| SHI Wen-tian,LI Ji-hang,LIU Yu-de,YAN Tian-ming,LIN Yu-xiang,WANG Lin.Comparative Study on High-precision Hole Test of TC4 Titanium Alloy by Additive and Subtractive Materials[J],51(11):347-359 |
| Comparative Study on High-precision Hole Test of TC4 Titanium Alloy by Additive and Subtractive Materials |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.11.033 |
| KeyWord:composite machining of additive and subtractive materials titanium alloy high-precision holes surface quality |
| Author | Institution |
| SHI Wen-tian |
School of Artificial Intelligence, Beijing Technology and Business University, Beijing , China |
| LI Ji-hang |
School of Artificial Intelligence, Beijing Technology and Business University, Beijing , China |
| LIU Yu-de |
School of Artificial Intelligence, Beijing Technology and Business University, Beijing , China |
| YAN Tian-ming |
School of Artificial Intelligence, Beijing Technology and Business University, Beijing , China |
| LIN Yu-xiang |
School of Artificial Intelligence, Beijing Technology and Business University, Beijing , China |
| WANG Lin |
School of Artificial Intelligence, Beijing Technology and Business University, Beijing , China |
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| Abstract: |
| The work aims to improve the hole accuracy and quality of additively manufactured titanium alloys. At a certain cutting speed, by changing the size of the feed rate, three kinds of processing were performed on the original hole formed by SLM (selective laser melting), the direct drilling of the additive plate, and the drilling after the SLM. Through comparative analysis, the surface quality, dimensional accuracy, and cutting force signal changes after machining were studied by different methods. The result was that the actual size of the original pores formed by SLM was generally smaller than the theoretical size, mainly due to the existence of the collapsed area and the powder adhesion area. With a feed rate of 20 mm/min and SLM after hole formation, the hole structure had the best processing quality and the least burr. Drilling can significantly improve the dimensional accuracy of the SLM-formed hole structure. The parameters of the cutting speed of 47 m/min and the feed rate of 20 mm/min were matched with the parameters of the SLM drilling method and the processing quality of the sample hole structure after drilling. The minimum dimensional error was 22 μm. Compared with direct drilling, the dimensional accuracy was improved by 40.5%. In the processing method of direct drilling of the additive plate, due to the extrusion between the secondary cutting edge of the tool and the hole wall, the hole wall would produce large cracks, and the pores caused the hole wall collapse. However, this phenomenon was improved in SLM drilling and then drilling processing methods. The dimensional error was as low as 22 μm, and the overall axial cutting force was the lowest, the maximum cutting force reduction percentage was 29%, and the average cutting force reduction percentage was 61%. The overall cutting force of drilling after additive manufacturing was significantly lower than the cutting force of direct drilling of the additive sheet. The fluctuation of the former cutting force was higher than that of the latter and had a certain periodicity. The tool that was drilled after the SLM hole was formed was more resistant to damage, but the wear resistance was poor. The main reason was that the tool and the metal powder remaining around the hole rubbed against each other, aggravating the tool wear. Compared with the direct drilling processing method of the additive sheet, in the processing method of drilling the hole after SLM, the tool was less resistant to wear, but it was resistant to damage. The main reason was that the tool and the metal powder remaining around the hole-structure rubbed against each other, which aggravated the tool wear, and its cutting resistance was lower, so the tool was more resistant to breakage. Discrete granular and nodular chips were mainly produced in SLM drilling and then drilling processing methods. The size was generally small, with a width of about 30 μm, and the chips can be effectively discharged. In the direct drilling method, the main strip-shaped chips were continuous, and the size was much larger than the chips in the post-forming processing mode, with a width of about 300 μm, which made it difficult for the tool to remove chips and accumulates more heat, which is unfavorable to the tool life. It is concluded that high-precision holes can be obtained by composite machining of TC4 titanium alloy by adding and subtracting materials, and its minimum size error is as low as 22 μm. |
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