本文選題：表面化學(xué)改性　切入點(diǎn)：磁性磨粒光整加工　出處：《太原理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：磁性磨料作為磁性磨粒光整加工技術(shù)的磨具,其性能直接影響零件的加工質(zhì)量、效率及成本,但由于目前的制備工藝難以實(shí)現(xiàn)批量制備高性能、低成本的磁性磨料,所以極大地制約了該技術(shù)的工業(yè)應(yīng)用。近年來,不少學(xué)者采用機(jī)械混合法制備了非固結(jié)磁性磨料,取得了很好的加工效果。非固結(jié)磨料具有許多優(yōu)點(diǎn),如制備工藝簡單,成本低,磁場作用下形成的“磁刷”剛性較低,能拋光復(fù)雜表面等。但目前該方法制備出的磨料存在以下兩方面問題:一方面,由于鐵磁相、磨粒相與結(jié)合劑之間難以形成良好的粘結(jié),在加工過程中,磨粒相易于飛散,影響對工件表面的加工質(zhì)量和加工效率;另一方面,鐵磁相與磨粒相粉末容易在結(jié)合劑中發(fā)生自身團(tuán)聚而難以均勻分散,會對工件表面產(chǎn)生劃傷等副作用,影響磁性磨料的加工均勻性。針對上述問題,本文提出采用偶聯(lián)劑對鐵磁相和磨粒相表面化學(xué)改性,來改善二者在結(jié)合劑聚乙烯醇中的相容性和分散穩(wěn)定性,之后再將改性粉末與聚乙烯醇機(jī)械混合均勻來制備非固結(jié)磁性磨料。本文主要對偶聯(lián)劑改性過程中的一些工藝參數(shù)進(jìn)行了實(shí)驗(yàn)研究,并對制備的磨料的性能指標(biāo)進(jìn)行分析測試。本文的主要研究內(nèi)容如下:1.分析了非固結(jié)磁性磨料光整加工平面原理和材料去除機(jī)理,敘述了非固結(jié)磁性磨料的組成及性能要求,介紹了加工介質(zhì)研磨液的分類及作用,重點(diǎn)對單個研磨粒子進(jìn)行受力分析,得出工件對研磨粒子的法向壓力Fpn和鐵磁相與磨粒相的粒徑比A有關(guān),并推導(dǎo)出A的理論范圍。2.制定了非固結(jié)磁性磨料的制備工藝流程,以活化指數(shù)為表征手段,通過單因素實(shí)驗(yàn)研究了改性過程中偶聯(lián)劑種類、用量、反應(yīng)溫度、反應(yīng)時間對改性效果的影響。結(jié)果表明:在相同實(shí)驗(yàn)條件下,鈦酸酯偶聯(lián)劑NDZ-101對還原鐵粉和白剛玉的改性效果較好,改性后粉體活化指數(shù)較高,疏水性較強(qiáng),且綜合考慮改性效果與經(jīng)濟(jì)性,選取最佳用量為3%,最佳反應(yīng)溫度為70℃,反應(yīng)時間為40min。3.通過磁回路測量裝置,測量了非固結(jié)磁性磨料的飽和磁感應(yīng)強(qiáng)度,評價其導(dǎo)磁性能,找出了磁感應(yīng)強(qiáng)度B達(dá)到飽和時磁場強(qiáng)度H和電流I的大小。然后建立現(xiàn)有磁回路裝置的三維模型,將非固結(jié)磁性磨料簡化為球形,采用Maxwell軟件對不同電流值下磨料的磁感應(yīng)強(qiáng)度進(jìn)行仿真,結(jié)果表明實(shí)測結(jié)果與仿真結(jié)果基本一致,測量準(zhǔn)確性較高。此外,以SUS304不銹鋼板為工件,研究其使用壽命,結(jié)果表明:非固結(jié)磁性磨料對初始粗糙度Ra為0.4μm左右的304不銹鋼板研磨加工,使用壽命較高,大約為36min。4.以加工平板工件為例,檢測了非固結(jié)磁性磨料的研磨加工性能。通過實(shí)驗(yàn)分別探究了偶聯(lián)劑種類、鐵磁相與磨粒相粒徑比、研磨液種類及配比、材料性質(zhì)對表面粗糙度和表面形貌的影響規(guī)律。結(jié)果表明:非固結(jié)磁性磨料加工性能優(yōu)良,加工后工件表面質(zhì)量高,達(dá)到鏡面效果。
[Abstract]:Magnetic abrasive, as the abrasive tool of magnetic abrasive finishing technology, has a direct impact on the quality, efficiency and cost of parts. However, it is difficult to produce high performance and low cost magnetic abrasive in batches. In recent years, many scholars have used mechanical mixing method to prepare unconsolidated magnetic abrasive, which has achieved good processing effect. Unconsolidated abrasive has many advantages, such as simple preparation process. The cost is low, the "magnetic brush" formed by magnetic field is less rigid, and can polish the complex surface. However, the abrasive prepared by this method has the following two problems: on the one hand, because of the ferromagnetic phase, It is difficult to form a good bond between the abrasive phase and the binder. In the process of processing, the abrasive phase is easy to fly away, which affects the processing quality and processing efficiency of the workpiece surface; on the other hand, Ferromagnetic phase and abrasive phase powder are easy to be agglomerated in the binder and difficult to disperse evenly, which will produce side effects such as scratching on the surface of the workpiece and affect the processing uniformity of magnetic abrasive. In this paper, the surface chemical modification of ferromagnetic phase and abrasive phase by coupling agent is proposed to improve their compatibility and dispersion stability in the binder polyvinyl alcohol. Then the modified powder and polyvinyl alcohol were mechanically mixed to prepare unconsolidated magnetic abrasive. In this paper, some technological parameters in the modification process of coupling agent were studied experimentally. The main research contents of this paper are as follows: 1. The plane principle and material removal mechanism of unconsolidated magnetic abrasive finishing are analyzed, and the composition and performance requirements of non-consolidated magnetic abrasive are described. The classification and function of grinding fluid for machining medium are introduced. The stress analysis of single abrasive particle is emphasized. The normal pressure Fpn of workpiece to abrasive particle and ferromagnetic phase are related to particle size ratio A. The theoretical range of A was deduced. 2. The preparation process of unconsolidated magnetic abrasive was established. By means of activation index, the type, amount and reaction temperature of coupling agent in the modification process were studied by single factor experiment. The results showed that the titanate coupling agent NDZ-101 had better modification effect on reduced iron powder and corundum under the same experimental conditions, the activation index of the modified powder was higher, and the hydrophobicity of the modified powder was stronger. Considering the modification effect and economy, the optimum dosage is 3, the optimum reaction temperature is 70 鈩，

本文編號：1625933