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Helical tunnel borer
paul_britton
Member Posts: 37 ✭✭
Hi,
I have been trying to model the drilling auger on this tunnelling machine...
Ignoring the propeller bit at the tip for now...
The central core is an ogive curve (like a rocket nosecone), I think. I can construct that fine...
I can get the helical path around it, but I can't get the cutter edge to sweep correctly. The swept shape seems to 'revolve' as it sweeps..
https://cad.onshape.com/documents/bfcab79745e70a807cb87497/w/181434d7c1ba5e4cda7ffba1/e/e5bc6e8a6dffd92eabc29438
Can someone tell me what I'm doing wrong please?
I have been trying to model the drilling auger on this tunnelling machine...
Ignoring the propeller bit at the tip for now...
The central core is an ogive curve (like a rocket nosecone), I think. I can construct that fine...
I can get the helical path around it, but I can't get the cutter edge to sweep correctly. The swept shape seems to 'revolve' as it sweeps..
https://cad.onshape.com/documents/bfcab79745e70a807cb87497/w/181434d7c1ba5e4cda7ffba1/e/e5bc6e8a6dffd92eabc29438
Can someone tell me what I'm doing wrong please?
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Best Answers
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paul_britton Member Posts: 37 ✭✭mahir said:@paul_britton , that's funny. Reading your question, I was about to suggest my Sweep Normal FS, but you beat me to it Glad it worked for you. I should probably make it a real FS document instead of burying it in my sandbox.
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ilya_baran Onshape Employees, Developers, HDM Posts: 1,202@paul_britton
We are always listening Over time, as priorities allow, we will incorporate more options into our sweep. Out of curiosity, though, now that you know it exists, what is the downside of using the custom feature?Ilya Baran \ VP, Architecture and FeatureScript \ Onshape Inc5 -
paul_britton Member Posts: 37 ✭✭ilya_baran said:@paul_britton
We are always listening Over time, as priorities allow, we will incorporate more options into our sweep. Out of curiosity, though, now that you know it exists, what is the downside of using the custom feature?
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Answers
Hello Paul!
Not obvious until you have seen one.
This is a constant-pitch/variable-diameter sweep.
"Bone Screws' (orthopedic surgical device) are very similar. Here is an example.
https://cad.onshape.com/documents/d3d8ded2a3002695f2f92b3b/w/63b87a811a1f307b9cd4c36b/e/72177004b5befa06cb7cd722
I have just found a featurescript feature called Sweep Normal that appears to keep the spine profile in the correct orientation during the sweep, ie it's plane normal to the surface of the core profile.. If only OS had this as a tick option in the standard sweep as well as the 'Keep profile orientation'
Which gets me to something like this...
https://cad.onshape.com/documents/bfcab79745e70a807cb87497/w/181434d7c1ba5e4cda7ffba1/e/e5bc6e8a6dffd92eabc29438
FAB!
We are always listening Over time, as priorities allow, we will incorporate more options into our sweep. Out of curiosity, though, now that you know it exists, what is the downside of using the custom feature?