need help fast 1/8 ball nose bits

[genek]

what is the best setting for the 1/8 ball nose bit for blue foam... i was getting a real good smooth cut but it took to long. now the time is good but the 3/d model is fuzzy. need help fast

[steve_g]

Gene

I can only get good cuts in foam when cutting in the conventional direction... see if your files are perhaps cutting in climb mode...

SG

[genek]

shows conventional... was cutting great but slow till tj got me to change some things... now it is real fuzzy...
like the pass dept, stepover feed rate plunge rate and to inches/sec
now i am in a bind... have to have sample ready by 9 a.m.

[genek]

i do have spindle..

[Rick W]

Eugene,

I have had good results in blue foam with

1/8" ballnose
9% stepover
12000 rpm
1.7in/sec feed
.5 in/sec plunge

Little to no sanding, but takes a while. I'm sure you could go a lot faster as long as you keep the step over the same. I just like the machine to run smooth,
no jerking etc. I have a 48" buddy with a router.

Hope this helps

Rik

[genek]

do not under stand what you step over is

[Rick W]

How far the bit steps over before doing the next pass.

Rik

[genek]

the number you have there

[Rick W]

Like this in your tool setting.

Rik

[genek]

what is your pass depth..

[Rick W]

I did a roughing toolpath first with a 1/2" bit 1/4" depth.

Rik

[Brady Watson]

In soft material, like insulation foam, you need to crank the RPM up and pull your move speed down to really lighten up your chipload. Soft materials like foam will pull out and 'snap back' when the chipload is too high as a result of your move speed being too high, or your RPM being too low.

You can also use a 4-flute ball end mill for finishing, which will also effectively reduce your chipload. You can cut insulation foam at 12 IPS and 8,000 RPM without breaking the bit - but the cut quality will be horrible.

Can't help you on the 'I want quality but I don't want to wait for it'. It is what it is.

-B