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Adding a smooth round after a draft

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Adding a smooth round after a draft

I need to add a round to the upper edge of the quilt, however the round becomes discontinuous at the split line of the draft. I dont understand how i can get around this,l and make the round smoother.

 

Any help is much appreciated

 

(Round is emphasized in image)

5 REPLIES 5

Re: Adding a smooth round after a draft

You need to define your parting line to be offset from the rounded edge rather than using the round tangent to determine it.  On the left side of your image, the parting line was the edge that existed before the round.  Once rounded, the parting line now has to be at the tangent of the round.  Redefine your draft so that it is offset from the edge and the round then will be entirely on one side of the mold.

 

I've sketched over your image a crude approximation of what I mean.

 

Capture.JPG

 
 
--
Doug Schaefer | Experienced Mechanical Design Engineer
LinkedIn

Re: Adding a smooth round after a draft

Thank you for the reply, however, the draft is a set height, I am unable to change that. I am also unable to change the position of the nose such that the edge of the quilt that needs rounding doesn't coincide with the split plane. 

 

in short, i need a way around this without changing the overall geometry? 

Re: Adding a smooth round after a draft

This is the shape prior to the round

Re: Adding a smooth round after a draft

Adding the round is changing the draft split.  When sharp, the split is at the sharp edge:

 

Capture.JPG

 

Adding the round moves the split down slightly, to the tangent of the radius (a bit hard to illustrate):

 

Capture2.JPG

 

Allowing the radius to define the split might also create an uneven parting line.

 

I'm not suggesting that the height of the straight parting line be changed, only that you define the parting line around the front away from the edge that you want top round:

 

Capture.JPG

 

This will give you a nice, smooth edge to round and will provide your tool maker a nice cleanly defined parting line to build the tool to.

 
--
Doug Schaefer | Experienced Mechanical Design Engineer
LinkedIn
Highlighted

Re: Adding a smooth round after a draft

Here's a quick Creo 2 model illustrating what I mean.  One end is built with a planar draft as you have it, the other with a curve based draft that defines the split away from the rounded edge.  I used a generous draft angle of 5 degrees to exaggerate the effect.

 
 
--
Doug Schaefer | Experienced Mechanical Design Engineer
LinkedIn
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