如何通过磨具加工的改进提升产品质量

模具的加工是控制产品质量的重要因素,对模具的结构进行合理设计,在产品设计的每个环节中都提高质量控制,保证每一个环节都可以顺利进行,最终提高产品质量。本文针对模具的加工的进行介绍,分析模具加工的质量控制,探讨出提高产品质量的因素。

金刚石树脂磨具的改进

以金刚石、立方氮化硼为磨料制造的树脂磨具、青铜磨具、陶瓷磨具、电镀磨具以及新兴的柔性磨具、单层钎焊磨具等超硬磨料的磨具 ,具有磨削力小、磨削温度低、磨削比高和加工精度高、效率高等特点 ;磨具的钢基体、铝合金、胶木以及新兴的铝 酚醛等不同材质的基体对磨具的寿命、加工效率和加工质量有着不同的影响规律 ;磨料、结合剂、辅助填料的弃旧更新以及配方的改进 ,有效地改善磨具性能 ,促进磨具更新换代 ;表面镀覆 ,磨料强度得以提高 ,同时减缓了对树脂结合剂的热冲击 ,提高了结合力 ,从而显著延长了磨具寿命 ;磨具的精加工和动平衡检查是保证高档精密磨具质量的重要措施。

Microstructure and cutting performance of CrTiAlN coating for high-speed dry milling

Using a closed field unbalanced magnetron sputtering system,the cemented carbide end mills were coated with a CrTiAlN hard coating,which consisted of a Cr adhesive layer,a CrN interlayer and a CrTiAlN top layer.The microstructure and mechanical properties of the coating were investigated by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,micro indentation and scratch test.The cutting performance of the coated end mills were conducted by high-speed dry milling hardened steel（P20,HRC 45）.The results indicates that the coating is composed of（Cr,Ti,Al）N columnar grains with nanolayers.The coating exhibits good adhesion to cemented carbide substrate and high microhardness of around 30 GPa.The coated end mills show significant improvement on tool life and much lower cutting force as compared to the uncoated ones.And the related mechanisms were discussed.

Prediction Model for Net Cutting Specific Energy in CNC Turning

A prediction model for net cutting specific energy in computer numerical control(CNC)turning based on turning parameters and tool wear is developed.The model can predict the net cutting energy consumption before turning.The prediction accuracy of the model is verified in AISI 1045 steel turning.The comparative experimental results show that the prediction accuracy of the model is significantly improved because the influence of tool wear is taken into account.Finally,the influences of turning parameters and tool wear on net cutting specific energy are studied.With the increase of cutting depth,the net cutting specific energy decreases.With the increase of spindle speed,the additional load loss power of spindle drive system increases,so the net cutting specific energy increases.The net cutting specific energy increases approximately linearly with tool wear.The results are helpful to formulate efficient and energy-saving CNC turning schemes and realize low‑carbon manufacturing.

Wear of CVD thick film diamond cutter while machining laminated flooring

The wide application of high pressure laminated (HPL) flooring has an insistent need for cutting tools with an excellent performance and fine cutting quality. Chemical vapor deposition (CVD) thick film diamond is a promising material for the machining of HPL flooring. In the present work, CVD thick film diamond tools were used to mill the wear resistance layer of HPL flooring. Wear volumes of flank face were examined by optical microscopy, and micro wear morphologies were observed by scanning electron microscopy (SEM). The experiments revealed that the predominant wear characteristics of CVD diamond tools were transgranular cleavage wear and intergranular peeling of the CVD diamond. Experimental results also showed that twin characteristic, cavity defect, micro crack and grain size of CVD thick film diamond contributed greatly to the wear process of CVD thick film diamond tools. The effects caused by the factors were also analyzed in detail in the paper.

Steel Valve Plate Grinding

In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with the focus on flat-grinding. It is also going to present the method of choosing grinding wheels and parameters, as well as their impact on the processing quality parameters （roughness, surface flatness and seat width）. The optimization of the grinding process ensures acceptable quality of the final product applying the smallest possible changes in parameters at non-uniform quality levels of the tools. Here we have to make sure that the machining process is acceptable in terms of processing cost as weIl. We are going to use the G-factor as the efficiency indicator for different tools.

Improving the Shape Accuracy by Simulating the Short-Stroke Honing Process

This study represents an approach to investigate a force controlled short-stroke honing process and especially the dependency between the type of finishing tool and the resulting shape accuracy. Based on a finite element analysis and a validation with special pressure measurement films, the contact mechanisms between the finishing tool and the workpiece are analyzed. In order to achieve a high surface quality without reducing the shape accuracy, the influence of different finishing tools with an individual material behavior on the resulting shape accuracy have been analyzed. With a variation of the geometry of the finishing tool as well as of the workpiece, different loading cases between the tool and the workpiece are considered in the finite element simulation. These results, combined with experimental investigations with different finishing films lead to an improvement of the surface quality without reducing the shape accuracy.