Field of Invention
The present invention relates to a method of converting a dual in line plated through hole
(PTH) IC component to a surface mount device (SMD).
Background of the Invention
The components used to develop electronic modules generally are of three types,
categorized as electronic, electrical and mechanical components. The electronic components
can be further divided into two categories i.e, active and passive components. The
transformer and other heavy duty items come under the category of electrical components
whereas all other assembly comes under the umbrella of mechanical items. The electronic
components include resistance, inductor, capacitor, diode, transistor and integrated circuit.
The components to be mounted on printed circuit boards (PCB) can be divided into two
categories. These are plated through hole (PTH) components and surface mount (SMD)
components. The components are selected as per PCB requirement.
However, a particular printed circuit board (PCB) may be designed only for surface mount
devices (SMD). Due to non-availability of such surface mount components, it may become
necessary to mount plated through hole (PTH) components in place of SMD components.
The prerequisite for mounting PTH components in place of SMD components is its conversion
to SMD component so that the PTH component is rendered suitable for the SMD component
foot print.

There is a need to develop a method for doing necessary physical modification on a plated
through hole (PTH) type dual in line IC (DIP) for mounting in place of a surface mount
device (SMD) IC component. It is necessary that the PTH DIP can be placed on the SMD
footprint of the PCB for its mounting and for this purpose the PTH DIP component leads can
be bent suitably using an inventive conversion tool of the present invention.
Summary of the Invention
The main object of the present invention is to provide a method for converting through hole
integrated circuit component to surface mount integrated circuit component without
changing its functional properties.
Another object of the invention is to provide a method for converting through hole integrated
circuit component to surface mount integrated circuit component while preventing breaking
of pin during conversion by designing the tools so that pressure required for bending is
applied only on the leads and not on the joints of the component package.
Yet another object of the invention is to provide a self sufficient bending tool that is reliable
and maintenance free. The developed tool provides the self sliding feature due to which DIP
is never stacked on the tool and slides to material bin as soon as the bending process takes
place. The tool bends DIP pin by 43° to 47°, but the pin should be bent by 85° to 87° for
solder purpose. Hence further bending is also required for suitable solder process. This
invention also includes the development of a manual hand tool for bending of pin to desired
bend angle.

A further object of the invention is to provide a tool which should be durable, inexpensive
and easily installable on standard preparation machines used for forming components used
in populating electronic modules.
The method of the present invention provides flexibility for using through hole component
instead of surface mount type (SMT) components. The modified component can be used on
footprints of surface mount components. The through hole component and surface mount
component both have identical functional parameters and differ by physical properties hence
the functional property of system where modified components are mounted remains same.
Thus, the present invention provides a method for converting a dual in line plated through
hole (PTH) IC component to a surface mount device (SMD) characterized by the steps of
bending the leads of the PTH IC component in two stages by 85° to 87° making it suitable
for soldering on the SMD foot print; thereby converting the PTH IC component to a surface
mount type component without changing the functional parameters of the component.
Brief Description of the Accompanying Drawings
The invention can be described in detail with the help of the figures in accompanying
drawings, where
Figure 1 shows a flow chart for the development of the method and tool
of the present invention.
Figure 2 illustrates the tool of the present invention developed from poly
resin bond cloth (PRBCF).

Figure 3 illustrates the tool developed from copper.
Figure 4 illustrates the finished tool of the present invention.
Figure 5 illustrates front view of the hand tool (Female) of the
present invention.
Figure 6 illustrates the hand tool view (Female)
Figure 7 shows the hand tool (Female) in front and side views.
Figure 8 shows hand tool front view (Male).
Figure 9 shows hand tool side view (Male).
Figure 10 shows the hand tool (Male) in front and side views.
Figures 11(a) to ll(k) show the arrangements in the pneumatic preparation
machine and its tool platform.
Figure 12(a) to 12(c) show different views of the finishing tool.
Detailed Description
Through hole electronic components have straight leads which can be pierced through a hole
for soldering purpose. The process of mounting is known as point through hole technology.
This technique may be defined as 'a circuit board packing technique in which the leads on
discrete components and chips are inserted through holes in the printed circuit board and
soldered from beneath. The through hole components have strong bond with the board but
require an extra drilling step. They also eliminate the board real estate underneath from
being used for other layers. The through hole integrated circuits are thicker than the surface
mount integrated circuits and surface area is also large in comparison with surface mount.

The surface mount components are smaller in size and their leads bent at near about right
angle for soldering. These are designed in such a way that the leads are never pierced
through printed circuit board, the components can be soldered at both side viz. component
side as well as solder side because the soldering takes place only at the layer where
component soldering is taking place and the leads of component are not going through PCB.
Therefore only bias holes take place on PCB. The technology used for mounting and
production of component is known as surface mount technology. It is a combination of
production and mounting of these components.
In the present invention a special tool has been developed to convert through hole DIP into
surface mount DIP. The PTH (plated through hole) DIP whenever procured due to non
availability of SMD (surface mount device) for use in electronic modules it becomes
necessary to place the PTH DIP on a SMD foot print PCB for soldering after bending the
leads by 85° to 87°.
The process of conversion of a dual in line plated through hole type integrated circuit to a
surface mount integrated circuit component (of the same electrical functional parameters) is
carried out in two stages to achieve precision in the area of planarity of SMD leads and the
footprints of the PCB where the component is mounted.
The development of the method of conversion of PTH to SMD component and the special
converter tool of the present invention is shown in the flow chart of Figure 1, which is self
explanatory.

The developed conversion tools have been illustrated in Figures 2 to 10 and 12(a) to 12(c).
The arrangements in the machine for automatic bending of the PTH leads are shown in
Figures 11(a) to ll(k).
The photographs in Image 1 to Image 12 illustrate the method of the present invention.
The process involves the bending of leads of the PTH integrated circuit by 43° to 47° is
carried out in a semi automatic pneumatic machine. This pneumatic machine (the operation
is based on applied pressure) is operated by an operator, hence the process of conversion
here is a semi automatic process. The bending of leads to 85° to 87° is carried out using a
hand tool and the process is manual. With the bending of leads the PTH component is
suitable for surface mount soldering.
For achieving the surface mount device configuration, the tool is mounted on a pneumatic
machine. A conveyor belt is provided over the tool for smooth movement of the integrated
circuit after the lead bending operation.
The pins are bent by 43° to 47° by applying pressure on IC pins. The integrated circuit stick
(the IC package) is placed nearer to tool so that the IC slides over the tool for conversion
process. Once the IC's come above on the tool pressing action takes place to bend IC leads
by 43° to 47°
The bending of leads of the PTH integrated circuit to 85° to 87° is achieved by using a
manual tool. This tool is a combination of a male part and a female part. It is developed
from PRBCF (polyresin base-) because this material is easily available and provides smooth
bending without cutting the leads. The partially bent PTH IC's are kept on the female part of

the developed tool and pressing action takes place. Ten integrated circuits can be placed on
female part of developed tool. A groove is provided on the female tool for the purpose. In
the male part a projection is provided in the form of a step. The step bends the leads of IC
and makes them suitable for soldering action.
Thus, the present invention provides a platform to convert through hole component into
surface mount component by bending DIP component lead. The advantages of this new
kind of developed machine tool consists on its flexibility of usage, on the possibility of
improving accuracy of pin (lead) bending of component so that the component can be
mounted on surface mount pad. The work suggests a mechanical process to change
physical nature of electronic component with high precision and accuracy. The mechanical
modification and formation of tool ensures the high degree of reliability of the system.
During the development of the method of the present invention the criteria for selection of
material for tool design were easy availability, easy machinability, cost effectiveness and
easy tooling.
In the present invention, first a tool designed with poly resin bond cloth (PRBCF) material
was used since it is easily available and machining and toolings are comparatively easy.
The PRBCF tool however, requires 0.5 mm projection on top. This projection does not
provide the strength to the tool and it is exposed to damage. Also, self sliding of DIP is not
possible on poly resin bonded sheet.

The other material which was tried for development of tool was copper. This tool was better
than PRBCF tool, but the expected results could not be achieved. Its advantages are easy
availability of material, easy machinability, tooling possible on available set up only and
possibility of IC sliding on copper metal. However, the main drawback here is the projection
of 0.5 mm on the tool head damaged during pin bending process. Also, copper provides the
sliding on top of tool but sometime during pin bending the DIP components pin get stuck
with tool and it affects the throughput.
Finally, the tool was designed with poly propylene. The main advantages of using poly
propylene were that the material is easily available, the machinability of material is very easy
and the tooling is easy hence the projection at top surface is not provided, and this
projection created artificially with the help of two phosphor bronze strips. These strip glued
with developed polypropylene tool, by using superglue. The phosphor bronze acts as a track
for IC, ICs slide easily and can be synchronized with the through put of stick hence pooling
doesn't take place.

WE CLAIM
1. A method for converting a dual in line plated through hole (PTH) IC component to a
surface mount device (SMD), characterized by the steps of bending the leads of the PTH
IC component in two stages by 85° to 87° making it suitable for soldering on the SMD
foot print;
thereby converting the PTH IC component to a surface mount type component without
changing the functional parameters of the component.
2. The method as claimed in claim 1, wherein said two-stage bending step comprises the
step of bending leads of the PTH IC component by 43° to 47° in a preparation machine
suitable for forming components with the help of a conversion tool installed therein; and
then bending said leads to 85° to 87° manually with the help of a specially designed
manual tool.
3. The method as claimed in claim 1, wherein said conversion tools are made from
polypropelene.
4. The method as claimed in the preceding claims, wherein said tools utilized for bending
the leads of the PTH IC component are so designed that the pressure required for
bending is applied only on the leads and not on the joints of the component package.

5. The method as claimed in the preceding claims, wherein said tools are provided with self
sliding feature so that the converted component is not stacked on the tool and slide to
material bin as soon as the lead bending process is over.
6. The method as claimed in the preceding claims, wherein a conveyor belt is provided for
smooth movement of the IC components after the lead bending operation.
7. The method as claimed in the preceding claims, wherein said PTH IC component has
identical functional parameters and differ only in physical properties from the SMD
component to be replaced.
8. A method for converting a dual in line plated through hole (PTH) IC component to a
surface mount device (SMD), substantially as herein described and illustrated in the
figures of the accompanying drawings.

The present invention relates to a method of converting a dual in line plated through hole
(PTH) IC component to a surface mount device (SMD).