1、数控加工注塑模具板许多机械工程师在他大学毕业后加入了需要计算机数学控制（数控）的加工和设计部门，可是没有多少毕业生现成的使用 CNC机械生产复杂的 CNC 部件。如果学生们对数控编程、夹具、数控机床进行更加熟悉，在设计阶段我们可以避免许多制造难度和节约成本。为了解决这个问题，CNC 加工过程开发出来。这个设计需要学生为了兴趣去设计和制造注塑模具。这个设计是一个独特加工结构。在工业中为注塑模具而设计时，我们选择的注塑造型非常流行，许多有趣的设计所包含的内容被超越。这个工作展示了一个教授电脑辅助绘图，创新的结构化小团体，为了获得更好的部分生产设计，这个团体教授所需要的设计技工了。 问题教你如何最好
2、的学生设计的必要技能创建复杂的计算机数字控制（CNC）部分？图 1、使用，MILLTRONICS RW12（右数控轧机）与 MILLTRONICS（左后方）引言数控轧机，图 1，是一个非一般的生产工具，但是，一些机械工程毕业生获得这些经验的机器。建设数控一部分给学生的机会了解重要的设计约束数控制造业，然后使它们更好地设计数控零件。为了教数控设计技能，建立了一个具有挑战性的数控加工项目要求学生挑选一个独特的部分生产用注塑成型。学生开始使用两个 6“6 1”，“铝板注塑模具制造板块。板块的兴建，以适应小生产，注塑成型机，这对于课程设计，图 2 中使用。围绕学生工作限制，例如壁厚，起草角度，分型线，
3、数控机床等可为比注塑模具制造更多使用，为了学习必要的技能，以完成最后项目，学生完成了许多较小的项目努力实现的总体目标。为了让课程更多的结构分为六个主题。这六个主题是：手动车床手动磨电脑辅助绘图用 SolidEdge 的快速原型设计变更FastCam 软件简单数控项目CamWorks 软件更复杂数控零件图 2：注塑机手动车床为了让学生积极参与机械车间，学生完成一个小项目使用手动车床。该项目的选择是手动车床围绕建立一个习惯部分，将在以后的课程。第二天的课，学生有唯一一个车床零件图，他们必须建立。如图 4。学生进入了不同的加工过程背景，于是开始是手工加工，要建立一个基本的加工原则。安全是始终强调在学
4、习加工技能。该车床部分的大小，使其成为一个适合模具板使扑克筹码。学生们将一个设计到雕刻该车床的空白，才将筹码模具它。该扑克芯片设计的第一个项目竣工使用 CamWorks，这将是在这节中讨论。后车床项目，但仍然在该课程的第一周，学生学习使用手册厂。该手册是一厂重要的出发点前的学生尝试使用数控铣床。该手册厂提供学生有机会获得更多反馈比数控加工。它给学生一个机会听加工的错误，并认为需要削减的力量在这种情况下材料（铝） 。手工加工提供更多反馈错误发生之前，因此，最好学习主题之前，移动基本铣磨使用手册在数控铣床。第一年的课程开办，学生有一个铅笔持有人，他们切断尺寸图纸一个铝块，如图 5。图 3：并行学习
5、迈向塑料注射方法图 4：手动车床项目 - 扑克芯片为空图 5：手动轧机项目 - 笔筒该笔筒项目运作良好，对教学的基本手工加工技能，但它不是一个非常有用的一部分。铝阳极氧化的学生给它的颜色，但铅笔持有人往往丢弃后不久，该课程。第二年的课程讲授，手册铣床项目改为一个相框项目。改变项目 Thegoal 是给学生一个组成部分他们将要保留。学生更加努力地工作和学习如果能为他们的项目是令人兴奋的，他们获得投资希望他们的项目在转好。快速原型的零件清楚地表明他们的学生可能会选择进行设计更改。常常有许多意想不到的设计，一所做的更改结果演习。这些变化显着改善该学生素质和教学设计的一部分学生宝贵的设计经验。一些快速
6、成型零件见图9。当学生完成了该手册铣床铝框，铝框被氧化。后获得氧化蓝色，信是用一个雕刻品尼高激光雕刻机，它删除了阳极氧化着色层。用SolidEdge 的计算机辅助设计为了使用一个数控铣床学生首先需要学习如何使用 1 电脑辅助绘图（计算机辅助设计）封装。学生们经验的起草工作，但很少有经验 SolidEdge 的。经过几年的教学讲座，学生的学习 SolidEdge 的，并开始使一个 CAD 绘图过程预计的注塑成型件，图 7。完成后各部分积极，学生创造的在 SolidEdge 的模具板。图 6：手册修订轧机项目 - 相框图 7：学生 CAD 设计期末报告（所有项目都成功完成）图 8：例子中的快速成型
7、过程中所作的部件FASTCAM 数控软件对加工过程跟踪，教授学生使用数控编程模式会话。该Milltronics 公司（该玫瑰哈尔曼数控品牌机）使用一个程序要求conversationalprogramming FastCam。虽然不一定是 FastCa 所有数控制造商使用的，几乎所有的数控机床有一些互动式，对话式编程排序模式，可以通过编程在数控直接控制台。第一个项目，学生使用的数控加工轧机是基于一个简单的程序，钻孔拼自己的名字在木桩上，图 8。经过简单的程序漏洞，使学生独特的木制牌匾，图 9。课程开始加工木材，因为它的廉价和非常宽容的学生的错误。在一般情况下，这个类使用了大量的小项目学习加工步
8、骤。学生们通常只由于几天的小任务来完成，而不是更大，更费时的任务。图 9：第一台数控编配用 FASTCAM 建设图 10：扑克芯片插入和空的模图 11：成品扑克芯片采用车床坯CAMWORKS 数控软件在完成了许多中间数控项目使用 FastCam，教授学生使用CamWorks。 CamWorks 是一种程序，允许用户生成工具路径的数控机床使用的 CAD 一部分。 CamWorks 是埃弗里功能强大，用户友好的程序，工程作为一个插件与 SolidWorks。学生完成的第一个项目使用 CamWorks 是一个扑克芯片设计。学生剪了一个设计到他们的手工车床零件和收紧成的插入筹码模具板，图 10。模具板
9、进行了由罗恩霍夫曼，数控机床车间技术员，所以学生只需要作出插入设计。所有至少在一个芯片设计的学生扑克然后学生被要求出示塑料扑克芯片，图 11。这也给学生练习使用塑料注射前的最后项目成型机。最终项目这两年已经教这门课程，每一个学生完成了他们个人的模具塑料板和运行注塑机生产的零件。以创建注塑成型项目的学生需要他们的计算机辅助设计技术，数控加工技术，CamWorks 软件技能，知识和注塑成型。一些最后学生项目列于图 12 和 13。图 12：一个火箭模型完成的项目图 13：一个大理石的游戏完成的项目对于每一个问题学生盘旋了最佳答案多么重要的一个议题是：1 浪费时间2 不重要3 - 中性4 - 重要5
10、 非常重要除了要求对这些每重要性题目，学生也被要求排名如何选择好课堂作业所涵盖的主题。出于同样的六个课题，学生被要求圈最好的答案，他们觉得如何他们对这个议题的经验：1 浪费时间2 差经验3 - 公平经验4 很好的经验5 优秀的经验 二。评估结果出了 16 名学生入读课程 14 完成了调查。该平均值的重要性和经验。结果 POST 的课实验室调查议题的重要性体会手动车床 3.68 4.43 手册米尔 4.25 3.93 民航处使用 SolidEdge 的 3.82 4.14 快速原型4.21 4.57FastCam 软件 4.43 4.36 CamWorks 软件 4.71 4.57。评价为了评估
11、这些项目的成效，以教数控产品设计过程中调查后作出。一，评估方法该调查包括对 6 个问题。每问题问的教学后跟一个专题的重要性他们的任务以及如何帮助他们学习的主题。这六个课程的调查中列出专题为：本手册车床本手册米尔电脑辅助绘图用 SolidEdge 的快速原型设计变更FastCam 软件简单数控项目CamWorks 软件更复杂数控零件 三。评估结论这次调查的结果显示，整体学生感受到所选课程的主题是重要的，他们有好这些主题的学习经验。展望了反应，最低的具体两个重要的排名主题是手册车床和学习电脑辅助绘图（CAD ）的使用SolidEdge 的。事实上，学习使用手动车床是不是一个真正的重要的课题，学习前
12、学习数控加工。然而，为了完成扑克芯片项目，学生需要使用车床准备扑克芯片插入一个空白。虽然不是真正的必要课题，为学生的平均手动车床的经验是 4.43，所以它仍是一个有趣的学习经验。此外为使该手册车床一个良好的开端课程和额外的车间技巧使用SolidEdge 的。基于对这个问题的意见，任何低分数来自人民，要用SolidWorks 的，而不是 SolidEdge 的。 SolidEdge 的用这主要是因为价格。校园广泛牌照无限 SolidEdge 的席位较 aSolidWorks 合同便宜。这两个方案都非常相似，它非常容易导入文件来回。最低排名的经验是手工磨项目。工厂转让给该手册是梯形笔筒项目。在此基
13、础上反馈，第二年该项目已更改为相框项目。四。评估的意见除了 6 对有问题的也有一节对课程的意见。最大的问题似乎有关，调度机时代。有两个数控机器可以使用，但每个学生要使用较新的数控机床。因此，这是一个挑战，让所有的学生在数控机床。报名仅限于 16 至 18 努力帮助学生机调度和基于教师加载过程中只能提供每年一次。这意味着不到 20 个年级的学生可以学习本数控加工过程。因此，尽管这将是好的允许超过 18 个课程的学生，拥挤是已经是排名第一的投诉。因此，尽管高的学生，想借此课程数目，有每年学生非常低的吞吐量。结论该课程的总体目标是让学生成为更好的数控部分设计师。在设计过程中需要大量的工作。学生被迫感
14、受到任何穷人的负担设计选择和被迫重新设计和工作，直到项目已顺利完成。在学生当然，图16，学到的技能，使他们产生复杂数控一部分，并根据调查评估，是一个非常愉快的和有益的经验。在此过程中使用的各种机器：四个手动车床两个手册米尔斯阿品尼高激光雕刻机两个 Milltronics 数控铣刀FDM 与立体快速成型机小规模的塑料注塑成型机CNC Machining Plastic Injection Mold Plates in theClasssAbstract After finishing their undergraduate educationmany Mechanical Engineering
15、 graduates join industryand design parts thatre quire Computer-Numeric-Control(CNC) machining, but too fewgraduates have the knowhowto actually use a CNC machine to produce a complexCNC part. If students were more familiar with the processof programming, fixturing, and running a CNC machine,many of
16、the manufacturing difficulties and costs could be avoided in the design phase. In order to address this issuea CNC machining course has been developed that requires students to design and machine plastic injection mold plates for an interesting, unique 3D part. Plastic injection molding was chosen f
17、or its prevalence in industry and for the many interesting design constraints that must beovercome when designing for injection molding. This work shows an innovative, structured, small group approach to teaching the computer aided drafting, machine shop, and design skills necessary to achieve bette
18、r production part designs.Index Terms Computer-Aided Drafting, Design, InjectionMolding, Machining.QUESTIONHow do you best teach students the design skills necessary tocreate complex computer-numeric-controlled (CNC) parts?INTRODUCTIONA CNC mill, figure 1, is a very common manufacturing tool used in
19、 industry, however, relatively few mechanical engineering graduates get hands on experience with these machines. Building a CNC part gives student the opportunity to understand the important design constrains of CNCmanufacturing, which then makes them better designers for CNC parts.In order to teach
20、 CNC design skills, students built a challenging CNC machining project. Students were required to pick a unique part to produce using plastic injection molding. Students started with two 6” by 6” by 1” aluminum plates to create plastic injection mold plates. The plates were built to fit into a small
21、 production, plastic injection moldingmachine that was used for the course project, Figure 2. Students worked around restrictions such as, wall thickness, drafting angles, parting lines, etc. A CNC machine can be used for much more than making plastic injection molds, but this project provided a goo
22、d hands-on CNC experience that involved many interesting tolerance and design issues. Students work on learning both the computer drafting skills and the hands-on machining skills necessary to draft and build the mold plates. The overall path of the software and hardware objectives of course can be
23、shown graphically inFigure 3.In order to learn the skills necessary to complete the final project, students completed numerous smaller projects working towards the overall goal. In order to give the course more structure the individual assignments were grouped into six generalized topics. The six to
24、pics were: The manual lathe The manual mill Computer Aided Drafting using SolidEdge Rapid Prototyping for design changes FastCam software for simple CNC projects CamWorks software for more complex CNC partsMANUAL LATHEIn order to get students actively involved in the machine shop, students completed
25、 a small project using the manual lathe and manual mill. The project chosen for the manual lathe was to build a revolved part that would get used later in the course. The second day of class, students are given a dimensioned drawing of a lathe part that they must build, Figure 4. Students enter the
26、course with very different machining backgrounds, so starting with the manual machining is necessary to establish a basic understanding of machining principles. Safety is always stressed when learning machining skills. The lathe part is sized such that it fits into a mold plate that makes poker chip
27、s. Students will engrave a design ontothe lathe blank before putting it into the poker chip mold. The poker chip design is the first project completed using CamWorks, which will be discussed in that section.After the lathe project, but still in the first week of the course,students learn to use a ma
28、nual mill. The manual mill is an important starting point before students try to use a CNC mill. The manual mill offers students the opportunity to get more feedback than CNC machining. It gives students a chance to listen for machining errors and to feel the forces needed to cut the material (in th
29、is case aluminum). Manual machining provides more feedback before errors occur, so its better tolearn basic milling topics using a manual mill before moving to the CNC mill. The first year the course was offered, students were given a dimensioned drawing of a pencil holder that they cut from an alum
30、inum block, Figure 5. The pencil holder project worked well for teaching basicmanual milling skills, but it was not a very useful part. Students anodized the aluminum to give it color, but the pencil holders were often discarded shortly after the course. The second year the course was taught, the ma
31、nualmilling project was changed to a picture frame project. Thegoal of changing the project was to give the students a part that they would want to keep. Students work harder and learn more if the project is exciting for them and they get invested in wanting their project to turn out well. The dimen
32、sioned drawing for the picture frame can be seen in Figure 6 and a finished picture frame can be seen in Figure 7. After students finished the manual milling of the aluminum frame, the aluminum frames were anodized. After getting anodized blue, the letter engraving was done using a Pinnacle laser en
33、graver, which removed the colored anodized layer.CAD USING SOLIDEDGEIn order to use a CNC mill student first needed to learn to usea computer-aided-drafting (CAD) package. Students had experience with drafting, but few had experience with SolidEdge. After a few instructional lectures, students learn
34、 SolidEdge and began the process of making a CAD drawing of their expected plastic injection molding parts, Figure 8.After finishing the positive of the parts, students created themold plates in SolidEdge.RAPID PROTOTYPINGIn order to help with design, every student was required tobuild their part us
35、ing Rapid Prototyping (RP). At Rose- Hulman has two rapid prototyping machines available, one using Stereolithography, the other using Fuse Deposit Modeling (FDM). The rapid prototyped parts clearly showed the student where they might choose to make design changes.Often there were many unexpected de
36、sign changes made as a result of the exercise. These changes significantly improved the quality of the student part designs and taught students a valuable design lesson. Some of the Rapid Prototyping parts are shown in Figure 9. On the machining track of the course, students were taught to use the C
37、NC conversational programming mode. The Milltronics company (the brand of the Rose-Hulman CNC machines) uses a program called FastCam for conversationalprogramming. While FastCam isnt necessarily the program used by all CNC manufacturers, nearly all CNC machines have some sort of interactive, conver
38、sational programming mode that can be programmed directly on the CNC console.The first project that students machined using the CNC mill was based on a simple program that drilled holes to spell their name in wooden blocks, Figure 10. Following the simple holes programs, students made unique wooden
39、plaques, Figure 11. The course started with machining wood, since its cheap and very forgiving of student mistakes. In general, this class used a lot of small projects to learn machining steps. Students were usually only given a few days to complete the small tasks, as opposed tolarger, more time co
40、nsuming tasks.CAMWORKS CNC SOFTWAREAfter completing the numerous intermediate CNC projects using FastCam, students were taught to use CamWorks. CamWorks is a program that allows a user to generate tool paths for a CNC machine using a CAD part. CamWorks is avery powerful, user friendly program that w
41、orks as a plug-in with SolidWorks. The first project students completed using CamWorks was a poker chip design. Students cut a design into their manual lathe parts and tightened the inserts into a poker chip mold plate, Figure 12. The mold plates were made by Ron Hofmann, the CNC machine shop techni
42、cian, so students only needed to make the insert design. All of the students made at least one poker chip design and then the students were required to produce plastic poker chips, Figure 13. This also gave the students practice using the plastic injection molding machine before the final project.FI
43、NAL PROJECTBoth years this course has been taught, every student finished their individual mold plates and ran the plastic injection molding machine to produce their parts. In order to create the plastic injection molding projects students needed their CAD skills, CNC machining skills, CamWorks soft
44、ware skills, and plastic injection molding knowledge. Some of thefinal student projects are shown in Figures 14 and 15.ASSESSMENTIn order to assess the effectiveness of these projects to teach CNC product design a post course survey was given.I. Assessment MethodsThe survey consisted of six pairs of
45、 questions. Each question asked the importance of teaching a topic followed by how well their assignments helped them learn that topic. The six course topics listed on the survey were: The Manual Lathe The Manual Mill Computer Aided Drafting using SolidEdge Rapid Prototyping for design changes FastC
46、am software for simple CNC projects CamWorks software for more complex CNC partsSession S2AFor each question students circled the best answer for how important a topic was: 1 Very important 2 Important 3 Neutral 4 Not important 5 A waste of timeIn addition to asking the importance for each of these
47、topics, students were also asked to rank how well the chosen class assignments covered that topic. For the same six topics, students were asked to circle the best answer, for how they felt about their experience for that topic: 1 Excellent Experience 2 Good Experience 3 Fair Experience 4 Poor Experi
48、ence 5 A waste of timeII. Assessment ResultsOut of the 16 students enrolled in the course 14 completed the survey. The average value of the importance and experience is shown in Table 1.III. Assessment ConclusionsThe results of this survey suggest that overall students felt the chosen course topics
49、were important and they had good experiences learning these topics. Looking into the specifics of the responses, the lowest two ranking topics in terms of importance were the Manual Lathe and learning Computer Aided Drafting (CAD) using SolidEdge. Indeed learning to use a manual lathe is not a truly important topic to learn before learning CNC machining. However, in order to finish the poker chip project, studentsneeded to use the lathe to prepare a blank poker chip insert. While not truly a necessary to
