Surface Finish
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The Journeyman’s Guide to CNC Machines Guidelines 169 5 10 20 40 80 160 200 300 400 500 1 10 100 1000 10000 1 10 100 1000 Diameter (D) mm RPM 0.05 0.1 0.2 0.4 0.8 1.6 3.2 6.4 12.8 25.6 1 10 100 1000 10000 1 10 100 1000 10000 RPM Feed Rate mm/min 16.5 Surface Finish It is impossible to achieve a close tolerance unless the finish produced is suitably fine. The economical range of surface finishes for turning and milling is 64-250 CLA (1.6-6.3μm); the extended range is 24-500 CLA (0.6- 12.6μm). Many factors affect the ability to produce a specific surface finish, feed, state of the cutter, lubrication and the physical properties of the material; accordingly, consider the values as a practical starting point. Insert Radius Surface Finish Tolerance Below 0.4 0.8 1.2 1.6 2.4 3.2 Ra μ m CLA mm Feed in mm / rev 0.6 24 ± 0.025 0.07 0.10 0.12 0.14 0.17 - 0.8 32 ± 0.050 0.08 0.12 0.14 0.17 0.20 0.23 1.6 64 ± 0.100 0.11 0.15 0.19 0.22 0.26 0.30 3.2 128 ± 0.150 0.17 0.24 0.29 0.34 0.42 0.50 6.3 250 ± 0.250 0.22 0.30 0.37 0.43 0.53 0.63 8.0 320 0.27 0.38 0.47 0.54 0.66 0.78 32 1280 1.08 1.32 1.56 Insert Radius Code Feed mm / rev 0.4 0.8 1.2 1.6 2.4 3.2 F1 0.25 - 3.7 2.7 2.0 1.4 0.9 F2 0.20 4.75 2.40 1.6 1.4 0.8 - F3 0.15 3.10 1.50 1.1 0.8 - - F4 0.10 1.30 0.60 0.4 - - - Surface Finish Ra μm In addition to feeds, use the values for the depth of cut for each pass for profile milling using ball end cutters. Cutter Diameter Surface Finish Tolerance Below 10 12 16 20 25 32 Ra μm CLA mm Feed in mm / rev 0.6 24 ± 0.025 0.25 0.28 0.32 0.36 0.40 0.45 0.8 32 ± 0.050 0.30 0.33 0.38 0.43 0.48 0.54 1.6 64 ± 0.100 0.40 0.44 0.51 0.57 0.63 0.71 3.2 128 ± 0.150 0.63 0.69 0.80 0.89 1.00 1.13 6.3 256 ± 0.250 0.80 0.88 1.01 1.13 1.26 1.43 8.0 320 1.00 1.10 1.26 1.32 1.41 1.79 32.0 1280 2.00 2.20 2.54 2.94 3.33 3.59 16.6 Feed and Speed Conversion Charts 16 16 16 16-3 Feedrate Conversion Chart Feedrate Conversion Chart Feedrate Conversion Chart Feedrate Conversion Chart 16 16 16 16-4 Speed Conversion Chart Speed Conversion Chart Speed Conversion Chart Speed Conversion Chart M/min rpm = Speed / Circumference = (M/Min) / (πD/1000) M/min = Revs × Circumference = RPM × (πD/1000) mm/rev mm/min = mm/rev×rpm mm/rev = mm/min÷rpm
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Surface finish escription
Transcript of Surface Finish
The Journeyman’s Guide to CNC Machines
Guidelines 169
5
10
20
40
80160200300400500
1
10
100
1000
10000
1 10 100 1000
Diameter (D) mm
RP
M
0.05
0.1
0.2
0.4
0.8
1.63.26.412.825.6
1
10
100
1000
10000
1 10 100 1000 10000
RPM
Fee
d R
ate
mm
/min
16.5 Surface Finish
It is impossible to achieve a close tolerance unless the finish produced is suitably fine. The economical range of
surface finishes for turning and milling is 64-250 CLA (1.6-6.3µm); the extended range is 24-500 CLA (0.6-
12.6µm). Many factors affect the ability to produce a specific surface finish, feed, state of the cutter, lubrication
and the physical properties of the material; accordingly, consider the values as a practical starting point.
Insert Radius Surface Finish
Tolerance Below 0.4 0.8 1.2 1.6 2.4 3.2
Ra µm CLA mm Feed in mm / rev
0.6 24 ± 0.025 0.07 0.10 0.12 0.14 0.17 -
0.8 32 ± 0.050 0.08 0.12 0.14 0.17 0.20 0.23
1.6 64 ± 0.100 0.11 0.15 0.19 0.22 0.26 0.30
3.2 128 ± 0.150 0.17 0.24 0.29 0.34 0.42 0.50
6.3 250 ± 0.250 0.22 0.30 0.37 0.43 0.53 0.63
8.0 320 0.27 0.38 0.47 0.54 0.66 0.78
32 1280 1.08 1.32 1.56
Insert Radius Code Feed mm / rev
0.4 0.8 1.2 1.6 2.4 3.2
F1 0.25 - 3.7 2.7 2.0 1.4 0.9
F2 0.20 4.75 2.40 1.6 1.4 0.8 -
F3 0.15 3.10 1.50 1.1 0.8 - -
F4 0.10 1.30 0.60 0.4 - - -
Surface Finish Ra µm
In addition to feeds, use the values for the depth of cut for each pass for profile milling using ball end cutters.
Cutter Diameter Surface Finish
Tolerance
Below 10 12 16 20 25 32
Ra µm CLA mm Feed in mm / rev
0.6 24 ± 0.025 0.25 0.28 0.32 0.36 0.40 0.45
0.8 32 ± 0.050 0.30 0.33 0.38 0.43 0.48 0.54
1.6 64 ± 0.100 0.40 0.44 0.51 0.57 0.63 0.71
3.2 128 ± 0.150 0.63 0.69 0.80 0.89 1.00 1.13
6.3 256 ± 0.250 0.80 0.88 1.01 1.13 1.26 1.43
8.0 320 1.00 1.10 1.26 1.32 1.41 1.79
32.0 1280 2.00 2.20 2.54 2.94 3.33 3.59
16.6 Feed and Speed Conversion Charts
16161616----3333 Feedrate Conversion ChartFeedrate Conversion ChartFeedrate Conversion ChartFeedrate Conversion Chart 16161616----4444 Speed Conversion ChartSpeed Conversion ChartSpeed Conversion ChartSpeed Conversion Chart
M/min
rpm = Speed / Circumference
= (M/Min) / (πD/1000) M/min = Revs × Circumference
= RPM × (πD/1000)
mm/rev
mm/min = mm/rev×rpm
mm/rev = mm/min÷rpm
