draft angles with cylindrical corner radius

[pjy]

If a drawing note specifies a profile feature to have a draft angle "all around", shouldn't any radius on the profile also have a draft angle, essentially making it conical rather than cylindrical?

 

[MikeHalloran]

That's the way I would read it.

If the radii are interpreted as portions of right circular cylinders, then they can't also be tangent to drafted surfaces, so you wind up with some awkward transitions.

Mike Halloran
Pembroke Pines, FL, USA

 

[ornerynorsk]

Depends on how it is specified on the drawing or in the model. It can be either way, and is up to the designer to specify. Corner or edge treatments in that situation should not be left unspecified.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[pjy]

Thank you for your replies:
In this instance the customer has also provided a model.
The instruction for this job/ customer is "build to print" and a note on the drawing states "machined as shown".
- Pictorially, the radii appear to be cylindrical
- The model provided has cylindrical radii
- The note, draft angle "all around" contradicts the model provided
My intent is to machine cylindrical radii "as shown" and modeled since the note "all around" contradicts the model. Technically, it would be wrong either way I choose, since I will be disregarding the note "all around" on a drawing that takes precedence over the model.

 

[MikeHalloran]

You might want to rough out just the detail on a piece of scrap, and show it to the customer before cutting his actual part, so adjustments can be made at little expense to anyone.



Mike Halloran
Pembroke Pines, FL, USA

 

[HGMorgan]

Less expensive and faster to model it, then show both models to customer.

Harold G. Morgan
CATIA, QA, CNC & CMM Programmer

 

[MikeHalloran]

The customer presumably already 'saw' a model, and didn't understand what (s)he was seeing.

Most customers understand physical models in their hands much better than they understand visualizations of models on a screen or on paper.



Mike Halloran
Pembroke Pines, FL, USA

 

[pjy]

I think the problem is that we are dealing with buyers or middlemen instead of engineers. This part was a casting, I suspect is unavailable or too pricey for the quantity needed, and which probably does not need draft angles... but the response to that question was in the form of a "machining" model. At least I have the model to support my interpretation.

 

[capnhook]

Yeah, why would anyone expect a "buyer" or "middleman" to know anything about how something is manufactured?

"Just look for the lowest number on the screen..." is their mode of operation these days.

Proud Member of the Reality-Based Community..

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