Week 14 challenge

AIM: The aim of this project is to model a butterfly valve and to apply GD&T to the different parts of the butterfly valve and the assembly.

INRODUCTION TO BUTTERFLY VALVE:

A butterfly valve is from a family of valves called Quarter turn-valves. In operation, the valve is fully open or closed when the disc is rotated a quarter turn. The "butterfly" is a metal disc mounted on a rod. When the valve is closed, the disc is turned so that it completely blocks 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 opened incrementally to throttle flow.

Butterfly valve body

The body is the housing for the internal components and it is the main part of the butterfly valve. The body connects to two pipes on its two sides and it regulates to flow. For the creation of this part, simple features like to revolve, extrude, and move objects are used in the modeling application of NX.

Features used to create the Butterfly Valve :

• Sketch
• Extrude
• datum plane and coordinate
• counterbore
• unite

Methodology:

Initially, Select the XY coordinate and click on the line tool from the Sketch tab.

After that sketch is Extruded, the ears of the butterfly valve are drawn and are copied on both sides of the cylindrical portion, then it is extruded.

Now a new plane is created on the surface of a cylinder using the datum plane option and a cylinder is created on that plane. then, The hole command is used to create a counterbore on that cylindrical surface.

Finally, three holes are created for mounting of the body and then, the part is saved.

Shaft

It is another important component of the butterfly valve. It inserts into the body of the valve and sits perpendicular to the direction of flow. It holds the disc inside the body and is clamped with the lever outside the body. It is created using simple features like revolve and extrudes features in the NX modeling environment. After the part creation is completed, the drawing is created in the drafting application of NX, and GD&T is applied using the features of NX. For this shaft, position tolerance should be given to the holes which hold the disc, a profile of the surface should be applied to the surface where the disc sits, and position tolerance for the cylindrical body of the shaft concerning the defined datums. Composite position tolerance is applied in the case of disc positioning holes as it repeats creating a pattern.

Features used to create Shaft :

• Sketch

• Revolve

• Datum plane

• Extrude

• Chamfer

• Methodology:

Initially, Select the XY coordinate and click on the line tool from the Sketch tab.

Revolve command is used to get the desired shape of the shaft.

Then Extrude command is used to create a recess portion in the front and rear portion of the shaft.

Finally, two holes of 12.5mm diameter are created in the rear recess portion of the shaft.

Retainer

This part helps to retain or to fix the shaft with the body of the butterfly valve. It prevents the shaft from coming out of the body and keeps it in position for the proper functioning of the disc inside the body. The creation of the retainer plate involves only a simplefeature like extrude in NX. For the GD&T application in the retainer plate, similar steps are followed as in the case of the disc. Primary, secondary and tertiary datums are defined properly as per the design intent, and datum targets are applied to the holes. Perpendicular and position tolerances are applied to lock the DOF of the retainer in position. A profile tolerance is also applied to control the upper

surface of the retainer.

Features used to create Shaft :

• Sketch

• Extrude

Methodology:

The 3D model of the Retainer is created with the help of given dimensions.

Initially, the concentric holes of 200mm and 56mm diameter are drawn and the other 3 circles of 20.3 mm diameter are drawn with the help of 150mmBCD by using the Pattern option.

Finally, the 2D sketch is extruded and the part is saved in the required folder.

Disc Plate

This disc plate is the main component of the butterfly valve which regulates the flow in the valve. The orientation of this disc determines the flow rate of the fluid. It is not perfectly circular, rather it is elliptical in profile. The holes in it help to position it properly on the shaft created earlier. A simple feature like extrude can create this part in NX. To apply GD&T for this part, the primary datum is defined on the surface where it comes in contact with the surface of the shaft, and perpendicular and perpendicular tolerances are applied as per the requirement. As the cost increases, while machining the entire contact surface, small circular datum targets are created and GD&T is applied to reduce the manufacturing cost.

Features used to create Shaft:

Sketch

Extrude

Lever

A lever is a handle that is used to rotate to regulate the flow. It is attached to the shaft with the help of a key to fixing it in position concerning it. So when it is rotated, the shaft rotates which in turn rotates the disc and regulates the flow inside the pipe. It is createdusing simple features like extrude in NX after the proper base sketch is created. For the application of GD&T on the lever, a section view is also created to show how different datums are defined and tolerances are provided. Position tolerance is applied to the proper holes after the perpendicular tolerance is applied to the first hole. To control the key slot, small tolerance is applied to the width of it. Profile

tolerances are provided to the surfaces which come to contact with other parts as per the requirement.

Features used to create Shaft :

• Sketch
• Extrude

Methodology:

With the help of 2D drawing of the lever, the 3D model of the lever is designed with the help of different operations.

The different operations used are Trim, Extrude, circle, Tangency, etc.

NUT:

It is the last part that helps to fix the lever in position with the stem. It allows to keep it in position or to disassemble whenever required. It is created using simple extrude and revolve features in NX. To apply GD&T for this nut, the primary datum is defined on the surface which comes in contact with the lever. Perpendicular tolerance is applied to the hole or the thread and is defined as datum B. Size tolerance is also applied to the thickness of the nut.

Features used to create Shaft :

• Sketch
• Extrude
• Revolve

1.The 3D modeling of the Nut is created with the given dimensions.

2.Initially the hexagonal shaped nut is extruded with a depth of 25mm and a hole of 37mm diameter.

3.Finally, the fillet of radius 10mm is provided by using the revolve option.

ASSEMBLY OF BUTTERFLY VALVE:

1.All the parts that are saved in the required folder is opened in the Add components tool box.

2.Now using the Move option and Assembly Constraints option the different parts are joined together with the help of Align,touch,infer/Axis operations.

3. Finally,the assembly of butterfly valve is saved in the folder where the other parts were saved.