Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: aluman on August 14, 2007, 08:32:14 AM
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Hello all
Before i start with my problem, please excuse my poor english.
I am looking for some macro for probing in X and Y directions. I will get material with completed outside machining and I will need to mill some pockets and holes into that semi-finished product. So i search for some solution for finding its exact position. I do not think that i need complete digitizing. I just need to touch material once in x direction and then once in Y direction
Thanks for any help
Aluman
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Hi, Aluman:
Depending on complexity, zarzul (a poster here) has a neat little optical edge finder that he sells pretty inexpensively - look in the bargain basement under edge finder. I have used his unit with good results.
Bob @ BobsShop - Works for me.
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Hi Bob
Thanks, its cool! I will purchase something like that, but i think that probing via some macro would be more accurate. In fact i am going to sell one of my cnc and my possible customer requires most accurate solution for edge finding. Anyway i will try this camera system for my other machine.
Any other ideas?
Aluman
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Hi, Aluman:
Not sure what you mean by "probing," if you dont want to want to use digitizing. But there was another shop made probe listed in a post somewhere on here (sorry, don't remember where). Don't think it is being offered for sale yet though. Maybe someone else knows another solution. Have you ever used a mechanicla edge finder - type that spins in the spindle and kicks out when it reaches an edge? Accurate and Inexpensive - can probably be found on E-bay or at any machine shop tool supplier.
Good luck.
Bob @ BobsShop
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Hi Bob
Thanks for your response.
I was thinking about something like auto tool zero for z axis. I am using mobile calibrator and i guess that i can make new button for each axis and implement some macro to them. Macros should be similar to auto tool zero macro. Thats only my vision. If you tell me that is necessary to use probe, i will do that. But digitizing wizard which i have found looks too complicated to me. As i wrote i need only to touch semi finished product from each side for accurate zeroing.
I will try to find that mechanical edge finder on ebay. I have never seen something like that.
Thanks for another good tip.
Regards Aluman
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I cannot understand why you need anything so complicated. If all you want is to place the workpeice in the same position time after time, then build a little jig and fasten it to your table. Put in the work piece, drilll it and pocket it and take it out. Put in the next piece. You are saying that the work you get is already machined on the outside, so there will be no difficulty with it fitting in the jig.
Jim
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Jim, you would not believe how long i tried to explain it to man who is interested in my cnc. I know it is the easiest way and i use it, but he saw similar system somewhere and just requires that.
I have sold few machines before and i have a lot of experiences with guys who necessary need 0,0001 accuracy of cnc, but then use material with +/- 0.5mm tolerance.
This man should be same so i have to make something more sophisticated.
Regards Aluman
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I thought perhaps, that I was missing some point or other.
He needs to go see how a proper CNC shop works. I think probab;y, that a jig is the most accurate, and certainly the speediest.
Jim.
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I fully agree with you, but i hope that someone here can recommend me some macro or wizard for probing in x,y directions.
If anyone wants to see my machine, follow this link http://aluminiumracing.com/arttechno/art6090-1.jpg
Yes, it came from china, but works perfect after complete reassembling. They used good parts, but the quality of assembling was terrible.
Regards Aluman
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Hi all
I have made modification of some auto tool zero macro and it works as i wanted. Now i have buttons for probing in each directions, but i have tried Brian's rotation set wizard and i found new problem. First i made rotation of coordinate system and then i touched material in X and Y direction for finding of zero point,
till here each move was done in right direction as coordinates were rotated, but when i hit goto z button i found that it does not work as i expected, because zero point was taken as without rotation of coordinates. Sorry if you do not understand what i am trying to say. Hope that picture will help
http://aluminiumracing.com/rotation.bmp
Any ideas?
Aluman
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Hi, Alum (forgive the familiariaty)
Looked at your pic and comments about finding a zero point. Your problem is because you are looking at your rectangle instead of looking at the x and y coordinates as being parallel lines. Even though you indicate an x-coordinate and then move down and over for a y coordinate (or vice-versa), you are only indicating two coordinates (lets call one 4 and the other 6). The mid point is 5. You are indicating edges (EDGE FINDER!) not angles. I am not aware of any instrument that will produce what you are trying to determine with only two inputs.
Maybe it is only I who is totally confused by what you are trying to determine. Good luck with your hunt and maybe someone with more savvy than I have will be able to help you.
Bob @ BobsShop
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I think someone who knows will answer soon.
Brett
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You cannot determine the position of your workpiece with the measurements you have made. There are not enough. I assume on each touch you have an X and Y co-ordinate. To determine the angle, you would have to know at least one other point. If for instance you know where the bottom left hand corner of the piece is, then you can work out the rotation and the adjustment to put it straight.
If you wish to lay the piece on the table in any position, and have the mathmatics work out the bottom left position, then you would need to make one more touch, to determine the angle of the left hand, or bottom side of the piece, From there (if the piece in square and the included angle is 90 o, the you can work out the rest.
Perhaps the easiest way, since you have written the macro, is to run it twice with a different radius. You would then get two points on each side, and the intersection of the two is the place you are looking for.
Jim
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You need to set the Zero point first... Then you can set the rotation. The math to find the zero point is not done in the wizard :(
I have not had time to go back and add the math that is needed :(
Thanks
Brian
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Hi guys
Thanks for advices. Thats what i was afraid of. Back to school and more studies of visual basic. I will let you know my results(few months later)
Cheers
Aluman
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See this: http://www.artsoftcontrols.com/MachCustomizeWiki/index.php?title=How_to_get_Data_from_a_Probe
And this: http://www.artsoftcontrols.com/forum/index.php?topic=2136.0
using this theory, I use a macro that:
finds g54 z
finds g54 x
finds g54 y
finds g55 z of a second spindle
jog to an offsite touch plate
finds x of touch plate
finds y of touch plate
finds z of touch plate
-Nick
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Hello Nick
I have used same sources for my simple macros. Does your macro work when you made rotation of coordinates?
If yes, how much for that? :-) It can save much time to me.
Regards Aluman
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Hi Aluman,
Sorry, I've never had to rotate the Mach coordinate system.
-Nick