to find.
Hood
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Ok good I have all axis moving the right ways then. I will copy the XML when i get to the shop tonight.
Thanks again
Zc
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I managed to get the mill oriented correctly tonight. In the input section. I had Home, ++ and -- all active for all 3 axis.
as I only have switches on one end of the X & Y axis. I simply set the Home and X-- and Y++ inputs as active. this seems to have fixed the issue. when i would ref all home. i think it was getting confused. it seems to be working correctly now!