FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)


TITLE OF THE INVENTION Method Of Manufacturing Marking Aid
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTOR
Mr. S.G.Padekar and Mr. U.R.Gogate
Both are Indian Nationals
of TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTION
The Following Specification Particularly Describes The Invention And The Manner In Which It Is To Be Performed.


FIELD OF INVENTION
This invention relates to the use of FRP aids for different operations like trim line marking, hole drilling, spot welding and stud welding on sheet metal components & manufacturing of FRP aids there of.
PRIOR ART
Various sheet metal components required for prototype vehicle are manufactured by pressing operation with the help of die & punch. Every sheet metal component manufactured requires trimming operation, holes to be drilled, spot welding of two sheet metal components, stud welding as per drawing.
Prior to this invention, these operations were carried out as followed;
a) For trimming & drilling operations the method followed was
The pressed sheet metal component is clamped at a suitable position on a vice. With reference to the drawing the trim lines and holes are marked manually on the job by using different conventional instruments.
The job is released from the vice and extra sheet available on the component during pressing is cut manually along the marking to get finished job. The holes are also drilled on the marking as per drawing. For making prototype vehicles we require many different types of sheet metal components & about 50 to 75 quantities of each type of component. This operation is required to be repeated for similar type of components.
b) For spot welding and stud welding operations, the method followed was;
The two sheet metal components that are to be assembled by spot welding are lamped together on a fixture. With reference to the drawing the spot welding areas and the
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locations for studs are marked manually and then the operation of spot welding and stud welding is carried out. These operations of manual marking & welding have to be repeated for every similar job.
Disadvantages in conventional methods
1. Time consuming method.
2. Requires lot of man power.
3. More possibility of errors due to manual operation.
4. No consistency in the measurements.
5. The operation is person based and not process based.
SUMMARY OF INVENTION
Objective of present method is:-
To manufacture FRP aids and use these FRP aids which shall be;
a) Process based & not person based.
b) Easy to operate by any person.
c) Accurate & faster way of manufacturing.
d) Consistency of measurements for all the jobs.
The above objectives are achieved by making a master component as per drawing. With the help of the master component to make FRP negative by lamination process. To release the FRP negative and trim at the respective trim lines. To drill holes in the FRP negative with reference to the impressions from the master component. To use this FRP negative as an aid for marking trim lines, holes and slots, spot welding spots and stud welding locations on other components of the Same type.
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STATEMENT OF INVENTION
Accordingly the present invention discloses Method of manufacturing marking aid comprising the steps of;
preparing a master component as per the drawings;
making FRP ( Fibre Reinforcement Plastic) negative of the master component by lamination process;
releasing the FRP negative from the master component and trim the respective trim lines;
making impressions on the FRP negative with reference to the impressions from the master component.
BRIEF DESCRIPTION OF DRAWINGS
According to the present invention
Figure 1 shows first component marked manually for the trimming line 1 and different
slots2&3 and holes 4 & 5. Figure 2 shows the component is cut to the required trimming line and the holes and
slots are made at the respective markings Figure 3 shows untrimmed sheet metal component 6 of the same type pressed on the
FRP aid 7. Figure 4 & Figure 5 shows sheet metal components to be assembled by spot welding
method are clamped together on a fixture. Figure 6 shows spot welding operation done to assemble these sheet metal
components Figure 7 shows negative impression of the sheet metal component taken by FRP
lamination on the component. Figure 8 shows the master sheet metal component with the studs welded on to it. Figure 9 shows FRP negative with the holes used as an aid for stud welding operation. Figure 10 shows similar type of sheet metal components on which the studs are to be
welded placed on the FRP aid for marking.
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DETAILED DESCRIPTION OF INVENTION
The following steps are followed to manufacture FRP aids and usage of the aids there of;
a) For trimming & drilling operations the method followed is;
With the help of die and punch and blank holder if required, depending on the design of the component, the sheet metal components are manufactured by pressing operations. The first component is marked manually for the trimming line 1 and different slots 2 & 3 and holes 4 & 5 as shown in Fig: 1 as per drawing. With reference to the marking the component is cut to the required trimming line and the holes and slots are made at the respective markings.
As shown in Fig: 2 FRP aid is manufactured from the master component. FRP lamination is done to the master component and after curing the FRP aid is released from the master component. This FRP aid is hand finished to get a good surface finish. Trim line is cut with reference to the impression from the master component. The holes and slots are made on the impressions from the master. This FRP aid is painted for better finish. The FRP component is now suitable to use as an aid. As shown in Fig: 3 the untrimmed sheet metal component 6 of the same type which are pressed on the press are placed on the FRP aid 7. The trim line of the FRP aid is marked on the untrimmed sheet metal component. The metal component is removed and trimmed with suitable equipments. The trimmed metal component is again placed in the FRP aid and the holes and slots are made with reference to the markings available on the FRP aid.
b) For spot welding operation, the method followed is;
The two sheet metal components as shown in Fig 4 & Fig 5 which are to be assembled by spot welding method are clamped together on a fixture. With reference to the drawing the marking for spot welding is done on the component with the help of conventional measuring instruments. As shown in Fig 6 spot welding operation is
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done to assemble these components. This first spot welded component is now considered as a master component for making a FRP aid. FRP lamination is done on this component so as to get a negative impression of the sheet metal component as shown in Fig 7. After curing the FRP aid is trimmed with reference to the impressions got from the sheet metal component. The holes, 8, are drilled on the FRP aid at the areas where the impressions of the spot welding are arrived from the master component during lamination. This finished FRP aid is now ready to be used for marking holes on similar type of other sheet metal components that are to be spot welded. The next components that are to be spot welded are clamped to the FRP aid by suitable clamping means. The spot welding operation is carried out at the holes provided on the FRP aid.
c) For stud welding operation, the method followed is;
With reference to the drawing locations of the stud that are to be welded on the sheet metal component are marked manually with help of conventional measuring instruments. The studs 9 are welded on these markings. As shown in Fig. 8 the sheet metal component with the studs welded on to it becomes a master component. .This master component is laminated by FRP. Before lamination the studs are covered with suitable material to avoid damage and for easy release of the FRP aid. After curing the FRP component is released to get a negative impression of the sheet metal component. Holes are drilled in the FRP negative at the locations of the studs. As shown in Fig. 9 this FRP negative with the holes is used as an aid for stud welding operation. Similar type of other sheet metal components on which the studs are to be welded is placed on the FRP aid as shown in Fig. 10. The FRP aid and the sheet metal component are clamped together by suitable clamping means and the marking for stud welding is transferred from the FRP aid on to the sheet metal component. The sheet metal component is removed and studs are welded at the marked locations.
Advantages of the FRP aids are;
a) Very less time required.
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b) Repeatability.
c) Consistency.
d) Accuracy.
e) Process based & not person based.
f) This method can be used for any type if component.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.
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WE CLAIM
1. Method of manufacturing marking aid comprising the steps of;
preparing a master component as per the drawings;
making FRP (Fibre Reinforcement Plastic) negative of the master component by lamination process;
releasing the FRP negative from the master component and trim the respective trim lines;
making impressions on the FRP negative with reference to the impressions from the master component.
2. The method of manufacturing marking aid as claimed in claim 1, wherein said impressions from master components are holes, slots, spot welding stud welding.
3. The method of manufacturing marking aid as claimed in claim 1, wherein the operations to be performed on the subsequent components are trimming, machining, drilling, milling, slotting, cutting, welding, clamping.
4. A method of marking impressions on components using the FRP negative manufactured as claimed in claim 1 by pressing and clamping subsequent components of same type to said FRP negative.
5. The method as claimed in any one of the preceding claims, wherein the subsequent components are worked on as per the markings done from the FRP negative.
6. The method of manufacturing marking aid substantially as hereinabove described with reference to the accompanying drawings.
Dated this 18th day of March 2009

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