Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: kcib on June 04, 2011, 02:37:18 PM
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I have just made a router/plasma cutting machine and have today been cutting air with the router to ensure all axis are working correctly , next step after that was to put a pencil in the spindle of router so that the roadrunner file would be drawn on table surface it came out perfectly apart from the fact that it was drawn upside down and back to front , I have tried various things to correct this problem without any luck does anybody have any ideas as to why it would machine a part upside down and back to front ????
Alan
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You have your X and Y axis moving backwards. Try going to Config >Homing Limits and check the "Reverse" box for both.
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Have already tried the obvious things to try and counteract the problem without any luck
Thanks
Alan
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If it's backwards and upside down, reversing the axis HAS to fix it.
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Have just reversed the "X" and "Y" axis as you said but then the axis DRO's are reading + when it should be minus and vice versa which then makes the homing position in the opposite corner , far left instead on near left , what else can i try ??
Alan
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Would be nice if we could see your setup in action or just pictures.
Easier to figure it out.
Jeff
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Homing position has nothing to do with the direction of the axis. You need to set up your home switches to accommodate the machine moving in the correct directions.
As for the DRO's, they'll read exactly what the g-code tells them too. If you want to run parts in negative coordinates, they need to be programmed that way. The Roadrunner is programmed in positive coordinates, so that tells me that your machine was running backwards.
If you have your home position in the back right, you can't have X+ go left, and Y+ move towards you.
You can use home offsets to set your home switches to be the max positive coordinates, which would make your 0,0 at the lower left.
As Jeff says, a pic or drawing of the machine layout would be a big help.
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Home switches are set to the max positive and 0,0 is at the lower left as it should be , cannot show any pics as I do not have a camera to hand but the machine is just a standard table with a gantry nothing fancy , I have now run a few of the sample files , roadrunner , skull and scorpion and I get the same result each time , I run the same files on my mill and they work fine , and all the settings on the router are the same apart from a couple of settings which would make no difference to what is happening.
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Axis travel on a knee type mill and a gantry mill are backwards to each other.
(;-) TP
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Home switches are set to the max positive and 0,0 is at the lower left as it should be
Then why are you expecting coordinates to be negative??? They can't be if it's setup as you describe.
Have just reversed the "X" and "Y" axis as you said but then the axis DRO's are reading + when it should be minus
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If the axis are at the home position and I then move any axis the DRO will read negative which is correct and as it should be but if I reverse the "X" and "Y" axis as you say then if the machine is homed and then the axis are moved the DRO read positive which is not correct if it were correct then my other 4 cnc machines are all incorrect.
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IF you set up work 0,0 to be the lower left of bed travel facing the front of the machine THEN all moves WILL be positive. WHere you setup Machine HOME is a totally different thing to where you work from. I see you refhome to the top left. that sets Machine zero as you say then all move in MACHINE corrds will be neg. BUT you don't WORK in machine coords you work in work coords.(;-)
Note my earlier statement IF your mill is a bed or knee mill it will move the axis BACKWARDS to a GANTRY setup for the same tool positioning. SO your setup cannot be the same direction wise to your gantry mill/router
Just a thought, (;-) TP