Week 14 challenge

DESIGN OF A BUTTERFLY VALVE AND APPLICATION OF GD&T

AIM: The objective of this project is to design a butterfly valve and apply GD&T to it'scomponents and final assembly using Siemens NX.

OBJECTIVE:

• The objective is to design & assemble the components of the butterfly valve using various modeling & assembly features in Siemens NX.
• Developing drawing sheets of butterfly valve assembly using various drafting tools.
• Understanding various GD&T symbols and applying the same to the butterfly valve assembly.

INTRODUCTION:

A butterfly valve is from a family of valves called quarter-turn valves. In operation, thevalve is fully open or closed when the disc is rotated a quarter turn. The "butterfly" is a metaldisc mounted on a shaft. When the valve is closed, the disc is turned so that it completelyblocks off the passageway.When the valve is fully open, the disc is rotated a quarter turn so that it allows an almost unrestricted passage of the fluid. The valve may also be openedincrementally to throttle flow.There are different kinds of butterfly valves, each adapted fordifferent pressures and different usage.

Here after modelling various components of the Butterfly valve, GD&T (GeometricDimensioning & Tolerancing) is applied to each component and final assembly.GeometricDimensioning and Tolerancing (GD&T) is a system for defining andcommunicating engineering tolerances. It uses a symbolic language on engineeringdrawings and computer-generated three-dimensional solid models that explicitly describenominal geometry and its allowable variation. It tells the manufacturing staff andmachines what degree of accuracy and precision is needed on each controlled feature ofthe part. GD&T is used to define the nominal (theoretically perfect) geometry of parts andassemblies, to define the allowable variation in form and possible size of individualfeatures, and to define the allowable variation between features.

There are several standards available worldwide that describe the symbols and define therules used in GD&T. One such standard is American Society of MechanicalEngineers (ASME) Y14.5. This article is based on that standard, but other standards, such asthose from the International Organization for Standardization (ISO), may vary slightly. TheY14.5 standard has the advantage of providing a fairly complete set of standards for GD&Tin one document. The ISO standards, in comparison, typically only address a single topic ata time.

Advantages of using GD&T:

• Saving Money - GD&T enhances design accuracy by allowing for appropriate tolerancesthat maximize production. For many projects, the process provides extra or bonustolerances, further increasing cost effectiveness.
• Offering Uniformity and Convenience - As a single, consistent language, GD&T reducesguesswork and interpretation while ensuring consistent geometries across design andmanufacturing.
• Assisting Digital Design Methods — Clear, concise GD&T data is readily adaptable to digitaldesign programs, including nearly universally used 2D and 3D CAD files.
• Ensuring Dimensional and Tolerance Requirements — By explicitly stating all designrequirements, a thorough GD&T process guarantees accurate fulfillment of all dimensionaland tolerance specifications.
• Providing Accurate Communication — Today’s intricate designs demand the mostaccurate and reliable communication. GD&T enables designers, manufacturers, andinspectors to communicate clearly with one other, saving time and making the processmore efficient.

COMPONENTS OF BUTTERFLY VALVE:

Various components of butterfly valve and GD&T applied to them are shown below.

1. BODY: Butterfly valves are usually fixed between two pipleines using flange couplings. Body of ourButterfly valve and GD&T applied to the same using Siemens NX CAD are shown below.

2. SHAFT: The disc/plate, lever and nut are assembled to this shaft.

3. DISC: When valve is fully opened or closed the disc is rotated a quarter turn.Disc is mounted onshaft. When the valve is closed, the disc is turned so that it completely blocks off thepassageway.When the valve is fully open, the disc is rotated a quarter turn so that it allowsan almost unrestricted passage of the fluid.

4. LEVER: Lever is mounted at an end of shaft outside the body. Hand lever is usually used in smallsized Butterfly valves. It is used to open or close the valve.

5. RETAINER: Retainer is a kind of washer fixed on the body of butterfly valve.

6. NUT: It is fixed at the top end of shaft to keep the lever and retainer on position relative to thebody of butterfly valve.

ASSEMBLY - BUTTERFLY VALVE:

After completing the modelling of various components of butterfly valve, all parts wereassembled together using Siemens NX Assembly workbench. also GD&T is applied.

CONCLUSION:

Butterfly valve is successfully assembled and GD&T applied to all parts and the assembly of the Butterfly valve.