基于无模铸型制造技术的碱性酚醛树脂适用性研究

发布时间：2018-06-13 07:06

  本文选题：增材制造 + 无模铸型制造技术　； 参考：《太原理工大学》2017年硕士论文

【摘要】：无模铸型制造技术(Patternless Casting Manufacturing,简称PCM技术)是将数字化信息驱动制造技术与树脂砂铸造技术巧妙结合的新型增材制造技术。其具有生产效率高、成本低、适合个性化定制等诸多优势,在制造业领域有着广阔的应用前景。就无模铸型制造技术而言,造型材料选择至关重要,呋喃树脂以其粘度低、渗透性好、强度高、旧砂回用性好等优点,在国内无模铸型制造技术中得到了普遍应用。但是,呋喃树脂的酸耗值较高,对原砂要求较高,高温稳定性较差,发气量较高,而且由于游离醛、游离酚的大量存在,增大了有害气体挥发量,在一定程度上影响了铸件质量。碱性酚醛树脂无酸耗性要求,对原砂适应性好、高温稳定性好、发气量相对较低。本文针对当前呋喃树脂存在的问题,进行了碱性酚醛树脂在无模铸造技术中的应用可行性研究,并进行了实验验证。针对无模铸型制造技术的特点与要求,选取了两种不同固化机理的碱性酚醛树脂,分别为酯固化自硬碱性酚醛树脂和热固型碱性酚醛树脂。研究了酯固化自硬碱性酚醛树脂和热固型碱性酚醛树脂的固化机理,分别对其适用性进行探究。酯固化自硬碱性酚醛树脂粘度高达80mPa?s,无法适配到当前设备的喷嘴中,选定无水乙醇作为稀释剂,在优化稀释比例为50%的条件下,引入十二烷基苯磺酸钠作为表面活性剂,使其粘度降到适用范围。在验证手工造型强度的基础上,进行PCM工艺验证。发现铸型抗拉强度仅为0.2 MPa,难以满足实际铸造的要求。目前看来,酯固化碱性酚醛树脂在PCM工艺中还达不到适用的条件。热固型碱性酚醛树脂通过30%无水乙醇稀释,粘度降至13.0 m Pa?s,同时满足了PCM技术的喷射工艺要求。通过实验确定了后处理工艺,实验表明180℃固化温度下固化60min的铸型满足浇铸要求。后期,对热固型碱性酚醛树脂进行PCM工艺上机实验,得到的铸型强度达到0.8MPa,发气量达到15.6ml/g。满足实际铸造要求。本文通过以上几个方面的论证和实验,得到了强度和发气性都满足实际铸造要求的铸型。将采用热固型碱性酚醛树脂在PCM工艺下打印出的阶梯试块进行浇铸,成功得到表面质量良好的阶梯试块铸件。经过拉伸实验,确定该铸件满足强度标准。至此,成功地将一种碱性酚醛树脂应用到无模铸型制造技术中,拓宽了无模铸型制造技术的使用范围,也为无模铸型制造技术的下一步技术优化提供了一定的参考。
[Abstract]:Patternless casting Manufacturing (PCM) is a new material increasing manufacturing technology which combines digital information driven manufacturing technology with resin sand casting technology. It has many advantages, such as high production efficiency, low cost, suitable for individualized customization, and has a broad application prospect in the field of manufacturing. As far as the mouldless manufacturing technology is concerned, the selection of moulding material is very important. Furan resin has been widely used in the mouldless moulding manufacturing technology in China because of its advantages of low viscosity, good permeability, high strength and good reusability of used sand. However, the acid consumption of furan resin is high, the demand of raw sand is higher, the stability of high temperature is poor, the amount of gas is high, and the volatile amount of harmful gas is increased because of the existence of free aldehyde and free phenol. The casting quality is affected to some extent. Basic phenolic resin has no demand for acid consumption, good adaptability to raw sand, good high temperature stability and relatively low gas generation. In view of the existing problems of furan resin, the feasibility of the application of basic phenolic resin in die less casting technology was studied, and the experiment was carried out. In view of the characteristics and requirements of the mouldless manufacturing technology, two kinds of alkalic phenolic resins with different curing mechanisms were selected, namely, ester cured self-hardening basic phenolic resins and thermosetting basic phenolic resins. The curing mechanism of ester cured self-hard basic phenolic resin and thermosetting basic phenolic resin was studied. The viscosity of ester solidified from hard basic phenolic resin is up to 80 mPas, which can not be adapted to the nozzle of current equipment. Anhydrous ethanol is selected as diluent and sodium dodecyl benzene sulfonate is introduced as surfactant under the optimized dilution ratio of 50%. Reduce its viscosity to the applicable range. On the basis of verification of manual molding strength, PCM process verification is carried out. It is found that the tensile strength of mold is only 0.2 MPA, which is difficult to meet the requirement of actual casting. At present, the ester-cured basic phenolic resin in the PCM process can not meet the applicable conditions. The viscosity of thermosetting basic phenolic resin was reduced to 13.0 m Paans by 30% anhydrous ethanol dilution, which met the requirements of PCM spray technology at the same time. The post-treatment process was determined by experiments. The results showed that the casting mold of solidified 60min at 180 鈩，

本文编号：2013168