The equipment used in an LED lamp plant

From the stencil printer to the burn-in rack: the main machines in an LED lamp factory, what each one does and what it means for buyers.

When people talk about a factory they tend to mention floor space and headcount, yet what really decides how a product turns out is the equipment inside. Making LED lamps brings several technical disciplines together: electronics assembly, work with plastic and metal parts, optical measurement and packaging. Each has its own machinery, and how well these pieces fit together shows how steadily a line runs. Below the equipment is grouped by function rather than by the order of the process, so it is clear what each machine is responsible for.

The circuit board area: the SMT line

The most complex part of the plant is the surface-mount technology (SMT) line. It usually consists of several machines in a row:

• Stencil printer. Applies solder paste to the board's pads through a metal stencil. The thickness and position of that deposit set the quality of every joint that follows.
• Pick-and-place machine. Takes chips, resistors and ICs from reels or trays and places them on the board under camera guidance. These machines can place thousands of parts an hour and set the pace of the whole line.
• Reflow oven. A conveyor oven with several temperature zones. As the board passes through, the paste heats, melts and then cools to lock the components in place. The temperature profile is matched to the paste and the parts being used.
• Automated optical inspection (AOI). Photographs each board and compares it with a reference, looking for shifted, missing or reversed parts and solder bridges.

Not every plant has AOI; on some lines an operator does this check under magnification. The principle stays the same: a faulty board has to be caught before it reaches assembly.

The driver and through-hole parts

A driver board carries larger components such as an electrolytic capacitor, an inductor and sometimes a fuse. These go through holes in the board and are soldered either on a wave soldering machine or by hand at soldering stations. This area also has test fixtures that check the driver's output current and voltage before it goes into a lamp. The driver is one of the most sensitive parts of a bulb, so this checkpoint deserves particular attention.

The assembly area

Here the LED board, driver, housing and cover come together. Typical equipment includes:

• Dispensers that apply thermal paste or cover adhesive in measured amounts;
• A cap crimping press that fixes the metal screw cap onto the housing, with adjustable force so the cap is neither loose nor cracking the plastic;
• Soldering equipment for the centre contact of the cap;
• A conveyor or rotary table that moves units between operators.

The degree of automation varies: on some lines most of these steps are manual, on others semi-automatic machines do them.

Test and measurement equipment

Checking an assembled lamp needs its own instruments:

1. Burn-in racks, where hundreds of lamps are switched on and left running at once.

2. An integrating sphere with a spectroradiometer, which measures luminous flux, colour temperature and colour rendering index.

3. A power analyser that records wattage, current and power factor.

4. A hi-pot tester that confirms the insulation does not break down.

These instruments need regular calibration. A sphere that is out of calibration gives wrong numbers, and the assessment of an entire batch is skewed as a result.

Marking, packing and support systems

Ratings are printed on the lamp by pad printing, laser or ink-jet. Packing may involve machines that fold and close boxes and tape outer cartons.

Less visible support systems matter just as much: grounded workstations that protect against static electricity, a compressed air supply, dry storage cabinets that keep components away from moisture, and control of temperature and humidity on the shop floor. Solder paste, for example, is kept refrigerated and brought gradually up to room temperature before use.

What a buyer can take from this

A list of machines is not a guarantee of quality in itself; the same equipment can turn out good or poor products. What it does is give direction when you question a manufacturer. A trade buyer might ask whether burn-in testing is done, which instrument measures the light output figures, and how batches are traced. Specific, clear answers suggest production has been set up with thought.

According to information given at its opening, Zaferoğlu Elektrik's plant in Ganja occupies 1,500 square metres and is fitted with modern equipment brought in from abroad. Its output is sold as Zəfər İşığı.