Need Help!- Feed Rate and Spindle Speed chart?

[jeffmorris]

How do I find out the best feed rate and spindle speeds for different router bits and materials? I know that too slow feed rate and too fast spindle speed cause "burning" of bit and material but what happens if the feed rate is too fast and the spindle speed is too slow? I checked the feed rate/spindle speed chart at http://www.amanatool.com/2008catalog..._feed_info.pdf but the slowest feed rate is 80 IPM and my CNC router's fastest feed rate is 20 IPM. My DeWalt trim router has spindle speed of 30,000 RPM and I thought that causes "burning" of bit and material. I ordered a router speed controller.

[ger21]

Originally Posted by jeffmorris but what happens if the feed rate is too fast and the spindle speed is too slow?

You'll either stall the spindle or snap the bit. At 20 ipm, you don't have a lot of options. Your best bet is to use single flute tools, which gives the same effect as doubling the feedrate.

[joejared]

Originally Posted by jeffmorris How do I find out the best feed rate and spindle speeds for different router bits and materials? I know that too slow feed rate and too fast spindle speed cause "burning" of bit and material but what happens if the feed rate is too fast and the spindle speed is too slow? I checked the feed rate/spindle speed chart at http://www.amanatool.com/2008catalog..._feed_info.pdf but the slowest feed rate is 80 IPM and my CNC router's fastest feed rate is 20 IPM. My DeWalt trim router has spindle speed of 30,000 RPM and I thought that causes "burning" of bit and material. I ordered a router speed controller.

typically, I set a dinc (depth increment) value, per http://www.oretek.com/micromill/user.shtml of around 0.025 to 0.035 at a feed rate of about 40 IPM and acheive reasonable success with aluminum. It sounds like you're working on wood. I agree with the previous poster on this thread. You need a really sharp single flute router tool. For wood, I barely run the router to about 4000 RPM and hog out 0.1 to 0.25" at a time. I could likely hog out 0.5" with my current setup, but each system is unique in terms of load capacity.

[solodex2151]

Originally Posted by ger21 You'll either stall the spindle or snap the bit. At 20 ipm, you don't have a lot of options. Your best bet is to use single flute tools, which gives the same effect as doubling the feedrate.

I agree with Ger on the single flute if your machine has that slow of a feedrate. However, depending on the material you are cutting 20 ipm might be enough. See my posts here for more information on how to calculate feedrate and spindle RPM.

On another note, I am not sure you are going to get the burning you are talking about. The bigger issue with running too slow a feedrate/too fast a spindle speed is that the cutter will wear out faster. Also, a secondary issue is more fine dust generated when cutting wood.

For metals, check the machinery's handbook. Also, as Ger pointed out, some manufacturer's design bits with different feed specifications. Check out Onsrud for bits.