【機械類文獻翻譯】基于注塑模具鋼研磨和拋光工序的自動化表面處理

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. 中文譯文基于注塑模具鋼研磨和拋光工序的自動化外表處理摘要這篇文章研究了注塑模具鋼自動研磨與球面拋光加工工序的可能性，它可以在數(shù)控加工中心完成注塑模具鋼PDS5的塑性曲面。這項研究已經(jīng)完成了磨削刀架的設(shè)計與制造。 最正確外表研磨參數(shù)是在鋼鐵PDS5 的加工中心測定的。對于PDS5注塑模具鋼的最正確球面研磨參數(shù)是以下一系列的組合：研磨材料的磨料為粉紅氧化鋁，進給量50毫米/分鐘，磨削深度20微米，磨削轉(zhuǎn)速為18000RPM。外表粗糙度Ra值可由大約微米改善至微米，通過用優(yōu)化

47、的參數(shù)進行外表研磨。 如果用球拋光工藝和參數(shù)優(yōu)化拋光，還可以進一步改善外表粗糙度Ra值，一般從微米至微米左右。而在模具內(nèi)部曲面的測試局部，用最正確參數(shù)的外表研磨、拋光，曲面外表粗糙度就可以提高約微米至微米。關(guān)鍵詞: 自動化外表處理 拋光 磨削過程 外表粗糙度 田口方法 一、引言步距研磨高度球磨研磨進給速度工作臺由于塑膠工程材料的重要特點,比方耐化學(xué)腐蝕性、低密度、易于制造,并且已經(jīng)日漸取代了金屬部件在工業(yè)中廣泛應(yīng)用。 在注塑成型領(lǐng)域，其對于塑料制品是一個重要工藝。設(shè)計的本質(zhì)要求是注塑模具的外表質(zhì)量,因為它直接影響了塑膠產(chǎn)品的外觀和性能。 加工工藝如球面研磨、拋光常用于改善外表光潔度。圖1 球面

48、研磨過程示意圖研磨工具(輪子) 的安裝的磨削工具車輪已被廣泛地用在常規(guī)的模具和模具精加工產(chǎn)業(yè)。安裝的幾何模型的整理工序引入英寸甲球面磨削工具自動化外表精加工處理模式的狀態(tài)下，完成系統(tǒng)開發(fā)英寸磨削速度，切削深度，進給速率，如研磨材料和車輪屬性自動化外表的磨削工具。和磨料顆粒的大小，是用于球形研磨過程的主要參數(shù)，如在圖所示。1。的最正確的球形研磨參數(shù)用于注射模具鋼中尚未調(diào)查是根據(jù)在文獻中。在最近幾年中，已經(jīng)進行了一些研究，在確定球拋光過程圖2的最優(yōu)參數(shù)。比方，已發(fā)現(xiàn)，可以減少使用的鎢硬質(zhì)合金球或輥在工件外表上的塑性變形，從而改善外表粗糙度，外表硬度和耐疲勞性。拋光過程是通過加工中心和車床。主要的拋

49、光參數(shù)，具有顯著的外表粗糙度的影響的滾珠或滾子材料，拋光力，進給速率，拋光速度快，潤滑和拋光通行證的數(shù)量，等等。最正確的外表的塑料注射模具鋼PDS5擠光參數(shù)的組合的潤滑脂，碳化鎢球的拋光速度為200毫米/分鐘，拋光力，300 N，和一個飼料為40m。使用的最正確球拋光參數(shù)的磨光外表的滲透深度為約2.5微米。通過拋光過程中的改良的外表粗糙度一般介于40和90之間。圖2 球面拋光過程概略圖本文研究的目的是開發(fā)球面磨削球拋光外表處理工藝的自由曲面，塑料注塑模具加工中心。自動化外表精加工的流程圖中，使用球面磨削和球拋光過程示于圖3中。我們開始設(shè)計和制造的球面磨削加工中心上使用的工具，其定位裝置。最正確

50、的外表球面磨削參數(shù)進行了測定，利用田口正交陣列的方法。四個因素，三個相應(yīng)的級別，然后選擇為田口L18矩陣實驗。的最正確安裝球面磨削參數(shù)，然后將其應(yīng)用于自由曲面載體的外表光潔度的外表研磨。為了改善外表粗糙度，地面進一步打磨，使用的最正確球擠光參數(shù)。PDS試樣的設(shè)計與制造選擇最正確矩陣實驗因子確定最正確參數(shù)實施實驗分析并確定最正確因子進行外表拋光應(yīng)用最正確參數(shù)加工曲面測量試樣的外表粗糙度球研磨和拋光裝置的設(shè)計與制造圖3 自動球面研磨與拋光工序的流程圖二、球研磨的設(shè)計和對準裝置要進行可能的球形研磨過程中的自由曲面，球研磨機的中心應(yīng)與z-軸的加工中心重合。的安裝的球形研磨工具和其調(diào)整裝置的設(shè)計，如在圖

51、所示。4。電動研磨機中，安裝在工具保持架有兩個可調(diào)的樞軸螺釘。以及研磨機球的中心對準的圓錐槽的取向組分的幫助。對準的粉碎機球，兩個可調(diào)節(jié)的支點螺絲擰緊后，對齊組件可以被刪除。中心之間的偏差的坐標球研磨機的柄部的時間是約5微米，這是由一個數(shù)控三坐標測量機測量。由振動引起的力的機床吸收由一個螺旋彈簧。所制造的球形研磨工具和球磨光工具被安裝，如下圖 5。主軸被鎖定的球面研磨過程和球拋光由主軸鎖定機構(gòu)的方法。模柄彈簧工具可調(diào)支撐緊固螺釘磨球自動研磨磨球組件圖4 球面研磨工具及其調(diào)整裝置圖5 a 球面研磨工具的圖片. b.球拋光工具的圖片三、矩陣實驗的規(guī)劃田口正交表 幾個參數(shù)的影響，可以有效地進行矩陣實

52、驗田口直交。要與上述球形研磨參數(shù)相匹配，研磨機的球直徑為10毫米，進給速度，磨削深度，和革命的電動研磨機的研磨材料被選定為四個實驗因素參數(shù)并指定為因子A到D見表1，在本研究中。每個因子的三個層次設(shè)置被配置為覆蓋感興趣的范圍內(nèi)，并確定了數(shù)字1，2，和3。三種類型的研磨材料，即，白色氧化鋁Al2O3，WA，碳化硅SiC和粉紅色的氧化鋁Al2O3，賓夕法尼亞州，選擇和研究。每個因子的三個數(shù)值的預(yù)研究結(jié)果的根底上確定的。 L18直交被選中的4個3級因素的球面磨削過程中進行矩陣實驗。表1 實驗因素和水平因素水平123A.碳化硅白色氧化鋁粉紅氧化鋁B.50100200C.研磨深度m205080D.120001800024000數(shù)據(jù)分析的界定 工程設(shè)計問題,可以分為較小而好的類型,象征性最好類型,大而好類型，目標取向類型等。 信噪比(S/N)的比值，常作為目標函數(shù)來優(yōu)化產(chǎn)品或者工藝設(shè)計。 被加工面的外表粗糙度值經(jīng)過適當?shù)亟M合磨削參數(shù)，應(yīng)小于原來的未加工外表。 因此,球面研磨