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CNC Mill for a Mountain Bike Component

texas-two-step

Steel
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#31
I'm fine tuning the CAM but have a few questions. Your drawing specifies two very small radius' one being 1mm and the other .5mm. There are other sections of your drawing where radial cuts meet flat surfaces and no radius is specified. Looking at the part from WheelsManufacturing.com their part has radius' at all transitions. What is the maximum radius you can live with at each of these transition points? Can I assume the .093" hole is tapped M3x8? Can it be a through hole?

Tom S.
The .5mm is likely an errant artifact left behind from my tinkering to get the model generated. The hole will be tapped as an M3x8 - cut through is fine if that's easier! I just blew out a WheelsMan (the replacement hanger) on Thursday. The unit they produce now is x8 depth and doesn't go through completely.

I think I blew it and removed some of the sketches that had the radius markings listed. I'm not sure how to best answer the question about the max radius ... perhaps what the tooling allows?

I have an acquaintance that did a quick draft from the file I created in order to help me learn more about modeling - he accomplished it in 8 steps. There is one image showing the diameter of the hanger as 27.5mm (radius of 13.75) at the transition. I'll check to see what the radius is on the axle portion - I'm sure he kept the file.
 

texas-two-step

Steel
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#32
Printed part came in today.

It's really, really close but a few dimensions are just slightly larger. Not sure yet as to why yet, will invest some time checking against the actual parts. It might have had to do with the conversion of the file to .stl - similar to what you experienced, just on a smaller scale.

Busy next two days with biz projects. Should have time Wed night to get into the details.
 

TomS

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#33
Here's a Drop Box link to the Fusion 360 file. A couple of notes. The CAM processes are not necessarily in order. I'm still learning Fusion CAM and working on refining it. All of the milling CAM is done with a 1/4" end mill. If the inside corner radius is too big I can look at a smaller end mill. I haven't looked at what size and flute lengths are available. The holes are drilled not bored or reamed. If a precision hole placement and size are required I can adjust the CAM to suit. My initial plan is to machine the Z height to final dimension, rough out the profile, and machine the bottom features including the three holes. Then use a fixture to locate the part using one of the two large holes and the small hole to machine the top features. Any comments, suggestions and criticism are welcome.

https://www.dropbox.com/s/kocw9eif7z183pk/Deraileur v11.f3d?dl=0

Tom S.
 

texas-two-step

Steel
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#34
Here's a Drop Box link to the Fusion 360 file. A couple of notes. The CAM processes are not necessarily in order. I'm still learning Fusion CAM and working on refining it. All of the milling CAM is done with a 1/4" end mill. If the inside corner radius is too big I can look at a smaller end mill. I haven't looked at what size and flute lengths are available. The holes are drilled not bored or reamed. If a precision hole placement and size are required I can adjust the CAM to suit. My initial plan is to machine the Z height to final dimension, rough out the profile, and machine the bottom features including the three holes. Then use a fixture to locate the part using one of the two large holes and the small hole to machine the top features. Any comments, suggestions and criticism are welcome.

https://www.dropbox.com/s/kocw9eif7z183pk/Deraileur v11.f3d?dl=0

Tom S.
I've managed to get access to Fusion 360. The model I generated in Inventor is certainly flawed to a degree and I suspect the issues you're experiencing in the CAM process are likely resulting from those errors. I'm working on creating a new model from the ground up but taking a more methodical approach and investing time in learning Fusion. It's significantly more flexible and feature rich than the Inventor product. I expect much better results.

Looking to having it ready by Sunday for review.

Thanks!
 

TomS

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#35
I've managed to get access to Fusion 360. The model I generated in Inventor is certainly flawed to a degree and I suspect the issues you're experiencing in the CAM process are likely resulting from those errors. I'm working on creating a new model from the ground up but taking a more methodical approach and investing time in learning Fusion. It's significantly more flexible and feature rich than the Inventor product. I expect much better results.

Looking to having it ready by Sunday for review.

Thanks!
Sounds good. The model you sent is workable but I did have some problems with the CAM but that could just be me. No reflection on what you put together. I'm still refining the CAM processes to get a more fluid machining cycle. I've got a couple of ideas of how to get a smaller radius on the "fishtail" end.

Tom S.
 

texas-two-step

Steel
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#36
Sounds good. The model you sent is workable but I did have some problems with the CAM but that could just be me. No reflection on what you put together. I'm still refining the CAM processes to get a more fluid machining cycle. I've got a couple of ideas of how to get a smaller radius on the "fishtail" end.

Tom S.
The 'fishtail' is one of those features I deleted. It's a revolute operation on the x axis. Almost finished with the newest rev of the drawing. :)
 

TomS

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#40
what are the chances we could put radius' here:
View attachment 229718
Same questions I had. See post #30. Also take a look at post #19. The link is to a vendor of this part. The pictures show radius' at the points indicated in your drawing. I'm setting up the CAM processes using a 1/4" end mill then will use something smaller for finishing the "fishtail" inside radius. Haven't come up with a size yet. Still working my way through learning Fusion CAM.

Tom S.
 

texas-two-step

Steel
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#41
what are the chances we could put radius' here:
View attachment 229718
It's no problem to add a fillet here, just an oversight on my part. Fillets are 2mm in size. Let me know if that's enough or if the cutting tool is larger and needs more radius in the fillet. Took advantage of this oversight and fixed up the revolute on the hanger face and cleaned up the appearance.

https://www.dropbox.com/s/o8zr90yxbeun1ad/Derailleur Hanger v4.f3d?dl=0

Let me know what you think! Thanks!
 

cs900

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#42
how large of a fillet can you put there? The larger, the easier it is to make. If you could get away with something like R.13-.15 that would be perfect for a .25 dia tool. If it hasto be smaller that's fine, it just increases machining time.
 

TomS

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#43
I haven't forgotten this project. I'm traveling in the southwest and wifi is intermittent at best.

Tom S.
 
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