# Large Cutting Depth and Layered Milling of Titanium Alloy Thin-Walled Parts

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## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

#### 2.1. Experimental Workpiece

#### 2.2. Experimental Conditions

#### 2.3. Experimental Design

#### 2.3.1. Rough Machining

#### 2.3.2. Semi-Finishing Machining and Finishing Machining

- ${V}_{c}=75m/\mathrm{min},{f}_{z}=0.0375mm/z,{a}_{p}=20mm,{a}_{e}=0.01mm$
- ${V}_{c}=75m/\mathrm{min},{f}_{z}=0.0375mm/z,{a}_{p}=40mm,{a}_{e}=0.01mm$
- ${V}_{c}=75m/\mathrm{min},{f}_{z}=0.0375mm/z,{a}_{p}=60mm,{a}_{e}=0.01mm$
- ${V}_{c}=75m/\mathrm{min},{f}_{z}=0.0375mm/z,{a}_{p}=75mm,{a}_{e}=0.01mm$

_{c}= 75 m/min, f

_{z}= 0.0375 mm/z, a

_{p}= 20 mm, a

_{e}= 0.01 mm; (b) v

_{c}= 75 m/min, f

_{z}= 0.0375 mm/z, a

_{p}= 40 mm, a

_{e}= 0.01 mm; (c) v

_{c}= 75 m/min, f

_{z}= 0.0375 mm/z, a

_{p}= 60 mm, a

_{e}= 0.01 mm; (d) v

_{c}= 75 m/min, f

_{z}= 0.0375 mm/z, a

_{p}= 75 mm, a

_{e}= 0.01 mm. The cutting depths (20, 40, 60, and 75 mm) and workpiece allowances (0.05 mm, 0.04 mm, 0.03 mm, and 0.02 mm) after each step are shown in Figure 7. Different processing parameters and machining allowances were selected during the process to ensure that the material had good rigidity and processing accuracy.

## 3. Machining and Measurement Results

#### 3.1. Machining

_{c}= 75 m/min; f

_{z}= 0.1 mm/z; a

_{p}= 15 mm; a

_{e}= 0.6 mm. A five-axis numerically controlled (NC) milling method without auxiliary support was used during semi-finishing and finishing. Cutting parameters were as described in the previous section. The processing path is shown in Figure 8.

#### 3.2. Contour Accuracy Measurements

## 4. Conclusions

- In the rough machining stage, a large cutting depth and layer milling method were used to improve efficiency. It takes 87.3 h to complete rough machining under the original processing technology. However, this process took only 52.7 h when using the new processing technology; thus, the machining efficiency was increased by 40%. At the same time, the suitable surface contours of parts were provided for semi-finishing and finishing.
- In the finishing stage, a one-shot forming method was used. The surface of the previous layer needs to be dressed when processing the next layer. The surface contour accuracy of parts was within the range of ± 0.30 mm.

## Author Contributions

## Funding

## Conflicts of Interest

## Nomenclature

v_{c} | cutting speed (m/min) |

f_{z} | feed per tooth (mm/z) |

a_{p} | cutting depth (mm) |

a_{e} | cutting width (mm) |

F | cutting force (N) |

M_{z}, M_{y} | bending moment (N m) |

${\sigma}_{\mathrm{x}}$ | normal stress (N/m^{2}) |

I_{z}, I_{y} | inertia moment (m^{4}) |

W_{z} | modulus of flexural section (m^{3}) |

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**Figure 7.**Semi-finishing and finishing machining: (

**a**) first layer; (

**b**) second layer; (

**c**) third layer; (

**d**) fourth layer.

Al | V | Fe | N | C | O | H | Ti |
---|---|---|---|---|---|---|---|

6.0 | 4.0 | 0.3 | 0.05 | 0.1 | 0.2 | 0.0125 | Rest |

Tensile Strength | Yield Strength | Elongation | Shrinkage |
---|---|---|---|

902 Mpa | 824 Mpa | 10% | 30% |

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## Share and Cite

**MDPI and ACS Style**

Zha, J.; Liang, J.; Li, Y.; Zhang, H.; Chen, Y.
Large Cutting Depth and Layered Milling of Titanium Alloy Thin-Walled Parts. *Materials* **2020**, *13*, 1499.
https://doi.org/10.3390/ma13071499

**AMA Style**

Zha J, Liang J, Li Y, Zhang H, Chen Y.
Large Cutting Depth and Layered Milling of Titanium Alloy Thin-Walled Parts. *Materials*. 2020; 13(7):1499.
https://doi.org/10.3390/ma13071499

**Chicago/Turabian Style**

Zha, Jun, Jianxin Liang, Yipeng Li, Huijie Zhang, and Yaolong Chen.
2020. "Large Cutting Depth and Layered Milling of Titanium Alloy Thin-Walled Parts" *Materials* 13, no. 7: 1499.
https://doi.org/10.3390/ma13071499