Thursday, 3 July 2014

Cutting speeds and feeds criteria

Guide speeds to allow calculation in 6063 T6 Aluminum alloy.

MRR value: 100cc/minute

Cutter size: 10mm
Cutter material: Carbide
TiCN coating
3 flutes.

Feed per tooth or chipload:
0.003" (0.0762mm)
(http://www.cobracarbide.com/catalog/technical_information_endmills.html

Using 3/8" cutter as reference as its closest to 10mm


Cutter speed = surface speed/cutter circumference
                      =
609000/(pi*10)= 19385 rpm (5sf)

Feed rate=
(19385*0.0762)*3= 4431 mm/minute. (3sf)

Thus cut depth = mrr/cutter diameter/feed rate
= 100 000/10/4431= 2.26mm (3.D.P)

Guide speeds to allow calculation in MDF

The settings in the last post for MDF were incorrect as they were for a single flute cutter

http://www.trend-uk.com/en/UK/productlist/2/36/spiral_cutters.html

according this this manufacture their spiral end mills designed for wood are suitable for speeds up to 24,000 rpm.

There is no information in regards to feed per tooth. However, MDF requires a high feed per tooth as it easily turns to dust rather than cut chips. Thus a large cut is required to prevent this from happening. The dust is very abrasive and reduces tool life. A 0.2mm chip load per revolution per tooth should be suitable. Due to this high chip load the number of flutes need to be reduced to allow time for chips to clear as not to load up the cutter so a 2 flute cutter will be used in this example.

RPM
Feed rate = (24,000*0.2)*2 = 9600 mm/minute.

Cup depth=mrr/cutter diameter/feed rate = 300000/10/9600 = 3.125mm

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