Re: [CAD_CAM_EDM_DRO] cutting force

Thanks for sharing this information with the group. It certainly looks
interesting. I printed it and will try to take a real good look asap.

thanks again !

Chris L

cdoughtynz wrote:

> Hi All,
> The following email is a reply I received after my inquiry "How to
> calulate the force required to rout a piece of wood".
> The example is the force applied to a spindle when a 12.7 mm dia
> cutter is feed into a piece of wood 20 mm deep and 75 mm per sec.
>
> HI,
>
> Sorry for being so late in my answer.
> Here are some basics of cutting mechanics. I hope it will help you.
> In order to find the force applied on the spindle, you need to know
> the chip
> thickess (or feed per tooth): it's the most important parameter. A
> good
> approach is to consider the force (F) as a linear function of the
> chip area
> (bh) with:
>
> b=depth of cut (mm)
> h=feed per tooth (i.e. the chip thickness)
>
> In routing or slotting, b is choosen by the operator while h can be
> written
> as a function of feed speed (Vf,mm/min), rotation rate (N,RPM) and
> number of
> teeth (Z) as:
>
> h= Vf/(N.Z)
> with h in mm.
>
> Thus, this results in:
> F=k.b.h
> with k=specific force coefficient (in N/mm2).
>
> k will mostly depend on:
> - the wood specie (especially its density)
> - the tool geometry
>
> So, as for tool geometry, you have also to take in consideration:
> -the rake angle of the tool.
> -the sharpness of the edge.
> For these latest parmeters there is no mathematical model; only
> experimentation and measurements with the tool you want to use can
> yield the
> actual forces.
>
> >From my experience in MDF board machining, with a sharp 10 degrees
> rake face
> tool, I found:
> k= 16 N/mm2
>
> Applying the previous rule, for a 20 mm depth of cut, N=10.000 RPM,
> Vf=75
> mm/sec and Z=3 teeth:
>
> h=75.60/(10.000.3)=0.15 mm/tooth.
>
> THus, the force applied can be approached by:
>
> F= 16.20.0.15= 48 N
>
> The better is to pratice some basic cutting tests with the tool and
> the
> specie you will use with 4 or 5 chip thickness. Then, you will be
> able to
> predict the foce for any process conditions (N, Vf, Z and b)
>
> I hope this will help you to solve your problem
>
> Regards.
>
> Jean-philippe Costes, Dr.
> National Reaserch Council, Innovation Center
> 3250 East Mall V6T 1W5
> tel : 604-221-3000, (5576)
> fax: 604-221-3088
> Vancouver, Canada
>
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