The production process of bulbs varies depending on the type. The following is the complete production process and key technical links of four common bulbs (incandescent, fluorescent, LED, heating):

1. Incandescent (traditional bulb)

Glass bulb manufacturing

• Raw materials: quartz sand, soda ash, etc. are melted into glass liquid at high temperature.

• Molding: The glass liquid is blown into the bulb shell through a mold to form a pear-shaped or spherical structure.

• Annealing treatment: Eliminate internal stress of the glass to prevent cracking.

Filament preparation

• Material: Tungsten wire (melting point up to 3422℃, high temperature resistant).

• Process: Tungsten wire is spirally wound to increase the luminous surface area.

Core column assembly

• Guide wire welding: Weld the two ends of the tungsten wire to the molybdenum guide wire, and the guide wire passes through the glass core column.

• Vacuum pipe installation: The core column reserves a vacuum pipe for subsequent vacuuming.

Packaging and exhaust

The stem and glass bulb are sealed by melting, and inert gas (argon/nitrogen) is filled after vacuuming to prevent the filament from oxidation.

High-temperature sealing: Seal the exhaust pipe to complete the airtightness of the bulb.

Lamp holder installation

The metal lamp holder (such as E27 screw mouth) is fixed to the bottom of the glass shell by adhesive, and the guide wire is connected to form a circuit.

Quality inspection

• Power-on test: Check brightness, life and whether there is leakage.

• Voltage resistance test: Ensure insulation performance.

2. Fluorescent lamp (energy-saving lamp)

Glass tube processing

The glass tube is bent into a U shape or spiral shape, and the inner wall is coated with fluorescent powder (converting ultraviolet light into visible light).

Electrode preparation

The surface of the tungsten wire electrode is coated with electron emission material (such as ternary carbonate) and loaded into both ends of the lamp tube.

Inflation and sealing

After vacuuming, mercury vapor and inert gas (argon) are injected.

High-temperature melting and sealing of the lamp tube.

Ballast and lamp holder assembly

Electronic ballast is integrated into the plastic lamp holder to adjust the current for stable light emission.

The lamp holder and the lamp tube are fixed by a plastic bracket.

Aging test

Continuously light for several hours to activate the phosphor and eliminate defective products.

3. LED bulbs

LED chip manufacturing

Semiconductor materials (such as GaN) are grown epitaxially by MOCVD and cut into tiny chips.

Packaging process

• Chip bonding: Bond the LED chip to the bracket.

• Wire connection: Gold or copper wire connects the chip electrodes.

• Fluorescent glue coating: Cover the phosphor layer to adjust the light color (such as blue light chip + yellow phosphor to produce white light).

Heat dissipation structure assembly

Allow LED modules to be welded on aluminum substrates or ceramic substrates, with heat dissipation fins or fans.

Drive power integration

Embed the AC-DC conversion circuit (constant current drive) into the lamp body to ensure stable power supply.

Optical design

Add a lens or reflector to control the beam angle and optimize the light distribution.

Assembly of the whole lamp

The housing (usually plastic or glass) is assembled with the heat sink and lamp holder (such as E26) into a whole.

Performance test

Luminous flux, color temperature, and color rendering index (CRI) testing.

Life test: simulate long-term use in high temperature and high humidity environment.

4. Environmental protection and safety

• Incandescent lamps: have been gradually eliminated due to low energy efficiency.

• Fluorescent lamps: contain mercury and need to be professionally recycled to avoid pollution.

• LED lamps: mercury-free and long life, but heavy metals in electronic components need to be handled.

5. Heating lamp (taking infrared heating lamp as an example)

Infrared Heat Lamp is mainly used for radiating heat energy rather than lighting. It is commonly used in industrial drying, animal breeding insulation or bathroom heating. Its production process combines high temperature resistant materials with directional heat radiation design:

1. Material selection and processing

Heating element material:

Tungsten wire or carbon fiber: high resistivity, high temperature resistance (tungsten wire melting point 3422℃, carbon fiber heat resistance up to 2000℃), through a special winding process to form a spiral or mesh structure to increase the heating area.

Lamp tube material:

Quartz glass: strong infrared transmittance (>90%), high temperature sudden change resistance (eliminate stress through annealing treatment).

2. Heating element processing

Tungsten wire processing:

Tungsten wire is wound into a double helix structure to reduce heat deposition and extend life.

Anti-oxidation layer (such as silicon dioxide) is coated on the surface to prevent high temperature oxidation.

Carbon fiber processing:

Carbon fiber is woven into bundles or meshes, and high temperature graphitization treatment is used to improve conductivity and stability.

3. Quartz tube molding and coating

Quartz tube blowing:

Quartz sand is melted at high temperature and blown into a transparent or milky white tubular structure (milky white quartz can scatter infrared rays and expand the heating range).

Reflective coating:

Aluminum or gold film is partially plated on the outer wall of the quartz tube to form a directional reflective surface to improve the efficiency of thermal radiation (such as the bathroom heating lamp focusing heat).

4. Electrode and seal assembly

Electrode installation:

Molybdenum sheet electrodes are welded at both ends of the heating element (molybdenum and quartz have similar thermal expansion coefficients to avoid cracking of the seal).

Inert gas filling:

Nitrogen or argon is injected after vacuuming to inhibit evaporation of the heating element (if it is a halogen heating lamp, a trace amount of halogen gas needs to be added to activate the regeneration cycle).

High temperature melting and sealing:

Electrodes and quartz tubes are sealed by hydrogen-oxygen flame to ensure airtightness.

5. Heat dissipation and protective structure

Metal bracket and protective net:

The stainless steel bracket fixes the lamp tube, and a metal protective net is installed on the outside to prevent contact burns or foreign body impact.

Ceramic base:

High temperature resistant ceramic lamp head (such as E27) is connected to the metal guide to prevent high temperature from melting the plastic.

6. Performance and safety test

Thermal radiation efficiency test:

Use infrared spectrometer to detect the radiation wavelength range (usually 2-5μm is the high efficiency infrared band).

Thermal shock test:

Instantly immerse the heating lamp in cold water to test the crack resistance of the quartz tube.

Life test:

Continuously work for more than 5000 hours, monitor the heating element attenuation rate and power stability.

7. Environmental protection and special design

Pollution-free process:

Avoid the use of harmful substances such as mercury and lead (different from fluorescent lamps).

Customized design:

Short wave/medium wave/long wave infrared lamp adjustment: Control the radiation wavelength through the heating element material and structure (such as carbon fiber biased towards long waves, tungsten wire is suitable for short waves).

The core of the production of heating lamps is to balance high temperature stability and thermal radiation efficiency. Its process combines the high temperature resistance technology of incandescent lamps with the directional optical design of LEDs, and is widely used in fields that require precise temperature control.

The production of different bulbs combines material science, electronic engineering and precision manufacturing technology. With the advancement of technology, LED has become the mainstream due to its high efficiency and energy saving, while traditional processes still have historical reference value.