Computer Aided Design 3
Assignment
Assembly Model and Individual Report TUTOR: Tony Roberts
STUDENT NAME: Arvydas Gordejevas
STUDENT NO: 2602021
SUBMISSION DATE: 20th May 2011
Contents 1. Commentary (Overall Design and Manufacturing Process) ................................................................ 2 2. Design for Manufacture and Assembly ............................................................................................... 2 3. Commentary (Collaborative Design Project) ...................................................................................... 5 4. Personal Progress ................................................................................................................................ 5 5. 3D Vehicle ........................................................................................................................................... 6 6. Exploded Assembly Model .................................................................................................................. 7 7. 2D Data Including Bill of Materials ..................................................................................................... 9
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1. Commentary (Overall Design and Manufacturing Process) The start of our project made us to go and do the research, which was very hard when you don’t understand what you are looking for. But it helped to learn more about ways of researching. First of all the design of radio control vehicle, from last year, have been looked at, which helped to understand a bit more what our part suppose to do – its purpose. After the research I start looking at how I going to design my part. This is where the different views have been used for our prospect. Things that are making your part to be constraint to something, leaving your creation less flexible, but in same time more challenging. It also needed to be thought how the product going to be maintained, how assembled, who is going to assemble it, and so on. The overall design of the radio controlled vehicle has been fully completed. Of course you will always find parts that could be improved better in one or another way. But that is where the meaning of the future starts: where won’t be things that couldn’t be improved, not with the technologies ant abilities we can get. I bet next year’s students will find things that they would do differently than from our perspectives. And this is what helps to know what you are doing: understanding your project background and filling its gaps. Manufacturing progress helped me to understand more about how computers can be helpful in producing parts. It is a pity that we didn’t made to the workshop to make our physical part using CNC machining, but learning how it can be done on NX6 and seeing a virtual mode of manufacturing process gave me a visual understanding of how it’s done and what steps need to be taken to achieve the final result.
2. Design for Manufacture and Assembly 1 Design for manufacture and assembly is a key facilitator of design and manufacturing integration. Through the use of some simple rules and additional numerical evaluation products may be effectively and efficiently examined for their ease of manufacture and assembly. Design for manufacture and assembly techniques are an engineering responsibility that provide a total product view. As such they must be applied early on in the development process before resource is committed to any one design and thus costly production problems avoided. Three well known ‘design for assembly’ techniques are those of Boothroyd‐Dewhurst and Lucas design for assembly (DFA) and Hitachi assemblability evaluation method (AEM) (Leaney, 1996a). These techniques are evaluative methods that analyse the cost of assembly of designs at an early stage in the design process, and use their own synthetic data to provide guidelines and metrics to improve the assemblability of the design (Leaney et al., 1993). The boothroyd‐Dewhurst DFA evaluation centres on establishing the cost of handling and inserting component parts. The process can be applied to manual or automated assembly, which is further subdivided into high speed dedicated or robotic. Regardless of the assembly system, parts of the assembly are evaluated in terms of ease of handling, ease of insertion and an investigation for parts reduction. The opportunity for this reduction is found by examining each part in turn and identifying
1
Happian‐Smith. J, (2001) Introduction to Modern Vehicle Design. 1st ed. Oxford: A Butterworth‐Heinemann Title.
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whether each exists as a separate part for fundamental reasons. The fundamental reasons are (Boothroyd and Dewhurst, 1989): 1. During operation of the product, does the part move relative to all other parts already assembled? Only gross motion should be considered – small motions that can be accommodated by elastic hinges, for example, are not sufficient for a positive answer. 2. Must the part be of a different material or be isolated from all other parts already assembled? Only fundamental reasons concerned with material properties are acceptable. 3. Must the part be separate from all those already assembled, because otherwise necessary assembly or disassembly of other separate parts would be impossible? In addition to DFA analyses, design for manufacture (DFM) analyses are used to aid in the detail design of parts for manufacture. DFM tools such as design for machining and design for sheet metalworking have been developed by the Boothroyd‐Dewhurst partnership to address specific processes and the design of parts suited to those processes (Boothroyd, Dewhurst and Knight, 1994). Since the early implementations of DFMA tool, steps have been taken to provide a more intergrated approach covering a greater portion of the product life cycle. Boothroyd‐Dewhurst have developed a number of Windows‐based tools and Lucas DFA has been incorporated into an integrated suite called TeamSET (Tinnetts, 1995). The tools are specific implementations of basic set of guidelines for DFA which are aimed at raising the awareness of engineering to the importance of assembly. The generic guidelines (Leaney and Wittenberg, 1992) are: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
Reduce the part count and types Modularize the design Strive to eliminate adjustments Design parts for ease of feeding or handling Design parts to be self aligning and self locating Ensure adequate access and unrestricted vision Design parts so they cannot be installed incorrectly Use efficient fastening or fixing techniques Minimize handling and reorientation Utilize gravity Maximize part symmetry Strive for detail design that facilitates assembly
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For central differential part the following DFM/A has been looked at:
1. The extruded part with a shape on it (circled in red ellipse) is designed to be installed to the chassis correctly. It also helps to be self aligned and self located, therefore makes the whole part to be installed with no mistakes. 2. It is also designed to fit two parts together correctly, self aligned and self located. For this you’ll find two pins and two pin holes on each side of the part. 3. Plus the design has been looked carefully for the future maintenance. At this point the top part can be unscrewed with two long screws, which holds the top part plus it gives an extra support to hold on the chassis, therefore it can be lifted up to get the access to the central differential, while the bottom part stays secured to the chassis. 4. And the last, but not least ‐ grooves have been made for the central differential to fit in, plus smaller diameter groove with the small wall thickness created to hold differential inside without any movements to the sides. 4 | P a g e
3. Commentary (Collaborative Design Project) My collaborative group: 1. 2. 3. 4.
Ivan – engine mounting Tayo – disk brake system Silvio – rear differential Abdel – front differential
Ivan was the most collaborative person at the beginning of this project because the biggest question was – where the engine was going to be mounted and how is it going to be mounted. These questions depended on the position of my central differential. With good communication throughout the whole project a lot of problems have been solved without any disagreement. Thus, giving all the reasons and understanding for our own responsible parts made things easy. Tayo advised at the beginning of the project that he would like to keep the braking system in the same position as last year, helping me know what I would need to consider for my part. With Silvio and Abdel collaboration was perfect. It was easy to agree with the height of the central differential dogbone, and they agreed to keep the same differential system that I intended to use, which is helping with making it easier to calculate the vehicles speed. At the end of this project it drew me in and I couldn’t help myself from wanting to have the perfect end result, therefore I was trying to motivate all our team members to do their best, and helped everyone and everywhere I could.
4. Personal Progress At the beginning of this project I was lost and didn’t understand what I was supposed to do. I didn’t know anything about radio controlled vehicles or anything about cars, and that’s why I felt like that ‐ lost. Throughout the research process, not only did I get comfortable with the part I was responsible for but also at the end of this project I now understand what drives a radio controlled vehicle and feel like I could design it all on my own. I believe that all this knowledge has been received throughout the whole design process, its problems finding and collaborating with the team and coming to the project meetings and trying to overcome any obstacles that were stopping us from moving forward. At the end of the project, I’ve taken responsibility to assemble a 3D vehicle. I was compiling all the parts into one folder and was trying to keep it very tidy. At the beginning of this project, I had noticed that all the previous year’s cars and their folders weren’t organised at all. They had the same files duplicated in almost all of their parts and some of them weren’t in the right directory which was then starting to create problems in opening files (parts). In addition to this, it made it more difficult to find the parts we were looking for. Therefore, I was trying to keep our vehicle folder free of duplicated parts, gave the name of one folder ‘car components’ – which was assigned to keep all the parts that we had used in our vehicle separate to what was used last year and folders, with our 5 | P a g e
names, representing the person responsible for their parts. I also kept the 3D assembly tidy too, grouped all the parts with relative ones. Personally this project gave me strength to believe in myself more, showed me how the group projects can help to solve any problem, even the ones that you are not familiar with. It also showed how good communication between the group members is important to get to the final stage without any mistakes.
5. 3D Vehicle This is a 3D vehicle from different point of views. The whole 3D assembly made on ‘Solid Edge’ is copied inside the CD, which is attached at the back of this report.
Picture 1 Side View
Picture 2 Top View
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Picture 3 Front View
Picture 4 Back View
Picture 5 ISO View
6. Exploded Assembly Model Next is exploded view of the assembly model. This also is available to view from ‘Solid Edge’ by changing a view to ‘Final Exploded’. Please note that exploded view haven’t been considering to all the single bits in a vehicle as individual exploded view of the responsible part have been made in previous assignment.
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PLACE
2
5
BILL OF MATERIALS DESCRIPTION
1
CENTRAL DIFFERENTIAL
2
FRONT DIFFERENTIAL
3
REAR DIFFERENTIAL
4
ENGINE MOUNTING
5
COOLING HEAD
6 7
FRONT SUSPENSION REAR SUSPENSION
MATERIAL ALUMINIUM 7075-T5 ALUMINIUM 7075-T5 ALUMINIUM 7075-T5 ALUMINIUM 7057-T5 ALUMINIUM ALLOY 413.0 STEEL STEEL
6 4
1
Solid Edge
3
DRAWN
NAME DATE Gordejevas 19/05/2011
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TITLE: 3D Exploded Vehicle SIZE DWG NO
UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN MILLIMETERS
A4 FILE NAME: 3D Exploded View SCALE: 1 : 5 WEIGHT:
REV
SHEET 1 OF 1
Solid Edge DRAWN
NAME DATE Gordejevas 19/05/2011
TITLE: Complete 3 View Vehicle SIZE DWG NO
UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN MILLIMETERS
A4 FILE NAME: Complete Vehicle SCALE: 1 : 5 WEIGHT:
REV
SHEET 1 OF 1