Machsupport Forum
Third party software and hardware support forums. => SmoothStepper USB => Topic started by: numbnutts on July 15, 2010, 05:24:04 PM
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Hi All,
Cant seem to see what Im doing wrong on this one Ill try and explain the problem,
Ok so I drew up my part and created the G-code file (I did the demo run in mastercam and everything seemed good), I then imported it into mach 3 and set up my stock, the display picture of my part in mach 3 seemed identical in layout and placement to mastercam, This is where it gets a bit strange.... when cutting, everything in the display looks good but the cut is completely in revers and upside down ( altho the picture looks correct the machine seems to be cutting a part that is turned 180 degrees to the left and flipped 180 degrees ) ?? I decided to finish the part as the shape would come out fine except the pockets were in reverse ( and on the wrong side ), Its kind of hard to describe , I have tried reversing the motors but this just seems to throw up more problems,
( I think if my mill head was flipped 180 and the work piece stayed where it was everything would come out correctly As an Example lol )
( Just a side note,, All the depths of cuts are fine )
If anyone has any ideas or would like to seem my profile or g-code file I can send it ( as its probably the only way to know what the hell I'm talking about ) ( its a bit to large to post )
Sorry if its not completely clear Its kind if hard to explain
Many Thanks
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Your machine is set up backwards. Sounds like both the X and Y axis are moving the wrong way.
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Hi yep the first thing i tryed was reversing the axis in homing and limits but it still wouldent cut corisponding tho the diagram layout in mach 3 , sounds weird I know :-\
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Please attach your xml and the code using the additional options button.
Hood
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Here we go it may look ok till its put on the machine
Thanks Guys
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First thing I notice is you have your keys for jogging set backwards from normal so that would suggest your axis are also reversed.
When you press the right arrow key your table should move to the left, does yours do that?
Hood
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Hi yep it does now i think because I changed the motor setting trying to sort out the problem but before it was as you said press right move left ( was like that for the cut ) i have just checked the part I cut against the mastercam layout it has basically flipped it 180 degrees across the x axis and done all the pockets that side so Im left with a part in revers ( all be it a very nice part lol )
Thanks for looking at it hood
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Ok so if you are at X0 and you MDI a G0X1 move does the table move left?
Hood
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Hi hood Im out by my machine and yep it moves to the left
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Weird one then, cant see how doing a MDI moves correctly but doing from code does not, will have a further look through the xml but cant see how anything can be wrong..
Hood
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Thanks Hood
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Ok guys I seem to have gotten it to cut as per the drawing, you were rite it was to do with reversing the axis ( but only one of them ) I think it was messing up before because i was reversing both of them which seems to create more trouble, currently Im using the following (which seems to follow the tool path on the mach 3 the screen perfectly )
Arrows
If i press the left arrow on my keyboard the table moves to the left ( I always thought this should be press left table goes right ? )
If I press the forward arrow on my keyboard the table moves back ( this was the way it should be anyway I believe ?)
MDI
If I type in G0X1 the table moves to the left ( as you look at it ) 1 mm
If I type in G0Y1 the table moves back ( towards you as you look at it )
Does this sound correct?
Thanks
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Left arrow and table should move right or if you think in relation to the cutter it is moving negative in relation to your work.
Right arrow and table should move left, cutter it is moving positive.
Up arrow and table should move towards you , cutter it is moving positive.
Down arrow and table should move away from you , cutter it is moving negative.
If you are at Y0 and you G0Y1 the table should move towards you as the cutter will be going positive in relation to the work.
Hood
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Hmmm everything is going in the correct direction except for the x axis but its the only way to get it to my G code file cutting correctly, do you think having the left arrow move the table left will cause me problems in the long run??
Thanks
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You can easily swap which key jogs which way and suppose its really up to you which way you have things. Standard is as said above but if you prefer the way you have it then keep it.
However if you wish to change its from Config menu then System Hotkeys. Click on X++ and a box will qppear asking you to choose which key, just click the right arrow key, next move to the X-- and this time press the left arrow key.
Hood
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having the left arrow move the table left will cause me problems
Hope my reply doesn't create confusion, but, I have the arrow keys set so that the table moves in the direction of the arrow for one XML,
then when i am doing something else ( like using a modified webcam and the image is reversed i have the arrow keys set so the table moves again in the direction the keys point, but it's actually reversed ), but the motors are set up conventionally for using the flyout / jogging
buttons.
Never had a problem.
BTW, the goofy reason for some of this is because, say, using the XBOX 360 along with a reverse / upside down image from a microscope and tracking things with Copycat, you can't afford to get the resulting code all screwed up!
As long as key assignment makes sense to you, i guess.....
RICH
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Thanks guys once again you helped out loads hopefully one day when I get better at this ill be able to answer a few questions myself lol
Just on a side note I have to cut about 20 of these parts the first 5 seem to have slight variations of about 0.01 - 0.1mm threw out the geometry does that seem acceptable for a bench top CNC ?( I mean its fine for the job Im doing I was just wondering if that seem bad compared to other peoples bench top set ups? ) and if so any ideas where the fault may lie?
Cheers
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P.s the part is like 117mm x 112mm roughly
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0.01mm is fine but 0.1mm is quite a bit but depends I suppose on the machine and whether its ballscrews, has backlash etc. Really shouldnt be much variation from part to part though.
What material is it?
Hood
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Hi Hood its 6082T6 aluminium, yep I have ball screws and have set my steps to within 0.01 or less so i was a bit confused maybe I should drop my speed a bit I was running at 150mm a min with a 6mm cutter at around 4000 rpm with a 0.5mm depth of cut no flood coolant just WD40 here and there to stop chip weld ,mind you these are some of the first proper parts I have done so ill have a play with speeds and feeds a bit
If you can think of anything to try that may improve accuracy that would be great
Many thanks
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Just wanting to make sure, is the variance between parts or within one part?
Hood
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It seems to between parts Im starting another batch next week so ill see how they come out
Thanks
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Parts should really be identical or very close to it if it is a machine issue as the slides should be moving the same way so backlash etc should be the same from one part to the next.
Because yours are different then it sounds more like an electrical issue, bad pulse etc.
Hood
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Ok hood ill let you know how the next batch go
Thanks for all your help