Week 14 challenge
Aim :- To model and assemble Butterfly Valve and apply GD&T
to the butterfly Valve.
Introduction:-
A butterfly valve is a valve that isolates or regulates the flow of
a fluid. The closing mechanism is a disk that rotates.
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.
Procedure:-
For modeling and assembly of butterfly valve different parts of
butterfly valve was designed such as
* Body
* Shaft
* Disc plate
* Retainer
* Lever
* Nut
* ScrewFor modeling above parts different Commands were used such
as
* SKetch:- Sketch is used to creat a 2D drawing which is later
used to form 3D model.
* Extrude:- It extrudes the sketch or selected sketch contours
in one or two directions to creat a solid feature.
* Hole:- A Hole feature is used to create holes on the model.
* Unite:- Unite is used to convert two or more solid bodies into
one solid body.
* Revolve:- It revolves a sketch or selected sketch contours *
around an axis to create a solid feature.
* Chamfer:- Chamfer is used to connect two adjacent faces
using an inclined line.
Overview of parts of Butterfly valve:
1] Body of butterfly valve
Initially, the sketch for the body of butterfly valve is drawn
using the sketching tools in NX CAD.
After that sketch is Extruded, then ears of the butterfly valve is
drawn and is copied on both sides of the cylindrical portion,
then it is extruded.
Now a new plane is crated on the surface of cylinder using
datum plane option and cylinder is created on that plane. then,
Hole command is used to create a counter bore on that
cylinderical surface.
Finally, three holes are created for mounting of the body and
then, the part is saved.
2] Shaft
* Sketch is created on a plane then, 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 is created in the rear
recess portion of the shaft.
Drafting of shaft:
* A1 size of sheet is used create drawing of shaft.
Here, only two datums are used as one degree of freedom
is required for efficient working of the shaft.
* Datum A1 and A2 is given to the part which comes in contact
with the body of butterfly valve.
* Datum B is given to the base of the shaft.
* Different tolerances are given to some features which are
important for functioning of the shaft.
3] Disc Plate
* 2D sketch is created on a plane as per the given dimensions.
* Then, the sketch is Extruded create Disc plate.
Drafting of Disc plate
* Datum target areas A1 and A2 is given to the side of the disc
which is going to come in the contact with shaft.* This two datum target area A1 and A2 forms datum A.
* Datum B is given to the one hole on the disc plate and Datum
C is given to the other hole.
* Then, the tolerances are given to the surface and features of
the Disc plate.
4] Retainer
* 2D sketch is drawn on a plane.
* Then the sketch is Extruded to create a Retainer.
Drafting of Retainer
* After modeling, drafting tool is used to create a drwaing of
retainer on A1 size drawing sheet.
* Datum target area A1,A2 and A3 is given to the surface which
comes in the contact with the upper surface of body.
* Datum B is applied to the one of the holes of retainer where
the screw is inserted.
* Datum C is applied to the other hole.
Finally, other tolerances are applied to the surfaces and
features of retainer.
5] Lever
* 2d sketch is created on plane with the provided dimensions.
* sketch is then Extruded to create Lever.
Drafting of Lever
* Datum A is given to bottom surface which comes in contact
with retainer.
* Datum B is given to the hole where the bolt is to be inserted.
* Datum C is given to the other hole to complete the constraint
the part.
* Finally, other tolerances are applied to the surfaces and
features of Lever.
6] Nut
* A hexagon is created on the plane and is then extruded to
get desired solid body.
* Another sketch is created on XZ plane, Sketch fillet is used to
create a arc which will gives smooth curve to the upper
surface of Nut.
Drafting of Nut
* Datum A is given to the bottom surface of Nut which is going
to come in contact with Lever surface.
* `Datum B is given to the Hole.
* Finally, other tolerances are given to the surfaces and feature
of Nut.
7] Screw
* 2D sketch is created on a plane as per the given dimensions.
Then, revolve command is used to create a screw and the
part is saved.
8] Assembly of Butterfly Valve
* Assembly file is opened in NX CAD.
* Above parts are added in the assembly file.
* Now, one by one parts are assembled using Move part
command and assembly constraint command.
* Different constraints are used to assemble butterfly
valve, such contraints are: Infer Axis, Touch, Align.
* Finally, assembly of BUtterfly vlave is saved in the folder
where all the other parts are saved.
Drafting of Assembly
* Datum target area A1,A2 and A3 is given to the ears of
the butterfly valve.
* Datum target area A2 and A3 is given with
perpendicular tolerance and Position tolerance
respectively.
* Sub datum D is given to the thrid ear.
Finally, other tolerances are given to the surfaces and
features of the Butterfly Valve.
