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L06 - Coggle Diagram
L06
Dimensioning
Parallel Dimensioning
Consists if several dimensions originating from a common reference surface surface also known as the datum
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Chain Dimensioning
Should only be used if the function of the object would not be affected by the accumulation of the tolerances
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Dimensioning of Circle, Arc and Hole
A circle is dimensioned by its diameter. An arc is dimensioned by its radius. Holes are located by their centerlines
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Assembly Modeling
In an assembly model, multiple parts are brought together to define a larger, more complex product representation. Assembly modelling facilitates the collaboration among designers, engineers, manufacturing technicians and others to ensure a product assembly works. Individuals in different disciplines can work concurrently, resulting in faster and less costly delivery of products to market.
How it works
Constructing an assembly normally begins with bringing in a base component, selected because of its central role. Each component brought in needs to be oriented and located relative to other components in the assembly. Assembly joints are used between elements of components.
In Fusion 360, multiple parts can be created and assembled in the same file. In many other CAD software, there will be individual part files, and an assembly file to place all parts together.
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Tolerance
Why is it important?
If tolerance is not given, exact measurement of the parts must be made. Rejection rate will be very high and is not realistic
The range of tolerance will translate into the manufacturing method needed, since different manufacturing method has different degree of tolerance
Same parts can be made from different companies and they have to be interchangeable. Tolerance ensures good quality control for parts from different companies
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Types
Bilateral Tolerance
Allowed to vary in two directions from the specified dimension. Both directions need not vary by the same amount
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Clearance Fit
Clearance fit is an air space or clearance which exists between the shaft and holes. Such clearance fits give loose joints. The clearance fit has to be joined with other fits so that the clearance fit can have its space
Inference Fit
a rigid shaft is joined to a more ductile hub or boss by a dimensional interference between the outside diameter of the shaft and the inside diameter of the hub.