【机械类文献翻译】基于注塑模具钢研磨和抛光工序的自动化表面处理

1、英文原文Automated surface finishing of plastic injection mold steel with spherical grinding and ball burnishing processesAbstractThis study investigates the possibilities of automated spherical grinding and ball burnishing surface finishing processes in a freeform surface plastic injection mold steel PD

2、S5 on a CNC machining center. The design and manufacture of a grinding tool holder has been accomplished in this study. The optimal surface grinding parameters were determined using Taguchis orthogonal array method for plastic injection molding steel PDS5 on a machining center. The optimal surface g

3、rinding parameters for the plastic injection mold steel PDS5 were the combination of an abrasive material of PA Al2O3, a grinding speed of 18 000 rpm, a grinding depth of 20 m, and a feed of 50 mm/min. The surface roughness Ra of the specimen can be improved from about 1.60 m to 0.35 m by using the

4、optimal parameters for surface grinding. Surface roughness Ra can be further improved from about 0.343 m to 0.06 m by using the ball burnishing process with the optimal burnishing parameters. Applying the optimal surface grinding and burnishing parameters sequentially to a fine-milled freeform surfa

5、ce mold insert, the surface roughness Ra of freeform surface region on the tested part can be improved from about 2.15 m to 0.07 m.Keywords Automated surface finishing Ball burnishing process Grinding process Surface roughness Taguchis method1 IntroductionPlastics are important engineering materials

6、 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 su

7、rface 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

8、 widely used in conventional mold and die finishing industries. The 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, de

9、pth 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 litera

10、ture.Fig.1. Schematic diagram of the spherical grinding processIn 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

11、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 roughness are ball or roller material,

12、 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 burni

13、shing 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 ba

14、ll-burnishing processThe 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 F

15、ig. 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

16、chosen for the Taguchis L18 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 p

17、arameters.Fig. 3. Flow chart of automated surface finish using spherical grinding and ball burnishing processes2 Design of the spherical grinding tool and its alignment deviceTo carry out the possible spherical grinding process of a freeform surface, the center of the ball grinder should coincide wi

18、th 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

19、 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 coordin

20、ate 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 pro

21、cess by a spindle-locking mechanism.Fig.4. Schematic illustration of the spherical grinding tool and its adjustment deviceFig.5. (a) Photo of the spherical grinding tool (b) Photo of the ball burnishing tool3 Planning of the matrix experiment3.1 Configuration of Taguchis orthogonal arrayThe effects

22、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 revol

23、ution 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

24、 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 ex

25、periment for four 3-level factors of the spherical grinding process.Table1. The experimental factors and their levels3.2 Definition of the data analysisEngineering design problems can be divided into smaller-the better types, nominal-the-best types, larger-the-better types, signed-target types, amon

26、g 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 spheri

27、cal 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 log10where:yi : observations of the quality characteristic under different noise conditions n: number of experimentAfter t

28、he 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.

29、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 resultsThe material used in this study was PDS5 tool steel (equivalent to AISI P20), which is commonly used for the m

30、olds of large plastic injection products in the field of automobile components and domestic 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 tre

31、atment 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 cente

32、r 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

33、 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

34、 controller of the machining center via RS232 serial interface.Fig.6. Experimental set-up to determine the optimal spherical grinding parametersTable 2 summarizes the measured ground surface roughness alue Ra and the calculated S/N ratio of each L18 orthogonal array sing Eq. 1, after having executed

35、 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 specimenExp.Inner array (control factors)Measured surface roughness value (Ra)ResponsenoABCDS/N(dB)Mean11111212223133342123522316231273132832139

36、3321101122111233121311132113142221152332163131173212183323Fig.7. Plots of control factor effectsThe 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, w

37、e 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

38、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.

39、A perfume bottle was selected as the 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 experime

40、nt. 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

41、 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 bu

42、rnished surface was about (2.150.07)/2.15 = 96.7%.Fig.8. Fine-milled, ground and burnished mold insert of a perfume bottle5 ConclusionIn this work, the optimal parameters of automated spherical grinding and ball-burnishing surface finishing processes in a freeform surface plastic injection mold were

43、 developed successfully on a machining center. The mounted spherical grinding tool (and its alignment components) was designed and manufactured. The optimal spherical grinding parameters for surface grinding were determined by conducting a Taguchi L18 matrix experiments. The optimal spherical grindi

44、ng 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

45、 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 gr

46、ound surfaces, and about 96.7% in terms of burnished surfaces. 中文译文基于注塑模具钢研磨和抛光工序的自动化外表处理摘要这篇文章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，它可以在数控加工中心完成注塑模具钢PDS5的塑性曲面。这项研究已经完成了磨削刀架的设计与制造。 最正确外表研磨参数是在钢铁PDS5 的加工中心测定的。对于PDS5注塑模具钢的最正确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50毫米/分钟，磨削深度20微米，磨削转速为18000RPM。外表粗糙度Ra值可由大约微米改善至微米，通过用优化

47、的参数进行外表研磨。 如果用球抛光工艺和参数优化抛光，还可以进一步改善外表粗糙度Ra值，一般从微米至微米左右。而在模具内部曲面的测试局部，用最正确参数的外表研磨、抛光，曲面外表粗糙度就可以提高约微米至微米。关键词: 自动化外表处理 抛光 磨削过程 外表粗糙度 田口方法 一、引言步距研磨高度球磨研磨进给速度工作台由于塑胶工程材料的重要特点,比方耐化学腐蚀性、低密度、易于制造,并且已经日渐取代了金属部件在工业中广泛应用。 在注塑成型领域，其对于塑料制品是一个重要工艺。设计的本质要求是注塑模具的外表质量,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、抛光常用于改善外表光洁度。图1 球面

48、研磨过程示意图研磨工具(轮子) 的安装的磨削工具车轮已被广泛地用在常规的模具和模具精加工产业。安装的几何模型的整理工序引入英寸甲球面磨削工具自动化外表精加工处理模式的状态下，完成系统开发英寸磨削速度，切削深度，进给速率，如研磨材料和车轮属性自动化外表的磨削工具。和磨料颗粒的大小，是用于球形研磨过程的主要参数，如在图所示。1。的最正确的球形研磨参数用于注射模具钢中尚未调查是根据在文献中。在最近几年中，已经进行了一些研究，在确定球抛光过程图2的最优参数。比方，已发现，可以减少使用的钨硬质合金球或辊在工件外表上的塑性变形，从而改善外表粗糙度，外表硬度和耐疲劳性。抛光过程是通过加工中心和车床。主要的抛

49、光参数，具有显着的外表粗糙度的影响的滚珠或滚子材料，抛光力，进给速率，抛光速度快，润滑和抛光通行证的数量，等等。最正确的外表的塑料注射模具钢PDS5挤光参数的组合的润滑脂，碳化钨球的抛光速度为200毫米/分钟，抛光力，300 N，和一个饲料为40m。使用的最正确球抛光参数的磨光外表的渗透深度为约2.5微米。通过抛光过程中的改良的外表粗糙度一般介于40和90之间。图2 球面抛光过程概略图本文研究的目的是开发球面磨削球抛光外表处理工艺的自由曲面，塑料注塑模具加工中心。自动化外表精加工的流程图中，使用球面磨削和球抛光过程示于图3中。我们开始设计和制造的球面磨削加工中心上使用的工具，其定位装置。最正确

50、的外表球面磨削参数进行了测定，利用田口正交阵列的方法。四个因素，三个相应的级别，然后选择为田口L18矩阵实验。的最正确安装球面磨削参数，然后将其应用于自由曲面载体的外表光洁度的外表研磨。为了改善外表粗糙度，地面进一步打磨，使用的最正确球挤光参数。PDS试样的设计与制造选择最正确矩阵实验因子确定最正确参数实施实验分析并确定最正确因子进行外表抛光应用最正确参数加工曲面测量试样的外表粗糙度球研磨和抛光装置的设计与制造图3 自动球面研磨与抛光工序的流程图二、球研磨的设计和对准装置要进行可能的球形研磨过程中的自由曲面，球研磨机的中心应与z-轴的加工中心重合。的安装的球形研磨工具和其调整装置的设计，如在图

51、所示。4。电动研磨机中，安装在工具保持架有两个可调的枢轴螺钉。以及研磨机球的中心对准的圆锥槽的取向组分的帮助。对准的粉碎机球，两个可调节的支点螺丝拧紧后，对齐组件可以被删除。中心之间的偏差的坐标球研磨机的柄部的时间是约5微米，这是由一个数控三坐标测量机测量。由振动引起的力的机床吸收由一个螺旋弹簧。所制造的球形研磨工具和球磨光工具被安装，如下图 5。主轴被锁定的球面研磨过程和球抛光由主轴锁定机构的方法。模柄弹簧工具可调支撑紧固螺钉磨球自动研磨磨球组件图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.球抛光工具的图片三、矩阵实验的规划田口正交表 几个参数的影响，可以有效地进行矩阵实

52、验田口直交。要与上述球形研磨参数相匹配，研磨机的球直径为10毫米，进给速度，磨削深度，和革命的电动研磨机的研磨材料被选定为四个实验因素参数并指定为因子A到D见表1，在本研究中。每个因子的三个层次设置被配置为覆盖感兴趣的范围内，并确定了数字1，2，和3。三种类型的研磨材料，即，白色氧化铝Al2O3，WA，碳化硅SiC和粉红色的氧化铝Al2O3，宾夕法尼亚州，选择和研究。每个因子的三个数值的预研究结果的根底上确定的。 L18直交被选中的4个3级因素的球面磨削过程中进行矩阵实验。表1 实验因素和水平因素水平123A.碳化硅白色氧化铝粉红氧化铝B.50100200C.研磨深度m205080D.120001800024000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。 被加工面的外表粗糙度值经过适当地组合磨削参数，应小于原来的未加工外表。 因此,球面研磨