Second SMT Line or a Third Shift: The ₹ Math

If the extra volume is less than about 40% of what your line ships today, a third shift is usually the cheaper rupee of capacity: in our worked example it costs about ₹23 per extra board in cash, against about ₹52 for a new second line on one shift. Above that gap, the night runs out of hours and the second line wins. The decision turns on the size and duration of the gap, not the machine price.

By the Mama Editorial Team. We scope camera projects for Indian factories. Last verified: 6 October 2026, against the statutes, notifications and sources cited inline.

If you don't yet know your line's real boards per placing hour and measured line efficiency, start with whether your SMT line can take PLI-scale volume.

Key takeaways

• A third shift adds at most 50% more staffed hours to a two-shift line. A second line on two shifts doubles them. That ceiling, not cost, decides most cases.
• Night hours place fewer boards. The UK Health and Safety Executive finds the risk of errors, accidents and injuries higher on the night shift.
• The third shift is not free on the books. If your unit is a company, Schedule II of the Companies Act raises depreciation by 50% for double-shift use and to 100% for triple-shift use.
• Night rules now have a defined path. The OSH Code lets women work before 6 a.m. and after 7 p.m. with their consent and prescribed conditions (section 43), set by the state for a private factory. Uttar Pradesh requires free transport, food, supervision and, since 2024, CCTV in premises and transport.
• A second line buys things a third shift cannot: room to grow past +50%, a fallback when one line is down, and the option to split high-mix work from volume work. On two settled shifts it costs only about ₹5 a board more.

What each option really gives you

The 26-day month assumes one weekly off, which the law requires: under section 26 of the OSH Code, "no worker shall be allowed to work in an establishment for more than six days in any one week". Sunday running needs a rotating crew.

A third shift is not exotic: in the CEERIS benchmark, contract-manufacturer SMT lines were staffed 112 hours per week, more than two 8-hour shifts on six days.

Why the night shift places fewer boards

Most SMT stops are short: a feeder error, a vision reject, an oven alarm. By day your process engineer is a shout away; at 3 a.m. a 10-minute fix waits until morning. The HSE adds that concentration and productivity "tend to decline ... during the night and early hours of the morning".

So plan the night at a lower line efficiency until your own data says otherwise (we assume 60% against 70%; not a benchmark), and give the night the long, stable runs, keeping changeovers, new-product trials and first-article checks on the day shift.

The worked ₹ example

Every input marked "assume" is illustrative. Replace it with your own.

Assume the line places 100 boards per placing hour on your main board (see the capacity method). It runs 2 shifts × 8 hours × 26 days = 416 staffed hours, and you have already raised measured line efficiency to 70%, close to the 75% world-class single-line mark. If you are well below that, recover the idle hours first. That gives 416 × 0.70 × 100 = 29,120 boards a month. Your buyer now wants 40,000 a month from next quarter, with talk of 50,000 next year. The gap is 10,880 boards.

Common inputs. Crew of 6 operators per shift (assume) at the Uttar Pradesh Category I (Gautam Buddha Nagar and Ghaziabad) semi-skilled minimum of ₹15,059 a month (basic ₹14,173 + VDA ₹886), set as interim relief by the state's order No. 374/36-2-2026 of 17 April 2026, effective 1 April 2026. The VDA is revised periodically, so check your current rate. Load it by an assumed 1.3× for statutory contributions and leave: ₹19,577 per operator, ₹1.17 lakh for a crew of six. Assume the line and its share of air-conditioning draw 40 kW while running, at ₹8 per kWh all-in.

Option A: third shift on the existing line. 208 extra staffed hours at an assumed 60% night efficiency gives 12,480 boards. Total output: 41,600.

Option B: second line, run on one day shift. Assume ₹4 crore all-in for the line: printer, placers, reflow, AOI, conveyors, feeders, installation, plus ESD flooring and air-conditioning for the new bay. It is a placeholder; get three quotes. Assume 55% line efficiency in the first months while a new crew learns a new line: 208 × 0.55 × 100 = 11,440 boards. Total output: 40,560.

At an assumed ₹50 conversion value-add a board, the third shift makes money from month one. The second line on one shift does not quite cover its cash cost (₹52 against ₹50) while it ramps.

Be fair to the second line. Those ₹52 are its worst months. At a settled 70% on one shift it makes 14,560 boards, and the cash cost falls to about ₹41 a board. On two settled shifts (two crews, double power and consumables, the same engineer and interest) it costs about ₹8.01 lakh a month for 29,120 boards: about ₹28 a board in cash, or ₹38 with double-shift depreciation. That is about ₹5–6 above the third shift's ₹23 and ₹32, for twice the extra volume. The night-shift case is also fragile. At 50% night efficiency instead of 60%, the third shift adds only 10,400 boards, short of the 10,880 gap, so 40,000 is missed.

The depreciation line. If your unit is a company, Schedule II of the Companies Act gives general plant and machinery a useful life of 15 years on single-shift working, with residual value ordinarily no more than five per cent of cost (departures must be disclosed and justified). For "double shift, the depreciation will increase by 50% for that period and in case of the triple shift the depreciation shall be calculated on the basis of 100%". On an assumed ₹4 crore line, single-shift depreciation is about ₹2.11 lakh a month; two shifts carry 1.5× that, and a third adds roughly ₹1.06 lakh more. Assets marked NESD, such as continuous-process plant designed to run 24 hours a day, get no extra-shift charge; a general SMT line normally falls in the 15-year class. It is a book charge, not cash, but a fair proxy for wear; your auditor confirms the treatment.

The volume where the answer flips

Now take next year's 50,000. That is a gap of 20,880 boards over today's 29,120.

• Third shift: even at day-level 70% efficiency, 208 night hours yield 14,560 boards. Total: 43,680. Short by about 6,300, with no hours left except Sunday.
• Second line on two shifts: 416 hours at 55% while ramping gives 22,880 boards. At 70% once settled, 29,120. Total: 52,000 rising to 58,240. It covers the gap, and now its interest and depreciation spread over twice the boards.

So the rule of thumb from this example:

The 40% boundary rests on 60% night against 70% day efficiency; recompute it with yours.

Two things push the boundary down. First, one-line risk: on three shifts a single line has no fallback, and one oven fault stops every board you make. Second, mix. CEERIS finds world-class high-volume lines above 80% efficiency and high-mix lines in the 60% range. If your new volume arrives as many small part numbers, a second line that takes the high-mix and NPI work can raise the efficiency of the first line, which then runs long volume jobs. A third shift cannot do that.

The night-shift paperwork, briefly

If women work on your SMT line, a third shift is also a compliance project. Section 43 of the OSH Code allows women to work before 6 a.m. and after 7 p.m. "with their consent", subject to conditions the appropriate government (for a factory, the state) prescribes. The OSH (Central) Rules, 2026, in force from 8 May 2026, show the direction (written consent, pick-up and drop, a well-lit workplace, CCTV on the way to toilets and facilities, emergency numbers), but bind only the central sphere; a private UP factory follows UP's conditions.

Uttar Pradesh's conditions come from its notification of 27 May 2022, as amended on 19 February 2024: - written consent, and no termination for declining night work; - free transport from home to workplace and back, plus food and supervision; - not less than three women (four before 2024) in the premises or a particular department; - CCTV in the premises and in night-shift transport, with a GPS tracker; - the arrangement sent to the regional factory inspector, who has up to seven days to verify it, then monthly reports.

Both were issued under the Factories Act, 1948, repealed on 21 November 2025; they continue where not inconsistent with the OSH Code (s.143(3)), so confirm with the UP labour department.

Price transport and cameras into Option A. Other states differ: see the state-by-state tracker.

Night allowance. We found no national statutory rate; the 10% is an assumption, so check local practice.

Power at night. Under the 2023 consumer-rules amendment, Time-of-Day tariffs apply to commercial and industrial consumers of 10 kW and above: solar hours 10–20% below normal, peak hours 10–20% above. Night is not cheaper by default; read your state commission's slabs.

For the general fixed-cost case for extra shifts outside electronics, see the ₹ case for a third shift.

What cameras can and cannot tell you here

What a camera can see. A camera over the loader, printer and conveyor shows when the line stopped and how long it waited, whether a 3 a.m. stop was a 4-minute splice or a 70-minute wait for the morning technician. Two weeks of that gives you your real night efficiency, the most important input above. It also shows gaps in the board stream on today's line, which are free capacity (where EMS hours leak).

What a camera cannot see. Placement accuracy, mispicks, solder quality or latent night-shift defects: your placer logs, SPI, AOI, test and field-return data answer those.

Counts, not persons. Measure line events: stops, waits, gaps. Do not score individual operators, and tell workers what the cameras are for before they go live, with a proper DPDP-ready worker notice.

Where Mama fits

Mama reads the cameras you have, or a few we add over the printer, loader and conveyor, and each morning sends you a short WhatsApp note on yesterday's line, night shift included: when it stopped and for how long. It watches machines and flow, not people. Send a short phone video of your SMT floor and we will show you where the cameras should go.

FAQ

Is a third shift always cheaper than a second SMT line? Per extra board, usually yes, while the gap fits in the extra 208 hours. In our example: about ₹23 against ₹52 in cash while the new line ramps, or ₹28 once it runs two settled shifts. Once the gap outgrows the night, or one-line risk matters, the second line wins.

What efficiency should I plan for the night shift? Lower than the day, until you have measured it. We assumed 60% against 70% by day. Measure two weeks of real night running before you commit volume.

Can women operators work the third shift in Uttar Pradesh? Yes, with written consent and the state's conditions: free transport, food, supervision, at least three women in the premises or department, CCTV in the premises and transport, the arrangement sent to the factory inspector, and monthly reports. Confirm the current version with the UP labour department.

How long before a second line ships boards? Ask your vendor: ordering, import, installation and customer qualification all take time. If next year needs a second line, order it while a third shift covers this year.