Machsupport Forum
Tangent Corner => Tangent Corner => Topic started by: lemo on May 22, 2007, 07:22:56 PM
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I am routing my first relief on my TAIG. Yessssssssssss!
I use a 3/32nd carbide ball end mill with a 1/4 tool diameter step over in MDF.
Works like a charm with 4IPM at up to a maximum 0.25 Inch cutting depth.
It seems... that I can go much faster. I started with 2IPM and now I tweaked it up to 4IPM.
Sounds good, no heat, simply carving away happily.
What would be the professional recommendations?
Is there a general table/rule of thumb/formula which can yield a recommended maximum speed for cutters and materials?
Or is this where the experience and the broken cutters start?
I plan to use aluminium at one stage.... but hesitate right now as I have no experience there.
One IPM might be to fast already... No idea.... so I stay away for now.
Thanks in advance for some insights
Lemo
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Here are some formulas :-
D = Diameter of cutter
T = Number of teeth
RPM = Revs per min
F = Feed
FT = Feed per tooth
S = Peripheral speed of cutter
PI = 3.1416
Cutter speed
S (ft/min) = D*PI*RPM
________ = 0.2618D*RPM
12
S (m/min) = D*PI*RPM
________
1000
Cutter revolutions
RPM = S (ft/min)
________
0.2618D
RPM = S (m/min)*1000
______________
PI*D
Feed per tooth
The suggested feeds are based on 1*dia for axial depth and 0.5 * dia for radial depth of cut.
Cutter dia Feed per tooth
inch mm inch mm
5/64 2.0 .0003 .0075
1/8 3.0 .0005 .013
1/4 6.0 .0010 .025
1/2 12.0 .0015 .037
1 25.0 .002 .050
FT = F
______
T*RPM
To increase axial depth to :-
1-1/2 *D reduce feed by approx 30%
2 * D reduce feed by approx 50%
To reduce radial depth to :-
1/4 * D increase feed by 200%
1/8 * D increase feed by 250%
Cutter feed
F = FT*T*RPM
Graham.
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Excellent! Thanks you so much Graham.
I did a search on cutting MDF and ran into the chipload formulas.
Good stuff. Now I also understand why high rpm and slow feed are not good as they produce to much heat.
I set my spindle RPM down, ran a bit faster, and voila, it actually started chipping away and stopped pulverizing.
However, I would not have done that without the formulas and insight as the speed is rather scary now.
That little TAIG mill is flying through that stuff. I bought one of those contact free thermometers which look like a gun a couple of years ago and never really used that. Now I took it and measured the temp of the bit's shank during operation. Just for fun... I am not such a stickler usually. And.... it does show. Funny, I tended to do the wrong thing, as in high rpm low feed, as I thought it would make it easier on the cutter. Wrong. Now it's flying, cool, without squeaking which it did a bit before.
Just Great!
Thanks again!
Lemo
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Lemo, check this out, it might help as well. Although if they don't agree with Grahams, take Grahams word. He is a Gcode Guru. ;D
http://www.wadeproco.com/
Brett