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Smooth out subtle flats along curved face

Smooth out subtle flats along curved face

Smooth out subtle flats along curved face

(OP)
I have a model of a tool that has a surface lofted curved face. When you look at the face up close on the screen you can see very subtle flats rather than a nice smooth face. My problem is we use a 4 axis WEDM cut to produce this face on the tool and the subtle flats end up in the finished tool. I thought the subtle flats was just a display thing with Solidworks. My Document image quality slider is all the way up. Does the display in some way actually control the geometry used for CNC WEDM?
Is there a way to insure the WEDM cut will be smooth as is the sketch geometry that creates the loft?
Because the loft requires a 4 axis cut our Wire guys are using the SW model geometry direct into Esprit with a new Mitsubishi WEDM machine.

thanks,
Tom

Tom Malinski
http://www.okayind.com/
Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

RE: Smooth out subtle flats along curved face

Honestly I would not think the pixels would cause this to happen. If the image Quality is maxed out and your using High quality, then that is the best its going to get. I don't think Esprit is going to make the resolution that you are seeing in the part.

Regards,

Scott Baugh, CSWP pc2
www.scottjbaugh.com

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RE: Smooth out subtle flats along curved face

Make planes through the part.  Create sketches on the planes and use "Tools --> Sketch Tools --> Intersection Curve" to bring the surface X-section into the sketch.  RMB on the curve and make curvature comb visible.  This will tell you if there are any inflections or loss of curvature.

batHonesty may be the best policy, but insanity is a better defense.bat
http://www.EsoxRepublic.com-SolidWorks API VB programming help

RE: Smooth out subtle flats along curved face

Check out the article on reducing SolidWorks file size at: http://www.capinc.com/pages/Support/KAPsCorner.cfm.  In the section about image quality the author introduces the display list.  I suspect that your EDM package is using the display list for its geometry when reading SW files directly.  If this is the case than what you see on the screen will be what you get as a part.  Having the image quality slider all of the way up should help.  I think the slider under Document Properties  -> Image Quality of the has more effect than the one under System Options -> Performance.

If adjusting these does not get you the quality that you need, you may have better luck exporting the file to a neutral format like STL where you have more control over the size of the flats.

Eric

RE: Smooth out subtle flats along curved face

(OP)
The Tick,
I did what you said, So what am I looking at now? The comb looks uniform all the way as it follows the sketch and I can slide the density all the way up to 400 and the comb still looks uniform. How does this tell me if there are flats?

Tom Malinski
http://www.okayind.com/
Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

RE: Smooth out subtle flats along curved face

I am not sure how expensive the process is, but you could do a test.  Move your slider all the way down to the lowest quality.  See if the part is affected in that manner.  Then you will know if the image quality has an effect on the finished part.

-Shaggy

RE: Smooth out subtle flats along curved face

(OP)
EEnd,
This is interesting, and supports what someone else told me but I had my doubts as to why a cnc machine would use a display list rather than the actual geometry.

Tom Malinski
http://www.okayind.com/
Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

RE: Smooth out subtle flats along curved face

(OP)
Shaggy, good idea

Tom Malinski
http://www.okayind.com/
Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

RE: Smooth out subtle flats along curved face

The curvature comb gives you a relative indication of curvature (1/radius).  Flatter curve = smaller curvature.

If the comb is smooth and doesn't have any severe dips or (worse) inflections (curvature comb changes sides), then your flat spots are due to display, not actual surface geometry.

batHonesty may be the best policy, but insanity is a better defense.bat
http://www.EsoxRepublic.com-SolidWorks API VB programming help

RE: Smooth out subtle flats along curved face

(OP)
It looks like its the display then because the comb is nice and uniform at its finest setting. this means that what EEnd said is probably true, that the WEDM machine is using the display list.
Thanks for your help

Tom Malinski
http://www.okayind.com/
Dell Prec 670, Xeon 3.8,2GB Ram, Nvidia Quadra FX 3450/4000 SDI
SWorks Pro & PDMWorks 2007 SP3.0

RE: Smooth out subtle flats along curved face

Can your WEDM machine read a STP file?  If it can, you may be able to tweak the export to provide sufficiently small triangles.

Eric

RE: Smooth out subtle flats along curved face

Eric,

STP or STEP is a true 3D file, just as Parasolid and ACIS formats are.  IGES can be hit or miss, and can be surfaces-only or solid (I think, but don't know for sure since I've never really had to resort to using it).  You might be thinking of STL which is typically used for stereolithography and other rapid prototyping systems.  STL files are indeed "faceted" with triangular faces.

Tom,

If your WEDM system can use Parasolid, ACIS or STEP (STP) files then that would be your best choice.  These files have nothing to do with the display on the screen.  They are true 3D representations of the part geometry.

For all my plastic parts, requiring machining of graphite to burn the tool steel, I have used the native SWX part files and parasolid files for sending to tool makers.  Most prefer the SWX part since they have SWX themselves.  Also, they usually need to scale the final geometry since they must compensate for shrinkage of the plastic.

The help you get on this forum is great, but it might help to share your part file.  Perhaps someone here can spot something else causing your problems.

- - -Updraft

RE: Smooth out subtle flats along curved face


Wedm machines do not do spline interpolation. Everything is chopped up in lines and arcs. If your postprocessor would use arc interpolation it would be possible to get rid of the facets. Obviously the actual parts will never resemble your cad data exactly as long as the curve definition in the nc data is not the same.

jelmerra

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