CAD question?

[JD Mather]

Not used for manufacturing because the stl model is not smooth - it will always be faceted.
Would you purchase a car, or cell phone, or diamond ring that had only planar faces?

Oh, OK for the diamond, but it should be obvious for the rest.

RP models (*.stl) are used for early prototypes, not generally for production parts.

No matter how "smooth" you make it - it will always be faceted and layered when made on the RP machine.
Different machines have different resolutions.
I always set my stl files to "Fine" or highest resolution - there is a trade-off on file size, the smoother the resolution the larger the file.
But at some point you also hit the resolution of the printer - generally not very good unless you have access to a very expensive (>$500k) machine.

[JD Mather]

Imagine manufacturing something as simple as a cylinder.
- as stl file the machine would have to mill individual tiny planar facetes.
- as true cylindrical geometry (extruded cylinder) the lathe simply turns the stock as the tool moves linearly.

I recommend you sign up for a basic machining class if you want to continue in this field.
I worked out on the shop floor for 8 yrs as a machinist and it always bothered me when designers would design some feature that couldn't be manufactured or manufactured at a reasonable cost or that a customer wouldn't look at and consider garbage.

[razorsbhc]

So I can`t use .STL for manufacturing? (because its not smooth polygons)

Then I must use Nurbs in AutoCAD, I guess. (with smooth curves)

Am I right?

[JD Mather]

Am I right?

Would you purchase a car comprised of only planar faceted faces? (similar to the "sphere" I posted earlier)
What products (other than diamond jewlery) would you purchase that was all faceted planar faces? (there are many products that are only planar faces - a box for shipping a product might be one example)
What products would your customer purchase that were all faceted planar faces?

Hey, where did that image go? For some reason I no longer see it.

[razorsbhc]

Hi again

So the answer is "Dont use .STL for manufacturing", Because I dont want flat planes. Which format shall I use then to the manufacturing? Whats it called with Nurbs?


I did some search on Google, and found this. Its how to use .STL for manufacturing.
There it says its about the resolution how smooth it will be, (I guess it will still be flat plans, but then very small, maybe it works?)

http://redeyeondemand.com/CADTOSTL.ASPX

[razorsbhc]

I also found this.

http://www.c4dcafe.com/ipb/topic/576...manufacturing/