Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: freshwatermodels on December 03, 2011, 10:13:39 PM
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I am interested in making a probe and using the Mach3 digitizing wizard. I have a 3 axis cnc router I am running on Mach3 with a Gecko 540 controlling it. I design in Rhino/Rhinocam.
Occassionally I need to reverse engineer an existing part. Usually it is a fairly complex organic shape that isn't easy to model in Rhino. I'd like to build or buy a probing head which doesn't look too difficult.
The question is where can I find some step by step information on how to wire the probe to the Gecko and where can I find step by step how to set-up and run the digitizing wizard?
I found Mach3 tough to set up but finally got it up and running with the Gecko. I just don't know where to begin to set up a probe or the digitizing wizard.
Any assistance in helping me find the information I need would be appreciated.
Jack
(http://i461.photobucket.com/albums/qq340/freshwatermodels/cnc_router.jpg)
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There are several threads on probing. Basicly you have two wires going to the G540 from the probe. One is for ground the other is the input. You have to set the ports and pins.
The wizzard sets the limits for the probing area. A point cloud file is created, based on the probing. The G31 command in the manual needs to be read.
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Sorry about this and off subject.
Is the blue circular item on top of the tan cabinet a Powerstat / variac and being used as the power supply for your controller by any chance?
If it is, discontinue using it since the ac primary is probably not isolated from the secondary and there is potential for a shock hazard.
Again sorry but just had to comment on what i think i am seeing.
RICH
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Occassionally I need to reverse engineer an existing part
Other than digitizing the part you could also use CopyCat using a cheap web cam ( you will get gcode ) or can take a picture of the part and trace over it in Cadd for
2d outlines. Just something to consider.
RICH
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Sorry about this and off subject.
Is the blue circular item on top of the tan cabinet a Powerstat / variac and being used as the power supply for your controller by any chance?
If it is, discontinue using it since the ac primary is probably not isolated from the secondary and there is potential for a shock hazard.
Again sorry but just had to comment on what i think i am seeing.
RICH
Rich,
I am using it to control the speed of the router. I have a standard power supply for the Gecko drives.
Jack
Occassionally I need to reverse engineer an existing part
Other than digitizing the part you could also use CopyCat using a cheap web cam ( you will get gcode ) or can take a picture of the part and trace over it in Cadd for
2d outlines. Just something to consider.
RICH
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I would suggest you check out Stirlings Crawler type 3d probing routine. I think it is just what you need.
It will crawl around the circumference of the part to define the area then probe the surface of the defined area.
Probably the best routine I have seen for MACH3 .
http://www.machsupport.com/forum/index.php/topic,4352.50.html
(;-) TP
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Rich,
I do a lot of tracing over pictures and drawings in Rhino using jpegs as bitmap backgrounds.
The rub comes when trying to model organic shapes like the following that was done from an expensive laser scan:
(http://i461.photobucket.com/albums/qq340/freshwatermodels/fordenny.jpg)
The result was used to have printed patterns made for rubber mold casting:
(http://i461.photobucket.com/albums/qq340/freshwatermodels/matecowl.jpg)
Sadly this project didn't work out well and wasted a lot of time converting a mesh to a nurbs model.
Jack
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I hope you have a LOT of Time on your hands as Point probing in Mach3 is a painfully slow process (;-) And looking at your SAMPLE product it is not going to work well WITHOUT a LOT of work.
Also further refinement is needed as MACH3 can not understand NURBS it only works in SIMPLE lines and arcs.
Just a thought, (;-) TP
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I would suggest you check out Stirlings Crawler type 3d probing routine. I think it is just what you need.
It will crawl around the circumference of the part to define the area then probe the surface of the defined area.
Probably the best routine I have seen for MACH3 .
Cheque's in the post Terry ;D
Ian
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I hope you have a LOT of Time on your hands as Point probing in Mach3 is a painfully slow process (;-) And looking at your SAMPLE product it is not going to work well WITHOUT a LOT of work.
Also further refinement is needed as MACH3 can not understand NURBS it only works in SIMPLE lines and arcs.
Just a thought, (;-) TP
TP,
My understanding is that Rhino is a nurbs based software. Maybe I am wrong? The rendering above is from Flamingo, a Rhino plug in renderer.
If I can get some cross sections I can loft them in Rhino. Ideally I can probe to Z coordinate along an X or y axis and end up with points. The points are connected to form a cross section. That is what I am after. I can then add some of the small details like the screw heads manually in Rhino. Mostly I need to get the complex shape into a form that I can edit.
I am trying to get away from laser or white light scans which are to expensive for what I am trying to do. Having the router, I am hoping to use it to take shapes off parts to be modeled.
Jack
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Mabe it's time for me to try it Ian. I am reverse engineering something for a project i am doing and it's time consuming.
May need to make a probe that can be destroyed. ;) Have one that cost a bunch and just don't have the courage to harm it. ;D
Guess another item on the list of stuff to play with.
Thanks for your work on the probe routine.
RICH
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HIYA Jack, Yes I understand what you are trying to do. The point I was making is that point probing in MACH can be a very tidious process and very time consuming to gather very detail shapes (high resolution).
You would probably have to set up a 4th axis to auto rotate the parts to gather ALL the data at one setting. That would make the final points file all relative to the base coords and it stay very accurate. OR you could do separate scans and then merge them into points file.
The point I was making with the nurbs is you will need to make sure that the final output does not contain NURBS shapes as MACH3 cannot process a nurb in the Gcode side it only understands lines and arcs in Gcode.
Other controllers can deal with nurbs directly in Gcode but not Mach3.
Please keep us up to date on your project, (;-)TP
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May need to make a probe that can be destroyed. ;) Have one that cost a bunch and just don't have the courage to harm it. ;D
I know what you mean RICH - it can get a tad scary, but to be fair that's probing. When I was developing the software I trashed plenty but they were all home made cheapies so no matter. I then came up with the "brilliant" idea of adding in a limit switch for overtravel which worked a treat but then discovered it wasn't my idea at all and had been around for ages. It therefore always seemed strange to me that expensive probes don't come with that protection.
Actually one of these days I must update the software with one or two improvements I've come up with. Time.....
Ian
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RICH, where is the faith(;-) I did that log ago when testing the G31. Oldest son send down a very high dollar probe to test accuracy with. All went well for about an hour ,then MACH did a NONO and that was about a $1000 mistake ( cost of repairs) (;-)
Have learned that is is NOT good to mix Gcode and CB in the same sentence(;-)
Straight Gcode probing is "VERY" dependable. I can very quickly gather many thousands of points without a glitch or a missed point.
Can't say the same thing for macro probing (crunch).
Ian Please keep the Check as I KNOW I still owe you many beers for all your help AND teaching (;-)
Just a thought or three, (;-) TP
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HIYA Jack, Yes I understand what you are trying to do. The point I was making is that point probing in MACH can be a very tidious process and very time consuming to gather very detail shapes (high resolution).
You would probably have to set up a 4th axis to auto rotate the parts to gather ALL the data at one setting. That would make the final points file all relative to the base coords and it stay very accurate. OR you could do separate scans and then merge them into points file.
The point I was making with the nurbs is you will need to make sure that the final output does not contain NURBS shapes as MACH3 cannot process a nurb in the Gcode side it only understands lines and arcs in Gcode.
Other controllers can deal with nurbs directly in Gcode but not Mach3.
Please keep us up to date on your project, (;-)TP
TP
I am very confused. Will Mach3 probing wizard output a point(s) or a point cloud that I can load into Rhino.? I don't want G code since there is no machining involved. Just need to get points off a part. Once I have points in Rhino, I can go from there easily. I am also considering manually using the router with a simple probe to obtain point coordinates but dread the task. I don't need high accuracy, if I am with in .015" I'm good, the parts I am designing are often off more than that!
Jack
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IF you are just gathering points disreguard the Gcode and Nurbs comments . (;-) I thought you were going to Machine the part when done.
Yes the Mach3 Probing Wizard will ouput an XYZ point cloud file that you can use.
(;-) TP
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TP,
OK, now we're on the same page! Thanks! I were to machine the part I would start with a model in Rhino and then run it through Rhinocam to post the G code to run in Mach3.
OK, now, where shold I start to learn about how to use the wizard and wire a probe to the Gecko? Is there anything like Art's wonderful Mach3 set-up tutorial?
Jack
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To wire up the Probe you would use an input pin on the Gecko that was not being used. One wire to teh pin and the other end to a common.
Then assign the port and pin number in Mach3 config so mach knows where to look for it.
Which Wizard are you looking at? There was a ture Wizard that comes up under the Wizards and there is a Plugin routine that Art wrote.
(;-) TP
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TP,
Thanks, I think I understand the wiring. I'll have to look at Mach3 as installed in my router computer and take another look at the Gecko.
I'm a model maker and a lot of the design work I do is reverse engineering and doing it so a model can be built. Most of what I design is pretty simple but some stuff like model outboard motor cowls and lower units are tough to design from scratch.
Most of what I design is intended to be cast in Britannia metal or resin though I do machine some wood/plastic/metal parts. Once I have the design done I send it out as an stl file for 3D printing which is what those blue parts are. The printed parts are used as patterns to make either a low temperature vulcanized silicone rubber mold or an RTV silicone rubber mold. Once in a while I machine brass patterns. Once the mold is made the parts are cast using a spincasting machine.
In the past we have spent as much as $2000 in scanning and my time to develop a shape in Rhino and it was a tough slog convertng the mesh to a nurbs model. Rhino doesn't do well in editing meshes even with the wiz bang gaming computer I now use. I need to work out a way to get reasonable price reverse engineering and I think the easiest way is to use the router to determine points that I can work from.
Regards,
jack
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Like I said before it can be a very time consuming proceedure. ANd to get an entire 3d shape of an object you may have to do it in 4th axis mode where you can get all the profiles. OR at least scan all 6 sides one at a time. You may want to set up a fixture to rotate the part without having to do multiple setups each time.
Really depends on the size and shape of the object.
Have you looked into laser scanning with Mach3 ???
(;-) TP
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I can't find the darned link or video, but the guy uses a cheap line laser along with a rotary table and a web camera. That gets you the scan of whatever and then you need to put the different scanning together with software.That is the part that cost's some $ ...I think the software was $500 to do it. In the end you get a 3d image out of it which can be be saved as a steel file. Accuracy was quite good. In fact there was a 1 hour TV show on laser scanning , within the last year or so,where he went through the whole thing and how it was all done...may have been one of educational TV channel.
Ring a bell to anyone out there?
RICH
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I assumed laser scanning was way too complicated and expensive? Am I missing something? About the only thing I have considered is shooting a laser at the object and taking pictures at 45deg angle and using them as bit map backgrounds to trace contours. I have seen this done at a museum using fancy software. I wouldn't have a clue where to find a suitable laser that I could afford.
Jack
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Art wrote a plugin to do video/laser probing with a $30 laser pointer . AND a point cloud generator to go with it. May be more of what you are looking for.
Look Here http://www.machsupport.com/forum/index.php/board,67.0.html
Hope that helps, (;-) TP
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Here is a link to the company that was on the TV show.
http://www.david-laserscanner.com
You may want to go to cnc zone as they have some posts on laser scanning for CNC.
I did a lot of searching at one time to find out how accurate a laser scan of a chemical facillity would turn out and didn't want to be BS'd by some follks.
If memory is right for cnc it was around .005" or so from a foot away. BTW, it would be interesting to go to a dental place that does the work since that's
how false teeth are manufactured today.
In all of this though, I think the important thing is the magic wand which converts the scan into a usable file.
RICH
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Rich,
I'm aware of "David" which is very limited and has been around for a while. Dentists use a scanner but they don't have much size capability. I use a dental lab to do my 3D printing and probably ask about their scanning capability. I have farmed out scanning, both laser and white light, and they are very expensive but in the case of the laser very accurate. The big problem was converting the resultant stl file to a nurbs model. I spent many hours one one of the projects. What I did was to do a numbrer of mesh splits and develop cross sections from the edges where the mesh was split.
I may well just use the router to manually take off point coordinates from the parts. Not fun but gets the job done.
I have found Mach3 very useful but my main issue with it is that information on the various wizards is sketchy at best and wading through many forums and yet many more posts seems quite cumbersome and in many cases hasn't answered my question as is the case in this thread. If only there was a reasonable way to sort out the facts and organize them in an easy to access manner.
Jack
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THe basic wizard is VERY simple you tell it the width and length of the scan. The max depth of Z to scan. Then add in the stepovers for X and Y (Resolution) and then the Wizard will generate a Gcode File that does all the probing work.
At the start of the Program RUN it asks for a file name to save to. AND at teh completion of the run it closes and saves the file.
THAT process will generate a POINTS file of the scan in XYZ format. Then I woul duse MachMesh to convert that into a STL or mesh file. Then use your favorite Mesh to do what ever.
I think I got the order right, (;-) TP
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MachMesh
to convert that into a STL
MachMesh ....never heard of MachMesh ???
RICH
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I think that should be MACHCLOUD (;-)
(;-) TP
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Where does the wizard output the probing data?
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Solved it: since I was using the lathe probing wizard I was missing the M40 and M41 Visual Basic calls for choosing an output file.
I just copied them from the Mill folder and now it works!