Specify mating and unmating force for an identified, fully configured connector pair under an agreed fixture, alignment, speed, travel and latch condition. Require each specimen's force–displacement record and confirmation of the intended final state. A peak in newtons alone cannot show whether the pair seated correctly, stopped early, or was tested with essential components removed.
This guide is for buyers comparing a connector assembly that must be joined during manufacturing or disconnected during authorized service. Its deliverable is a repeatable acceptance method tied to the offered bill of materials. It does not establish a universal comfortable hand force, a safe extraction load, terminal retention strength, electrical rating or environmental qualification.
The key purchasing distinction is between a number describing an interface and evidence describing the complete operation. An attractive low-force quotation can become unusable when the production seal, wire population, cover or locking sequence is added. A more complete offer can be easier to assess even when its reported force is higher.
Separate the forces before comparing quotations
Use a different name and acceptance field for each mechanical operation. Mating force describes joining the specified halves. Unmating force describes separating them under the stated release conditions. A latch-release action, a connector position assurance movement and a terminal pull test are separate operations, even if the equipment records all of them in newtons.
The public TE FASTIN-FASTON specification 108-20020, Rev. D3, dated April 2009, illustrates this distinction: its tables separate connector mating, single-contact engaging, contact retention and crimp tensile tests. Its connector mating procedure explicitly states a locking-device condition and travel rate. This older family-specific document demonstrates why method details matter; it is not a current specification for another connector or a source of universal force limits.
On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.
| Quoted evidence | Actual question answered | Required boundary |
|---|---|---|
| Mating-force trace | How much axial force accompanied the defined joining operation? | Both halves, population, accessories and starting state |
| Unmating-force trace | What force separated the pair after the specified release action? | Release sequence, direction, support and cycle history |
| Latch-release measurement | What input operated the latch? | Actuation point, tool and mechanism condition |
| Terminal retention result | Did a contact remain secured inside its housing? | Contact, cavity and retention method |
| Crimp pull result | How did the conductor termination withstand its specified tensile test? | Wire, terminal and preparation method |
Use the connector CPA and mating-assurance guide to define the completed latch state. Force measurement supplements that confirmation. Neither a satisfactory force nor a recognizable click independently proves correct cavity population, electrical continuity or sealing.
Freeze the complete pair in the sample definition
Identify the two mating part numbers, drawing revisions, contact options, cavity population and any permitted empty positions. Include seals, cavity plugs, covers, cable exits, backshells and secondary devices that are present during the intended operation. Where the connector attaches to a panel or board, identify that support arrangement as part of the sample configuration.
State whether the test concerns a fully terminated harness or a component-level specimen. A result from loose housings can be useful development evidence, but the purchase decision must say whether it covers the assembled article. Photograph or sketch the relevant configuration rather than relying on a family name shared by many variants.
Create a comparison row for every intentionally different population. A reduced-contact demonstrator, a maximum-population assembly and an asymmetrical mixed-contact layout may address different questions. Do not describe a lighter population as the worst case without a reason tied to the exact design and assembly operation.
For product discussions, the solar power connector category is a starting point for identifying candidate interfaces. Compatibility, force performance and all other ratings still require evidence for the exact proposed pair; a category listing is not an approval record.
Distinguish a contact estimate from assembly evidence
Samtec's mating and unmating force paper, Rev. 0 dated August 2014, explains an idealized force estimate for certain contact arrangements and identifies misalignment-related plastic binding as an excluded effect. It also describes qualifications using different position counts. That distinction is useful: a contact calculation can support early planning, while the offered assembly still needs evidence appropriate to its construction.
Ask a supplier to label every number as calculated, measured, interpolated or specified. These categories should not disappear when values are copied into a commercial comparison sheet. Record what the calculation includes and what remains outside its boundary, especially accessories or guidance features that exist in the production assembly.
Do not multiply an isolated contact's peak by the number of circuits and then declare the product accepted. The project may choose such an estimate for fixture planning, but acceptance requires a defined basis and an agreed treatment of excluded effects. The receiving team should be able to distinguish preliminary capacity planning from a demonstrated result.
Describe the real assembly operation before choosing the fixture
Write down where the operator or machine applies force, what supports the opposite half, and how the mating axes are guided. Identify whether the product is approached directly, through a restricted opening, or using a lever or assist mechanism. A direct axial laboratory measurement and an operator input at a lever are different quantities.
A fixture can make an assembly look better by giving it alignment support that the installed product lacks. It can also make a satisfactory connector look worse by clamping it crookedly or distorting a compliant housing. The method should explain which degrees of movement are constrained and which reproduce the intended installation.
Keep the connector acceptance test separate from workplace ergonomic approval. A laboratory trace does not establish a safe repetitive hand task. If the production operation requires human assessment, identify that separate owner and deliverable. The RFQ can require usable evidence without inventing a universal force that every operator can repeatedly apply.
Agree alignment and cable support without hiding the difficulty
Specify the reference surfaces used to align the halves and record the permitted method of adjustment. Include the approach direction and the condition at which displacement is zeroed. If intentional offset conditions are required, label them separately from the nominal alignment condition and define them through the approved drawing or test plan.
For a terminated harness, support the cable so its weight or bending load is treated consistently. Explain whether that load is intentionally included in the measured operation. Do not subtract an undocumented cable-force estimate after the result exceeds the limit. If a correction is part of the method, establish and validate it before collecting acceptance data.
Take a fixture photograph showing the force path and cable restraint. That single image often resolves a comparison that otherwise takes several emails: one laboratory pushed a housing directly while another pulled the wires or loaded a cover. Require a configuration change record when the fixture or support arrangement changes.
Control speed, travel and sample preparation
The RFQ should name the governing method and its revision, then resolve any application-specific fields that the method leaves open. These include crosshead speed, travel endpoints, hold periods, sample temperature and the preparation sequence. Use values supported by the chosen product documentation and approved plan, not numbers copied from an unrelated manufacturer's test.
Define how complete seating is recognized. The endpoint may be an approved dimension or another documented state; it should not simply mean that the test machine reached its programmed travel. State how the operator handles a failure to seat and what stops the operation before a fixture or product is damaged.
Record lubrication and cleaning as controlled sample attributes. Do not allow a difficult sample to be treated informally until it produces a pleasing force trace. If the manufacturer permits a process treatment, include its identity and application instructions in the approved configuration. Compare treated and untreated results only as different, clearly labeled conditions.
Preserve first-operation evidence and cycle history
Assign the sample identifier before mating. Record whether it was shipped mated, checked during harness manufacture, operated during incoming inspection, or used for a demonstration. A reported first measurement is not necessarily the first physical mating of the interface.
When the project asks for initial and later-cycle evidence, preserve the sequence for each individual pair. Reusing a convenient laboratory mate can introduce an unrecorded history on one side of the interface. Specify whether each test uses a dedicated pair or a controlled reference mate, and document replacement criteria for the latter.
The PV connector mating-cycle and unlocking guide addresses life-cycle planning and authorized handling. The present acceptance question is narrower: which force record belongs to which sample state? Do not create unnecessary extra cycles merely to produce more data; follow the agreed sequence and preserve the original observation.
Capture the curve instead of retaining only its maximum
Request a force–displacement trace, the acquisition settings and the method used to identify the reported peak. Keep the raw file or an agreed export alongside the readable plot. A smooth presentation graphic with no retained underlying data can prevent later investigation of a short event or a changed filter setting.
Mark relevant events where they can be identified reliably: first engagement, the approved seated state, release initiation and separation. Do not label every change in the curve as a specific mechanism without corroborating evidence. A force rise may justify investigation; it does not by itself establish which part is binding.
Retain the result for every specimen, not just a curve assembled from average values. An average trace can conceal a short peak appearing at different travel positions in different samples. If averages are useful for development, show them as additional analysis while keeping individual acceptance decisions visible.
Check whether the measurement system can support the decision
Ask the laboratory to identify the force transducer, the relevant measurement range, calibration status and displacement measurement used for this setup. A calibration certificate alone does not show that the complete fixture and data-processing chain is appropriate for a narrow acceptance interval. Request the laboratory's stated uncertainty or other agreed decision information for the actual method.
Preserve the distinction between machine travel and connector-interface travel. Fixture movement or compliance can make the two different. If the endpoint criterion refers to a seated product dimension, document how that dimension is established; do not quietly substitute crosshead movement because it is already available in the machine export.
Specify the treatment of clipping, lost data or an interrupted run before testing. A flat top at the instrument range boundary cannot be assumed to represent the product's true peak. An invalid acquisition needs an investigation and an authorized replacement observation, not an invented value or a favorable average from the remaining data.
Keep sample acceptance separate from a production capability claim
A few conforming samples demonstrate the observations obtained on those specimens under the stated method. They do not automatically establish the force distribution across future production. Ask the quality owner to define the sample selection, lot coverage and statistical claims appropriate to the purchase decision.
Where several production variants share a qualification report, request the rationale for coverage. Compare the tested population and accessories with the ordered configuration. If the scope is uncertain, put that uncertainty in the release record rather than describing the entire family as qualified by association.
Use a simple three-part result for each specimen: valid method execution, required final assembly condition, and conformity with the specified force criteria. A specimen may fail any one of these without invalidating the usefulness of the other observations. For example, an interrupted trace may show a damaged latch that still needs investigation, even though its peak cannot support force acceptance. Keeping these decisions separate prevents the evidence file from becoming a collection of unexplained pass stamps.
Give unmating its own method and acceptance statement
Specify how the latch or assist mechanism is released before measuring separation. If a release tool is required, identify it and the permitted use. A test that tries to pull a locked connector apart may answer a retention or abuse question, not the intended service-unmating question.
Separate the release input from the subsequent axial separation measurement when they occur at different locations or use different motions. If an instrument captures a combined operation, describe that boundary. Do not compare its reported peak directly with a result that excludes the release action.
Perform these mechanical checks on a de-energized setup with suitable product handling. The method must not be interpreted as permission to disconnect a powered circuit. For a procurement request, state the mechanical test condition and leave energized switching capability to the relevant manufacturer evidence and electrical design review.
Hypothetical example: the smallest peak is not the best offer
Assume a fictional project has already approved a complete-assembly mating limit of 80 N, a seated-travel interval of 11.8–12.2 mm, and an unlocked separation limit of 55 N. These numbers are invented solely to demonstrate a purchasing decision; they are not connector recommendations or an ergonomic standard.
Three fictional suppliers report the following single-sample observations. The table is illustrative data, not a SINAWATTS test or a customer result. A real acceptance plan would define the sample population, measurement decision rule and additional required evidence before testing.
On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.
| Offer | Reported mating peak | Endpoint and configuration | Purchasing disposition |
|---|---|---|---|
| A | 52 N | Stops at 10.9 mm; seated state not demonstrated | Hold: low peak does not meet the endpoint requirement |
| B | 72 N | 12.0 mm; full approved configuration; separation 43 N | Candidate for acceptance, subject to all agreed evidence |
| C | 65 N | 12.0 mm; production seal omitted | Hold: result does not represent the purchased assembly |
Offer B has an apparent force allowance of 80 − 72 = 8 N before accounting for the agreed measurement decision rule. Suppose the fictional contract uses a conservative upper decision value of measured peak plus a stated 3 N uncertainty allowance. The decision value becomes 75 N, leaving 5 N below the limit. This is an example of a pre-agreed rule, not a universal treatment of uncertainty.
If a later full-configuration specimen measures 78 N under that same rule, its decision value is 81 N. The team cannot simply call it a pass because the displayed peak is below 80 N. Conversely, changing the rule after testing to rescue a borderline offer would destroy comparability.
Close the other example criteria with equally explicit decisions. If the fictional contract applies the same 3 N allowance to separation, Offer B's upper decision value is 43 + 3 = 46 N, below its 55 N limit. Suppose the contract separately requires a measured seated dimension plus or minus a 0.10 mm allowance to remain entirely within 11.8–12.2 mm. B's 12.0 mm result gives 11.90–12.10 mm and meets that rule. A different specimen reading 12.15 mm would span 12.05–12.25 mm and remain on hold, even with an acceptable force. These invented decision rules demonstrate why a favorable force trace cannot close an unresolved seating measurement; they are not universal metrology requirements.
The useful RFQ response is therefore not a ranking from 52 to 72 N. It is a record of complete configuration, successful seating, valid measurement and disposition. Offer A needs endpoint investigation; Offer C needs representative evidence. Neither should be awarded the work on the strength of its lower peak alone.
Put the evidence request into a compact supplier schedule
Define required deliverables next to their acceptance purpose. That makes the request easier to price and prevents a large qualification report from obscuring an unanswered application question. Separate an existing report that can be supplied immediately from additional work proposed for the project.
On small screens, swipe or scroll sideways to read every column. Keyboard users can focus the table and use the arrow keys.
| Deliverable | Minimum content | Review question |
|---|---|---|
| Configuration sheet | Both halves, revisions, population and accessories | Is this the assembly being purchased? |
| Method sheet | Fixture, speed, alignment, endpoints and release sequence | Can the comparison be repeated? |
| Sample history | Pair identifiers and documented operations | Does the evidence cover the requested state? |
| Individual results | Curves, peaks, endpoints and observed final condition | Did every required criterion receive a decision? |
| Exception record | Original result, investigation and authorized disposition | Were failures preserved rather than erased? |
If the configuration or test boundary is still unclear, send the mating-pair drawings and assembly constraints with a force-evidence RFQ. Identify the missing fields explicitly so any quotation can distinguish available documentation from proposed project work. Do not assume a particular test service or capability without written confirmation.
Resolve supplier disagreements without testing until something passes
When two laboratories disagree, first compare sample identity, mate history, fixture, zero position, speed, release state and data processing. Repeat testing is useful only after the team knows what question the repeat is intended to resolve. Repeatedly mating the same sample can make the investigation a different experiment from the original acceptance test.
Preserve the first valid result and create a separate investigation record. If a fixture error is established, document the evidence and the authorized invalidation rule. If the result represents an actual product issue, a later favorable value should not silently replace it.
Define who can approve a deviation and whether approval applies to a named sample, a limited lot or a revised design. Give the decision an expiry or review trigger where appropriate. Purchasing should receive a clear release status, not an ambiguous email saying that engineering is generally comfortable with the connector family.
Translate qualification evidence into an incoming plan
Qualification evaluates a defined design and test sequence; receiving inspection controls supplied lots. Avoid turning every shipment into an improvised qualification campaign. Ask the responsible quality team to define the incoming checks, sample selection and escalation based on the approved product and process risks.
Useful receiving fields include both part identities, lot traceability, correct population, specified accessories and any controlled operation used for sampling. If mating-force verification is required, keep the reference mate and fixture under control. A worn or substituted inspection mate can make the receiving result difficult to interpret.
Require notification for changes affecting the approved assembly or evidence basis. Examples to review include contact revision, seal revision, lubrication process, cavity population, fixture support and data-processing method. A supplier's statement that the product remains in the same family is not sufficient to close a relevant change.
FAQ
Is a low mating force always preferable?
No. The result must accompany correct seating and the required final condition. A low peak from incomplete travel or omitted components is not favorable evidence. Select against the approved assembly requirements, including the separate electrical and environmental requirements, rather than choosing the smallest available number.
Can terminal retention data replace connector unmating data?
No. Terminal retention concerns a contact held within its housing. Unmating concerns separation of the identified pair under a defined release condition. Request the appropriate report for each interface, and keep the criteria separate in the drawing and supplier comparison.
Can suppliers quote a per-contact value?
They can provide a clearly labeled estimate or specified contact-level value, with its assumptions. The buyer must decide whether it is adequate for preliminary planning. Do not present it as a measured complete-assembly acceptance result unless evidence actually covers that configuration and operation.
Should every test include the locking mechanism?
It depends on the question and governing method. Define the mechanism's state explicitly, including whether its actuation is measured separately. Component-interface characterization may intentionally exclude a mechanism, while an assembly-operation assessment may include it. Neither result should be substituted for the other without review.
What should happen when a sample exceeds the limit?
Preserve the original data and follow the agreed hold and investigation process. Check method validity before deciding whether the issue belongs to the product or setup. Retesting, rework, deviation and lot release need documented rules; an unexplained favorable repeat is not a complete disposition.
Does a supplier report establish compatibility with another brand?
Only if the evidence explicitly covers the proposed mating pair and the manufacturers' applicable conditions permit that use. Similar appearance, nominal position count or a satisfactory force trace does not establish electrical, sealing or durability compatibility between unrelated components.
What information helps obtain a useful quotation?
Provide the mating-pair identities, assembly drawings, populated circuits, accessories, installation support, expected service operation and required evidence. State quantity and timing as project inputs, then request written confirmation of price, lead time and available verification work. None of those commercial or capability details should be inferred from this guide.
Close the purchasing decision with the complete operation
Release the connector against a named configuration, a repeatable method and an explicit decision for each required criterion. Keep the original curves, sample history and deviation records linked to the purchase specification. This lets the next team understand what was actually demonstrated when a part, mate or assembly process changes.
For the next review, include your complete assembly, intended handling method and required force records in the connector RFQ. The useful outcome is a comparable evidence package that supports a defined assembly operation and makes unresolved questions visible before purchase.