Assembly of a Simple Clamping System Under a Virtual Environment
Team 4
ENME 414 – Dr. Zhang
12/12/1999
By:
Victor Basumallick
Christina Burek
Steven Deutch
Peter J. Orlik
Table of Contents
Title Page
Abstract 3
Introduction 3
Basic Methodology/Approach 3
Summary 7
Appendix 1 9
- Bill of Materials
Appendix 2 10
- Assembly Drawings
Abstract
In order to develop a cost effective & time reducing assembly process in the Pro/Engineer 2000 environment, it was necessary to re-define the purpose of our project and identify the necessary steps for its completion. Then the parts list was developed and 3-D models were created (see Appendix 1 & 2). A rough draft was constructed labeling each part’s functional requirements. Team 4 used Pro/Engineer 2000 to create several animated assembly processes. This provided an order to which the parts would be assembled. After reviewing the assembly procedures, one final procedure will be developed and animated in Pro/Engineer 2000. Additionally, the team developed a web page to document the progress and success of the project.
Introduction
In today’s cutting edge marketplace, companies need to develop innovative ways of keeping manufacturing costs down in order to keep their products competitively priced. In the manufacturing arena, the assembly process is one area where excessive cost has been significantly reduced or eliminated by using CAD software to create assemblies in the cost free environment of the virtual computer world. Team 4’s goal was to study and recreate an assembly process and/or operating procedure for manufacturing components using Pro/Engineer 2000. The team then animated the process to view the assembly sequence of components on the shop floor.
Basic Methodology/Approach
Overview
The creation of an animation sequence of the injection mold requires that the parts be created and assembled. The assembly sequence needs to be constructed as simply and efficiently as possible, to accurately represent parts on the shop floor which maybe considerably large and difficult to handle. The animation was constructed using the Pro/Engineer 2000 animation package. The animation of the injection mold follows the order in which it was assembled in Pro/Engineer (see Appendix 1 for parts list). First, the base part was called into the main window. Then each additional part was brought in and aligned to the "base" part, much in the same way as it was done in the assembly. When the component is finished being assembled, the animation file is converted to a movie format such as ".mpg".
Assembly and Animation Sequence
After several revisions of the initial assembly, Team 4 concluded that two subassemblies were required to assemble the injection mold. The two subassemblies were needed to eliminate the interference due to the dowels, which prevented the pins from being inserted into the arm of the base plate. The first step was to put together the first subassembly (see Figure 1).
Figure 1. The First Subassembly consisting of the Middle
Plate, 2 Pins, and 2 Broad Arms.
The subassembly was required since the dowels in the main assembly (see Figure 3) prevented the pins from being inserted into the joints of the broad arms and the middle plate. The subassembly was put together by aligning the hole at one end of the broad arm to the hole on the protrusion of the middle base plate. While the holes were aligned a pin was slid into the hole, holding the two parts together. The process was repeated for the remaining broad arm.
Second step was to slide the four dowels, one by one, through the four corner holes of the middle base plate. Then the right base plate was inserted onto the dowels. The nuts and washers were screwed in place to secure the right base plate on the dowels.
The third step was to make the second subassembly (see Figure 2). This subassembly was required for the same reasons as the first subassembly, to circumvent the dowels of the main assembly.
Figure 2. The second subassembly consisting of
the Left Base Plate, 4 Arms, and 2 Pins.
The construction of the left sub assembly was similar to the construction of the first subassembly. One of the arm’s holes was aligned with a hole on one of the two protrusions on the base plate. Once aligned, a pin was inserted and the second arm was aligned and placed on the other side. This process was repeated for the second set of arms.
The next step in the assembly process was to slide the previous subassembly into the four remaining ends of the dowels, making sure that everything aligned properly. To ensure this alignment, the middle assembly was slide from one end of the dowels (where the right base plate was place) to the left end of the dowels. By sliding the middle base plate to the right end the dowels were brought into alignment and allowed the second subassembly to be easily placed onto the four dowels. Then the four remaining washers and nuts were screwed into place.
The last step was to align the top most broad arm on the middle base plate with the corresponding top two arms on right base plate and slide in a pin into the hole. This process was repeated for the bottom broad arm and corresponding arms. This concludes the assembly process of our injection mold (see Figure 3).
Figure 3. Finished assembly of the injection mold.
Movie Creation
After the animation is finished, the file is converted into a playable movie format such as “.mpg”. The movie is made by taking the animation file and saving it as a “.vrml” file. Then this file is played and recorded simultaneously using the "Pro/Fly-Through" option. This file specifies the “flight path” of the file. This file is saved as a “.mpg” file, which can then be played on “.mpg” players such as Windows Media Player.
Web Page Creation
Team 4 created a web page in order to display the animated training video to a wider audience. The address is: Web pages are written in a script called html, which stands for HyperText Markup Language. The content of the page is typed in plain text. Formatting and images are added using tags such as <a href…> (for a link) and <b> (for bold text). The framework of the web page is structured information, and it may contain images or multimedia files that the user can download for General Image Format, and is the most efficient way of putting images on the web. The JPEG format is better for photographs and many color images. A model from Pro/Engineer must be changed to a different format before it can be used in other applications, such as PhotoShop. A screen capture can be made using the camera on the Silicon Graphics Interfaces. This will initially be saved in .sgi format. To alter the format, double click on the image’s icon and change the options. Team 4 found that saving the images in TIF format worked best for transporting them to PhotoShop. Once in PhotoShop, the image can be resized, changed color, and/or saved as a different format such as JPEG.
Images and words can be used as links within the document for navigation purposes. The user clicks on these links, which act as buttons. Team 4’s web page uses frames, which is another tool to control navigation. This separates the screen into distinct areas that contain different types of material. The menu on the side stays in place while the content of the main frame changes as a result of navigation on the menu.
Microsoft PowerPoint, a presentation/slide package, has a tool to convert slides to html format for the web. For multimedia, like the animation movie, the simplest thing to do is make it downloadable. Team 4 made a link to the MPEG file that was created from the Pro/Engineer 2000 animation. The link simply accesses the file in the public directory and ftp it to the user’s computer.
Summary
Most of our time has been spent learning the animation function in Pro/Engineer 2000. There is a different vocabulary associated with the animation function. There are events and key frame sequences. There are snapshots, which can be interpolated into a smooth motion, and there are drivers, which specify motion using a driving function (such as rotation or a sine curve).
By incorporating the subassemblies, time has been saved as two different groups could work on the two different subassemblies and then bring them over to another person or group to assemble the entire unit. This would allow the two-subassembly groups to start to work on another subassembly. This is a very efficient process, saving time and increasing worker productivity.
The assembly process is a key component in making any product viable commercially. If something cannot be assembled quickly and efficiently, then the amount of money spent on manufacturing increases, which results in the product having a larger market price. While on the other hand, a correct and efficient assembly process can cut time and costs, allowing a smaller price tag on the market shelf.
Our end goal applies Pro-Engineer technology to provide on-the-spot automated instructions to assembly line workers. This will free the supervisors to worry about larger problems, and thus make the assembly plant more efficient.
Appendix 1
Bill of Materials
1
Right Base Plate (1) Middle Base Plate (1) Left Base Plate (1)
Threaded Dowels (4) Pins (6) Washers (4)
Nut (8) Arm (4) Broad Arm (2)
Appendix 2
Part Drawings
1