Finial rotary Optimization

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meadowridge
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Finial rotary Optimization

Post by meadowridge »

I have been asked to make 30 copies of an old finial that a guy is doing for a restoration project. I have what I think is a good copy of the finial coded in Aspire which I have attached.
Total length: 5 and ¼ inches long
widest diameter: 2 and ½ inches.
My problem is in looking at the time estimates. I am coming in at almost 2 hours machine time per finial starting with square stock. I have tried different bit configurations etc but not seeing a significant improvement in the time estimate. Am I missing an optimization available in Aspire that could improve these times? Seems like a small piece like this should be able to be carved much faster.

Also I am thinking maybe even though this is a fairly stout piece and I am planning to do the rounding using a different holding method on my spindle and then switch to a four jaw chuck for the rest of the steps, I should at least support the end using a tailstock center through the roughing pass. Should I set a vector boundary for finishing to the wide part of the tip and then wait to remove my tailstock then?

Thanks in advance for any help you can provide.
Attachments
Finial image.jpg
finial 3.crv3d
(1.24 MiB) Downloaded 72 times

garylmast
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Re: Finial rotary Optimization

Post by garylmast »

A few ideas to speed things up is change you rounding toolpath. From 1/8 to ¼-inch which speeds things up by 15-minutes Change your roughing toolpath to 50% stepover and feed rate to at least 100 inches/min. , which speed things up another 15-minutes. And I didn’t see a lot a difference using the last three smaller finish toolpath which can eliminate another 15-minutes. Those 3 ideas knocks off 45-minutes.

Gary

meadowridge
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Re: Finial rotary Optimization

Post by meadowridge »

Thanks, That certainly helps. I haven't used the rounding toolpath gadget before so I missed what it was doing. I was thinking the 3 extra finish passes would give a sharper inner corner since it they are programed with a 1/16 inch ballnose rather than the 1/4 inch ball the rest of the profile is programmed. I believe this should work sort of like rest machining. I will run the your suggestions and then compare the two to see if I can get by with the less clear sharp inner corners.

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SteveNelson46
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Re: Finial rotary Optimization

Post by SteveNelson46 »

Unless I misunderstood something I don't really think you need to use a ballnose for the roundover. A bit that cuts a flat surface is better. I cut a square blank 1/8" larger than final diameter and knock the corners off with the table saw. Then create a separate file that is 1/8" larger in diameter and use the spiral wrapping gadget with a 1.25" spoilboard surfacing bit, .5" stepover and a DOC of .0625". Cut time is about 3 minutes depending on feed rate. As with any rounding toolpath, setting z-zero is critical to get an exact diameter.
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Spiral Rounding 2.5 Dia.crv3d
(670.5 KiB) Downloaded 66 times
Spiral Gadget Setup.png
Steve

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SteveNelson46
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Re: Finial rotary Optimization

Post by SteveNelson46 »

Also, you might save a little time and get a better finish using the Moulding toolpath.
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Finial Moulding TP.crv3d
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Steve

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SteveNelson46
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Re: Finial rotary Optimization

Post by SteveNelson46 »

To save a little more time you could use a 1/8" TBN with an 8% stepover instead of a 1/16" TBN. Just looking at the preview there isn't much, if any, difference in quality.
Steve

meadowridge
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Joined: Tue Jun 10, 2014 3:43 pm
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Re: Finial rotary Optimization

Post by meadowridge »

Thanks SteveNelson46 as it turned out shortly after my last reply, The guy that asked me to look at this for him, told me the customer he was working for decided to go another direction. It was an interesting learning exercise but I lost my urgency to work on this. I have a blank ready to go but since I am also a beekeeper and there is a lot to do right now out in my apiary. I plan to play with this a bit later. I was thinking that a molding toolpath might be helpful as well. Thanks for the help though, I appreciate it.

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Re: Finial rotary Optimization

Post by Greolt »

A highly skilled wood turner would produce these fairly quickly with consistent dimensions.

However a highly skilled wood turner I am NOT.

My setup has the same spindle thread on my rotary axis as my wood lathe for the following reason.

The finial blank can be mounted in a chuck and the consistent shape can be produced on the CNC with the rotary axis.

With the time saving advantage of not needing a fine finish. Larger dia ball nose and greater stepover etc.

Then the job can be transferred to the lathe still attached to the chuck.

Then sanded at the higher speed available on the lathe to achieve the desired finish quality.

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