Amin 6,457 اشتراک گذاری ارسال شده در 25 دی، ۱۳۸۸ What IS Pro/ENGINEER? Actually, Pro/ENGINEER is a suite of programs that are used in the design, analysis, and manufacturing of a virtually unlimited range of products. In this lesson, we will be dealing only with the major front-end module used for part and assembly design and model creation, and production of engineering drawings. There are a wide range of additional modules available to handle tasks ranging from sheet metal operations, piping layout, mold design, wiring harness design, and other functions. You might like to visit the Parametric Technology Corporation home page to find out more. In a nutshell, Pro/ENGINEER is a parametric, feature-based solid modeling system. "Feature-based" means that you create your parts and assemblies by defining features like extrusions, sweeps, cuts, holes, slots, rounds, and so on, instead of specifying low-level geometry like lines, arcs, and circles. This means that you, the designer, can think of your computer model at a very high level, and leave all the low-level geometric detail for Pro/E to figure out. Features are specified by setting values of attributes such as reference planes or surfaces, direction of creation, pattern parameters, shape, dimensions, and others. "Parametric" means that the physical shape of the part or assembly is driven by the values assigned to the attributes (primarily dimensions) of its features. You may define or modify a feature's dimensions or other attributes at any time (within limits!). Any changes will automatically propagate through your model. You can also relate the attributes of one feature to another. For example, if you are designing a new engine, the diameter of the cylinder will automatically change if you change the diameter of the piston. "Solid Modeling" means that the computer model you create is able to contain all the information that a real solid object would have. It has volume and therefore, if you provide a value for the density of the material, it has mass and inertia. In the lectures we will discuss the differences between solid modelling and previous CAD paradigms such as 2D, 2-1/2D, 3D wireframe and so on. The most useful thing about solid modeling is that it is impossible to create a computer model that is ambiguous or physically non-realizable. Whether or not the part could actually be manufactured is another story! With solid modelling, you should not be able to create a model that could not physically exist. This is quite easy to do with just 2D or wireframe modelling. For example, the figure below shows what appears to be a three-pronged tuning fork at the left end, but only has two square prongs coming off the handle at the right end. The 3-Pronged Blivot An important aspect to feature-based modeling in Pro/E is the concept of parent-child relationships. Without going in to a lot of detail at this time, a child feature is one that references a previously created parent feature. A change to the parent feature will usually affect the child. For example, deleting a parent feature will delete all its children. Pro/E has special functions available to manage parent/child relationships. This can get pretty complicated with a complex model, so we will leave the details for later. However, you should keep parent/child relations in mind when you are specifying feature references for a new feature you are creating, If the parent feature is temporary or is likely to change, what effect will this have on the children? Will the references still correctly capture your design intent? Once your model is created, it is very easy to get Pro/E to produce fully detailed standard format engineering drawings almost completely automatically. In this regard, Pro/ENGINEER also has bidirectional associativety - this means you can change a dimension on the drawing and the shape of the model will automatically change, and vice versa. To a new user of the program, this is almost magic! If you do not at some point say (or at least think) "WOW!" while learning how to use Pro/E, then you are very hard to impress indeed. برای مشاهده این محتوا لطفاً ثبت نام کنید یا وارد شوید. ورود یا ثبت نام 2 نقل قول لینک به دیدگاه
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