Die Change Time on Power Presses: What a 70-Minute Change Costs an Indian Press Shop (₹)

Measured honestly, from the last good stroke to the first approved part, a die change in many Indian sheet-metal and auto-component press shops can run to an hour or more. There is no published Indian benchmark; the one recorded Indian study we found measured 120–228 minutes on high-speed presses, and this article uses 70 minutes as an illustrative assumption. Very little of that time goes on actually swapping the die. Most of it is waiting: for the die to come back from the tool room, for the one crane in the bay, for a spanner, for the QC inspector to sign off the first part. On one press doing three changes a day, our worked example puts the cost at roughly ₹2.85–4.2 lakh a month.

By the Mama Editorial Team. Not another SMED primer: this is about the named minutes on an Indian press floor (T-bolts, the EOT crane, the first-off card) and what they cost.

Key takeaways

• Start the clock at the last good stroke and stop it at the first approved part. "Die change time" that ends when the die is clamped leaves out the trial strokes and the QC wait, and those are often the biggest pieces.
• The swap itself is rarely the problem. In a recorded changeover study at an Indian stamping division, workers went to the tool room more than ten times per change, costing about 30 minutes. In one 213-minute change, 32 minutes went on mounting, removing and re-mounting a die that was set wrong, and 28 minutes on fastening it.
• Price the press-hour, not the setter's wage. Labour is small money; a standing press is big money, more so if it is your bottleneck.
• Some minutes must stay. State factory rules have long required an authorised person to test a power press's safety devices after tool setting before it runs again. Treat that check as part of the clock, not something to cut.
• Two weeks of honest timestamps beat any target. They show which bucket to attack first.

Why die changes are getting more frequent

ACMA reported industry turnover of ₹7.6 lakh crore in FY2025-26, up 12.7%, with supplies to OEMs up 16.3%. For a Tier-2 press shop in Chakan, Manesar or Hosur, growth often arrives as more part numbers and more frequent call-offs rather than longer runs of one bracket. Toyota took its die changes from hours down to minutes decades ago; you don't need that history, only where your own minutes go.

Where the minutes actually go: an Indian study

The most useful primary evidence we found is a 2011 Thapar University M.E. dissertation by Gaurav Tyagi, Designing of New Chute Plate for Quick Die Change on High Speed Presses. It was carried out at the stamping division of Crompton Greaves in Ahmednagar, which makes motor laminations on high-speed presses with progressive tools. Every changeover was video recorded and timed with a stopwatch.

What it found:

• Average changeover times of 120 to 228 minutes across four presses (New Aida, Aida 125, Danly and Ching Fong).
• The author found workers walking from the press to the tool room more than ten times per change, which took about 30 minutes. On the 200-tonne Ching Fong, a single recorded change of 213 minutes shows trip after trip: for a spanner, an Allen key, an eye bolt, then the feeder gears and the pneumatic gun.
• In the same change, the die was placed, found misaligned with the chute, removed and placed again. That cost 15 + 9 + 8 = 32 minutes.
• Clamping with eight bolts took 28–35 minutes and two people. Shut-height setting with a pneumatic gun took about 15 minutes with three operators. Changing the mechanical feeder gears took 35 minutes.
• Simply moving external work (fetching tools, gears and the next die) to before the press stopped cut changeover time by 37%, before any hardware was bought.

The six buckets of an Indian press-shop die change

1. Die not ready. The die comes back from its last run with a burr problem, a broken pilot or a missing stripper spring, and the tool room starts on it only after the press has stopped.
2. Crane wait. One EOT crane serves the whole bay. Two changes in the same hour means one press waits.
3. Unclamping and clamping. Manual T-bolts, clamp heights that differ from die to die, a spanner borrowed from the next press.
4. Shut height, feeder and coil. Ram adjustment, feed pitch, straightener settings and the next coil's width.
5. Trial strokes and strip adjustment. Inching, a few hits, checking the strip, adjusting, hitting again.
6. Safety test and first-off approval. The authorised person checks the guards and two-hand control. Then the first part goes to QC and waits for a signed first-off card.

Bucket six is partly fixed by law and by your customer. Gujarat's Factories Rules, 1963, for example, had a Schedule VI (reproduced here by a compliance publisher; we could not reach an official copy) saying no press may be used after setting, resetting or adjustment of the tool until an appointed or authorised person has inspected and tested every safety device, unless the adjustment disturbed none of them. The four Labour Codes took effect on 21 November 2025 and the Factories Act was folded into the OSH Code. Gujarat's OSH rules (Gazette, 12 June 2025) state they are made in supersession of the 1963 rules, and we found no power-press schedule in them. In states that haven't finalised rules under the Codes, the old factory rules broadly continue during the transition. Check your state's current position; the practice itself is not in doubt. UK guidance on presses says the daily inspection and test must be repeated after setting, resetting or adjustment of the tools when any guard or protection device has been disturbed, which a full die change almost always does. On the quality side, IATF 16949 clause 8.5.1.3 expects job set-ups to be verified, with first-off/last-off comparison where applicable.

So don't shorten the check. Stop the press waiting for it: the authorised person and the inspector should be at the press when the die is ready, not paged after.

A worked ₹ example: one 250-tonne press, three changes a day

Every figure below is an assumption for illustration. Wages are not from any state notification; check your state's current minimum-wage order for your trade and use your own payroll.

The press and the shop. A 250-tonne mechanical press in a two-shift Tier-2 shop, running progressive and compound dies for brackets and reinforcements. It does three die changes a day, 26 days a month, which is 78 changes a month. The measured average is 70 minutes from last good stroke to approved first-off.

Value of a press-hour. We assume ₹2,500 an hour on a cost basis, worked out the way our machine hour rate guide explains. If this press is your bottleneck, a lost hour is lost output, and contribution is the better measure: assume ₹4,000 an hour.

Crew. Assume a setter costing the company ₹35,000 a month and a helper at ₹20,000, which works out to about ₹168 and ₹96 an hour (÷26 days ÷8 hours). Assume 15 minutes of an inspector at ₹25,000 a month for each change. Trial scrap: assume 10 parts at ₹40 of material each.

The press-hours are 80–86% of the total. A speed bonus or an extra helper barely moves that; shortening the stop does.

What 30 minutes back is worth. Suppose die staging, a crane booking slot and a "QC at the press" rule bring the average to 40 minutes, with every safety and quality check still in place. That saves 78 × 30 minutes = 39 press-hours a month. On the cost basis that is ₹97,500 a month. On the bottleneck basis it is ₹1,56,000 a month, about ₹18.7 lakh a year from one press. Ninety-one hours of change time is also about 22% of a two-shift month (26 days × 16 hours = 416 hours). That is the capacity behind many "we need another press" conversations.

How owners measure it without a consultant

1. Put a change card at each press. It has six times: last good stroke, die at press, crane at press, first trial stroke, first-off handed to QC, QC approval.
2. Run it for two weeks on your two busiest presses, with no target yet.
3. Sort the minutes into the six buckets and rank them.
4. Count changes as well as minutes. Mark which changes the schedule planned and which were forced by a die breakdown, a coil shortage or a quality hold. Forced changes are a planning problem.
5. Fix the external work first: die staged and pre-checked by the tool room, tools and clamps in a trolley at the press, crane booked against the change schedule, QC told 15 minutes ahead. This is where the 37% in the Indian study came from, with no hardware.
6. Then price the hardware. Hydraulic clamps, standard clamp heights, die carts and motorised shut-height adjustment are worth buying once the bolting and crane buckets are the ones left.

If one setter covers several presses, the queue for him is its own bucket. We cover that in one setter, five machines. If first-off rejections are frequent, the trial-stroke bucket is really a quality cost, priced in what a 3% rejection rate costs.

What cameras can and cannot tell you here

A camera that sees the press and its approach can timestamp what a change card gets wrong: when the ram last stroked and stroked again, when the die cart or crane hook arrived, how long the press stood with nobody at it, and how long the first part sat on the QC table. Across every change, not just the ones someone wrote down, that makes the buckets hard to argue with.

What a camera cannot do:

• It can't tell you why the die wasn't ready. The cause lives in the tool room and the die-maintenance log, not on the press floor.
• It can't judge the setting. Shut height, feed pitch and strip alignment are measured with gauges and the first-off inspection, not with pixels.
• It can't certify the safety test. It shows someone at the press for four minutes, not whether the two-hand control was properly tested. Guarding, and the gaps a camera leaves in it, are covered in our press and forging shop safety guide.
• It can't always tell a die change from a breakdown without the schedule or a supervisor's tag, and one press often hides another.

People will be in these frames. Count them as aggregates: how many were at the press, and for how long. Never use the footage to rank setters. Give workers notice under the DPDP Act, as described in our worker CCTV notice guide.

Where Mama fits

Mama reads the cameras you already have, over RTSP/ONVIF, or ones added where there's a blind spot. Every morning it sends the owner a plain-language note on where the press-hours went yesterday: which presses stood longest during changes, which bucket the minutes fell into where the video can show it, and what that was worth in rupees. It watches presses, dies and flows. It doesn't watch named people. Leave an email or phone in the form below and Mama will get back to you with where the hours are likely going, a camera plan for your press bay, and a proposal.

FAQ

What is a good die change time for a power press in India? There is no published Indian benchmark; it depends on press size, die type, clamping and coil handling. The useful benchmark is your own: measure last good stroke to approved first-off for two weeks, then aim to remove the waiting buckets.

Should die change time include first-off approval? Yes. The press isn't producing saleable parts until the first-off is approved, and IATF 16949 expects set-ups to be verified.

Do hydraulic die clamps pay back in an Indian press shop? They can, after the free fixes. If staging and crane scheduling have removed the waiting and bolting still takes 15–30 minutes, price that saving per press-hour with the table above and compare it with the clamp quote.

Can we skip the safety check after a die change to save time? No. State factory rules have long required it (Gujarat's 1963 schedule is one example), and whatever your state's rules now say, testing guards and two-hand controls after a die change is basic press safety. Save time by having that person ready when the die is set, not by skipping the test.