A supplier sends a photograph of a neat hexagonal crimp and a pull-test result marked “pass.” Before approving it, connect that evidence to the exact cable, lug, tool and die used. A result without those identities is difficult to reproduce and cannot establish that another production setup will behave the same way.
For battery-cable buyers, the useful deliverable is a crimp process record: an identified tooling combination, a defined test method and traceable measurements. This guide explains how to request that record without inventing universal pull forces, crimp dimensions or compression percentages.
Identify the die beyond its size marking
A die code is not necessarily the conductor cross-section. Klauke’s D 22 table, for example, lists D2250 for 50 mm² with code 14 and a 5 mm crimp width. That table covers its stated copper compression-lug and connector families; it does not approve every 50 mm² lug or fine-stranded cable. Klauke D 22 tooling data.
Request the die manufacturer, complete part number, profile and identification marks. Add the tool model, tool serial number, die holder or adapter where applicable, and the instruction revision used for setup. Record both halves when the system uses a matched die pair. A photograph of an impressed number helps confirm identity but does not replace the compatibility documentation.
Link this tooling record to the cable manufacturer and part number, conductor material and strand construction, plus the lug manufacturer, part number and barrel design. If an alternative tool is proposed, request written support for that exact combination and identify the verification needed before substitution.
For battery terminals, also distinguish the cable-barrel operation from the terminal’s later bolted connection. Crimp approval does not establish the torque or performance of that separate interface.
Put the process definition into the RFQ
Ask each bidder to complete the same table. Treat missing limits as an engineering question to resolve before sample approval.
| RFQ item | Information to provide or request | Evidence to retain |
|---|---|---|
| Cable and lug combination | Exact part numbers, revisions, conductor construction and permitted preparation | Applicable compatibility document and material identities |
| Tooling identity | Tool, die set, profile, adapters and identifiable equipment numbers | Setup sheet and legible identification photographs |
| Crimp sequence | Strip length, insertion requirement, crimp count, locations and order | Marked drawing or controlled work instruction |
| Geometry check | Required dimensions, measurement points, instrument and limits | Actual readings with method and sample IDs |
| Pull test | Test purpose, specimen preparation, fixtures, loading method and acceptance criteria | Individual results, units and failure observations |
| Cross-section | Section locations, preparation method, measurements and acceptance reference | Overview, scaled images and measured results |
| Ongoing verification | Checks after setup changes, maintenance or material substitution | Release decision and retained production records |
The supplier should distinguish existing evidence from testing proposed for your order. Ask who performs each test, whether it is included in the quotation, and which samples will be consumed. This makes quotations comparable without assuming that any particular supplier owns a laboratory.
Define what the pull test is measuring
State whether the test evaluates the conductor-to-barrel connection or a finished assembly that includes insulation support and other load-bearing features. The specimen configuration must match that purpose.
TE’s small-wire crimping paper highlights secure gripping, specified pulling speed and disengaging an insulation crimp when the test requires it. Its scope is small open-barrel F-crimps; use these as method questions, not as a battery-lug procedure or a source of transferable force limits. TE crimp inspection guidance, pages 1–2.
For the lug under review, request the fixture arrangement, loading direction, grip spacing where specified, test rate, sample conditioning, instrument identity and applicable calibration record. Photograph how the lug tongue is restrained. Otherwise, an apparent difference between suppliers may partly reflect their fixtures.
Require a result for every tested specimen, with force units and an observation: conductor withdrawal, wire fracture, barrel damage or grip slippage. A tester stopped at an agreed proof load establishes survival to that load; it does not measure the ultimate pull-out force. Wire fracture away from the barrel likewise should not be relabelled as measured conductor withdrawal. Have the approved method determine whether the observed outcome is acceptable or requires retesting.
Do not average away an individual failure when the agreed criterion applies to each specimen. Keep excluded results with their reasons so an invalid grip event cannot silently disappear from the report.
Ask for an interpretable cross-section
A cross-section report should show where the specimen was cut, not just an enlarged image. Identify the crimp impression and the section plane on an overview photograph. For a barrel with several impressions, agree which locations must be examined and how they represent the process.
Interpower describes cutting, grinding and polishing its specimens to inspect geometry and conductor compression. This illustrates why a section is a prepared measurement specimen rather than an ordinary product photograph. Interpower cross-section and pull-test explanation.
Request a scale bar, sample ID, preparation record and the measurement reference. Distinguish observed gaps, strand arrangement, barrel condition and dimensional results from the reviewer’s acceptance decision. If the report uses “compression ratio,” require its formula, measurement boundaries and acceptance source; the percentage alone is not comparable across different definitions.
TE notes that cross-section requirements differ between applications and that perfect symmetry is not the acceptance target for every crimp. Its illustrated F-crimp features must not be imposed on a closed-barrel hexagonal or indent crimp. TE cross-section guidance, page 3.
For your lug, obtain the applicable profile-specific criteria. Do not create a “zero visible gaps” requirement from a marketing image. If preparation damage makes a feature uncertain, record the uncertainty and prepare another identified specimen rather than editing the image.
Use separately identified companion specimens when both intact pull testing and destructive sectioning are required. A sectioned crimp cannot represent an intact specimen in a subsequent retention test.
Decide what the evidence actually supports
Suppose the die identification matches, every pull specimen meets its agreed criterion, but the section report identifies a barrel defect. The pull results do not cancel that finding. Investigate it against the relevant acceptance document and resolve the disposition before approval.
Conversely, an attractive section does not prove electrical performance or production consistency. Keep resistance measurements in a separate record with a defined measurement span; the four-wire Kelvin guide explains that boundary.
For production release, connect the approved evidence to the actual setup. If a die, tool, cable construction or lug revision changes, determine which evidence remains applicable. The broader first-article and change-control guide covers the approval workflow; the crimp record supplies the specific technical evidence within it.
Buyer FAQ
Can a die marked 50 be used with every 50 mm² lug?
Do not select it from the number alone. Confirm the manufacturer’s code meaning, terminal family, cable construction, tool compatibility and required profile. Similar markings can describe different tooling systems.
Does a high pull result prove a good electrical connection?
It establishes a mechanical result under the recorded method. Electrical resistance, temperature behaviour and environmental durability require their own relevant evidence. Keep the acceptance decisions connected, but do not substitute one result for another.
Must every finished cable be sectioned?
Sectioning consumes the specimen. Define sampling and requalification with the responsible engineer, considering the application and governing requirements. Routine checks and destructive companion samples should be identified separately.
What should I send for a comparable tooling quotation?
Send the cable and lug drawings or exact part numbers, conductor construction, intended process volume and required evidence table. Ask suppliers to identify tooling charges, destructive sample quantities, test providers and reporting scope separately.
Request a traceable crimp process proposal
Send a cable assembly RFQ with the cable–lug combination and required records. Ask for written confirmation of the proposed tooling, acceptance references and available evidence before approving samples.