Milling
 

Milling in corners


​The problem

Corner radius = 50% x Dc

Taditional corner milling

Considerations

Machining into corners requires careful considerations of the suitable arc of cutter engagement, and also of the appropriate feed rate.

  • When feeding the cutter into internal corners, the radial arc of engagement will increase and place extra demands on the cutting edge.
  • Often, the process becomes unstable, creating vibration and an insecure process.
  • Wobbling cutting forces often create undercutting of the corner.
  • There is also a risk for frittering the tool edges, or total tool break down.​

 

Solution No 1

Corner radius = 75% x Dc

Mill a bigger component radius​

Solution No 2

Corner radius = 100% x Dc

Use a smaller cutter

​

Solution – limit the arc of engagement

Using a programmed radius (circular milling) to reduce the arc of engagement and a radial cut will reduce the vibration tendencies, which will allow higher depths of cut and feed rates.

  • Mill a bigger corner radius than stated in the drawing. This can sometimes be favorable, as it allows the use of a bigger cutter diameter in roughing, which maintains high productivity.
  • Alternately use a smaller Dc cutter to mill the desired corner radius.

Roughing
A programmed radius of 50% Dc is optimal.

Finishing
For finishing, it is not always possible to have such a large radius; however, the cutter diameter should be no larger than 1.5 x component radius (e.g. corner radius 10 mm = max 15 mm).​

 

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