chad fisher

Ultra High Precision Surfacing help.

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Hello

 

I need some advice on machining this and getting the most from mastercam. Were in the early testing stages of trying to cut this and we are trying to work on surface finish. Needs to be optical quality. The machine is a Ultra precision diamond turning machine. Program is in metric and using a .5mm diamond ball nose. Currently I am only testing on about 4 of the squares using Surface/Parrallel and just using 3 Axis. I will go to multi axis later but I need to get the surface finish better

 

Material Alum

35000 RPM

Step Over .01um

Total Tolerance .00005

Line/Arc Filter checked but xy, xz, yz, is unchecked

One way filtering on

 

Is there a better toolpath to use? We do not want arcs in the program. We require the code to be broken into .005 micron segments. I know the code is huge but this not a problem for us.

 

Any help would be appreciated. I know this is out of the normal

 

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Turn off filter it will still reduce code, but without filter it will be raw code. Maybe out of the normal, but we have worked with customers doing work down to the picometer.  Not sure how you are accomplish what you are doing on a turning machine milling and that as peaked my interest. You said a better finish what are you currently reporting and what are you looking for?

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Optical quality?

 

I think you're into polishing....you can get a really nice finish but I don't think you'll approach that level needed on a machine with a spinning carbide tool

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Optical quality?

 

I think you're into polishing....you can get a really nice finish but I don't think you'll approach that level needed on a machine with a spinning carbide tool

 

With a grind tool it is possible, but you need the right equipment and tooling to accomplish it. Polishing or lapping it is what I have seen done for years to accomplish this kind of finish. Had a customer years ago that does optical forms for lens. Like what is show here they make a Master tool and then electroplate nickel to the mold. When it gets thick enough they remove the lens and no polishing needed. 

Edited by 5th Axis Consulting
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With a grind tool it is possible, but you need the right equipment and tooling to accomplish it. Polishing or lapping it what I have seen done for years to accomplish this kind of finish. Had a customer years ago that does optical forms for lens. Like what is show here they make a Mastercam tool and then electroplate nickel to the mold. When it gets thick enough they remove the lens and no polishing needed. 

 

Learn something new every day

 

:cheers:

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I'm not knocking Mastercam, but if you truly need optical quality, I don't think Mastercam is up to the task due to using triangulated mesh. CamTool is most certainly capable as it is one of the only cam systems that uses surface data rather than triangulted mesh. When I took the die mold training at Makino in Michigan, CamTool had a display where they were machining optical lenses for headlights. Truly amazing quality and speed. Nothing Mastercam would be capable of, especially using surface parrallel toolpaths.

 

Carmen

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If you want no arcs you will want to turn off the arc filter. For the segment length that would be under the smooth settings on the same page.

 

As for camtool, that is the biggest pos software I have ever seen. I did a head to head test and Mastercam blew it away. If you want a high end software for doing that type of work look at Tebis. Anything else is just going to be spending money for the sake of spending money.

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All I can say is we use NX to get the proper output and our scallop hgt is .0000003mm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PEACE :D

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TEBIS and PowerMill are known for having high accuracy and good surface finish.

 

But like Hardmill said, a tiny scallop height can help a lot. I´m of the opinion that filters change the original output of the system regardless the tolerance you set to them, so it becomes even more difficult to get a WYSIWYG result... Don´t get me wrong, I like filters, but they´re not suitable for such tight requirements IMHO...

 

Have you also considered the options on the machine side to achieve what you want? Like finishing cycles, such as Fanuc nano smooth machining... Or Heidenhain Cyle 32?

 

Without a capable machine correctly set to achieve such quality, all your efforts on the CAM side will be worthless...

 

Just saying...

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Just found a nice video about FANUC Nano Smoothing...

 

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Turn off filter it will still reduce code, but without filter it will be raw code. Maybe out of the normal, but we have worked with customers doing work down to the picometer.  Not sure how you are accomplish what you are doing on a turning machine milling and that as peaked my interest. You said a better finish what are you currently reporting and what are you looking for?

 

 

You are correct about the the aluminum, grow nickel, then re machine for a molding process. This diamond turning/milling is something I kind of fell into. Its a whole new world of machining and a very small one at that. People tend to be very secretive when they prove a process out or find something that works in their favor.

 

The machine is a precitech. Its setup like an lathe but with  a  B axis and a milling spindle, its basically a mill tipped on its side. Its a 5 axis machine built on granite, air bearing spindles, and hydrostatic ways. They are very precise and repeatable. Tooling is an actual diamond cutting edge, yes.......... the type of jewelry you buy for the wife.  I am in a situation where the machine is only as good as  the code generated. In a 2D  test its pretty easy to get down into the single digit RA nanometer finishes.

 

Once we go to 3d and even simple 3d shapes Mastercam will give a banding effect when we check the surface with our measuring equipment.

 

Thanks for the replies!

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All I can say is we use NX to get the proper output and our scallop hgt is .0000003mm

 

Two different things.

  1. Scallop height is based on your Max. stepover...
  2. Surface accuracy is based your Toolpath tolerance... 

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You are correct about the the aluminum, grow nickel, then re machine for a molding process. This diamond turning/milling is something I kind of fell into. Its a whole new world of machining and a very small one at that. People tend to be very secretive when they prove a process out or find something that works in their favor.

 

The machine is a precitech. Its setup like an lathe but with  a  B axis and a milling spindle, its basically a mill tipped on its side. Its a 5 axis machine built on granite, air bearing spindles, and hydrostatic ways. They are very precise and repeatable. Tooling is an actual diamond cutting edge, yes.......... the type of jewelry you buy for the wife.  I am in a situation where the machine is only as good as  the code generated. In a 2D  test its pretty easy to get down into the single digit RA nanometer finishes.

 

Once we go to 3d and even simple 3d shapes Mastercam will give a banding effect when we check the surface with our measuring equipment.

 

Thanks for the replies!

 

The banding or faceting effect is something I have always struggled to control on a consistent basis in Mastercam.

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The banding or faceting effect is something I have always struggled to control on a consistent basis in Mastercam.

 

Something I found when comparing NX output to Mastercam output (I think we've discussed this before). I always found the NX toolpaths to be of a better finish, and also the machine just seemed to run a little smoother.

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Sounds like a new tool should be made that adds Surface Quality back into the finish toolpath.
We could make a tool that checks the accuracy of a toolpath to the mathematical surface model.
Using the same tools we use to Validate points for Inspection. we can even make a error color display map.

toolpath_errormap.png

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Something I found when comparing NX output to Mastercam output (I think we've discussed this before). I always found the NX toolpaths to be of a better finish, and also the machine just seemed to run a little smoother.

I took an NX Freeform Modeling course a few months back and the instructor said the type of spline used can greatly effect the surface quality and how it machines. They recommended only using 3 degree or 5 degree splines.

 

Both NX and Mastercam license their tool paths from Moduleworks?

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Both NX and Mastercam license their tool paths from Moduleworks?

 

That's my understanding. I would like to know how the same toolpath engine gives a better finish in one software than the other. It tells me its a setting(s) that need to be adjusted in Mastercam but the potential is there.

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I have no experience with this particular application but I can tell you to not use Surface Parallel for this.  Surface High Speed Raster with no filter is well capable if everything else is inline, tool, holder, feeds etc...Yes CAMTool does machine the surface data direct but triangle machining (Mastercam, PowerMill, etc..) can produce the finish you are looking for. You can try Flowline on one of those faces if you want, it machines the surface data direct for comparison.

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Long, long shot here, but if you can make them work on your form the 'Wireframe' toolpaths, Swept, Loft, etc..will produce more accurate motion than any mesh machining or direct surface machining technologies can produce. We do have customers cutting lenses with the wireframe toolpaths, they produce the most pure motion. There is no ModuleWorks technology in our 3D High Speed Toolpaths past the Holder tilt.

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I have no experience with this particular application but I can tell you to not use Surface Parallel for this.  Surface High Speed Raster with no filter is well capable if everything else is inline, tool, holder, feeds etc...Yes CAMTool does machine the surface data direct but triangle machining (Mastercam, PowerMill, etc..) can produce the finish you are looking for. You can try Flowline on one of those faces if you want, it machines the surface data direct for comparison.

 

 

Trying now. Thanks for posting this. I will throw some data up after I run this and analyze it under the Zygo

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I agree with Matthew.  It's the lack of wireframe toolpaths in MC4SW that is keeping me from making the switch.  Hopefully one day they will decide to add them.

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We do diamond turning here but I am on the Moore Nanotech side rather than the Precitech side of things. 

 

With a grind tool it is possible, but you need the right equipment and tooling to accomplish it. Polishing or lapping it is what I have seen done for years to accomplish this kind of finish. Had a customer years ago that does optical forms for lens. Like what is show here they make a Master tool and then electroplate nickel to the mold. When it gets thick enough they remove the lens and no polishing needed. 

Correct. Generally, no polishing is required though with the proper single crystal diamond tooling from a supplier like Chardon Tool or K&Y Diamond. We direct turn <5nm finishes all day long in copper and aluminum. Milling is a slightly different animal but it is still possible with a precision machine from Precitech or Moore Nanotech and the proper air bearing spindle with less than 50nm of runout.



Do you have any pictures of the part as it currently looks? I might have a few ideas on how to improve the finish but also as a fellow diamond turner, I just find what are making very interesting :)

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