本文選題：模具制造 + 激光拋光　； 參考：《北京工業(yè)大學》2015年碩士論文

【摘要】：拋光能提高模具耐磨性和耐腐蝕性以及工件精度,延長其使用壽命和維護周期,因此,模具拋光是模具制造過程中非常重要的加工工序,但模具表面精加工一直是模具加工領(lǐng)域中一個未能很好解決的難題。目前,模具自動拋光技術(shù)仍存在很多問題,如電拋光、電化學拋光和磨削等會導致邊角變圓,較深區(qū)域未被加工等,因此,當前自動拋光技術(shù)無法實現(xiàn)非平整表面模具和有邊角的模具的加工。模具表面精加工主要依靠手工研磨來完成,也是模具鉗工勞動強度大的重要原因之一。激光具有獨特的加工優(yōu)勢,激光拋光因其加工的諸多優(yōu)點,被廣泛認為是一種極具潛力的拋光方法。而光纖激光器的能量轉(zhuǎn)化率較高,且壽命長,適合工業(yè)應用,因此本文采用了連續(xù)模式的光纖激光研究了拋光模具鋼的加工工藝。基于控制能量密度的考慮,本文研究了低離焦量低功率和高離焦量高功率兩種情況,采用固定功率和掃描速度,通過變化離焦量來改變能量密度,進行2316模具鋼單光束單道掃描試驗。研究表明在這兩種情況下,隨著離焦量增大,重熔表面的粗糙度呈現(xiàn)先降低后增大的趨勢,該現(xiàn)象與SSM(surface shallow melting)機制和SOM(surface over melting)機制吻合。隨離焦量增大,相同離焦量和掃描速度下,表面凸起會更加明顯,同時,與低離焦量低功率加工條件相比,高離焦量高功率下熔融區(qū)域更寬。激光熱導焊模型的分析結(jié)果揭示了該現(xiàn)象的成因,因此,高離焦量高功率的加工條件更利于單道激光拋光。進一步采用正交試驗設計的方法,研究了激光功率、掃描速度、掃描間隔和離焦量對平面拋光的影響。實驗結(jié)果表明:1)激光參數(shù)對平面拋光的加工效果影響順序為:掃描間隔激光功率掃描速度離焦量。2)比較掃描速度為70 mm/s和100 mm/s這兩種加工條件,平面拋光的加工效果差異很小,因此,為了提高效率,應選擇較高的速度。3)在適當?shù)募す夤β省呙杷俣群蛼呙栝g隔下,較大的離焦量能夠?qū)崿F(xiàn)較好的激光拋光加工效果。4)在最佳參數(shù)下,2316模具鋼的粗糙度Ra約為1.000μm降到了0.231μm。
[Abstract]:Polishing can improve the wear resistance and corrosion resistance of the die, as well as the precision of the workpiece, prolong its service life and maintenance period, therefore, the die polishing is a very important processing procedure in the mould manufacturing process.However, die surface finishing is a difficult problem in die processing field.At present, there are still many problems in automatic polishing of mould, such as electric polishing, electrochemical polishing and grinding, etc.Current automatic polishing technology can not realize the processing of non-smooth surface mould and die with edge angle.The finishing of die surface mainly depends on manual grinding, which is one of the important reasons for the labor intensity of die pliers.Laser has a unique processing advantage. Laser polishing is widely regarded as a potential polishing method because of its many advantages.The energy conversion of fiber laser is high, and its life is long, so it is suitable for industrial application. Therefore, the continuous mode fiber laser is used to study the processing technology of polishing die steel.Based on the consideration of the control energy density, the low and high defocus power conditions are studied in this paper. The fixed power and scanning speed are used to change the energy density by changing the defocusing amount.The single beam single channel scanning test of 2316 die steel was carried out.The results show that the roughness of the remelted surface decreases first and then increases with the increase of defocus, which is consistent with the mechanism of SSM(surface shallow melting and SOM(surface over melting.With the increase of defocusing amount, the surface bulge will be more obvious at the same defocusing amount and scanning speed. At the same time, compared with the low defocus and low power processing conditions, the melting region will be wider under the high defocusing and high power conditions.The analysis results of laser thermal conductivity welding model reveal the cause of this phenomenon. Therefore, the processing conditions with high defocus and high power are more favorable to single pass laser polishing.Furthermore, the effects of laser power, scanning speed, scanning interval and defocus on planar polishing were studied by orthogonal design.The experimental results show that the order of influence of laser parameters on the machining effect of planar polishing is: scanning interval laser power scanning speed defocus amount. 2) compared with scanning speed of 70 mm/s and 100 mm/s, the processing effect of plane polishing is very small.Therefore, in order to improve efficiency, choose a higher speed. 3) at the appropriate laser power, scanning speed and scanning interval,A larger defocus can achieve a better laser polishing effect. 4) under the optimum parameters, the roughness Ra of the die steel is about 1.000 渭 m and 0.231 渭 m.
【學位授予單位】：北京工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG142.45
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本文編號：1771319