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遥控器盒盖的塑料模具设计,机械毕业设计全套
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1 Shiou FJ, Chen CH (2003) Determination of optimal ball-burnishing parameters for plastic injection molding steel. Int J Adv Manuf Techno Chao-Chang A. Chen Wen -Tu L Based on the injection mold steel grinding and polishing processes automated surface treatment 1 Introduction Plastics are important engineering materials due to their specific characteristics, such as corrosion resistance, resistance to chemicals, low density, and ease of manufacture, and have increasingly replaced metallic components in industrial applications. Injection molding is one of the important forming processes for plastic products. The surface finish quality of the plastic injection mold is an essential requirement due to its direct effects on the appearance of the plastic product. Finishing processes such as grinding, polishing and lapping are commonly used to improve the surface finish. The mounted grinding tools (wheels) have been widely used in conventional mold and die finishing industries. The nts 2 geometric model of mounted grinding tools for automated surface finishing processes was introduced in. A finishing process mode of spherical grinding tools for automated surface finishing systems was developed in. Grinding speed, depth of cut, feed rate, and wheel properties such as abrasive material and abrasive grain size, are the dominant parameters for the spherical grinding process, as shown in Fig. 1. The optimal spherical grinding parameters for the injection mold steel have not yet been investigated based in the literature. Fig.1. Schematic diagram of the spherical grinding process In recent years, some research has been carried out in determining the optimal parameters of the ball burnishing process (Fig. 2). For instance, it has been found that plastic deformation on the workpiece surface can be reduced by using a tungsten carbide ball or a roller, thus improving the surface roughness, surface hardness, and fatigue resistance. The burnishing process is accomplished by machining centers and lathes. The main burnishing parameters having significant effects on the surface nts 3 roughness are ball or roller material, burnishing force, feed rate, burnishing speed, lubrication, and number of burnishing passes, among others. The optimal surface burnishing parameters for the plastic injection mold steel PDS5 were a combination of grease lubricant, the tungsten carbide ball, a burnishing speed of 200 mm/min, a burnishing force of 300 N, and a feed of 40 m. The depth of penetration of the burnished surface using the optimal ball burnishing parameters was about 2.5 microns. The improvement of the surface roughness through burnishing process generally ranged between 40% and 90%. Fig. 2. Schematic diagram of the ball-burnishing process The aim of this study was to develop spherical grinding and ball burnishing surface finish processes of a freeform surface plastic injection mold on a machining center. The flowchart of automated surface finish using spherical grinding and ball burnishing processes is shown in Fig. 3. We began by designing and manufacturing the spherical grinding tool and its alignment device for use on a machining center. The optimal surface spherical grinding parameters were determined by utilizing a Taguchis orthogonal array method. Four factors and three corresponding levels were then chosen for the Taguchis L18 nts 4 matrix experiment. The optimal mounted spherical grinding parameters for surface grinding were then applied to the surface finish of a freeform surface carrier. To improve the surface roughness, the ground surface was further burnished, using the optimal ball burnishing parameters. Fig. 3. Flow chart of automated surface finish using spherical grinding and ball burnishing processes 2 Design of the spherical grinding tool and its alignment device To carry out the possible spherical grinding process of a nts 5 freeform surface, the center of the ball grinder should coincide with the z-axis of the machining center. The mounted spherical grinding tool and its adjustment device was designed, as shown in Fig. 4. The electric grinder was mounted in a tool holder with two adjustable pivot screws. The center of the grinder ball was well aligned with the help of the conic groove of the alignment components. Having aligned the grinder ball, two adjustable pivot screws were tightened; after which, the alignment components could be removed. The deviation between the center coordinates of the ball grinder and that of the shank was about 5 m, which was measured by a CNC coordinate measuring machine. The force induced by the vibration of the machine bed is absorbed by a helical spring. The manufactured spherical grinding tool and ball-burnishing tool were mounted, as shown in Fig. 5. The spindle was locked for both the spherical grinding process and the ball burnishing process by a spindle-locking mechanism. Fig.4. Schematic illustration of the spherical grinding tool and its adjustment device nts 6 Fig.5. (a) Photo of the spherical grinding tool (b) Photo of the ball burnishing tool 3 Planning of the matrix experiment 3.1 Configuration of Taguchi s orthogonal array The effects of several parameters can be determined efficiently by conducting matrix experiments using Taguchis orthogonal array. To match the aforementioned spherical grinding parameters, the abrasive material of the grinder ball (with the diameter of 10 mm), the feed rate, the depth of grinding, and the revolution of the electric grinder were selected as the four experimental factors (parameters) and designated as factor A to D (see Table 1) in this research. Three levels (settings) for each factor were configured to cover the range of interest, and were identified by the digits 1, 2, and 3. Three types of abrasive materials, namely silicon carbide (SiC), white aluminum oxide (Al2O3, WA), and pink aluminum oxide (Al2O3, PA), were selected and studied. Three numerical values of each factor were determined based on the pre-study results. The L18 orthogonal array was selected to conduct the matrix experiment for four 3-level factors of the spherical grinding process. nts 7 Table1. The experimental factors and their levels 3.2 Definition of the data analysis Engineering design problems can be divided into smaller-the better types, nominal-the-best types, larger-the-better types, signed-target types, among others 8. The signal-to-noise (S/N) ratio is used as the objective function for optimizing a product or process design. The surface roughness value of the ground surface via an adequate combination of grinding parameters should be smaller than that of the original surface. Consequently, the spherical grinding process is an example of a smaller-the-better type problem. The S/N ratio, , is defined by the following equation: =10 log10(mean square quality characteristic) =10 log10 ni iyn 121 where: yi : observations of the quality characteristic under different noise conditions n: number of experiment After the S/N ratio from the experimental data of each L18 orthogonal array is calculated, the main effect of each factor was determined by using an analysis of variance (ANOVA) technique and an F-ratio test. The optimization strategy of the smaller-the better problem is to maximize , as defined by Eq. 1. Levels that maximize will be selected for the factors that have a significant effect on . The optimal conditions for spherical grinding can then be determined. 4 Experimental work and results The material used in this study was PDS5 tool steel (equivalent to AISI P20), which is commonly used for the molds of large plastic injection products in the field of automobile components and domestic nts 8 appliances. The hardness of this material is about HRC33 (HS46). One specific advantage of this material is that after machining, the mold can be directly used for further finishing processes without heat treatment due to its special pre-treatment. The specimens were designed and manufactured so that they could be mounted on a dynamometer to measure the reaction force. The PDS5 specimen was roughly machined and then mounted on the dynamometer to carry out the fine milling on a three-axis machining center made by Yang-Iron Company (type MV-3A), equipped with a FUNUC Company NC-controller (type 0M). The pre-machined surface roughness was measured, using Hommelwerke T4000 equipment, to be about 1.6 m. Figure 6 shows the experimental set-up of the spherical grinding process. A MP10 touch-trigger probe made by the Renishaw Company was also integrated with the machining center tool magazine to measure and determine the coordinated origin of the specimen to be ground. The NC codes needed for the ball-burnishing path were generated by PowerMILL CAM software. These codes can be transmitted to the CNC controller of the machining center via RS232 serial interface. Fig.6. Experimental set-up to determine the optimal spherical grinding parameters Table 2 summarizes the measured ground surface roughness nts 9 alue Ra and the calculated S/N ratio of each L18 orthogonal array sing Eq. 1, after having executed the 18 matrix experiments. The average S/N ratio for each level of the four actors is shown graphically in Fig. 7. Table2. Ground surface roughness of PDS5 specimen Exp. Inner array (control factors) Measured surface roughness value (Ra) Response no A B C D my1 my2 my3 S/N(dB) Mean my_ 1 1 1 1 1 0.35 0.35 0.35 9.119 0.350 2 1 2 2 2 0.37 0.36 0.38 8.634 0.370 3 1 3 3 3 0.41 0.44 0.40 7.597 0.417 4 2 1 2 3 0.63 0.65 0.64 3.876 0.640 5 2 2 3 1 0.73 0.77 0.78 2.380 0.760 6 2 3 1 2 0.45 0.42 0.39 7.530 0.420 7 3 1 3 2 0.34 0.31 0.32 9.801 0.323 8 3 2 1 3 0.27 0.25 0.28 11.471 0.267 9 3 3 2 1 0.32 0.32 0.32 9.897 0.320 10 1 1 2 2 0.35 0.39 0.40 8.390 0.380 11 1 2 3 3 0.41 0.50 0.43 6.968 0.447 12 1 3 1 1 0.40 0.39 0.42 7.883 0.403 13 2 1 1 3 0.33 0.34 0.31 9.712 0.327 14 2 2 2 1 0.48 0.50 0.47 6.312 0.483 15 2 3 3 2 0.57 0.61 0.53 4.868 0.570 16 3 1 3 1 0.59 0.55 0.54 5.030 0.560 17 3 2 1 2 0.36 0.36 0.35 8.954 0.357 18 3 3 2 3 0.57 0.53 0.53 5.293 0.543 Fig.7. Plots of control factor effects The goal in the spherical grinding process is to minimize the surface roughness value of the ground specimen by determining the optimal level of each factor. Since log is a monotone decreasing function, we should maximize the S/N ratio. Consequently, we can determine the optimal level for each factor as being the level that has the highest value of . Therefore, based on the matrix experiment, the optimal abrasive material was pink aluminum oxide; the optimal feed was 50 mm/min; the optimal depth of grinding was 20 m; and the optimal revolution was 18 000 rpm, as shown in Table 3. The optimal parameters for surface spherical grinding obtained from the Taguchis matrix experiments were applied to the surface finish of the freeform surface mold insert to evaluate the surface roughness improvement. A perfume bottle was selected as the nts 10 tested carrier. The CNC machining of the mold insert for the tested object was simulated with Power MILL CAM software. After fine milling, the mold insert was further ground with the optimal spherical grinding parameters obtained from the Taguchis matrix experiment. Shortly afterwards, the ground surface was burnished with the optimal ball burnishing parameters to further improve the surface roughness of the tested object (see Fig. 8). The surface roughness of the mold insert was measured with Hommelwerke T4000 equipment. The average surface roughness value Ra on a fine-milled surface of the mold insert was 2.15 m on average; that on the ground surface was 0.45 m on average; and that on burnished surface was 0.07 m on average. The surface roughness improvement of the tested object on ground surface was about (2.150.45)/2.15 = 79.1%, and that on the burnished surface was about (2.150.07)/2.15 = 96.7%. Fig.8. Fine-milled, ground and burnished mold insert of a perfume bottle 5 Conclusion In this work, the optimal parameters of automated spherical grinding and ball-burnishing surface finishing processes in a freeform surface plastic injection mold were developed successfully on a machining center. The mounted spherical grinding tool (and its alignment components) was designed and manufactured. The optimal nts 11 spherical grinding parameters for surface grinding were determined by conducting a Taguchi L18 matrix experiments. The optimal spherical grinding parameters for the plastic injection mold steel PDS5 were the combination of the abrasive material of pink aluminum oxide (Al2O3, PA), a feed of 50 mm/min, a depth of grinding 20 m, and a revolution of 18 000 rpm. The surface roughness Ra of the specimen can be improved from about 1.6 m to 0.35 m by using the optimal spherical grinding conditions for surface grinding. By applying the optimal surface grinding and burnishing parameters to the surface finish of the freeform surface mold insert, the surface roughness improvements were measured to be ground surface was about 79.1% in terms of ground surfaces, and about 96.7% in terms of burnished surfaces. Acknowledgement The authors are grateful to the National Science Council of the Republic of China for supporting this research with grant NSC 89-2212-E-011-059. nts nts基于注塑模具钢研磨和抛光工序的自动化表面处理 摘 要 本 文 研究 了 注塑模具钢自动研磨与球面抛光加工工序 的 可能性 ，这种 注塑模具钢 PDS5的 塑 性 曲面 是在 数控加工中心 完成的。 这项研究已经完成了磨削刀架的 设计 与 制造 。 最佳表面研磨参数 是在 钢铁 PDS5 的 加工中心测定 的。 对于 PDS5注塑模具钢 的最佳球面研磨参数是以下一系列的组合：研磨 材料的磨料 为 粉红氧化铝 ，进给量 500 毫米 /分钟 ， 磨削深度 20 微米，磨削转速为 18000RPM。 用优化 的 参数 进行 表面研磨 ， 表面粗糙度 Ra值 可由大约 1.60微米改 善至 0.35微米 。 用球抛光 工艺和 参数优化抛光 ， 可以进一步改善表面粗糙度 Ra值 从 0.343微米至 0.06微米左右 。在 模具 内部 曲面的测试部分 ， 用最佳参数 的 表面研磨、抛光 ，曲面表面粗糙度就可以提高约 2.15微米到 0 0.07微米 。 关键词 : 自动化表面处理 抛光 磨削加工 表面粗糙度 田口方法 1 引言 塑胶工程材料由于其重要特点 ,如耐化学腐蚀性、低密度、易于制造 ,并已日渐取代金属部件 在 工业 中广泛 应用 。 注塑成型 对于 塑料制品 是 一个重要 工艺。注塑模具的表面质量是 设计 的本质要求 ,因为它直接影响了塑胶 产品的外观 和性能。 加工工 艺 如 球面 研磨、抛光常用 于 改善表面光洁度 。 研磨工何模型 将 介绍 。 自动化表面处理 的球磨 研磨工具 将得到 示范 和 开发 。 磨 削速度 , 磨 削 深度 ，进给速率和 砂轮 尺寸 、研磨材料特性 （ 如磨料粒度 大小）是球形研磨 工艺 中 主要的 参数 ，如图 1（ 球面研磨过程示意图 ） 所示。 注塑模具钢的球面研磨 最 优化参数 目前 尚未在文献 得到确切的 依据 。 nts 图 1 球面研磨过程示意图 近年来 ， 已 经 进行了一些研究 ， 确定 了 球 面 抛光工艺 的 最优参数 (图 2) （ 球面 抛光过程示意图 ）。 比如 ，人们 发现 , 用碳化钨球滚 压的方法可以使 工件表 面的 塑性变形减少 ,从而改善表面粗糙度、表面硬度、抗疲劳 强度。 抛光的 工艺 的过程 是由 加工中心 和 车床 共同完成的。对 表面粗糙度有重大影响 的 抛光 工艺 主要参数，主要是 球或滚子材料 ， 抛光 力， 进给速率 ,抛光速度 ,润滑、抛光 率及其他因素等。 注塑模具钢 PDS5的 表面抛光的参数优化 ， 分别结合 了 油脂润滑剂 ，碳化钨球 ,抛光速度 200毫米 /分钟 ,抛光力 300牛， 40微米 的进给量。 采用最佳参数 进行表面研磨和球面抛光的深度 为 2.5 微米 。 通过抛光 工艺， 表面粗糙度可以 改善大致为 40 至 90。 具 (轮子 )的安装已广泛用于传统模具 的制造 产业 。 图 2 球 面 抛光过程示意图 步距 研磨高度 球磨研磨 进给速度 工作台 进给 研磨球 工作台 研磨深度 研磨表面 nts 此项 目 研究的目的是 ， 发展 注塑 模具 钢的 球形研磨 和 球面抛光工序 ，这种 注塑模具 钢的 曲面 实在 加工中心完成 的。 表面光洁度 的 球研磨与球抛光 的 自动化流程工序 ，如图 3所示。 我们开始自行设计和制造的球面研磨工具及加工中心 的对 刀 装置 。 利用田口正交法 ， 确定了表面球研磨最佳参数 。 选择 为 田口 L18型矩阵实验相应 的 四个因素和三个层次 。 用 最佳参数进行表面球研磨则适用于一个曲面表面光洁度 要求较高的 注塑模具 。 为 了 改善表面粗糙 , 利用最佳球 面 抛光工艺 参 数，再进行对表层 打磨 。 图 3自动球面研磨 与 抛光工序 的 流程图 2 球研磨的设计和对准装置 实施过程中可能出现的曲面 的 球研磨 ,研磨球 的中心应和 加工中心 的 Z轴 相一致。 球面研磨工具的安装及调整装置 的 设计 ，如 图 4（ 球 面 研磨工具及其调整装置 ） 所示 。 电动磨床展开 了 两个 具有 可调支撑螺丝 的 刀架 。 磨床 中心正好与具有辅助作用 的圆锥槽线配合 。 拥有磨床 的 球接轨 ,当 两个可调支撑螺丝被收紧时，其后的 对准部件 就 可以拆除 。研磨 球中心坐标偏差约 为 5微米 , 这是衡量一PDS 试样的设计与制造 选择最佳矩阵实验因子 确定最佳参数 实施实验 分析并确定最佳因子 进行表面抛光 应用最佳参数加工曲面 测量试样的表面粗糙 度 球研磨和抛光装置的设计与制造 nts个数控坐标测量机 性能的重要标准。 机床的 机械振动 力 是 被 螺旋弹簧 所 吸收 。球形研磨球 和 抛光工具 的安装，如图 5（ a. 球面研磨工具的图片 . b.球抛光工具 的 图片 ） 所示 。为使 球面磨削加工和抛光加工 的进行， 主轴 通过 球锁机制 而被锁 定。 图 4 球 面 研磨工具及其调整装置 图 5 a. 球面研磨工具的图片 . b.球抛光工具 的 图片 模柄 弹簧 工具可调支撑 紧固螺钉 磨球 自动研磨 磨球组件 nts3 矩阵实验的规划 3.1 田口正交表 利用矩阵实验田口正交 法，可以 确定参数 的有影响程度。 为了配合上述球面研磨参数 ， 该材料磨料 的研磨 球 (直径 10 毫米 ),进给速率， 研磨 深度 ,在次研究中 电气磨床被 假定为 四个因素 ， 指定为 从 A 到 D（见表 1 实验 因素和水平 ）。三个层次的因素 涵盖了不同的范围特征 ,并用 了数字 1、 2、 3 标明。 挑选三类磨料 ,即碳化硅 ,白色氧化铝 ,粉红氧化铝 来 研究 . 这 三个数值的 大小取决于 每个因素 实验结果。 选定 L18型正交矩阵进行实验 ，进而研究 四 三级因素的球形研磨过程 。 表 1实验因素和水平 因素 水平 1 2 3 A. 碳化硅 白色氧化铝 粉红氧化铝 B. 50 100 200 C.研磨深度（ m） 20 50 80 D. 12000 18000 24000 3.2 数据分析的界定 工程设计问题 ,可以分为较小 而好的 类型 ,象 征性最好类型 ,大 而好 类型 ， 目标 取向 类型等 。 信噪比 (S/N)的 比值 ，常 作为目标函数 来 优化产品或 者 工艺设计 。 被加工面的 表面粗糙度值经 过 适当 地 组合磨削参数 ， 应小于原来的 未加工 表面 。 因此 ,球面研磨过程 属于工程问题中的 小 而好类型。这里的 信噪比 （ S/N） ,按下列公式定义 : =10 log10 平方等于质量特性 =10 log10 ni iyn121 1 这里， yi 不同噪声条件下 所 观察 的 质量特性 n 实验 次数 从每 个 L18型正交实验 得到的 信噪比 （ S/N） 数据 ，经 计算 后， 运用差异分析技术 (变异 )和 歼比检验 来测定 每一个 主要的 因素 。 优化 小而好类型的工程问题 问题更是尽量 使 最大而 定 。 各级 选择 的 最大化将 对最终的 因素有重大影响 。 最优条件可 视 研磨球 而 待定 。 nts4 实验工作和结果 这项研究使用的材料是 PDS5工具钢 (相当于艾西塑胶模具 )， 它 常用 于 大型注塑模具产品在国内汽车零件 领域和国内设备。 该材料的硬度约 HRC33(HS46)。 具体好处之一是 , 由于 其 特殊的热处理前处理 ， 模具可直接用于未经进一步加工工序 而对 这一材料 进行 加工 。式样 的设计和制造 ,应 使 它 们可以安装在底盘 ，来测 量相应的反力。 PDS5试样的加工 完毕 后 ， 装在大底盘 上在 三 坐标 加工中心进行了铣 削，这种加工中心是由 钢铁公司 所生产 (中压型三号 ),配备 了 FANUC-18M公司 的 数控控制器 (0.99型 )。 用 hommelwerket4000 设备 来 测量前 机 加工 前 表面的 粗糙度 ,使其 可达到 1.6微 米 。 图 6试验 显示了 球面磨削加工 工艺的 设置 。 一个由 Renishaw公司 生产的 视频触摸触发探头 ，安装在 加工中心 上，来 测量 和 确定和原 始式样的 协调 。 数控代码所需要的磨球路径 由 PowerMILL软件产 。 这些代码经 过 RS232串口界面 ， 可以传送到 装有 控制器的数控加工中心 上。 图 6 完成了 L18型 矩阵实验后， 表 2 （ PDS5 试样 光滑 表 层的 粗糙度 ） 总结了 光滑 表面 的 粗糙度 RA 值 ， 计算 了每一个 L18 型 矩阵实验的信噪比（ S/N） ,从而 用于方程（ 1）。通过表 2提供的各个数值，可以得到
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