Endmill Geometry

Feb 05, 2009 3 Replies

Hi all



For endmills such as



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XR 07.pdf



(177 series) which are 4 flute and centre cutting (as I understand it) why is there no capability of simple Z plunge 'drilling'? Or ramping at greater than 7 degrees?



And if I'm to circular interpolate at 7 degree ramp is it only necessary to consider the circumference-path traced out by the tool centre and the Z depth per revolution ..... or is it more complicated than that ? :)



Thanks Rob


It will clog at the gashes because during a straight z axis plunge you are generating a ribbon-shaped chip and routing it almost directly upwards into a sharp-cornered dead-ended gullet area.

Better is to use a 2 flute and radius the gash as shown here:

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Where possible, blending a raduised gash into an exagerated secondary axial end clearance provides the best roll-out action on straight plunge.

Ideally where ramping a helical path I like the hole to be larger than the tool by at least 1x the tool radius but YMMV

OK thanks.

If I'm using a 10mm endmill to ci a 22mm hole (giving a 38mm circumference traced out by the tool centre)

Then will the max Z increment per revolution be 38 x sin7 = 4.6mm ??

4.6mm is much more than the local rep recommended!

Material: mild steel

Rob.

"Bipolar Bear" wrote:

You should always use the inner circumference, or the circumference of any pre-drilled hole when calculating the feed. Remember, drilling is by far the fastest way to remove the center of a hole.

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