International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 13 - Apr 2014
Semi-Automatic Metal Spinning Machine
Rahul Waghchaure1, Rohin Nanaware2, Pranav Tupe3, P. Nikkish4, Prof. Rameez Hudli5
K. J. College of Engineering and Management Research, Mechanical department, Pune University, Pune, India.
Abstract— This machine is developed mainly for the
purpose of reduction in requirement of a skilled workforce. The
spinning machine consists of a mandrel mounted onto the
headstock spindle. A work piece on which operation is to be
performed is clamped in between this mandrel and the tailstock
(dead centre). The operation is performed by a blunt tool on a
spinning lathe. Spinning process primarily is a cold working
operation wherein, the material is formed by applying force onto
it, without any material removal.
The semi-automatic metal spinning machine is a
modification of the manual machine by using hydraulic aids to
control the entire operation, in order to reduce requirement of
skilled labour, mitigate the effect of labour shortage, to improve
overall efficiency in the current process, improving consistence
and repetitiveness along with an overall reduction in cost. The
hydraulic metal spinning machine setup consists of a swivel arm,
top plate, transverse plate, longitudinal plate and three hydraulic
cylinders connected to the 3 plates, to assist in appropriate
motion generation. The arrangement of the plates and cylinders
has been meticulously planned and analysed to ensure it imitates
the human operator motion during his operation of the machine.
III. METHODOLOGY
A mandrel is mounted on head stock which is the driving
section of the lathe. A metal disc is then clamped in between
the mandrel and the pressure pad which is further attached to
the tailstock. The mandrel is then rotated at high speed which
causes the disc clamped against it to be rotated as well. A
force is applied onto the work piece which causes the plasticflow of the work piece material over the mandrel. The tool,
mostly a roller, applies force to rotating material.
The semi-automatic metal spinning machine is a
modification of cross slide. The cross slide provides
longitudinal and transverse motion along with angular
arrangement. The cross slide is shown in figure 1.
Keywords— Metal spinning, spin forming.
I. INTRODUCTION
Metal spinning is a metal working process wherein a metal
disc rotates at high speed to be formed into a symmetrical part
by the action of a blunt tool. Basically, it is the manufacturing
process that forms a sheet metal into the desired shape. It is an
excellent means for quickly generating a round hollow metal
form. The spinning process allows for the rapid production of
multiple jobs as well as quick reiteration of the same, since,
only the mandrel needs to be changed in case of a different
job.
II. WHY THIS DEVELOPMENT?
The purpose behind modification of the currently used
manual metal spinning machine lies in the fact that previously,
the operation had to face problems of a higher manufacturing
time, availability of skilled labour and uncertainty of the
workforce to operate the same. This necessitated the
modification of the spinning machine wherein the manual
effort required to produce a component were entirely
eliminated. The setup being the same, the force required to
assist in production of the work pieces is now provided by the
various hydraulic cylinders. Thus, this mechanization of the
entire process helps to counter the various drawbacks of the
manual process explained earlier. Moreover, it was a low cost
solution as the cost of fully automated machines available in
the market is very high and unaffordable to the Small and
Medium Enterprises (SME’s).
ISSN: 2231-5381
Figure 1- The cross-slide of a spinning lathe
The semi-automatic metal spinning machine uses the
same base bracket as that of the cross slide. Additionally, it is
provided with a longitudinal plate parallel to the machine
spindle. This plate has a counter bore in which a bar is
inserted in it to assist the plate to swivel like the lathe
compound slide. The rails are mounted on this plate, on which
a plate is mounted to generate a longitudinal motion of the
tool.
The plate mounted on the longitudinal plate has transverse
rails mounted over it. The rod end of the longitudinal cylinder
is attached to this plate. Thus, the transverse plate gives
longitudinal motion.
For transverse motion of the tool, another cylinder is
attached to the transverse plate. This cylinder has its rod end
attached to the top plate.
The top plate has a tool arm and swivel cylinder mounted
on it. The tool arm is pivoted about a point on the top plate;
the end of which is attached to the swivel cylinder.
Initially, the swivel cylinder extends slightly to provide a
small deflection to the work piece. The transverse cylinder
then retracts the tool away from the mandrel in transverse
direction. The longitudinal cylinder helps in moving the tool
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 13 - Apr 2014
along the axis of the spindle. This type of sequence ensures
smoother flow of the work piece during operation. Figure 2
shows a CATIA model of a semi-automatic metal spinning
machine.
Hence, the force generated at the roller end can be
calculated asX * 0.15 = 1 * 70
X = 466.67 Kg-f
(1)
Where, ‘X’ is the force in Kg-f generated at the roller end of
the lever.
Hence, 466.67Kg-f is the force applied by which the
effective spinning occurs.
B. Replacement by Hydraulic System
Now, according to mechanical design (refer to figure 3 &
4, the leverage on the operator side is reduced from 1m to
approximately 0.594m.
Figure 2- The Semi-Automatic Metal Spinning Machine
IV.
RESULTS
I. Calculations
The following calculations are made with respect to figure
3. These calculations provide a superficial analysis for the
selection of cylinders that can suit the size of the cross slide.
A. Practical Observations
According to practical visual interpretations, it has been
observed that a normal human operator of 60-70 Kg can
successfully spin a material as hard/tough as Stainless Steel
(SS). SS is the toughest material that can be formed on the
machine.
At the time of spinning, it is observed that the operator
tends to apply partially or completely his self-weight on to the
lever as shown in image [3].
Figure 4- Machine operation using hydraulic force.
So the force generated on the free end is calculated again,
now that we know the spinning force is,
466.67 * 0.15 = 0.594 * P
P = 117.84 Kg-f
(2)
Where, P is the force generated at the operator side after
modification in of the mechanical design.
From equations (1) and (2); it can be seen that due to
decrease in leverage, the force needed for spinning increases
drastically.
By referring to various catalogues available in the market,
the following two sizes of cylinders (refer Table I) were found
Figure 3- Operation during manual Spinning
to be most suitable for the modification in the cross-slide.
TABLE I
Piston
Rod
Piston
Area
mm
mm
mm2
Rod
Area
mm2
Operating Pressure Range
15
25
35
50
Push
Pull
Push
Pull
Push
Pull
Push
Pull
50
16
19.64
2.01
294.56
2364.4
490.94
440.67
687.31
616.93
987.8
881.3
63
25
31.18
4.91
467.65
394.01
779.41
656.68
1091.18
919.35
1558
1313.36
The stroke of the cylinders can vary as per the type of
work piece. However, we have already considered a
modification of cross slide, so in this case, the stroke of the
cylinders generally will not and should not exceed 0.35m
as, further, the assembly of cylinders and other components
will be affected.
ISSN: 2231-5381
II. Other Recommendations
This machine is recommended for industries like
automobile, aerospace, defence industry where typical
sheet metal working takes place in large quantity.
This machine is also a good substitute in places where
high automation is not possible and not required.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 10 Number 13 - Apr 2014
V. DISCUSSION
To ensure proper flow of material, use of three
cylinders has been done which provide their three
respective motions, i.e. longitudinal, transverse and swivel.
After the assembly of the machine it needs to be
mounted on the spinning lathe. Thus, the modification of
the machine is such that it doesn’t require major changes in
the current setup of the spinning lathe. For this purpose, the
specifications of the spinning lathe must be known before
the design of the spinning machine. The design of all other
components thus will also depend on the specifications of
spinning lathe.
Finally, the motion of the cylinders is controlled by
simple push-button system. The hydraulic circuit may vary
from the hydraulic circuit designer’s point of view.
ACKNOWLEDGMENT
We thank Mr. Y. G. Waghchaure (Proprietor- Special
Equipments, Jejuri MIDC) for providing us with this
opportunity to work in the development of this machine.
We also thank our guide ‘Prof. Rameez Hudli’ for sharing
with us his valuable knowledge and experience. We also
would like to thank our Head of Department of Mechanical
Engineering ‘Dr. Ajit. M. Kate’ for his constant support
and encouragement. Lastly, we thank all those who have
directly or indirectly helped us in the development of this
machine.
Figure 5- Modified machine setup with hydraulics
VI. CONCLUSION
The machine is a substitute where high automation is
not possible and not required. The machine eliminates
human efforts.
For obtaining a fine degree of finish to the final
product, three cylinders have been provided, i.e.,
longitudinal, transverse and swivel. The size of the
machine essentially depends upon the specifications of the
spinning lathe.
REFERENCES
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Machine Design – R. S. Khurmi, J. K. Gupta (S. Chand
Publications)
Mechanical Engineering Materials – O. P. Khanna (Dhanpat
Rai Publications)
FDM- R. S. Vaishwanar, Rajesh Prasad and Subhash Chander
Research Paper on “Metal forming: An Analysis of Spinning
Process” by John Monaghan
Manufacturing Processes for Engineering Materials- Serope
Kalpakjian, Steven Schmid.
Research Paper on “Analysis of Material Deformation and
Wrinkling Failure”- Wang, Lin
Research Paper on “Introduction to Aluminium as an
Engineering Material”- M. H. Jacobs, University of
Birmingham, UK.
Catalogues on Hydraulic Cylinders by Dutta Industries Pvt.
Ltd., Pune.
Workshop Technology- S. K. Hajra Choudhury, A. K. Hajra
Choudhury, Nirjhar Roy
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