What's a realistic speed expectation?

[shilala]

I have a Buddy 48PRStandard with PC router. My control computer is black vipered out to barebones and is getting a comm rate of 75-76 on the usb hub. I have nothing else on the laptop, not even a mouse. And I mean nothing.

I usually just cut wood. Projects are generally of hardwoods.
I cut quite a bit of 3d stuff modeled in Aspire, I make lots of sawdust.
Up until now I've been running very slow with, for instance, 3 inch/sec, .25 pass depth on a .25 ball nose at 10,000 or 13,000rpm (I adjust according to how it sounds), 10-15% stepover being something I consider flying. That's very agressive for me and it seems brutally slow, making project cut times very long. I've not gone past that threshold except on some earlier trials that ended up in major comm errors that I've since corrected.

I'm finally ready to move on to making furniture, the reason why I added the Bot to my shop. I'll be starting a lingerie dresser soon, a Christmas present for my beautiful wife. I'd like to get it done by Christmas, and at the rate I run my machine, well, you get it. ;)

Can you guys give me some instances of your material, cut speeds, etc. so I can form a baseline as I move ahead and test my machine's limits? I don't want to just go at this wildly crashing, burning and breaking bits, now that that stuff is thankfully behind me.
Your input would be a huge help and greatly appreciated. :)
Thank You!!!

[dlcw]

One of the things I listen for is a screaming bit. That means you are running the feedrate to slow or the bot to fast. A screaming bit is a hungry bit. It needs more material to munch on.

For most hardwood (oak, walnut, cherry, bubinga) projects I run the spindle at 10K RPM at around 3.5 - 4.0 ips. If the bit is a little noisy I will bump the feed rate up a little at a time (no more then .5 - 1.0 ips). If you start bumping up more then this, you will be messing with the ramping speeds that the software has calculated for your project and you could run into problems there. Most hardwood projects I use a 2-flute 1/4" downcut spiral, for cutting, with excellent results. When I built a set of bar stools for a customer out of hickory, I had to use a 2-flute 3/8" downcut spiral because I was having to cut a lot deeper then the 1/4" would allow. Besides the 3/8" has less flex producing more accurate cuts.

[chiloquinruss]

With all of the feed rates set exactly the same:

3d is SLOW
2d is FAST

Russ

[Brady Watson]

I cut quite a bit of 3d stuff modeled in Aspire...

3D machining has a whole different set of speed parameters, since the Z axis is the limiting factor.

Have a look at the write up (http://www.shopbotblog.com/index.php/2008/03/a-ramping-the-vr-command-and-how-to-tune-your-tool-for-maximum-performance/) I did a few years ago. It will help you to get in the range you want & you can fine tune from there.

-B