The simple formula for rotary feedrate is 115 * (XY Feedrate) / Wrap diameter. Actually 114.5916, but close enough.
So for Mike's example 115 * 200 / 4 = 5750 degrees per minute (in round numbers) A large number, but is only around 15 rpm, which is not fast at all for rotary work.
In WinCNC and ShopBot control software this formula has been added to the rotary post processors so that the user selected XY feed will be automatically applied to the rotary axis. I am fairly sure that it could be added to most other controls that allow math in the code.
That said, most of the successful high quality guitar neck cutting that I have witnessed was done in robust jigs, not on the rotary axis. The length and density of the part often requires additional support beyond what most rotary axes provide. Especially of you are looking for mass produced high quality components.
Something to consider...
The rotary axis moves negative because it performs like moving table. Moving the material negative while the bit remains fixed. To achieve proper wrapped axis positive action, the rotary must move negative
The chuck thread direction, which in many cases ae not required, are coincidental
Users browsing this forum: No registered users and 2 guests