Scallop Height

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18 Nov 2010 17:39 - 18 Nov 2010 17:42 #5413 by BigJohnT
Scallop Height was created by BigJohnT
For some strange reason I wanted to know the resulting scallop height for different tip radius/feed per tooth combinations when facing off a part in the mill. It was quite a struggle for me to finally arrive at the formula with the help of some friends on the IRC. Andy pointed out that the result would only be true for the center of the cut where the tip is perpendicular to the path and the rest would be less, so this gives you the highest peak size.

For those that "want to know"
r = tip radius, c = feed per tooth
r-(r*COS((2*ASIN(c/(2*r)))/2))

The results were interesting (for me) to see in my spreadsheet with different combination.

John
Last edit: 18 Nov 2010 17:42 by BigJohnT.

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18 Nov 2010 22:12 - 18 Nov 2010 22:32 #5421 by piasdom
Replied by piasdom on topic Re:Scallop Height
BigJohnT wrote:

For some strange reason I wanted to know the resulting scallop height for different tip radius/feed per tooth combinations when facing off a part in the mill. It was quite a struggle for me to finally arrive at the formula with the help of some friends on the IRC. Andy pointed out that the result would only be true for the center of the cut where the tip is perpendicular to the path and the rest would be less, so this gives you the highest peak size.

For those that "want to know"
r = tip radius, c = feed per tooth

r-(r*COS((2*ASIN(c/(2*r)))/2))

The results were interesting (for me) to see in my spreadsheet with different combination.


never had to use scallop height, also had to look to see "what" it was. i'm guessing it is needed for 3-d milling?
i never had to do 3-d and still i look at youtube,others to see. it's amazing what ya'll can do :) i have no machines
at home(and work never required it), but i have a cnc(small sherline) that can and been thinking about trying something.
beed trying to get a cad/cam program to convert a dxf file, but everthing i try doesn't work. because i need to learn A LOT
more about cad/cam. never used that before either :) congrats on finding the formula !
Last edit: 18 Nov 2010 22:32 by BigJohnT.

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18 Nov 2010 22:31 - 18 Nov 2010 22:34 #5422 by BigJohnT
Replied by BigJohnT on topic Re:Scallop Height
Actually I wanted it for face milling to compare insert tip radius to feed to see what would give me a comparable finish to some extent. It is also useful when you are using a ball end mill...

Have you tried Sheetcam? It seems to do ok with DXF files.

John
Last edit: 18 Nov 2010 22:34 by BigJohnT.

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19 Nov 2010 00:53 #5425 by piasdom
Replied by piasdom on topic Re:Scallop Height
BigJohnT wrote:

Actually I wanted it for face milling to compare insert tip radius to feed to see what would give me a comparable finish to some extent. It is also useful when you are using a ball end mill...

Have you tried Sheetcam? It seems to do ok with DXF files.

John


never heard of sheetcam,will look for it thanks.

when i said 3-d, i know they use a ball mill. and scallop height to know the distant between passes.
the shorter the pass between passes leaves less ridges. if you can look very close to a 3-d product,
you can see the ridges :)
thanks again for sheetcam!

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19 Nov 2010 12:43 #5437 by BigJohnT
Replied by BigJohnT on topic Re:Scallop Height
If you have a DXF file you need to convert to a tool path I can do that if you need one in the mean time. A good DXF file all the lines and arc ends will touch the next line or arc and not overlap. Sometimes you have to zoom in a lot to see the ends. If you have gaps and or overlaps it confuses most simple cam programs.

John

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22 Nov 2010 10:45 - 22 Nov 2010 10:52 #5525 by piasdom
Replied by piasdom on topic Re:Scallop Height
i appreciate that, this is what i usually make. if too big,let me know.
don't worry about drilling the holes, the pockets are why i would use cam/cad.

been looking at sheetcam, interesting. looks like it's what i need. will be looking around for
video/info on how to use.

again for the help !
Last edit: 22 Nov 2010 10:52 by piasdom.

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22 Nov 2010 10:57 #5527 by piasdom
Replied by piasdom on topic Re:Scallop Height
trying to get the file small enough for forum

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22 Nov 2010 11:10 - 22 Nov 2010 11:11 #5529 by piasdom
Replied by piasdom on topic Re:Scallop Height
can't get file under forum limit. if' this doesn't work i'll give up:)

==================================================

well, thanks anyway, i'll get it sooner or later :)
Last edit: 22 Nov 2010 11:11 by piasdom.

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22 Nov 2010 13:26 #5534 by BigJohnT
Replied by BigJohnT on topic Re:Scallop Height
You can just e-mail it to me...

John

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22 Nov 2010 16:05 - 22 Nov 2010 17:40 #5538 by piasdom
Replied by piasdom on topic Re:Scallop Height
thru this forum? couldn't find a place to email /w an attachment.

is there a site like pastebin for files ? thought i saw one somewhere.

found this
filebin.ca/xmztc/4PortAOA.DXF

don't know how long it will be there, says it can be
removed any time :) let me know
Last edit: 22 Nov 2010 17:40 by piasdom.

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