Phones and Components Going Missing on the Line: How EMS Plants Reconcile (₹)
Are chipsets, displays or finished phones going missing between your store and your packing table? Reconcile them stage by stage, by serial for high-value parts and by reel for the rest. In a worked example checked on 17 Oct 2026, a 0.1% unexplained gap on an assumed 78,000-handset month at an assumed ₹6,000 component cost per phone is about ₹4.7 lakh a month, before GST effects.
Last checked: 17 Oct 2026
By the Mama Editorial Team. Every figure carries its source and date. Our own inputs are marked "assume"; replace them with your bill of materials, purchase invoices and production reports.
Key takeaways
- Most of the value passes through your store as bought-in parts. PIB cites industry estimates that domestic value addition across Indian electronics manufacturing is 18%–20% (PIB, 1 Apr 2026). The rest arrives on reels, in trays and in display boxes.
- A gap is a number, not a suspicion. Opening stock plus issues, minus returns, minus good output multiplied by the BOM, minus logged scrap and machine rejects, is the unexplained balance for a work order.
- Paperwork explains most first-time gaps. Unposted partial-reel returns, unlogged rework swaps and scrapped boards that still carry chips all look like "missing" stock until someone writes them down.
- Reconcile by value class. Displays, chipsets and finished handsets are few and serialised, so count them daily by serial. Passives on reels are reconciled by reel and work order.
- Unaccounted stock has a tax cost. The CGST Act blocks input tax credit on goods "lost, stolen, destroyed, written off", and lets the officer tax unaccounted goods as if they had been supplied.
- A camera shows movement at fixed points, not counts. It can show when a tray left the store or the rework bench. It cannot count 0402 parts on a reel.
Why this matters more in 2026
The volume running through Indian EMS floors has multiplied. Mobile phone production rose from ₹18,000 crore in 2014–15 to ₹5.45 lakh crore in 2024–25, per the PIB backgrounder of 11 Oct 2025. ICEA, the mobile and electronics industry body, gives the same ₹5,45,000 crore figure for FY25 in its press release of 19 Aug 2025.
The production-linked incentive drives that volume. The large-scale electronics PLI, approved by the Cabinet on 21 Mar 2020, pays 4% to 6% on incremental sales over a base year of goods made in India. By February 2026 it had reached ₹11,01,813 crore of production, 136% of target, per PIB on 1 Apr 2026.
The same PIB release of 1 Apr 2026 counts more than 300 mobile manufacturing units operating in India. It also cites industry estimates that domestic value addition is 18%–20%. That figure covers electronics manufacturing as a whole, not phones alone, but it means roughly four rupees in five of output value is material someone else made and an EMS store is holding.
More throughput through the same stores and rework benches turns the same small percentage gap into a much larger rupee figure. Our general piece on employee theft in Indian factories covers gate, store, dispatch and scrap across sectors. This one goes inside the EMS line, where the counts actually break.
The chain a part passes through, and where counts break
A component is counted in a different unit at almost every stage. That is where gaps are born: a reel counted in pieces at receiving becomes "one reel" on the feeder and "a partial" on return.
| Stage | Counted in (unit) | Record that should exist | Where the count usually breaks |
|---|---|---|---|
| Receiving and store | Pieces per reel or tray; serials for displays | GRN, reel label, incoming count | Reel label quantity taken on trust; short reels surface weeks later on the line |
| Kitting for a work order | Reels, trays, pieces | Kit list against BOM and work-order quantity | Extra allowance issued "for attrition" with no record of how much |
| Line side and feeders | Reels loaded; placements | Feeder load log, machine placement and reject log | Parts dropped or rejected by the placer not posted; leftovers at changeover moved to the next job |
| Rework and repair bench | Boards in and out; parts drawn | Rework log with board serial and part replaced | Removed chips and replacement parts not logged; see our piece on the SMT rework queue |
| Returns to store | Partial reels, unused trays | Return note against the work order | Partial reels returned without a count, or never returned; floor-life-expired reels set aside |
| Scrap and write-off | Boards, displays, housings | Scrap note with serial and reason | Scrapped boards still carrying a chipset and memory, written off as "one PCB" |
| Final assembly, packing, dispatch | Finished units by serial | Packing list against serials built | Built count and packed count compared as totals, not serial by serial |
Partial reels coming off the line often sit until their moisture floor life is in question; our piece on moisture-sensitive parts waiting on the SMT floor covers that bill. And scrapped boards are the quietest leak: a board scrapped after reflow still holds the most expensive parts in the BOM.
The reconciliation formula, per work order
Run this per work order. A monthly stock-take tells you something is wrong; a work-order reconciliation tells you where.
Unexplained gap = opening line stock + issued to the line − returned to store − (good output × BOM quantity) − logged machine rejects − logged rework replacements − logged scrap − closing line stock.
Every term needs a record. If a term has no record, the gap is a paperwork gap first. Fix the record, rerun the sum, and only then ask whether anything left the building.
Moulding plants run the same sum as resin issued against parts made. In EMS the highest-value items are serialised, so you can reconcile them one by one.
Count by serial or by reel: split by value class
A display or a chipset carries a serial or lot label; a 0402 resistor is one of thousands on a reel.
IPC-1782, the Standard for Manufacturing and Supply Chain Traceability of Electronic Products (October 2016 edition), sets four traceability levels, from Basic to Comprehensive, with requirements "as agreed between user and supplier". A plant that already links chipset lot or serial to board serial for its customer can use the same data to reconcile.
Use three bands. These cadences are our suggestion, not a standard:
- Class A, daily by serial: finished handsets, display assemblies, chipsets and memory, camera modules.
- Class B, per work order by tray or piece count: batteries, connectors, shields, housings.
- Class C, per work order by reel: passives and other low-value reel parts, compared against the machine's placement and reject log.
Worked ₹ example: what a 0.1% gap costs
Assume a mid-size EMS plant building 3,000 handsets a day across two shifts, 26 days a month: 78,000 handsets a month. Assume a component cost of ₹6,000 per handset, split as below. Use your own BOM costing.
| Value class (assumed split) | Component cost per handset (₹, assumed) | Units consumed per month | 0.1% gap (units per month) | 0.1% gap (₹ per month) |
|---|---|---|---|---|
| Chipset and memory | 2,500 | 78,000 | 78 | 1,95,000 |
| Display assembly | 1,500 | 78,000 | 78 | 1,17,000 |
| Camera modules | 600 | 78,000 | 78 | 46,800 |
| Battery | 300 | 78,000 | 78 | 23,400 |
| PCB, passives, connectors | 500 | 78,000 | n/a (reel parts) | 39,000 |
| Housing, packaging, accessories | 600 | 78,000 | 78 | 46,800 |
| Total | 6,000 | 4,68,000 |
A 0.1% gap across the BOM is about ₹4.7 lakh a month, or about ₹56 lakh a year, in this worked example. Two thirds of it sits in just two lines: chipsets with memory, and displays.
A 0.1% display gap here is 78 units a month, three a day: a number you can find by serial before the shift ends. The passives line sits inside the normal noise of placement rejects and is best reconciled per reel and work order.
Finished handsets are different again. If every unit carries a serial and an IMEI, the expected gap is zero, so a missing handset is an event to trace, not a percentage to tolerate. Assume five finished handsets a month at an assumed ₹9,000 ex-factory value: ₹45,000 a month.
The GST side of a missing part
The tax law treats a missing part as more than a stock loss. These are statements of the CGST Act text, from the CBIC consolidated version updated to 30 Sep 2020; confirm the current position with your tax adviser.
- No input tax credit on lost goods. Section 17(5)(h) blocks credit on "goods lost, stolen, destroyed, written off or disposed of by way of gift or free samples".
- Stock records are a statutory duty. Section 35(1) requires a "true and correct account" of production or manufacture of goods and of stock of goods.
- Unaccounted goods are taxed as supplied. Under section 35(6), where goods are not accounted for, the proper officer "shall determine the amount of tax payable" on them "as if such goods... had been supplied".
Assume the components carry 18% GST on your purchase invoices (check your own; ICEA's 19 Aug 2025 release described mobile phones as being taxed at 18% at that date). Then the credit lost on ₹4.68 lakh of missing parts is about ₹84,000 a month. With the parts themselves, the worked gap is about ₹5.5 lakh a month, or about ₹66 lakh a year.
What to fix first, before anyone is questioned
- Count partial reels on return. A return note without a counted quantity makes the next work order's opening stock a guess.
- Log every rework swap against a board serial. A chipset removed at the bench is either reballed, returned or scrapped. All three need a line in the log.
- Write off scrapped boards at BOM value. A scrapped board is the chipset, memory and display connector on it, not "one PCB".
- Post placement rejects. Pull the placement machine's reject or pick-up error count per feeder and post it against the work order.
- Reconcile Class A daily by serial. Displays and chipsets issued, fitted, reworked, scrapped and returned should close to zero each day.
- Compare packed serials with built serials, not packed totals with built totals.
If a gap remains after these six, it is a real gap. That is the point at which a general approach to internal theft applies. Our employee theft piece covers evidence handling under the Bharatiya Sakshya Adhiniyam.
What cameras can and cannot tell you here
Cameras earn their place at the fixed points that material passes through: the store counter, the line-side supermarket, the rework bench, the scrap bin and the packing table. Our overview of cameras in electronics and EMS plants covers the other gaps a line's own logs miss: ESD discipline, changeovers, manual stations and rework.
What a camera can show:
- When a tray, reel or carton moved, and whether the movement lined up with an issue or return slip.
- Whether scrap bins were emptied on schedule or at odd hours.
What a camera cannot show:
- How many parts are on a reel, or whether a reel label is right.
- Which chipset was fitted to which board; that is the traceability system's job.
- Intent. A tray that moved without a slip may be a rushed changeover, not a theft.
Count material and aggregates, not people. Footage of recognisable workers is personal data under s.2(t) of the DPDP Act, 2023; tell workers in writing what is recorded and why (see the worker CCTV notice under DPDP).
Where Mama fits
Mama reads a factory's existing cameras and sends the owner a short morning note on where hours and material flow broke down the day before, such as movement at the store or rework bench outside the logged issues. It watches machines and flows, not individuals, and it does not replace your traceability system or your stock records. Leave an email or phone in the form below and Mama will get back to you with a camera plan.
FAQ
What is a normal component gap for an EMS line? We found no published Indian industry benchmark for an acceptable unexplained component gap (checked 17 Oct 2026). Set your own tolerance from your past work orders, separately for each value class, and expect Class A serialised parts to close to zero.
Why does my monthly stock-take not reconcile when each work order looks fine? Usually because leftovers move between work orders without a record: partial reels at changeover, rework parts drawn from the next job's kit, or late scrap write-offs.
Do I lose GST credit on missing components? Section 17(5)(h) of the CGST Act blocks input tax credit on goods "lost, stolen, destroyed, written off". Section 35(6) lets the officer tax goods that are not accounted for as if they were supplied. Ask your tax adviser how this applies to your write-offs.
Can cameras count components on the line? No. A camera can show when a reel, tray or carton moved and whether that matched a slip. Counting parts on a reel needs a reel counter or the placement machine's own log.
Should finished handsets be reconciled by count or by serial? By serial. A total count can match while one serial is missing and another is duplicated. With serials and IMEIs on every unit, the expected gap is zero.