Offset rotary path

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bobgob
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Offset rotary path

Post by bobgob »

I'm new to using the rotary axis and having trouble figuring out how to design a part. It starts with a 2x2 20" long (1.5" x 1.5" x 20"). I don't want to round the whole thing. I just want to round the last inch to a 1" diameter. But that 1" needs to be off center. See attached view looking down the rotary axis. I've watched the vectric tutorials but I'm still not getting it. Can someone point me in the right direction? I imagine this is simple but need a pointer.

To complete the part I need to lower the top 0.25". That leaves the rounded end 0.25" above the middle of the length (18") of board. Do I have to do this as another job? That is, leave it on the rotary axis but create another job (non rotary) so I can move the gantry in the y axis instead of the rotary axis? Or is there a way to control a 4th axis instead of having the rotary emulate my Y axis.

Or would I be better off designing this in another program (other software, tinkercad, ...) and exporting the STL file?

Any pointers would be greatly appreciated.
Attachments
1inch_offcenter.jpg

bobgob
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Re: Offset rotary path

Post by bobgob »

Here is a picture. I drew this in tinkercad and can export it from there and into Aspire to make the part. But I'm trying to learn Aspire better and wondering if I can do the whole thing in Aspire.
OffsetPart.jpg

chrisC
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Re: Offset rotary path

Post by chrisC »

I haven't had much luck with rotary toolpaths in Aspire with anything that does not start out as "round". I'm not sure I would even call Aspire's rotary axis machining "rotary". It is a wrapped toolpath - a toolpath wrapped around what is assumed to be a blank that is a cylinder.

Aspire doesn't support 3+1 machining (XYZ + A). For that, you are better off with looking at something like other software - but the learning curve is steep.

Something that might be easier to do in Aspire with this particular model is 2-sided machining rather than rotary.

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TReischl
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Re: Offset rotary path

Post by TReischl »

It will cut just fine as modeled. As to modeling it in Aspire? If you already have something that produces 3D models what is the point?
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eph210
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Re: Offset rotary path

Post by eph210 »

One of the ways it can be done in Aspire is as follows:
Start a rotary job with the dimensions of your material (2" diameter by 20").
Create a circle of the diameter of your material (2") and centre it in the workspace by using F9.
Create a circle with the diameter of your desired section (1") and place it totally inside the previous circle with the desired offset.
Select the inner circle and use the unwrap vector tool to create a profile.
There will be two drive rails created at the edge of the workspace, shorten these to your desired length (1").
Use a two rail sweep with the new drive rails and the profile vector.

The bigger circle is just to indicate the working area of the rotary job and any shape has to fit inside that circle to unwrap properly.

Euan

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JoeBlow
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Re: Offset rotary path

Post by JoeBlow »

This can be modeled in Aspire. Use the vector unwrapper tool, offset your 1" circle then apply. Create shorter drive rails as Eph210 suggests and run a 2 rail sweep. Since you wanted the dowel ends to be .25" higher than the square, I also unwrapped a square and applied to the 18" portion of material not rounded. I have yet to create a true square with the unwrapper tool but feel it can be done with some tweaking.

Personally, I would start with square stock in the rotary and round the 2 ends as desired. Then while the piece is still on the rotary, switch to a 2D pocket toolpath to reduce one side as needed to achieve your offset. This would take some fidgeting as well but I think would be quicker, easier and more precise. Purely conjecture but that is where I would start.
Screenshot (2).png
Screenshot (4).png
Here's the rotary file if interested....
Offset Rotary Test.crv3d
(1.34 MiB) Downloaded 20 times
Beautiful Things Function Better

bobgob
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Re: Offset rotary path

Post by bobgob »

TReischl wrote:
Thu Sep 10, 2020 12:47 pm
It will cut just fine as modeled. As to modeling it in Aspire? If you already have something that produces 3D models what is the point?
There are two points (reason for my post). One is simply to learn Aspire better. The other is that I was hoping, if there is a way in Aspire, to create a more efficient toolpath. If you look at the part it is simply an offset cylinder on the ends with a milled down center. If I could cut those two paths it would be a lot more efficient than milling the entire part (which is what happens when I import the stl). But mostly about learning.

bobgob
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Re: Offset rotary path

Post by bobgob »

JoeBlow wrote:
Fri Sep 11, 2020 10:33 am
This can be modeled in Aspire. Use the vector unwrapper tool, offset your 1" circle then apply. Create shorter drive rails as Eph210 suggests ...
This is excellent! Thank you JoeBlow and Eph210! :D :D

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rscrawford
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Re: Offset rotary path

Post by rscrawford »

Just offset the centres by half an inch towards one side of the 2x2 (when placing the wood piece between the centres in your 4th axis). No need to make this a complex problem by trying to model it offset.
Russell Crawford
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SteveNelson46
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Re: Offset rotary path

Post by SteveNelson46 »

rscrawford wrote:
Tue Sep 15, 2020 2:31 am
Just offset the centres by half an inch towards one side of the 2x2 (when placing the wood piece between the centres in your 4th axis). No need to make this a complex problem by trying to model it offset.
I think that would probably work if the rounded ends were completely contained within the blank. I think the op wants one side of the rounded end to be above or proud of the flat surface. The only way I can see to do it is to use the unwrapper for the flat edges.
Steve

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