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					Govt. Polytechnic, Mumbai                                                                        Rubber Technology

                                                       MOULD DESIGN
PROGRAMME : Rubber Technology
                                                                      Credit            Examination scheme




                                          Compulsory
                           Prerequisite




                                                       Optional
 Course       Course                                                               Theory
  Code         Title                                              L   P    Total             PR    OR   TW    Total
                                                                                   TH   TS

   RT         Mould
                           -      C       -     1     2      3      -      -                 -     50    50   100
  07301       Design
1. Theory papers duration 3 hrs.
2. Theory paper assessment is internal and external.
3. The assessment of practical, oral, term work is internal except mark (*).
4. (*) The assessment is internal and external.
5. C = Compulsory, O = Optional.
RATIONALE: Subject gives insight to Rubber Technician for design of different types of dies
used in rubber moulding and extrusion. Rubber Technologist should be able to understand
various aspect of die design like shrinkage values, material of construction and designing for
different moulding techniques.

OBJECTIVES:
      Should be able to understand various factors considered in design of rubber moulds.
      Should be able to design rubber moulds for moulding extrusion.

THEORY:

1. Introduction to Rubber Material

2. Behaviour of Rubber in mould (Flow Properties)

3. Explanation of curing, mould shrinkage-its calculation, core, cavity, moulding cycle time
   (Also splitting of moulding cycle in its elements)

4. Introduction of rubber moulding Machines and Processes ( compression, transfer, injection)

5. Introduction to detail study of mould construction for different moulding process. This will
   include
       a) Feeding of Raw materials to mould
       b) Component ejection system
6. Detail designing of mould components
       a) core, cavity, moving parts etc.
       b) Design of guide pin bushes.

7. Compression moulds:
     a) Design of positive mould, semi-positive mould
      b) Single cavity and multi cavity mould
      c) Flash allowance, shrinkage allowance and draft allowance

       RT07301(Revision no.3)                                                                           Page 1 of 3
Govt. Polytechnic, Mumbai                                                 Rubber Technology


8. Transfer moulds:
       a) Design of Transfer pot and punch

9. Extrusion die design:
   Design aspects of a) Pipe die-Mandrel, Land length, angle of entry
                      b) Profile die-Elementary study

10.Fabrication:
        a) Material for mould fabrication. Types of steels to be used for mould
            making. Heat treatments for mould components of mould (core, cavity, guide,
            bushes, pins etc.), surface treatment
        b) Machines and machining processes required for mould making. Lathe, drilling,
            shaping, pentograph, spark erosion. Advantages and limitations of machining
            processes with reference to tolerance and surface finish, time, cost etc.
        c) Selection of processes
        d) Mould polishing and chrome plating

11. Calculations to find out the mould design and mould making cost. Costing of mould.
    Preparation of mould manufacturing quotations.

Term Work

Assignments
   1.            From the shrinkage factors given for the rubbers calculate the cavity
      dimensions for the given products (e.g. cylinder, tube, and sheet moulded items only) for
      various rubbers. The data to be provided.
   2.            Calculate the projected cavity area. (for horizontal projection and vertical
      projection) and the total volume for the given products (moulded items only)
   3.            Calculation of the hydraulic pressure for the given moulds for given press of
      Ram Dia and Platten size
   4.            Mould is to be designed for the Injection moulding for the given article. The
      platen size of the press is 18x18 inch. Arrange the cavities in such a manner that the
      arrangement is symmetrical and calculate the total runner length for the design.
   5.            Calculate the speed of extrusion in metres and grams for an given profile and
      given extruder capacity.

Any other assignment as decided by the faculty.

Drawing Sheets.

               1. Detail drawing of a rubber to metal bonded products like Engine
                  mounting/oil seal
               2. Drawing of a hand-build component like hose or expansion bellow
               3. Drawing of a single cavity compression mould for a simple Rubber Article
               4. Drawing of a mould for a metal to rubber bonded product
               5. Drawing of mould for a rubber bellow
      RT07301(Revision no.3)                                                       Page 2 of 3
Govt. Polytechnic, Mumbai                                                   Rubber Technology

              6.   Drawing for a multi of mould for a oil seal
              7.   Drawing for a multi cavity injection mould for a rubber article
              8.   Drawing for a multi cavity transfer mould for a rubber article
              9.   Drawing for extrusion die for a given profile




      RT07301(Revision no.3)                                                         Page 3 of 3

				
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