Toughened Glass

Product Code 94107
Quality and Standards IS 2553:1971
IS 6180:1971
IS 6640:1972
Production Capacity: Qty. Quantity: 4,80,000 sq.ft.
Value : Rs.1,98,00,000
Uploaded on July 2007


Toughened glass acquires a degree of strength for excess of the strength of normal glass sheet or plate glass, which if broken shatters into small and comparatively harmless pieces. It is claimed that the resistance to mechanical stock of toughened plate glass is 4 to 5 times more than that of ordinary plate glass. A toughened glass has better resistance to the vibration, mechanical shock and abrasion.

Toughend Glass has to pass the following important tests :

  • Transfer strength test on sheets on simply supplied (Modules of rupture and electricity)
  • Impact test: By following weight on sheets supported on two wooden battens
  • Impact by falling weight on sheet evenly bedded (on putty)
  • Impact by falling weight on edge of sheet
  • Repeated twisting tests
  • Sand blast abrasion
  • Thermal tests

Because of the strength and other specific physical properties mentioned above, it finds applications in the following fields:
i. Automobile : Cars, trucks, industry buses, tempos etc.
ii. Railways : Coaches
iii. Defence : Fleets, vehicles factory
iv. Commercial : Hotels, shops complex
v. Air ports : Doors

Market Potential

With increased transportation facilities the demand of the product is increasing at a steady pace specially in the automobile industry, railways, ships building both for production and replacement.

Basis and Presumptions

The project is based on single shift of 8 hours with 300 working days.

Implementation Schedule


Period(in months)

Project preparation and acquirement of shed, provisional registration etc. 2
Procurement of machinery and raw materials 6
Installation of machinery and equipment, appointment of labours etc. 2
Procurement of raw materials and starting trial production 1
Total 11

Technical Aspects

Process of Manufacture

The glass plate is heated to a temperature above its softening point and then subjected to rapid cooling. The glass is suddenly chilled and in this process contracts towards the core. It stretches until it has solidified and is no longer able to contract further at this stage the core is still soft. It contracts against restrained exercise by the solidified upper layer of the glass. This compression is responsible for the strength of the glass sheet, which is limited to about 20,000 lb/sq.inch. Thus it is highly stressed and the resultant force is able to nullify the external impact.

The intensity of the stresses depends on the rate of cooling, co-efficient of expansion, thermal conductivity of the glass, its specific heat, elasticity, and certain other physical properties.

Toughening Process

The raw plate glass sheet which is free from waviness, distortion etc., is cut to required size and shape and then all the edges are ground and polished as per end use of the product. This is called edge grinding and polishing and is very important for toughening because it will lead to breakages during process. No glass sheet can be toughened without edge grinding and polishing.

Washing and Drying

After the edge grinding and polishing the glass sheets are washed manually or by machine and then dried. The glass sheets are fed into the furnace (Electrically operated). The sheets are kept in the furnace above its softening point, which varies according to the composition of glass. After attaining required temperature the glass sheets are removed out of the furnace and placed in the air blowing quenching boxes for 20 to 25 seconds. After quenching glass sheet is toughened. For bend glass toughening, the glass sheets passes through a set of dies (as per shape) after furnace and then to the quenching boxes.

Quality Control and Standards

IS 2553:1971
IS 6180:1971
IS 6640:1972

Financial Aspects

A. Fixed Capital

Land and Building


Land About 3000 sq.mtrs. @ Rs.2000 6000000
Built up area Work shed = 400 mtrs @ 4000 1600000
  Building, workshop 100mtrs @ 3000 300000
  Laboratory block 40 mtrs. 110000
  Boundry wall 100000
  Water Tank 100000
Total 8210000

Plant and Machinery


Imp/ Ind.


Value (Rs.)

Electric toughening furnace complete with refractory lining, heating elements, thermo-couples, recorders, operating panel board, oil circuit breaker, temperature controller etc. to heat the sheet glass at its softening point as per following specifications: Ind. 1 2000000
Maximum kW: 185      
Maximum temp. 800ºC      
No. of zone: 6      
Maximum sheet glass size: 84” x 36” (7'x 3')     LS
Electric supply: 400/440V, 3 phase     LS
Air quenching blower with motor dia 1450 mm, motor 175 HP for cooling heated glass Ind. 1 550000
Super structure and ducting (Fabricated locally) Ind. 1 250000
Hydraulic equipment for curved sheets Ind. 1 600000
Blowing boxes and moulds for curved sheets Ind. 1 set 80000
Edge working machine for edge arising with motor, starter, grinding wheel, water tough and V belt Ind. 2 sets 120000
Vertical notching machine complete with motor, starter, V belt etc., for edge working Ind. 1 80000
Vertical grinding machine complete with motor, starter, V belt etc., for edge working Ind. 1 80000
Vertical polishing machine with motor, starter, V belt etc. Ind. 1 80000
Drilling machine for drilling holes in the sheet glass for shaping suitable drilling 1” bore with 3” x 2” cast iron table with 10”/12” drilling centre Ind. 1 100000
Cutting machine with arm table, cutting rail and swivel cutting head for shaping Ind. 1 100000
Drying and washing machine with blower, starter, heater conveyor, roller etc., for washing and drying the sheets Ind. 1 200000
Testing equipments Ind.    
Rectification machine to detect surface scratch Ind. 1 40000
Polariscope inspection line with poloroid sheet, light etc., for testing the strain/in the glass Ind. 1 35000
Other testing equipments for testing Ind. 1 30000
Maintenance and workshop machines Ind. 1 set 80000
Lathe machine complete with accessories Ind. 1 180000
Pillar drilling machine Ind. 1 20500
Power saw machine 10” Ind. 1 20000
Hand drill 25 mm size Ind. 1 set 10000
Hand grinder 6” size Ind. 1 10000
Tools for die making Ind. LS 20000
Bench vice Ind. 2 sets 8000
Compressor Ind. 1 50000
Pumps for water supply Ind. 2 50000
Total 4703500
Electric Sub-station
LT panel
Electricals like busbar, distribution board, main switch, cables etc. 1000000
Taxes, freight octroi, transit expenses and handling including transformer 10% 300000
Erection and commissioning such as unit construction, steel structures etc., and supervisory charges 7% 225000
Electrification charges 7% 225000
Contingencies and price escalation 5% 150000
Misc. equipments such as trolleys, glass cutting tables etc. 50000
Office equipment like typewriter,almirah, furniture, trolleys for carrying sheet glass etc. LS 100000
Pre-operative Expenses 50000
Total 6803500

Machinery and Equipments

Staff and Labour (per month)



Salary (Rs.)

Total (Rs.)

Production-cum-Factory Manager 1 20000 20000
Administrative officer- cum-Accountant 1 15000 15000
Marketing executive 1 18000 18000
Production supervisor 1 12000 12000
Foreman 2 6000 12000
Furnace operator 1 5000 5000
Edge working operator 3 3500 10500
Glass cutter 1 3500 3500
Packing-cum-despatch clerk 1 3500 3500
Steno-typist 1 4500 4500
Clerk 1 4500 4500
Security staff 2 3000 3000
Fitters 3 4500 13500
Peon 1 3000 3000
Factory staff      
Skilled labour 2 4800 9600
Unskilled labour 2 3500 3500
Total Total
+ Perquisites @ 22% on salary 32472
Total 180072

Raw Materials (per month)
(75% Production in the year)

Sheet glass 32,000 sq.ft. @ Rs.26 per sq.ft. 832000
Packing materials LS 52000
Total 884000

Other Contingent Expenses (per month)


Postage and stationery 2000
Telephone expenses 3000
Consumable stores 5000
Repairs and maintenance 10000
Transportation charges 15000
Advertisement and publicity 10000
Insurance 2200
Sales expenses 15000
Misc. expenses 3000
Total 65200

Utilities (per month)


Power 50,000 kWH units @ Rs.5.00 per unit cost 250000
Water LS 10000
Total 260000

Total Recurring Expenditure (per month) 1389272
Total Working Capital for 2 Months 2778544

Land and building 8210000
Machinery and Equipment 6803500
Working capital 2778544
Total 17792044

Machinery Utilization

75% utilisation of machinery and manpower has been taken into consideration.

Financial Analysis

Cost of Production (per year)


Total recurring cost 16671264
Depreciation on building @ 5% 410500
Depreciation on machinery and equipment @ 10% 470350
Depreciation on Furnace @ 20% 400000
Interest on investment @13% 2312966
Depreciation on other equipments and furniture @ 25% 25000
Total 20290080

Total Capital Investment

For calculation purposes, it is assumed that the unit shall manufacture flat toughened glass of size 5 to 6 mm. the average sale prices of which is taken at Rs.70 per sq.ft. total 3,84,000 sq.ft. (per year), after allowing rejection of 24,000 sq.ft., the saleable quantity will be 3,60,000 sq.ft., @ Rs.60/- per sq.ft.

Value of Turnover in Rs 23400000

Net Profit (per year)

  Turn over – Cost of production 1
Total working capital 3109920

Net Profit Ratio


Net profit per year x 100

Turn over per year


Rate of Return


Net profit per year x 100

Total investment


Break-even Point

Fixed Cost (per year)


Depreciation on Furnace @ 20% 400000
Depreciation on office equipment and furniture 25000
Depreciation on machinery and equipment 470350
Depreciation on building 410500
Interest on total investment 2312966
Insurance 26400
40% of salaries and wages 864345.6
40% of other contingent expenses + Utilities (excluding insurance) 1550400
Total 6059962



FC x 100

FC + NP (per year)


Additional Information

a. Capacity utilisation has been assumed at 75% in the 1st year.
b. The raw materials and sales prices have been taken at the prevailing market and sales prices have been considered ex-factory

  • M/s. Associated Erectors (Calcutta)
    14 A, S.N. Banerjee Road,
    Kolkata-700 013.
  • M/s. Andrew Yule and Co. Ltd.
    Yule House, B. Civil Row,
    Kolkata-700 001.
  • M/s. Punam Machine and Tools
    10, Ganesh Chandra Avenue,
    Kolkata - 700 013.
  • M/s. Eastern Engineering Works
    7, Fancy Lane, II Floor,
    4 A, Courz in House Street, Kolkata - 700 001.
  • M/s. Supertuf Industries
    3/93, DB Gupta Road,
    Paharganj, New Delhi.

Raw Material Suppliers

  • M/s. Shree Vallabha Glass Works
    Vallabha Vildyanagar,
    Via Anand, Dist. Kaira, (Gujarat)
  • M/s. Hindusthan Pilkington
    Glass Works Ltd.
    Assansol, (West Bengal)
  • M/s. Triveni Sheet Glass Works Ltd.
    Bhurpur, Allahabad (UP).
  • M/s. Indo Asahi Glass Works Ltd.
    Hazaribag, (Bihar)
  • M/s. Haryana Sheet Glass Works Ltd.
    20th Mill Stone,
    P. S. Rai, Sonepat,
  • M/s. Saraikela Glass Works Ltd.
    Kandra, Singhbum, (Bihar)

For further information please contact

Information Manager
TIMEIS Project