Key takeaways
- Audit the tool before it moves: die height, shut height, tonnage at the rated stroke, wear on punches and the last approved sample, all recorded in one document signed by both suppliers.
- A tool sized for a 160 T press can run on a 200 T frame only if the shut height closes within the stroke; a 310 mm die in a 400 mm shut height needs a 70 mm bolster spacer.
- Prove capability, not appearance. Thirty consecutive parts with a 0.38 mm range on a ±0.4 mm dimension give σ = 0.093 mm and Cpk 1.43; a 0.6 mm range gives Cpk 0.91 and a tool that is not ready.
- Tool refurbishment is quoted as a one-time charge separate from the piece price, so the buyer can see what the transfer costs before the first order.
- If more than two stations need replacement punches, a cracked section and a worn stripper, a new tool is usually the better route than a transfer.
The tool is the asset. The drawing is not, and neither is the last supplier's memory of how the tool ran. Most transfer tooling from an existing supplier fails on the second point: the tool arrives on a pallet with a shut height nobody recorded, a stripper held together with a bolt that is not original, and no approved sample to compare the first-off against. The new supplier then spends four weeks rebuilding information the old supplier had for years.
The commercial risk sits in the gap between the last good part and the first new one. During that gap the customer is either buying from the outgoing supplier at the old price, holding buffer stock, or both. A transfer that is planned as a logistics exercise takes three months. One planned as an engineering release takes four to six weeks and lands on the drawing tolerance.
What has to move with the tool?
Eight things, and the tool is only the first. A transfer that moves the steel and nothing else is a tool move, not a production transfer.
- The tool, top and bottom, with the die set, guide pins and all stations intact.
- Tool assembly and detail drawings, including the revision that matches the current part.
- The tryout or process sheet, showing shut height, tonnage, lubrication, strip feed and the press it last ran on.
- The approved sample or golden part, signed and dated by the customer, not by the supplier.
- The checking fixture, if one was built for the programme. If it stayed behind, the transfer is already weaker.
- The wear-part list, with punch and die insert part numbers, so spares can be ordered before the first regrind.
- Material certificates from the last production run, so the new supplier can start on the same grade and yield band.
- The change log, showing every engineering change since the tool was built and whether the tool was modified to suit.
What does the condition audit record?
The audit is a measurement exercise with a signature at the end. Everything below is a number, not a comment.
| Checkpoint | What to record | What fails if it is skipped | Ganesh note |
|---|---|---|---|
| Die height and shut height | mm, measured on the assembled tool | Tool will not close in the new press | Recorded against the press shut height before scheduling |
| Tonnage at rated stroke | tonne-force, from the process sheet | Press overload or under-tonnage forming | Checked against the 20–300 T press range |
| Bed and bolster size | mm, tool footprint | Tool overhangs the bolster | Bed size confirmed per press |
| Stroke and shut height of the last press | mm | Spacer or ram adjustment missed | Spacer height calculated, not guessed |
| Punch and die wear | mm, against the wear limit | Size drift from the first stroke | Punches measured and listed for replacement |
| Stripper and springs | Condition, free length | Part lifts with the punch, double hits | Springs replaced as a set, not one at a time |
| Guide pins and bushes | Clearance, scoring | Off-centre load, uneven burr | Bushes replaced where clearance exceeds spec |
| Last approved sample | Part with date and signature | No acceptance reference | Golden part retained at the new supplier |
| Fixture and gauges | Present or missing | First article has no method | Fixture rebuilt if the original is unavailable |
| Tool ownership | Document reference | Disputed release, tool held back | Ownership stated on the purchase order |
The audit is also where the refurbishment scope gets agreed. A tool with two worn punches is a maintenance job. A tool with a cracked die section, a distorted stripper plate and a worn guide set is a rebuild, and the buyer should see that split before the tool leaves.
Does the tool fit the new press?
It fits if the tonnage, the shut height and the bed all close at the same time. Two out of three is a broken tool.
Start with tonnage. A tool designed to run at 96 tonne-force on a 160 T press can run on a 200 T frame: 96 tonne-force is 60% of the 160 T rating and 48% of the 200 T rating, so both are inside a 75% working limit. On the Ganesh press range of 20 T to 300 T, that tool has two homes, and the choice depends on shut height rather than tonnage.
Shut height is where transfers fail. Suppose the tool assembles to a 310 mm die height and the new press has a 400 mm shut height with a 180 mm stroke. Subtract a 20 mm clamp allowance and the gap is:
400 − 310 − 20 = 70 mm
That 70 mm needs a bolster spacer or a ram adjustment within the stroke. A 70 mm spacer is normal. A 160 mm spacer on a tool with a small die set is a stability problem, because the spacer raises the working line and the press deflects more under load.
Bed size is the third check. A tool with a 1,200 × 800 mm footprint needs a bed that supports it with the load centred. Off-centre loading on a mechanical press tilts the ram, and the tilt shows up as a taper across the part and uneven punch wear. If the tool has to sit off-centre, the tonnage available at that point is lower than the nameplate figure.
What does tryout have to prove?
That the tool holds the drawing tolerance, measured, on consecutive parts.
The convention worth using is 30 consecutive parts off the transferred tool, measured on the closing dimension with a gauge that has a known R&R. Take the range, divide by the d2 constant for n = 30, which is 4.09, and you have an estimate of standard deviation.
Worked example. The closing dimension is ±0.4 mm. Thirty consecutive parts show a range of 0.38 mm.
- σ = 0.38 / 4.09 = 0.093 mm
- Cpk = 0.4 / (3 × 0.093) = 1.43
That tool is ready. Repeat it with a range of 0.60 mm:
- σ = 0.60 / 4.09 = 0.147 mm
- Cpk = 0.4 / (3 × 0.147) = 0.91
That tool is not ready, even though every individual part is inside tolerance. The second tool will pass first article and then produce rejects as soon as the coil changes or the punch wears. The decision at that point is a punch change, a die insert correction or a drawing relaxation, and it should be taken at tryout while the tool is still on the bench.
Tryout quantity matters for the same reason. Fifty parts prove the tool can make a part. Three hundred prove it can make a part after the strip has run, the die has warmed and the scrap has cleared. For a progressive tool with six stations, 300 pieces is two or three coils, which is the minimum sample that shows a feed problem.
Who owns the tool, and what does the contract say?
Ownership should be settled before the transfer, not during it.
If the tool was invoiced as a separate line item, it is normally customer property, and ISO 9001:2015 clause 8.5.3 requires a supplier holding customer property to identify, protect and safeguard it, and to report loss or damage. That clause is the lever when an outgoing supplier is slow to release. If the tool was absorbed into the piece price, the supplier owns it and the customer has to buy it out or build new.
Three terms belong in the transfer purchase order:
- Release condition: the tool, drawings, tryout sheet and approved sample are released before the final payment on the last production order clears.
- Condition on receipt: the new supplier records the condition within five working days of arrival and reports any damage before tryout.
- Storage and maintenance after the transfer: whether the tool is stored at the supplier, who pays for preservation, and what triggers a maintenance interval.
The guide to customer-owned tooling covers the storage, preservation and production-control side in more detail, including what a tool record should contain after the transfer is complete.
What does transport do to a press tool?
A tool is a precision assembly that can weigh several tonnes, and moving it is the least engineering-heavy part of the transfer and the most common source of damage.
Four rules cover most of it. Move the tool closed and clamped, with the guide pins protected by sleeves or timber blocks. Crate it so the load path runs through the die shoe and the base, never through the punches or the stripper. Fit a shock or tilt indicator to the crate, so damage is visible before the tool is unwrapped. And record the condition with photographs at both ends, so a bent guide pin can be attributed.
Preservation matters as much as impact. A tool stored for six months needs a hard film or a grease coat on every machined face, not a wipe with oil, and the crate needs a desiccant charge. Ground and polished die surfaces rust in a coastal warehouse within weeks, and rust pits on a die section become burr on the part.
Weight also decides the route. A tool that needs a crane at both ends cannot be moved by a courier, and it needs a press with enough bed and bolster to take the load. Confirm the lifting points on the tool before the transport is booked, because a tool lifted by the wrong eyes can distort the die set before it ever reaches a press.
What Ganesh does on a transfer
Ganesh runs an in-house tool room for press tools, progressive dies, welding fixtures and checking fixtures, across five units in Mumbai (Vasai) and Nagpur, on presses from 20 T to 300 T with a 250 T punching press. A transferred tool is audited on arrival, measured against its own drawings, and quoted as a one-time refurbishment charge separate from the piece price.
The tryout runs on the press the tool will actually produce on, not on the largest frame available, because a tool run at half its rated tonnage behaves differently in production. First article inspection and PPAP are available, and the plants hold ISO 9001:2015 and ISO 14001:2015. Customer programmes include Mahindra, Mahindra Powerol, Godrej & Boyce, TKE, Eros Elevators, Minda, Gunnebo and Indian Railways.
Where the tool needs more than maintenance, the press tool and die capability page sets out what can be rebuilt in-house. The stamping and press tool hub carries the related guides on die maintenance and tool life.
What to put in the transfer RFQ
- Tool drawings, the revision and the die height, in millimetres.
- The press the tool last ran on: tonnage, shut height, bed size and stroke.
- The last approved sample, photographed with dimensions marked, and the datum scheme.
- Station count, tool type (compound, progressive, transfer) and strip width.
- Drawing revision for the part, and any engineering change since the tool was built.
- Annual volume, release pattern and the buffer stock available during the gap.
- Ownership status and the expected release date from the current supplier.
- Whether the checking fixture transfers, or has to be rebuilt.
Send the data pack through the quotation route. The RFQ checklist tool lists the fields that most often go missing, and the press tonnage calculator gives a first estimate of whether a candidate press will carry the tool before the audit is scheduled.
When a transfer is the wrong decision
Three cases, and saying so is cheaper than discovering it at tryout.
The first is a tool built for a part that has changed. If the drawing revision moved a hole or changed a flange by 5 mm, the tool needs modification, and modification of a worn tool is often more expensive than a new tool built to the current revision. Compare the refurbishment quote with a new tool quote on the same scope, not on the old tool's original price.
The second is a tool at the end of its life. A progressive die that has been ground through its wear allowance will not hold size after a rebuild, because the die section height is already below the design value. The progressive die maintenance guide explains how to read the remaining life from the regrind record.
The third is a tool with no documents. Without tool drawings, a wear-part list and a sample, the new supplier is reverse-engineering a tool that already exists. That work is quoted as engineering time, and it delays the first article by weeks. Where the volume justifies it, a new tool with a clean data pack is the faster route to a stable part. The tooling cost versus piece price guide sets out how to compare those two options on total programme cost.
Frequently asked questions
How long does a press tool transfer take?
The audit and paperwork take one to two weeks, transport and cleaning another one to two, and tryout with first article two to six weeks. Plan on four to six weeks from release of the tool to a signed first article for a straight transfer, and four to ten weeks where refurbishment is in scope.
Who owns the tool when we change suppliers?
Whoever the purchase order says. If the tool was paid for as a separate line item, it is normally customer property and must be released with the tool drawings and tryout record. Get the release in writing before the final payment on the old supplier's last order.
Can a transferred tool hold the original tolerance?
It can hold what the tool was built to, not what the drawing asks for. A transfer is the moment to measure the tool's real capability on 30 consecutive parts. If Cpk comes out below 1.33 on the closing dimension, the choice is refurbishment, a drawing relaxation or a new tool.
What documents should come with the tool?
Tool assembly and detail drawings, the tryout or process sheet, the approved sample or golden part, the checking fixture if it exists, the wear-part list, the material certificates from the last run and the change log. Missing documents cost more to reconstruct than the tool costs to move.
Is a transfer cheaper than a new tool?
Usually, when the tool is under ten years old, the geometry has not changed and fewer than three stations need work. Once a stripper, a die section and most punches need replacement, the refurbishment plus the tryout risk approaches the cost of a new tool built for the current press.
Sources
Moving a tool? Send the tool data pack first
Share the die height, shut height, tonnage, station count, last approved sample and the drawing revision. We return a condition-audit scope and a tryout plan before the tool leaves the current supplier.
Start a tool transfer