Assembly Modeling

Assembly ModelingIn an assembly model, components are brought together to define a larger, more complex product representation. : 

Ken Youssefi Mechanical Engineering Dept. 1 Assembly ModelingIn an assembly model, components are brought together to define a larger, more complex product representation. Assembly modeling is a tool that allows and facilitates the collaboration among designers, analysis people, manufacturing people, and others, to insure their assembly works together. This enables individuals in different disciplines to work concurrently, resulting in faster and less costly delivery of products to market.

Assembly Modeling : 

Ken Youssefi Mechanical Engineering Dept. 2 Assembly Modeling Constructing an assembly 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. Geometric relations (constraints) are used between elements of components.

Assembly Modeling : 

Ken Youssefi Mechanical Engineering Dept. 3 Assembly Modeling Bottom-Up Design (Modeling) – this is a logical, traditional, and most common approach. The individual parts a created independently, inserted into the assembly, and located and oriented (using the mating conditions) as required by the design. The bottom-up-approach is the preferred technique if the parts have already been created (off the shelf). It allows the designer to focus on the individual parts. It also makes it easier to maintain the relationships and regeneration behavior of parts than in the top-down approach.

Bottom-Up Design (Modeling) : 

Ken Youssefi Mechanical Engineering Dept. 4 Bottom-Up Design (Modeling) The components (parts) are created first and then added to the assembly file. This technique is particularly useful when parts already exist from previous designs and are being re-used.

Assembly Modeling : 

Ken Youssefi Mechanical Engineering Dept. 5 Assembly Modeling Top-Down Design (Modeling) – In this approach, the assembly file is created first with an assembly layout sketch. The parts are made in the assembly file or the concept drawing of the parts are inserted and finalized in the assembly file. In other words, the final geometry of the parts have not been defined before bringing them into the assembly file. The approach is ideal for large assemblies. Combination – basic geometry for a part is established first, then it is brought into an assembly for further refinements.

Locating & Orienting Parts in the Assembly Mating Conditions : 

Ken Youssefi Mechanical Engineering Dept. 6 Locating & Orienting Parts in the Assembly Mating Conditions The coincident mating condition is applied between to planar faces Most common mating conditions are Coincident, Concentric, Tangent, Coplanar, Parallel and Perpendicular faces, and Offset faces. Coincident Each face is specified by its unit normal vector, n, and a point on the surface, P. The coincident condition is satisfied by forcing n1 and n2 to be opposite of each other, and the two faces touch each other such that P1 and P2 are coincident An offset option is provided for this command

Mating Conditions - Concentric : 

Ken Youssefi Mechanical Engineering Dept. 7 Mating Conditions - Concentric Concentric The concentric mating condition is applied between to cylindrical faces The concentric mating condition is achieved by forcing the axes to become collinear. Each axis is defined by two points.

Mating Conditions – Coplanar (Aligned) : 

Ken Youssefi Mechanical Engineering Dept. 8 Mating Conditions – Coplanar (Aligned) Coplanar The coplanar mating condition is applied between to planar faces, and forces them to lie in the same plane. Each face is specified by its unit normal vector, n, and a point on the surface, P. The coplanar condition is satisfied by forcing n1 and n2 to be in the same direction, and the two points, P1 and P2, are chosen to lie on the two edge to mate

Mating Conditions – Tangent : 

Ken Youssefi Mechanical Engineering Dept. 9 Mating Conditions – Tangent The tangent mating condition is applicable between a planar and cylindrical surfaces or two cylindrical surfaces. Tangent

Other Mating Conditions : 

Ken Youssefi Mechanical Engineering Dept. 10 Other Mating Conditions Parallel Perpendicular Surface intersecting an edge Edge intersecting a point Angles of surfaces/planes to each other Relationship of a geometry to a coordinate system

Degrees of Freedom : 

Ken Youssefi Mechanical Engineering Dept. 11 Degrees of Freedom There are six degrees of freedom.  Translation – movement along X, Y, and Z axes (three degrees of freedom). Rotation – rotate around X, Y, and Z axes (three degrees of freedom).

Degrees of Freedom : 

Ken Youssefi Mechanical Engineering Dept. 12 Degrees of Freedom Two selected surfaces become co-planar and face in opposite directions. This constrains 3 degrees of freedom (two rotations and one translation) Two planar surfaces are made parallel, not necessarily co-planar, and face the same direction (similar to Align Offset except without the specified distance). Constrains two degrees of freedom (two rotations) Coincident Parallel

Creating an Assembly : 

Ken Youssefi Mechanical Engineering Dept. 13 Creating an Assembly Part Part Assembly

Creating an Assembly Example : 

Ken Youssefi Mechanical Engineering Dept. 14 Creating an Assembly Example The example assembly requires three mates to fully define it. First constrain: Mate between the hollow faces as shown. Hollow faces

Example : 

Ken Youssefi Mechanical Engineering Dept. 15 Example Second Constrain: Align the right faces of both components. Right side faces

Example – Switch Plate : 

Ken Youssefi Mechanical Engineering Dept. 16 Example – Switch Plate Switch plate consists of two components, plate and fasteners.

Example – Switch Plate : 

Ken Youssefi Mechanical Engineering Dept. 17 Example – Switch Plate First Constrain: Insert select the cylindrical face of the fastener and the cylindrical face of the switch plate. Two degrees of freedom remains, the fastener can still move in and out and rotate inside the hole.

Example – Switch Plate : 

Ken Youssefi Mechanical Engineering Dept. 18 Example – Switch Plate Second Constrain: mate the flat circular back face of the fastener and the flat front face of the switch plate.

Example – Switch Plate : 

Ken Youssefi Mechanical Engineering Dept. 19 Example – Switch Plate Align Orient could be used to line up the slot on the screw head with the flat top face of the switch plate. The assembly is fully defined

Slide 20: 

Ken Youssefi Mechanical Engineering Dept. 20 Example

Assembly in SolidWorks : 

Ken Youssefi Mechanical Engineering Dept. 21 Assembly in SolidWorks Insert → Component → Existing Part Open an Assembly file File → New → Assembly Insert a component model You can also drag and drop components into the assembly file

Assembly in SolidWorks : 

Ken Youssefi Mechanical Engineering Dept. 22 Assembly in SolidWorks Mate command Select entities Type of Mates Specifies distance and angle for Mates Advance Mates

Assembly in SolidWorks : 

Ken Youssefi Mechanical Engineering Dept. 23 Assembly in SolidWorks Hold down Alt and drag a component over potential mate partners. The component becomes transparent and the pointer changes when it is over a valid mate partner. Drop the component to apply the mate. To create SmartMates while dragging a component: You can use the SmartMates to save time. Move the part Right click on the part to be modified

Assembly in UG : 

Ken Youssefi Mechanical Engineering Dept. 24 Application Assembly Assembly in UG

Assembly in UG : 

Ken Youssefi Mechanical Engineering Dept. 25 Assembly in UG

Slide 26: 

Ken Youssefi Mechanical Engineering Dept. 26 Assembly in UG

Slide 27: 

Ken Youssefi Mechanical Engineering Dept. 27 Assembly in UG

Pro/E Mate Commands : 

Ken Youssefi Mechanical Engineering Dept. 28 Pro/E Mate Commands

Summary : 

Ken Youssefi Mechanical Engineering Dept. 29 Summary An assembly contains two or more parts, parts are referred to as components.  Mating conditions are relationships that align and fit components together in an assembly.  Components and their assembly are directly related through file linking. Changes in the components affect the assembly. Changes in the assembly affect the components.

Analysis of the Design : 

Ken Youssefi Mechanical Engineering Dept. 30 Analysis of the Design Design analysis is the evaluation of a proposed design based on the criteria established in the ideation phase. Typical analysis Property Analysis Evaluates a design based on its physical properties: strength, deflection, size, volume, center of gravity and rotation, thermal and fluid properties, ….. Finite Element Analysis, Finite Element Modeling

Design and Analysis : 

Ken Youssefi Mechanical Engineering Dept. 31 Design and Analysis Kinematics Determines the motion of assembly without regard to loads Mechanism Analysis Evaluates the motion and loads associated with mechanical systems made of rigid bodies connected by joints Dynamic Determines the loads that drive or create the motion of a mechanism

Design and Analysis : 

Ken Youssefi Mechanical Engineering Dept. 32 Design and Analysis Functional Analysis Determines if the design meets the requirements specified in the ideation phase. Engineering goals (targets)

Design and Analysis : 

Ken Youssefi Mechanical Engineering Dept. 33 Design and Analysis Human Factors Analysis Evaluates the design to determine if the product serves the physical, emotional, mental and safety needs of the consumer. How a design interacts with the dimensions, range of motion, senses and mental capabilities of the people using the product. Reference: The Measure of Man, by Henry Dreyfuss.

Design and Analysis : 

Ken Youssefi Mechanical Engineering Dept. 34 Design and Analysis Aesthetic Analysis Evaluates a design based on the look and feel of the product. The product is analyzed by industrial designers, marketing people and environmental and human factors engineers. Difficult to measure and quantify.