计算机辅助制造CAM习题答案

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Chapter 2
2.7 For NC part-programming purposes, one has to know the exact surface being machined. Which CAD representation scheme(s) is appropriate for this application?
Review Questions
Chapter 1
1.1 Discuss the advantages and disadvantages of using transfer-line technology in a high-tech manufacturing facility.
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Mass production with transfer line helps to produce more, better, and less expensive goods. Transfer line with automated machines and systems outproduce tens of hundreds of human workers. Mass-produced identical goods were plentiful and inexpensive. However, variety is limited due to the high cost of change over in the manufacturing system.
Chapter 2
2.3 Discuss the advantages and disadvantages of using a 3-D solid model in mechanical part design.
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A 3-D solid model not only captures the complete geometry of an object but it also can differentiate the inside and the outside of the space occupied by the object in three-dimensional space. By using this property the volume of the object and the intersection between two objects can be calculated. Many other volumerelated properties can also be obtained from the model. Hidden surface/line removal and a shaded image can be produced as well. Solid models contain complete information; therefore, not only can they be used to produce engineering drawings, but engineering analysis can be performed on the same model as well.
Chapter 1
1.2 Discuss the mechanical designer’s role in a manufacturing facility.
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Product design is the first step of the manufacturing activity that deals with the conceptualization and planning of the physical and functional characteristics of a product. The purpose of engineering design is to study how to design a product so that manufacturing cost and time can be reduced while preserving the functional requirements of a product.
Chapter 1
1.3 What are major developments of CAM technology?
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The major technologies of CAM include CAD, group technology (GT), computer-aided process planning (CAPP), NC, flexible manufacturing systems (FMSs), computer-integrated manufacturing (CIM) and so on.
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Figure 2.22
V1 L1 V2 L3 V2 V6 V2 V6 L4 F3 V3 V7 F1 F2 F3 F4 F5 F6 F7 F8 L1 L2 L3 L4 L5 L6 L7 L8 L9 E99 V9 V9 E1010 V10 V10 V6 F6 L7 V7 L9 F8 V5 F2 V5 L8 F7 V10 V3 V10 V7 L5 F4 V1 F1 L2 V3 F5 V9 V5 V8 V4 V8 V9 V4 V1 L6 V4
F - E + V =2
4-6+4=2
Figure 2.18 Topology of a tetrahedron
Chapter 2
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2.12 Show a B-rep of the part shown in Figure 2.47.
V1 L1 V2 L3 V2 V6 V2 V6 L4 F3 V3 V7 F1 F2 F3 F4 F5 F6 F7 F8 L1 L2 L3 L4 L5 L6 L7 L8 L9 E12 E23 E34 E14 V1 V2 V3 V4 V6 F6 L7 V7 L9 F8 V5 F2 V5 L8 F7 V10 V3 V10 V7 L5 F4 V1 F1 L2 V3 F5 V9 V5 V8 V4 V8 V9 V4 V1 L6 V4
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V1 L1 V2 L3 V2 V6 V2 V6 L4 F3 V3 V7 F1 F2 F3 F4 F5 F6 F7 F8 L1 L2 L3 L4 L5 L6 L7 L8 L9 E99 E910 E1010 V9 V10 V6 F6 L7 V7 L9 F8 V5 F2 V5 L8 F7 V10 V3 V10 V7 L5 F4 V1 F1 L2 V3 F5 V9 V5 V8 V4 V8 V9 V4 V1 L6 V4
Chapter 2
2.3 Discuss the advantages and disadvantages of using a 3-D solid model in mechanical part design.
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Although they are powerful in representation, many deficiencies still exist. For example such systems have extreme computation and resource (memory) requirements, an unconventional way of modeling objects and a lack of tolerances capability have all hindered CAD applications.
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Chapter 2
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2.8. Show mathematically that the B-Rep file in Figure2.18 is a valid solid. (Use Euler’s formula)
For objects without holes, Euler-formula
Chapter 1
1.4 What is the trend of manufacturing?
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From both the product demand and manufacturing batch size, we can see a trend of manufacturing. Before the Industrial Revolution, demand was low and products were all custom-made. Machine shops produced primarily small-batch products. From the turn of the century to the 1950s, the world was transformed from a society with few industrial products for few people to abundant products for everybody. Demand for industrial products grew fast, and to respond to the demand, mass-production techniques were developed. However, the desire to have more product variety has changed production from high volume to medium-and small-batch quantities.
Chapter 2
2.6 What are t来自百度文库e differences between a wire-frame model and a solid model?
wire-frame model Representation bounding edges Information ambiguous Volumetric property no Hidden image no solid model entities complete yes yes
Wire-frame model: only boundary edges information � Surface model: boundary edges + surface can’t tell the difference of inside and outside of the surface � Solid model: complete information can differentiate the inside and the outside of the surface
Chapter 1
1.4 What is the trend of manufacturing?
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In the 1980s, small batch dynamic production environs are needed. The production technology that has resulted produces better, inexpensive products in response to rapid demand changes. In the modern manufacturing industry, it is predicated on automation while maintaining its flexibility. Automation should provide good quality and low cost, and flexibility, all necessary to adapt to changes of the product and demand.