EN 16602-70-26:2019
(Main)Space product assurance - Crimping of high-reliability electrical connections
Space product assurance - Crimping of high-reliability electrical connections
This Standard specifies:
• Requirements for the following crimping wire terminations intended for high reliability electrical connections for use on customer
spacecraft and associated equipment operating under high vacuum, thermal cycling and launch vibration:
• removable contacts, single wires
• removable contacts, multiple wires
• coaxial connectors, ferrules
• lugs and splices.
NOTE These are the most common used crimping wire termination and are represented in Figure 1 1.
• The general conditions to be met for the approval of terminations other than the above mentioned ones.
NOTE Additional forms of crimps, not covered in this standard, are listed (not exhaustively) in the informative Annex A.
• Product assurance provisions for both the specific and the generic terminations mentioned above.
• Training and certification requirements for operators and inspectors (clause 5.5.2), additional to those specified in ECSS Q ST-20.
This standard may be tailored for the specific characteristics and constraints of a space project, in conformance with ECSS-S-ST-00.
Raumfahrtproduktsicherung - Crimpen von hochzuverlässigen elektrischen Verbindungen
Assurance produit des projets spatiaux - Sertissage de connections électriques haute fiabilité
Zagotavljanje kakovosti proizvodov v vesoljski tehniki - Stiskalno spajanje kontaktov visoko zanesljivih električnih konektorjev
Ta standard določa: • Zahteve za naslednje žične priključke za stiskalno spajanje, namenjene za izredno zanesljive električne konektorje za uporabo na vesoljskih plovilih in povezani opremi odjemalca, ki delujejo pri visokem vakuumu, toplotnih cikličnih obremenitvah in vibracijah ob izstrelitvi: • odstranljive kontakte, posamezne žice • odstranljive kontakte, več žic • koaksialne konektorje, tulke • ročaje in spojnice. OPOMBA: To so najpogosteje uporabljani žični priključki za stiskalno spajanje in so predstavljeni na sliki 1.1. • Splošne pogoje, ki jih je treba izpolnjevati za odobritev priključkov, razen že zgoraj navedenih. OPOMBA: Dodatne oblike kodrov, ki niso obravnavane v tem standardu, so navedene (ne izčrpno) v informativnem dodatku A. • Določbe za zagotavljanje varnih proizvodov za posamezne in splošne priključke, navedene zgoraj. • Zahteve za usposabljanje in potrjevanje za upravljavce in inšpektorje (točka 5.5.2) poleg zahtev iz standarda ECSS Q ST-20. Ta standard se lahko prilagodi posameznim lastnostim in omejitvam vesoljskega projekta v skladu s standardom ECSS-S-ST-00.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Raumfahrtproduktsicherung - Falten von hochzuverlässigen elektrischen VerbindungenAssurance produit des projets spatiaux - Sertissage de connections électriques hautes fiabilitésSpace product assurance - Crimping of high-reliability electrical connections49.140Vesoljski sistemi in operacijeSpace systems and operations49.060Aerospace electric equipment and systemsICS:Ta slovenski standard je istoveten z:EN 16602-70-26:2019SIST EN 16602-70-26:2019en,fr,de01-maj-2019SIST EN 16602-70-26:2019SLOVENSKI
STANDARDSIST EN 16602-70-26:20151DGRPHãþD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16602-70-26
March
t r s { ICS
v {ä r x râ
v {ä s v r Supersedes EN
s x x r tæ y ræ t xã t r s v
English version
Space product assurance æ Crimping of highæreliability electrical connections
Assurance produit des projets spatiaux æ Sertissage de connections électriques haute fiabilité
Raumfahrtproduktsicherung æ Falten von hochzuverlässigen elektrischen Verbindungen This European Standard was approved by CEN on
{ November
t r s zä
C Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN and CENELEC memberä
translation under the responsibility of a CEN and CENELEC member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels y any means reserved worldwide for CEN national Members and for CENELEC Membersä Refä Noä EN
s x x r tæ y ræ t xã t r s { ESIST EN 16602-70-26:2019
Figures Figure 1-1: Example of interconnections described in this Standard . 8 Figure 5-1: Example of crimping tools . 17 Figure 5-2: Example of a typical connector barrel and single wire crimping . 21 Figure 5-3: Example of a typical connector barrel and multi-wire crimping. 22 Figure 5-4: Example of a typical ferrule shield crimping . 23 Figure 5-5: Examples of typical lug and splice wire crimping (1 of 2) . 25 Figure 5-6: Examples of typical lug and splice wire crimping (2 of 2) . 26 Figure 5-7: Qualification process test procedure flow chart . 28 Figure 5-8: Quality control during crimping operation . 34 Figure 5-9: Visible workmanship standards . 36 Figure 5-10: Workmanship examples and crimp micro-sections . 37 Figure 5-11: Shift performance test flowchart . 44
Tables Table 5-1: Equipment for verification process . 18 Table A-1 : Guideline for selector setting - Four-indent crimp (dispersive) - Single wire . 48 Table A-2 : Guideline for selector setting - Four-indent crimp (dispersive) - Two wires . 49 SIST EN 16602-70-26:2019
NOTE
These are the most commonly used crimping wire connections and are represented in Figure 1-1. • The general conditions to be met for the approval of connections other than the above mentioned ones. NOTE
Additional forms of crimps, not covered in this standard, are listed (not exhaustively) in the informative Annex A. • Product assurance provisions for both the specific and the generic connections mentioned above. • Training and certification requirements for operators and inspectors (clause 5.5.2), additional to those specified in ECSS-Q-ST-20. This standard may be tailored for the specific characteristics and constraints of a space project, in conformance with ECSS-S-ST-00. SIST EN 16602-70-26:2019
Normal socket Normal male
Enlarged socket Enlarged male
MDM socket MDM male
Coax socket Coax male
Power socket Power male
Butt splice Parallel splice
Lug
Figure 1-1: Example of interconnections described in this Standard SIST EN 16602-70-26:2019
EN reference Reference in text Title EN 16601-00-01 ECSS-S-ST-00-01 ECSS system - Glossary of terms EN 16602-10-09 ECSS-Q-ST-10-09 Space product assurance - Nonconformance control system EN 16602-20 ECSS-Q-ST-20 Space product assurance - Quality assurance EN 16602-60 ECSS-Q-ST-60 Space product assurance - Electrical, electronic and electromechanical (EEE) components EN 16602-60-05 ECSS-Q-ST-60-05 Space product assurance – General requirements for hybrids EN 16602-70 ECSS-Q-ST-70 Space product assurance - Materials, mechanical parts and processes EN 16602-70-08 ECSS-Q-ST-70-08 Space product assurance - Manual soldering of high-reliability electrical connections EN 16602-70-38 ECSS-Q-ST-70-38 Space product assurance - High-reliability soldering for surface-mount and mixed technology EN 16602-70-71 ECSS-Q-ST-70-71 Space product assurance - Data for selection of space materials and processes
SAE-AS-22520,
24 October 2011 Crimping tools, , wire termination, General specification for
SAE-AS-7928B 10 March 2011 Terminals, lugs, splices, conductor, crimp style, copper, general specification for
ISO 7500-1:2004 Metallic materials - Verification of static uniaxial testing machines - Part 1: tension/compression testing machines - Verification and calibration of the force-measuring system SIST EN 16602-70-26:2019
ESCC 3901, Issue 2 May 2013 ESCC generic specification No. 3901 Wires and cables, electrical, 600V, low frequency
Process identification and documentation. • New crimp combinations beyond those identified in the Scope. • Test methods and acceptance criteria for both specific and generic types of interconnections are specified. • Quality assurance measures for both the operator and the inspector are prescribed: Training and certification of personnel, Calibration of tools and equipment, Workmanship standards and acceptance criteria, Inspection criteria and sequence, Records from material incoming inspection through delivery of the end product, including KIP, MIP, travellers, follow-up sheets, log books, traceability samples and the handling of deviations by RFA or NCR. It is important to perform the work taking into account health and safety regulations, and in particular the national standards on this subject. SIST EN 16602-70-26:2019
Depending on supplier and customer business agreement. 5.1.1.2 Facility cleanliness a. The supplier shall provide cleaning services for production facilities where high reliability crimping is performed. b. Production facilities where high reliability crimping is performed shall be maintained in a clean and tidy condition. c. Loose material that can cause contamination of the crimped connection shall be removed.
NOTE
For example: Dirt, dust, oils and cut wire strands. d. Furniture shall be kept to a minimum in the work areas and be arranged to allow easy and thorough cleaning of the floor. e. Working surfaces shall be covered with an easily cleaned hard top, antistatic mat or have a replaceable surface of clean, non-contaminating silicone-free paper. 5.1.1.3 Environmental conditions a. The crimping area shall have a controlled environment, which limits entry of contamination.
b. The area shall be continuously controlled as follows: 1. room temperature: (22 ± 3) °C; 2. relative humidity:
(55 ± 10) %. SIST EN 16602-70-26:2019
c. A minimum of 90 % of the work area shall be shadow-less and without severe reflections. 5.1.2 Tools and equipment 5.1.2.1 Crimping tools a. The supplier shall provide the tooling necessary for continued high quality crimping. NOTE
Examples of crimping tools are shown in Figure 5-1. b. Tools used shall employ an integral ratcheting mechanism, which controls the crimping operation in conformance to SAE-AS-22520. NOTE
The mechanism ensures that, once the operation is started, the tool cannot be opened until the crimping cycle is complete. c. Tools shall be sealed on one setting value in case of variable settings tools. d. Tool calibration shall be verified in conformance with the clause 5.5.6 requirements. e. Proper operation of the integral ratcheting mechanism or the positive stops on pneumatic tools shall be verified as defined in clause 5.5.6. f. Before starting a crimping process on a new terminal size and wire type, the tool used for crimping of the previous wire type shall be returned to the tool storage. g. If the tool settings seals are found removed or broken, the tool shall be removed from the work place and returned immediately for recalibration. h. Tools used in the crimping operation shall be clean and excess lubricant removed before crimping starts. i. Tools shall be individually labelled. NOTE
This identification is recorded in the manufacturing connector follow up sheet. SIST EN 16602-70-26:2019
Contact crimping tool
Splice-lug crimping tool
Figure 5-1: Example of crimping tools 5.1.2.2 Insulation strippers a. The supplier shall provide the tooling necessary to avoid damage to the conductor. b. The selection of thermal or precision cutting devices, manual or automatic power-driven, shall ensure integrity of the conductor strands.
c. Wire stretching by use of mechanical strippers shall be avoided. d. The conductor shall not be twisted, ringed, nicked, cut or scored by stripping operation. e. Both thermal and mechanical stripping tools shall be calibrated periodically on sample evaluation during a production run. f. For coated wires the exposure of underlined base metal shall be a cause for rejection. SIST EN 16602-70-26:2019
c. Twisting action during cutting operation shall be avoided.
d. <> e. The cutting edges shall be regularly checked for damage and maintained in a sharp condition. 5.1.2.4 Test and monitoring equipment a. The supplier shall provide the equipment specified in Table 5-1 necessary for verification activities specified in clause 5.4.3.
Table 5-1: Equipment for verification process Performance tests activity Equipment characteristic <> <> Tensile strength (in conformance with clause 5.4.3 requirements) Tensile testing machine conforming to ISO 7500 class 1 or better. Axial load applied at a rate of (20 – 40) mm/min ±2 mm/min Visual inspection Magnification ×7 to u40 Monitoring requirements of the process
Temperature 15 °C to 30 °C, acc×±ate to ±1 °C Relative h×midity (RH) 40 % to 70 %, acc×±ate to ±1 % 5.2 Crimping operations for different types of interconnections 5.2.1 General a. The supplier shall visually examine wires, terminals and connector contacts for cleanliness, absence of oil films and freedom from tarnish or corrosion before assembly. b. The supplier shall perform cleaning of the work pieces using IPA.
c. Further cleaning or other treatment shall not be carried out except the case when validation and qualification of a cleaning product was performed on all used materials. d. The supplier shall handle work pieces with clean lint free gloves or finger cots. e. Before a crimping activity, tools at the operator’s station shall be verified to conform to those selected in accordance with the applicable PID or procedures. SIST EN 16602-70-26:2019
g. Strands shall not be left outside or cut back to reduce the conductor diameter to fit an undersized barrel.
h. The supplier shall use tools as specified in SAE-AS-22520 for the crimp contact configuration. NOTE
Examples of crimping parameters are given in Table A-1 to Table A-6 i. The supplier shall take provisions to avoid degradation of the silver plated wire caused by tarnish during storage.
j. <> k. The crimping of single solid wires shall not be used. 5.2.2 Material selection a. The supplier shall use silver plated copper multi stranded wire and braided shield cable procured in conformance with the requirements from ESCC generic specification 3901.
b. In cases where other types of wire and wire finishes are used a request for approval (RFA) in conformance with DRD from Annex D from ECSS-Q-ST-70 shall be provided to the customer for approval. NOTE
Examples of wire and wire finishes needing RFA include nickel- or fused tin-plated wires, stainless steel, phosphor bronze, copper, constantan, and nickel alloys. c. The supplier shall use high strength copper alloy wire for 24 AWG, 26 AWG and 28 AWG crimped joints. NOTE
Soft or annealed copper wire are not acceptable for crimped joints of 24 AWG, 26 AWG and 28 AWG size.
d. The supplier shall use space-qualified components having gold plated finishes in conformance with ECSS-Q-ST-60. e. Specific items such as ferrules, splices, contacts and lugs shall be purchased to SAE-AS-7928 specification.
f. When gold plating is not available the finish shall be in conformance with ECSS-Q-ST-70-71. NOTE
Ferrules, splice, contacts and lugs supporting an external nickel layer can be used in case there is no alternative finish, although tool wear is accelerated. g. Cadmium, chromate-coated cadmium, tin-lead and non-fused tin-plating shall not be used. NOTE
Tin-lead finish is not acceptable for crimp connection due to creep. SIST EN 16602-70-26:2019
a. The supplier shall perform a review of all the materials, tools and techniques planned to be used to ensure conformance to requirements of this standard and as a means of identifying potential problems. NOTE
Type of wire includes base material, number of strands, plating metal, type and thickness of insulation. b. Dies, setting of controls for the length of strip in automatic stripping machines and the selection of specific locators or positioners for crimping tools, shall be selected to meet process requirements. NOTE
The requirement is valid for power driven and manual crimping processes as well as for size and tolerance for crimping tools. c. The results of the review shall be documented in a specific internal procedure. 5.2.4 Contact barrel and single wire crimping a. The supplier shall give preference to the selection of single multistranded wire interconnections. b. The supplier shall not use strands of wire doubled backed to increase the conductor diameter. c. The supplier shall use a specific contact to be compatible with the cross-sectional area of the wire.
NOTE
Examples of a specific contact include reduced, normal or enlarged barrel. d. For 28 AWG up to 16 AWG wire sizes, the insulation clearance shall be maintained between 0,3 mm and 1,0 mm. e. For wire size bigger than 16 AWG the insulation clearance shall be maintained between 0,3 mm and 2 mm. f. On D-sub contacts, a transparent shrink fit insulation sleeve shall be applied over the rear of the contact and the wire insulation both to cover the insulation clearance and to prevent any risk of a short circuit. NOTE
Examples of crimping parameters are given in Table A-1. An example of a typical contact barrel and an example of single wire crimping is shown in Figure 5-2. g. Multistranded type of wire shall be used in case the filler wire is used to increase the conductors diameter. h. The use of potting, to ensure insulation at the rear of connectors with removable contacts, shall not be used except when authorized by the customer through RFA. NOTE
The use of potting on these types of connectors can violate specification from manufacturer and can invalidate the qualification status of the connector itself. SIST EN 16602-70-26:2019
Figure 5-2: Example of a typical connector barrel and single wire crimping
5.2.5 Contact barrel and multiple wire crimping a. Requirements of this clause shall be applied when single multistranded wire crimping cannot be used. b. The maximum number of wires in one crimp barrel shall be two.
c. The sum of the two nominal conductor sections shall be compatible with the crimp barrel used
d. Both conductors shall be of the same material and support the same plating finish. NOTE 1 For example: both are silver plated and not a combination of silver and nickel plated, both are high-strength copper alloy and not a combination of pure copper and high-strength copper alloy. NOTE 2 Strand wires or conductors can be inserted straight into the barrel or twisted together to obtain a “single” conductor. e. Axial strength measurements shall be performed in compliance with requirements in clause 5.4.3.2. NOTE
Examples of crimping parameters are given in Table A-2 and an example of a typical contact SIST EN 16602-70-26:2019
1. the actual strength measurement is performed on one of the wires (the smaller, if two different sizes are used); 2. the axial strength requirement is determined as specified in requirements of clause 5.4.3.2 for the actual size of wire pulled, assuming a barrel size equal to that wire’s gauge. NOTE
Examples of crimping parameters are given in Table A-3 and an example of a typical connector barrel and multi-wire crimping is shown in Figure 5-3. g. The conductor diameter shall not be increased by the use of individual strands of wire or double back wire. h. Multistranded type of wire shall be used in case the filler wire is used to increase the conductors diameter. i. For 28 AWG up to 16 AWG wire sizes the maximum insulation clearance shall be maintained between 0,3 mm and 1,0 mm.
Figure 5-3: Example of a typical connector barrel and multi-wire crimping SIST EN 16602-70-26:2019
a. The shielding
on coaxial cables shall be ensured by braided strands. b. Axial strength measurements shall be performed in compliance with requirements from clause 5.4.3.3. c. <> d. Only one braided shield shall be crimped in one ferrule connection. e. The braid end shall only be located at the ferrule crimp level in order to prevent any risk of short circuit between central pin and braid strands. f. Following crimping, the assembly shall be protected by shrink tubing. NOTE
Examples of crimping parameters are given in Table A-6 and an example of a typical ferrule shield crimping is shown in Figure 5-4.
Figure 5-4: Example of a typical ferrule shield crimping 5.2.7 Lug and splice wire crimping a. Only tools specified by the manufacturer of the terminals shall be used. b. The maximum number of wires shall be ten on the same assembly. c. Seven wires maximum shall be on the same side.
d. All conductors shall be of the same material and within a size range of 4 wire gauges including odd and even AWG sizes on the same side. e. If the number of conductors on the same side is more than two all conductors shall be positioned parallel in the terminal barrel before crimping. SIST EN 16602-70-26:2019
h. Following crimping, the assembly shall be protected by shrink tubing. NOTE
Examples of typical lug and splice wire crimpings are shown in Figure 5-5 and Figure 5-6. i. In case the number of conductors on the same side is limited to two then the conductors may be twisted together to form a single conductor. j. For 28 AWG up to 16 AWG wire sizes the maximum insulation clearance shall be maintained between 0,3 mm and 1,0 mm. SIST EN 16602-70-26:2019
Butt splice crimping
Two sided parallel splice crimping
One side parallel splice crimping
Figure 5-5: Examples of typical lug and splice wire crimping (1 of 2) SIST EN 16602-70-26:2019
Crimping of lug
Crimping of lug with filler wire
Microgaph of crimping of lug with filler wire
Figure 5-6: Examples of typical lug and splice wire crimping (2 of 2) 5.3 Requirements for crimp configuration qualification 5.3.1 General a. All crimp configurations shall be qualified in compliance with requirements from clause 5.3.2. b. The supplier shall document the data of successful process qualification in a specific internal procedure to ensure continued high quality of production performance. c. <> d. Any change to an element of the qualified crimp configuration specified in requirement 5.3.1a shall be qualified. SIST EN 16602-70-26:2019
NOTE
Examples of materials include cables and crimp items. g. In case qualification is needed, the supplier shall issue an RFA. 5.3.2 Qualification process test procedure a. The supplier shall perform tensile strength tests on samples prepared at a number of tool settings, in conformance with the requirements specified in clause 5.4 and in conformance with the following process: 1. Ten samples prepared at the point specified by the crimping tool manufacturer as a starting point for calibrating tools. 2. For connector contacts the tool indenter opening is then adjusted in convenient increments above and below this point, and ten samples pulled at each increment.
3. For lugs, splices and ferrules, ten samples are prepared at each setting of the crimping tool and pulled. 4. A plot is made with increments being close enough together to obtain a smooth curve. 5. The maximum in tensile strength is then determined and evaluated. 6. The optimum tool setting lies approximately in the middle of the flat top portion of the tensile-strength plot. 7. In case of very close average tensile strength values, the microsectioning of the samples relevant to the concerned settings is performed to identify the best setting. NOTE
Typical settings of crimping tool are given in Annex A.2. b. The supplier shall validate satisfactory results achieved from the final tool setting at the operating point on a minimum of ten samples in conformance with the methods defined in clause 5.4 and according to the following process:
1. Tensile strength tests are performed on five samples corresponding to the operating point. 2. <> 3. Metallographic tests are performed on a minimum of three samples corresponding to the operating point. 4. Not tested samples are retained for reference. c. Test data shall be recorded in a qualification report. d. The qualification report shall include the results of the search for the optimum tool setting specified in requirement 5.3.2a. SIST EN 16602-70-26:2019
Figure 5-7 presents a flow chart of the Qualification process test procedure of clause 5.3.2. Wire / braidunder ESCC specification?Wire / braidintrinsic tensile strength already characterized?Wire / braidintrinsic tensile strength already characterized? YES
NO Ensure the intrinsic wire / braid tensile strenth characterization(clause 5.4.3.5)[Average values on 10 samples]Wire / braid batch is the same than the already used on a previous qualified crimpingconfiguartion?YESNONONOChoice of the crimp item: Crimp item barrel section > wire /braid section to be crimped intoOptimum setting search (clause 5.3.2)Optimum setting research:For connector contacts:- Average tensile strength values on 10 samples of the chosen setting- Average tensile strength values on 10 samples of the just above settingOptimum setting qualificationOptimum setting research:- 10 samples with the chosen setting,- 5 samples for tensile strenght testsYESYES Figure 5-7: Qualification process test procedure flow chart SIST EN 16602-70-26:2019
a. The supplier shall submit samples to the tests specified in clauses 5.4.3 and 5.4.4.
NOTE
The number of samples is dependent on the specific process requirement (in conformance with clauses 5.3.2 ,5.3.4, 5.5.5 and 5.5.6.2 requirements).
b. Test samples shall meet the requirements of clause 5.5.4.1.
c. Records of all results shall be tabulated in conformance with 5.5.7.
5.4.2 <> a. <>
b. <>
c. <> SIST EN 16602-70-26:2019
b. The connections shall be loaded until failure occurs.
c. The value at failure shall be recorded, together with the information as to whether the failure was “pull-out”, “break in crimp” or “break in wire”.
d. The required ultimate axial strengths for compactive and dispersive crimped joints shall be determined as specified in clauses 5.4.3.2 and 5.4.3.3. NOTE
A typical test fixture for testing ferrule lug,
splice and contact crimps is shown in Figure A-6. e. The clamping of the free bare ends of wire or metallic braided shield directly in the clamping fixtures of the tensile machine shall not be used. 5.4.3.2 Contact barrel wire crimping a. The required axial strength of the crimped assembly shall be 75 % of the intrinsic wire strength as specified in clause 5.4.3.5. NOTE
Examples of typical values of intrinsic wire strength of ESCC qualified wires and the 75% requirement are detailed in Table B-1. b. <> c. In case of two crimped wires the axial strength the measurement shall be performed on one of the two inserted wires and be at least 75 % of the intrinsic strength of the wire. d. If two different wire gauges are used then the test specified in 5.4.3.2c shall be performed on the smaller of the two. e. Only one tensile test per sample is performed and the test shall be continued until failure occurs. 5.4.3.3 Ferrule
a. The required axial strength of the crimped assembly shall be 75 % of the intrinsic wire or braid strength as specified in clause 5.4.3.5. b. Axial strength measurements shall be performed only on the shield after removal of the core dielectric. 5.4.3.4 Lug and splice a. The required axial strength of the crimped assembly shall be 75 % of the intrinsic wire or braid strength as specified in clause 5.4.3.5. b. In the case of several equal wire sizes crimped into the same barrel axial strength measurements shall be performed on only one wire per sample. SIST EN 16602-70-26:2019
d. In the case where opposed wires are tested a specifically designed test fixture shall be used.
NOTE
A typical test fixture is shown in Figure A-6 e. Only one tensile test per sample is performed and the test shall be continued until failure occurs. 5.4.3.5 Characterisation of intrinsic wire / braid strength a. Intrinsic strength of wire or metallic braided shields shall be determined as follows: 1. A minimum of ten samples of 200 mm length from the wire batch to be used for the crimped assembly are prepared for testing by first stripping the insulation from both ends of the wire,
2. For metallic braided shield axial strength measurements are performed only on the shield after removal of the core dielectric, 3. To avoid wire or metallic braided shield strands damage in the clamping area, suitable end tabs, such as soldered splice are used, 4. The samples are tested to failure at a rate of (20 – 50) mm/min, 5. The maximum load achieved is recorded, 6. In case of failure in the clamps the result is discarded, 7. Intrinsic wire strength is calculated by averaging a minimum o
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...