This document describes the fabrication of a helicoidal screw in Trichy, India for use in a blasting machine. It aims to fabricate helicoidal screws at low cost using simple mechanical methods. The design and fabrication process are explained in detail, including material specifications, dimension calculations, and the forming procedure using heating and stretching with a chain block. Photos show the completed screw, which was successfully fabricated to meet design requirements for conveying material in a blasting machine.

1. FABRICATION IN TRICHY
2016
DURAIPANDI.R, MANIKANDAN.S
GANESAN.S &
EVERSENDAI CONSTRUCTION PRIVATE
LIMITED; INDIA.
12-06-2016
HELICOIDAL SCREW
FABRICATION IN TRICHY
FACTORY
2016
DURAIPANDI.R, MANIKANDAN.S,
GANESAN.S & Production team of Zone 3
EVERSENDAI CONSTRUCTION PRIVATE
LIMITED; INDIA.
2016
HELICOIDAL SCREW
FABRICATION IN TRICHY
FACTORY

2. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
ECI Page 2
AIM:-
By using of simplest mechanical work, the helicoidal screw fabrication shall complete with very low
cost; and in future, the helicoidal screw conveyor shall fabricate by our own and not to purchase in
outside is our objective.
Meanwhile the helicoidal screw function shall fulfil its original requirement / fit to the purpose of
base design.
So the Helicoidal screw design calculation, fabrication method is briefly explained to make for our
own and to fulfil of blasting machine (shot & Grit) conveying purpose by simplest mechanical
application & its fabrication cost shall be in very less.
FUNCTION OF SCREW:-
It is basically used to transfer the Shot & Grit material (blaster) from one end to other end by the
action of helicoidal screw. It is circulating through conveyor & feeding the automatic / manual
blasting machine for surface cleaning purpose.
CORE TEAM:-
 PRODUCTION (CNC & ZONE-3)
 QUALITY
 PAINTING
SCOPE OF SCREW FABRICATION:-
The existing Automatic blasting screw conveyor design is the base /basic reference. Here we would
like to highlight the drawing preparation & its fabrication method is our scope of work.
It has consists of several blades in the form of helicoidal shape welded with shaft or pipe for move or
transfer the material.
It has further classified in five parts.

3. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
ECI Page 3
1) HELICOIDAL Drawing preparation
2) Material Specification & Its Dimensions
3) Development size calculation
4) Fabrication procedure
5) Practical bending photos
1) HELICOIDAL SCREW DIAGRAM:
The helicoids screw diagram is shown in FIG.1.
FIG.1.
2) MATERIAL SPECIFICATION OF SCREW & ITS DIMENSIONS:-
Parameter value
Flight diameter or screw
diameter
370mm
Flight thickness 6mm
Pitch or spacing between the
blades
370mm
Shaft or pipe diameter 90mm
Direction of rotation RHS
Material grade E350B0

4. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
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MATERIAL CHEMICAL AND MECHANICAL PROPERTIES
SPECIFICATION CHEMICAL PROPERTIES
HE
AT
NO.
MT
C.N
O.
THK.
OF
PLAT
E IN
(mm)
%C
(0.2M
AX)
%M
n
(1.55
MAX
)
%S
(0.04
5MA
X)
%P
(0.045
MAX)
%Si
(0.03-
0.45)
%Al
(0.010
MIN.)
%
Nb
%Nb+V+
Ti
(0.25MA
X)
% CE
(0.47MA
X)
1552806
347565
6M
M
0.15 1.28 0.01
1
0.018 0.119 0.056 0.
02
4
0.046 0.367
MECHANICAL PROPERTIES GRADE
YS
Mpa
(350MIN
)
UTS
mPa
(490
MIN
)
EL%
(22
MIN)
BEND(2
T)
YS
Mpa(3
50MIN)
428 551 28 OK 420 E350B0
TYPE OF PITCH:
“P” represents pitch of screw
“D” represents diameter
Hence Standard Full Pitch is P/D=1
Used for conveying material horizontally or inclines
3) DEVELOPMENT SIZE CALCULATION FOR FLIGHT:
To prepare of annular shaped blank, the following steps shall be followed. The annular shaped blank
as shown in FIG.2.
FIG.2.

5. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
ECI Page 5
“H” represents Height or Width of Blank
“R” Outer Radius of Blank
“r” Inner Radius of Blank
“Θ & Δ” Slit Cutting Angle
“L” Outer Arc Length
“l” Inner Arc Length
Step-1: Inner and Outer Arc Length Calculation
The inner and outer profile diagram of flight as shown in FIG.3. & 4.
Inner Arc Length:-
FIG.3.
Inner Arc Length (l) = ( ) +
= ( 90) + 370
=√216843.795
=465mm

6. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
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Outer Arc Length:-
FIG.4.
Outer Arc Length (L) = ( ) +
= ( ∗ 370) + 370
=√1488048.84
=1219.85mm
Step-2:
The Height / Width shall found by (OD – ID)/ 2
OR
Height or Width = (screw diameter (OD) or flight diameter – pipe / shaft diameter (ID)) / 2
H = 452-172 / 2 = 140

7. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
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STEP 3:- RADIUS OF FLIGHT DEVELOPMENT as shown in FIG.5.
FIG.5.
tan = = , and r = R-H
Outer Radius: -( Outer Arc length X Width (Height)) /( Outer Arc Length – inner arc Length )
Outer radius (R) = =
.
.
= 226 mm
Inner radius(r) = R-H =226-140 =86MM
Step 4:- ANGLE CALCULATION FOR RADIAL CUT
Θ=360- Δ
Δ = (LX360)/ (2 R)
= (1220X360)/ (2 226)
Δ = 309.29 degree
Θ =360-α =360-309.29 =51 degree
51° shall cut for seating purpose.
In accordance with base design / purpose the material shall be cut as per figure 2.

8. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
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4) PROCEDURE TO FORM HELICOIDAL SCREW:-
The fabrication setup of helicoidal screw forming as shown in FIG.6.
FIG.6.
After completion of 4 steps or once the required / designed blank is prepared, the following
procedure shall be followed.
4.1 The raw material identification, traceability and its mill test certificate review are minimum
requirements & it is not limited so.
4.2 The material shall consume with less wastage, hence prepare a flat annulus shaped blank having
opposed later sides and an inner and outer peripheral edge.
One end of
Chain block
engaged with
blank temporary
support
Other end of
Chain block
engaged with
end of the pipe
Pull chain by man
FABRICATION
SETUP

9. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
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4.3 There being a radial slit extending between inner and outer peripheral edge, it forms the inner
and outer arc.
4.4 The inner and outer arcs interposed between two lines radially diverging from the centre point
of the annulus shaped blank.
4.5 Fix the blank (split ring configuration) of inner peripheral edge on pipe with partial weldment on
the shaft.
4.6 Engage the one end of chain block to pipe and other end to blank with the help of temporary
supports.
4.7 Apply the heat along the inner peripheral edge to red hot condition (below the critical
temperature) the temperature shall be in uniform and control measure is important.
4.8 Stretch the blank during heating by engaged chain block up to helicoidal form with required
pitch.
4.9 Both start and end point are should be 90degree to pipe.
4.9 For making second flight connect the one end of spilt ring configuration to end of first formed
helicoidal without mismatch by partial weldment and then follows the step 4.6 to 4.9.
4.10 After completion of helicoidal screw forming make partial weldment into permanent weldment
at joint area.
RESULT:
Flight profile with welding as shown in FIG.7.
FIG.7.
Joint weldment
Partial
weldment

10. HELICOIDAL SCREW FABRICATION IN TRICHY FACTORY
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Completed screw as shown in FIG.8.
FIG.8.
CONCULSION:-
The fabrication of helicoidal screw completed successfully in our factory for blasting machine use by
applying heat & manual mechanical application (chain block) and achieved successfully with exact fit
to the purpose of design drawing requirement.
It has used physically and confirm the purpose of the application.
Prepared by Approved by
PITCH
SCREW DIAMETER
PIPE OR SHAFT
FLIGHT