Rotary Machining Rounding Toolpath

Topics related to wrapped rotary machining in Aspire or VCarve Pro
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BenjaminwithCNC
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Rotary Machining Rounding Toolpath

Post by BenjaminwithCNC »

Good afternoon everyone!

I use the Rounding Toolpath to round my Square Stock. Nothing complicated. Normal Rounding Toolpath (the radial one). As the rounding takes a lot of time, i tried using a bigger bit. Ended up using a 32mm Straight Flutes End mill. The Stock is 74 mm diameter thick.

I've attached a picture of the End mill and a Picture of the anomaly.

Going 58% Stepover or any Numer was leaving these stripes on the Stock (picture attached).

I tested this with 99% Stepover and the result is better, the lines are farther apart. The Lines are still there though.

I ask, what is the cause of these lines. As the Stepover is 99% meaning that it cuts 1% of the bit diameter 2 times, meaning there should not be any line at all. But there are.

I'm new to woodworking physics, so maybe there is something i don't see.

Ah and for the machine, there is nothing loose, the machines is perfectly tight. Planing the table, or other woodwork is working very precise. Only this Rotary axis is troubling me.

Benjamin
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WeChat Image_20210812144758.jpg
Picture Better99 % Stepover.jpg

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SteveNelson46
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Re: Rotary Machining Rounding Toolpath

Post by SteveNelson46 »

Check to see if the head stock and the tail stock are perfectly aligned. Especially the vertical alignment. Also, keep in mind that the further away the tailstock is from the headstock any misalignment is magnified. Using a smaller tool will help some.

EDIT: Although I have never tried it, you could mount a laser pointer, maybe a cat toy, in the headstock to check the alignment.
Steve

Charlie_l
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Re: Rotary Machining Rounding Toolpath

Post by Charlie_l »

Check the tramming of you spindle/router. If it is a little crooked on the mount the large diameter bit face will not be squared to the wood.
Charlie
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adze_cnc
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Re: Rotary Machining Rounding Toolpath

Post by adze_cnc »

While tramming, etc. might be the solution another thought is: with a 58% or a 99% step-over any imperfections in the router bit itself will produce such anomalies.

If you put a straight edge on the tips of the two vertical cutting edges are the horizontal edges 100% flat? Is one of the two tips of the vertical cutting edges further forward than the other when it makes contact with the material?

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BenjaminwithCNC
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Re: Rotary Machining Rounding Toolpath

Post by BenjaminwithCNC »

@ SteveNelson46: Thank you for the hint. Head and Tailstock are alined perfectly though. The Laserpointer idea is great.

@Charlie_I: Like i said, it's not from the Spindle. Perfectly alined also.

@ adze_cnc: You were right!!! It is the Router Bit. It seems to curve itself to the outside. so it is 1mm smaller on the inside than on the outside. I believe thought that this is not some iregularity, but has to do with the bit geometry.

So now, can you suggest me any Router Bits/ Types for planing those Round Stocks fast?

Thank you already very much

Benjamin

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IslaWW
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Re: Rotary Machining Rounding Toolpath

Post by IslaWW »

"So now, can you suggest me any Router Bits/ Types for planing those Round Stocks fast?"

Of coarse, speed is relative to what you are used to:
Gary Campbell
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BenjaminwithCNC
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Re: Rotary Machining Rounding Toolpath

Post by BenjaminwithCNC »

Seeing your video, shows that the Radial Strategy has the same finish as mine. So it's not just me. For someone not having a Lathe but a Router with an indexer i guess best strategy is Spiral Cut with a Bit as big as possible.

Thank you for your time and help.

GBU Benjamin

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SteveNelson46
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Re: Rotary Machining Rounding Toolpath

Post by SteveNelson46 »

Gary Campbell on YouTube shows some different techniques.

Steve

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