A broken chain is the most common repair at a jewellery counter. Done badly, the repair leaves a stiff joint, discoloured links or a chain that breaks again next to the repair. A jewellery laser welding machine makes most chain repairs quicker and neater, because it heats only the joint. Here is how it works, where it helps, and where it has limits.
Laser welding is not soldering
Indian jewellers often call a laser welder a "laser soldering machine", but the two processes are different:
- Soldering joins parts with solder, a separate alloy that melts at a lower temperature. A flame heats the joint and the area around it.
- Laser welding melts the chain's own metal at a spot as small as 0.2 mm, using short pulses of laser light. You can add a filler wire of the same metal if the joint needs more metal.
Because the heat stays at the spot, the links next to the repair keep their shine and do not soften.
Step 1: check the chain first
- Where is the break? At the clasp, the jump ring, or a link in the chain.
- Solid or hollow? Many lightweight chains are made from thin tube. Hollow chains need much more care.
- Worn or clean break? A link worn thin will break again beside a new weld. Worn links and clasps are often better replaced.
- Karat: any filler wire or new part should match the chain's metal.
Step 2: repairing with the laser
- Clean the joint so dirt and oil do not spoil the weld.
- Close the link so the two ends meet tightly.
- Hold the chain under the microscope and line up the joint on the crosshair.
- Weld with short pulses, one spot at a time, working around the joint.
- Add filler wire only if there is a gap or a worn section.
- Check that the chain moves freely, then finish lightly.
Hollow and very fine chains: the limits
Hollow chains can have very thin walls. Bench jewellers report that a pulse strong enough for solid metal can blow a hole in a thin hollow wall. The usual approach is to build up each broken end with a little filler wire first, then join the built-up ends with gentle pulses.
Some repairs are better done another way: a chain worn thin along its length, or a woven chain with many broken strands, may need new sections rather than a weld. Always practise on a scrap chain of the same karat and construction before touching a customer's piece.
The right Semsons Tech machine for chain repair
Our 200 W jewellery laser welding machine lists chain and clasp repair among its main uses. It joins a link or jump ring without heating the rest of the chain.
| Feature | Why it matters for chains |
|---|---|
| Weld spot 0.2 to 3.0 mm | Small enough for fine links and jump rings |
| Pulse 0.1 to 20 ms, up to 150 J | Adjustable for thin or heavier links |
| 10x microscope with CCD camera | You can see the joint clearly while you weld |
| Built-in argon nozzle | Shields the weld from air (you arrange the argon cylinder) |
| Built-in chiller, single-phase 220 V | Runs in a normal workshop |
The machine costs ₹6,49,000 including GST and can be booked for ₹50,000. For a full comparison with pulse arc welders and torches, see our laser soldering machine buying guide. Our laser welding vs soldering guide explains how the heat travels in each process.
Before you buy, check
- How many chain and small repairs come in each week.
- Whether you repair fine and hollow chains, which benefit most from a laser.
- Your power supply and the space for the machine.
- Who trains your operator and services the machine.
Where to see and buy it
These are the Semsons Tech machines for this job. The store links let you book online; the other links open the full specifications or a quotation request.
| Machine and where to buy | Key facts |
|---|---|
| 200 W jewellery laser welding machine Buy or book on our store Full specifications | 200 W pulsed YAG, up to 150 J per pulse, weld spot 0.2 to 3.0 mm 10x microscope with CCD camera, built-in chiller, single-phase 220 V ₹6,49,000 incl. GST; book for ₹50,000 |
The best way to judge is to watch a chain being joined. Book a demonstration or call +91 98216 12340.