For its best practice in gold jewellery manufacturing, the iconic Indian lifestyle company Titan Company Limited were one of five winners of the 7th International Best Practice Competition held in May 2021 for their project, Perfect Bond – An Innovative Locking Method for Rubber Moulds used in Lost Wax Casting of Gold Jewellery.

 

 Titan exports its products to 32 countries. It manufactures jewellery using the lost wax casting process (Fig 1). The cavity created at the Mould Cutting stage is vacuumed and injected with wax to create wax pieces of the design (Waxing stage). The Rubber mould cutting required highly skilled manual operation and dexterity. Moreover, the blades used to cut would break frequently, risking injury to the operator. Mould locking mechanisms worldwide create only 20%-60% vacuum. Wax piece quality that depends upon rubber mould alignment and locking mechanism and the subsequent vacuum formation was affected. This impacted the gold casting quality, which in turn affected the quality of the gold jewellery. There was only 15% First Time Acceptance of wax pieces. The 85% defective gold castings that were reworked led to gold loss. All this affected workforce productivity and bottom line performance.

                                                                            Figure 1: Lost Wax Casting Process Flow

From a total of 69 ideas from same and cross-industry learning of joining and locking mechanisms in carpentry, bookbinding, stapler pins, etc., the team developed an innovative locking method inspired by ziplock bags that can be pressed together to form an airtight seal and can be readily reopened. After its implementation in May 2019, Titan achieved consistent locking of the moulds across sizes and designs with 100% vacuuming and increased the First Time Acceptance to 99.5% at the Waxing stage (Fig 2). Also, the mould cutting in the ziplock pattern was deskilled by customising a C-type (Omega) profile cutter that gives the perfect fit for the male and female mould profiles simultaneously, with 100% vacuum. Titan has applied for patents for both innovations. The traditional lock-making process took 180 secs, while the current method is completely safe with the cutting directed away from the body, and takes just 30 secs. The judges were impressed that this best practice could be a great learning for the jewellery and lost wax casting industry both locally and globally.

                                                           Fig 2: Perfect Bond – Results Achieved FY 2019 Vs. FY 2021   

For further information on this best practice including a presentation by the Titan team, and to learn from 1000’s of other best practices, join the BPIR.com.

Posted by: Ahmed Abbas
Author: Dr. Almas Tazein
Source :

https://www.bestpracticecompetition.com

BPIR Category : 3.2.6 Review and improve design process
3.4.1 Design product/process/service enhancements
3.5.1 Test effectiveness of new/revised products/process
9.6.5 Manage workplace cleanliness, health & safety
11.6.4 Manage physical risk
14.3.5 Reengineer business processes & systems
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