1 Introduction
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Investigation of the repeatability of MIRS for machining multiple samples
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Investigation of the influence of machining parameters on MIRS and their repeatability
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Investigation of the influence of the clamping strategy on the MIRS
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Investigation of machining-induced distortion
2 Methods
2.1 Machining-induced residual stress experiments
Tool properties | Kennametal1 F3AA1200AWL |
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Type | Regular end mill |
Diameter | 12 mm |
Tool holder | HSK-A 63 |
Material | Cemented carbide 10% Co, 0.6% Cr, 89.4% WC max. grain size 3 μm |
Number of flutes z | 3 |
Helix angle | 45° |
Cutting edge radius | - |
Length | 76 mm |
Coating | - |
Mode | Cutting speed vc (m/min) | Feed per tooth fz (mm) | Feed rate vf (mm/min) | Material removal rate Qw (mm3/min) | Average chip thickness hm (mm) |
---|---|---|---|---|---|
Mode 1 | 200 | 0.04 | 637 | 7600 | 0.023 |
Mode 2 | 200 | 0.1 | 1592 | 19100 | 0.058 |
Mode 3 | 200 | 0.2 | 3183 | 38200 | 0.115 |
Mode 4 | 450 | 0.04 | 1432 | 17200 | 0.023 |
Mode 1 | Mode 2 | Mode 3 | Mode 4 | |
---|---|---|---|---|
Vise | M1A M1B M1C | M2A M2B M2C | M3A M3B M3C | M4A M4B M4C |
Side clamps | M1D | M2D | M2D | M4D M4E |
2.2 Temperature experiments
2.3 MIRS hole-drilling measurements
Increment in mm | Depth in mm |
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0 | - |
0.0127 | 0.0127 |
0.0127 | 0.0254 |
0.0127 | 0.0381 |
0.0127 | 0.0508 |
0.0127 | 0.0635 |
0.0127 | 0.0762 |
0.0127 | 0.0889 |
0.0127 | 0.1016 |
0.0127 | 0.1143 |
0.0127 | 0.127 |
0.0254 | 0.1524 |
0.0254 | 0.1778 |
0.0254 | 0.2032 |
0.0254 | 0.2286 |
0.0254 | 0.254 |
0.0254 | 0.2794 |
0.0508 | 0.3302 |
0.0508 | 0.381 |
0.0508 | 0.4318 |
0.0508 | 0.4826 |
0.0508 | 0.5334 |
0.0508 | 0.5842 |
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The maximum residual stress (MaxRS) with MaxRSx along x-direction, MaxRSy along y-direction, and MaxRSxy in shear direction is defined as the highest absolute value of RS, which includes compressive (negative) RS as well
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The depth of the MaxRS tm (tmx, tmy, tmxy)
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The penetration depth tp (tpx, tpy, tpxy), which is defined as the thickness of the layer containing MIRS and here detected as the depth at which the absolute value of MIRS drops below 20 MPa
2.4 Machining-induced distortion experiments and simulations
Mode 1 | Mode 2 | Mode 3 | Mode 4 | |
---|---|---|---|---|
Vise | M1A M1B | M2A M2C | M3B M3C | M4A M4B |
3 Results and discussion
3.1 Force analysis
Mode 1 | Mode 2 | Mode 3 | Mode 4 | |
---|---|---|---|---|
Spindle speed n (rot/min) | 5305 | 5305 | 5305 | 11937 |
Duration per rotation tr (s) | 0.0113 | 0.0113 | 0.0113 | 0.005 |
Cutting edge frequency fc (Hz) fc = 1/tr·3 | 265 | 265 | 265 | 597 |
3.2 Temperature analysis
3.3 Machining-induced residual stress analysis
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MIRS repeatability within one sample—leads to increased understanding of measurement process and variability of MIRS within a single sample
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MIRS repeatability of multiple samples sharing same machining condition—leads to increased understanding of MIRS consistency among different samples
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Comparison of MIRS from different machining modes—leads to increased understanding of influence of machining parameters on MIRS
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Comparison of MIRS from different clamping strategies—leads to increased understanding of influence of clamping on MIRS
3.3.1 Machining-induced residual stress repeatability within one sample
3.3.2 Machining-induced residual stress repeatability of multiple samples sharing the same machining condition
3.3.3 Comparison of machining-induced residual stresses from different machining modes and their repeatability
Mode 1 | Mode 2 | Mode 3 | Mode 4 | |
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MaxRSx ± RSTDx (MPa) | 115 ± 39 (34%) | 185 ± 39 (21%) | 135 ± 24 (18%) | 139 ± 73 (53%) |
MaxRSy ± RSTDy (MPa) | 125 ± 36 (29%) | 182 ± 32 (18%) | 141 ± 23 (16%) | 136 ± 73 (54%) |
MaxRSxy ± RSTDxy (MPa) | 33 ± 16 (49%) | 52 ± 15 (29%) | 49 ± 12 (25%) | 47 ± 14 (30%) |
tpx ± tp−RSTDx (μm) | 56 ± 22 (39%) | 74 ± 12 (16%) | 177 ± 62 (35%) | 62 ± 18 (29%) |
tpy ± tp−RSTDx (μm) | 56 ± 19 (34%) | 70 ± 11 (16%) | 180 ± 22 (12%) | 62 ± 18 (29%) |
tpxy ± tp−RSTDxy (μm) | 21 ± 11 (52%) | 49 ± 14 (29%) | 105 ± 26 (25%) | 34 ± 14 (41%) |
3.3.4 Comparison of MIRS from different clamping strategies
3.4 Wafer analysis
3.4.1 Comparison of experimental data
Mode (x-position of measured edges) | Mode 1 (x1=2.6 mm and x2=22.4 mm) | Mode 2 (x1=1 mm and x2=24 mm) | Mode 3 (x1=2.4 mm and x2=22.6 mm) | Mode 4 (x1=1 mm and x2=24 mm) | ||||
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Sample ID | M1A | M1B | M2A | M2C | M3C | M3B | M4B | M4A |
PDDmax (mm) | 0.062 | 0.045 | 0.14 | 0.116 | 0.152 | 0.116 | 0.123 | 0.047 |
FDDmax (mm) | 0.024 | 0.02 | 0.056 | 0.032 | 0.032 | 0.025 | 0.028 | 0.014 |
Ratio PDDmax | 73% | 83% | 76% | 38% | ||||
Ratio FDDmax | 83% | 57% | 78% | 50% |
3.4.2 FEM wafer distortion analysis
Mode 1 | Mode 2 | Mode 3 | Mode 4 | |||||||||||||
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Exp./Sim. Sample ID | Exp M1A | Sim M1A | Exp M1B | Sim M1B | Exp M2A | Sim M2A | Exp M2C | Sim M2C | Exp M3B | Sim M3B | Exp M3C | Sim M3C | Exp M4A | Sim M4A | Exp M4B | Sim M4B |
x-coord. of edges (mm) | 1, 24 | 1, 24 | 2.6, 22.4 | 2.6, 22.4 | 1, 24 | 1, 24 | 1, 24 | 1, 24 | 2.4, 22.6 | 2.4, 22.6 | 1, 24 | 1, 24 | 1, 24 | 1, 24 | 1, 24 | 1, 24 |
PDDmax (mm) | 0.085 | 0.064 | 0.045 | 0.034 | 0.142 | 0.129 | 0.116 | 0.088 | 0.114 | 0.104 | 0.196 | 0.161 | 0.047 | 0.036 | 0.123 | 0.082 |
FDDmax (mm) | 0.034 | 0.022 | 0.020 | 0 | 0.056 | 0.025 | 0.031 | 0.026 | 0.026 | 0.008 | 0.042 | 0.018 | 0.014 | 0.004 | 0.028 | 0.027 |
Ratio PDDmax | 75% | 76% | 91% | 76% | 91% | 82% | 77% | 67% | ||||||||
Ratio FDDmax | 65% | - | 45% | 83% | 31% | 43% | 29% | 96% |