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quinta-feira, 26 de março de 2015

Flexures!

Não há maneira de se exagerar a importância DESTA Lição do Grande Mestr, Dan Gelbart, o que isto abre de possibilidades para o Corte Laser CNC é incrível, imagines, máquinas de uma peça só e fazer do Acrílico, material de Mola!

Nem cá ponho mais do que estas Fontes de Sabedoria, para que vocês se CONCENTEM só nesta Matéria fenomenal...

Vejam só esta imagem!


Uma máquina de 1 SÓ PEÇA, com 2 Alavancas, e Molas Lineares!


Building Prototypes Dan Gelbart part 10 of 18 Flexures







Mas tem ainda mais, pessoal das Engenhocas e Fabbers, uma Lição completa do MIT...
Sobre o mesmo assunto, mais aprofundado!


Flexures

© Marcel Thomas

1 Introduction
Flexures are bearings that allow motion by bending load elements such as beams. The arrangment of beams can be designed to be compliant in its degree(s) of freedom (DOF), but relatively stiff in its degree(s) of constraint (DOC). This allows engineers to provide motion in desired directions, but constraint in other directions. Flexures are important for engineers because they allow stiction-less, controlled, limited-range motion. These well-designed, well-understood springs can then be implemented in precision machines to allow the development of medical devices and machines for electronic fabrication. This entry is about understanding the most important parameters for flexure design. The functional requirements for flexures include (but are not limited to): desired kinematics, range of motion, stiffness, load capacity, repeatability, mode shapes/frequencies, and an error budget.
Designing flexures involves developing a model, using FEA, and experimentally verifying the models. There should be a pencil-and-paper approximation that allows you to see which variables are most important and it gets you in the ballpark of the correct dimensions. In other words, the model shows you which direction to go and by how much. How short can I make this beam so that it can be at 30% of the yield stress? The model should answer questions like that, keeping real-world constraints in mind.
By carefully applying these equations to your system, you should have a decent approximation for its behavior. Once the equations are developed, you should put these variables in a MATLAB script or an Excel spreadsheet. That way, you can change one variable at a time and see how that affects the entire system. Flexures are typically modeled using FEA, which is the subject of another entry.




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