DESIGN OF BUTTERFLY VALVE AND APPLYING GD&T TO THE PARTS AND ASSEMBLY
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.
DESCRIPTION OF BUTTERFLY VALVE:The different parts of the Butterfly valve are as follows:
1.BODY OF BUTTERFLY VALVE:
1.Initially, the sketch for the body of the butterfly valve is drawn using the circle tool in NX software.
2.After extruding the sketch which is drawn,the ears of the Butterfly valve is drawn and then it is copied on both sides of the cyclindrical portion.
3.Now, the datum plane option is used to create cyclidrical portion and the counter bore option is used to provide a counter bore to the part with the specified dimensions.
4.Finally, the hole is provided for the mounting of the body and it is saved in the required folder.
2.SHAFT:
1.The 2D drawing given in the figure is used to convert the Sketch into 3D model with different operations.
2.The revolve option is used to create the shaft by rotating it through 360°.
3.Now the extrude option(Subtract) is used to provide the recess in the front and rear portion of the shaft.
4.Finally,the two holes of 12.5mm diameter is provided in the rear recess portion of the shaft and the part is saved in the required folder.
DRAWING OF SHAFT:
1.Here,Only two datums A and B are given since the movement of shaft in one direction is required as per it's function.
2.Datum A1 and A2 are given which comes in contact with the body of the butterfly valve.
3.Datum B is provided at the base of the shaft.
4.All the other tolerances like profile of a surface,flatness, composition position tolerance and the size tolerances are given to the other features.
3.RETAINER:
1.The 3D model of the Retainer is created with the help of given dimensions.
2.Initially,the concentric holes of 200mm and 56mm diameter are drawn and the other 3 circles of 20.3 mm diameter is drawn with the help of 150mmBCD by using Pattern option.
Finally, the 2D sketch is extruded and the part is saved in the required folder.
DRAWING OF RETAINER:
1. After the modeling, the part is taken to the drafting portion where the three datums A,B,C are applied.
2.Datum target areas A1,A2,A3(Primary datum-A) is applied to one side of the Retainer which comes in contact with the upper portion of the body.
3.Datum-B is applied to one of the holes of the retainer where the bolt is inserted.
4.Datum-C is applied to the other hole of the retainer.
5.Finally, the other tolerances like Perpendicularity,position,profile of a surface are applied to the other holes and the surfceof the retainer, the drawing is saved in the required folder.
4.DISC PLATE:
1.Initailly,with the help of 2D drawing the disc plate is designed.
2.The ellipse with a minor and major radius is created and then the two holes of 12.5 diameter is given.
3.Finally, the sketch is extruded and the part is saved in the required folder.
DRAWING OF DISC PLATE:
1.The datums are applied to the disc in the drafting section.
2.Datum target Areas A1,A2(Primary Datum-A) is given to one side of the disc which comes in contact with the Stem/Shaft.
3.A datum B is given to one hole of the disc and the other datum is given to the other hole.
4.All the other tolerances like Perpendicularity tolerance to datum B and position tolerance to datum C and profile of a surface tolerance is given to the outer boundary surface.
5.LEVER:
1.With the help of 2D drawing of the lever,the 3D model of the lever is designed with the help of different operations.
2.The different operations used are Trim,Extrude,circle,Tangency etc.
3.Finally,the part is saved in the required folder.
DRAWING OF LEVER:
1.After the design of the lever, the drafting of the lever is done for applying the GD&T.
2.Three datums A,B,C are applied to the part.
A datum- To the bottom surface of the lever that comes in contact with the other surface.
B datum- It is applied to the hole where bolt comes in contact.
C datum- It is applied to the other hole to completely constraint the part.
Finally,all the other tolerances like position,Flatness,Profile of a surface are applied to the part.
6.NUT:
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.
DRAWING OF NUT:
1.After finished creating the design of nut,the drafting portion is opened for applying GD&T to the nut.
2.Now,the datums A and B are applied to the base of the nut and the hole of the nut.Perpendicularity Tolerance of .25 is given to the hole of the nut.
7.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.
DRAWING OF ASSEMBLY:
1.After the assembly of butterfly valve,the datums A,B,C,D are given.
2.Datum target areas A1,A2,A3 are given to the ears of the body with Perpendicularity tolerance and position tolerance.
3.Other tolerances like profile of a surface,flatness are given.Position tolerances with respect to the axis of B,C,D datums are given corresponding to the ears of the body.
4.Finally,the GD&T of assembly is saved in the required folder.
CONCLUSION: Therefore,the Butterfly valve is created and the Geometric Dimensioning and tolerances are applied with the help of using NX-12 software.