1、ASD STANDARD NORME ASD ASD NORM prEN 2812 Edition P 3September 2008 PUBLISHED BY THE AEROSPACE AND DEFENCE INDUSTRIES ASSOCIATION OF EUROPE - STANDARDIZATIONAvenue de Tervuren, 270 - B-1150 Brussels - Tel. + 32 2 775 8126 - Fax. + 32 2 763 3565 - www.asd-stan.orgICS: 49.060 Supersedes Edition P 2 Se
2、ptember 1996 Descriptors: Aircraft industry, aircraft equipment, cable, stripping ENGLISH VERSION Aerospace series Stripping of electric cables Srie arospatiale Dnudage des cbles lectriques Luft- und Raumfahrt Abisolieren von elektrischen Leitungen This “Aerospace Series“ Prestandard has been drawn
3、up under the responsibility of ASD-STAN (The AeroSpace and Defence Industries Association of Europe - Standardization). It is published for the needs of the European Aerospace Industry. It has been technically approved by the experts of the concerned Domain following member comments. Subsequent to t
4、he publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or functionally, without re-identification of the standard. After examination and review by users and formal agreement of ASD-STAN, it will be submitted as a dr
5、aft European Standard (prEN) to CEN (European Committee for Standardization) for formal vote and transformation to full European Standard (EN). The CEN national members have then to implement the EN at national level by giving the EN the status of a national standard and by withdrawing any national
6、standards conflicting with the EN. Edition approved for publication 30 September 2008 Comments should be sent within six months after the date of publication to ASD-STAN Electrical Domain Copyright 2008 by ASD-STAN prEN 2812:2008 (E) Contents Page Foreword2 1 Scope 3 2 Normative references 3 3 Strip
7、ping processes and associated tools .3 4 Identification, inspection and calibration5 5 Qualification .7 6 Health, safety and environmental aspects9 Annex A (normative) Defects illustrations . 10 Annex B (informative) Mechanical stripping . 12 Annex C (informative) Laser stripping 13 Annex D (informa
8、tive) Thermal stripping. 14 Foreword This standard was reviewed by the Domain Technical Coordinator of ASD-STANs Electrical Domain. After inquiries and votes carried out in accordance with the rules of ASD-STAN defined in ASD-STANs General Process Manual, this standard has received approval for Publ
9、ication. 2 prEN 2812:2008 (E) 1 Scope This standard specifies the conditions for stripping and inspection of stripping tools and the stripped ends of electric cables for aerospace applications. Various stripping processes exist. The choice of a process depends upon the properties of the particular c
10、ables to be stripped and/or on the specific requirements for the end product to be achieved. The processes specified today in this document are: manual stripping; mechanical stripping; laser stripping; Thermal stripping. 2 Normative references The following referenced documents are indispensable for
11、 the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2083, Aerospace series Copper or copper alloy conductors for electrical cables Product standard. EN 34
12、75-701, Aerospace series Cables, electrical, aircraft use Test methods Part 701: Strippability and adherence of insulation to the conductor. EN 3719, Aerospace series Aluminium or aluminium alloy conductors for electrical cables Product standard. EN 4434, Aerospace series Copper or copper alloy ligh
13、tweight conductors for electrical cables Product standard (Normal and tight tolerances). EN 4651, Aerospace series Copper-clad aluminium alloy conductors for electrical cables - Product standard.1)3 Stripping processes and associated tools 3.1 General recommendations Precise definition of tools to u
14、se on a particular wire or cable standard is under the responsibility of the user. It is particularly important to know from which ASD Product Norm conductors are coming (for examples: EN 2083, EN 3719, EN 4434, EN 4651) for the mechanical stripping process. Availability of a common tool able to str
15、ip different gauges or cable sizes is recommended. If tools are designed for particular applications, differentiation by colours is recommended. Size and weight of tools has to be appropriate for the envisaged use. 1) Published as ASD Prestandard at the date of publication of this standard. 3 prEN 2
16、812:2008 (E) When it is essential to control the length of insulation to be removed an adjustable abutment must be part of the tool. 3.2 3.3 Manual stripping 3.2.1 Use The use of this process must be strictly limited to insulations and jackets of the cables for which other methods are impractical. N
17、evertheless, with thermal stripping and the arrival of small laser machines, this manual practice must be progressively eliminated for aerospace use and stay permissible only for small batches. 3.2.2 Application Manual stripping by scalpel, razor blade or other cutting tool is carried out on cables
18、over 5 mm2cross-section, sheaths of shielded cables, fire-resistant cables and coaxial cables, unless another stripping process is specified. Mechanical stripping 3.3.1 Use This process is generally the most used in particular for single wires. Various power tools are also adapted to strip round cab
19、les, such as single wire screened jacketed and coaxial, and flat cables. The simplicity of manual pliers makes these tools ideal for work in the field. For illustration, see Annex B (Informative). 3.3.2 Stripping with manual tools The blades of tools can have different profiles and dimensions. Vario
20、us assembly shapes are now available. A blade can have several marked cavities of different sizes. When the tool is closed, the edges of the blades shall be in the same plane and form a cutting circumference whose diameter is greater than the maximum diameter of the conductor of the cable to be stri
21、pped. Blades must be replaced as pairs. The manual stripping tools with V shaped cutting blades or shearing type blades are forbidden (see Figure 1 and Figure 2). Figure 1 V shaped cutting blades Figure 2 Shearing type blades 3.3.3 Stripping with power tools These tools use blades with the same gene
22、ral characteristics as those defined in 3.3.2. 4 prEN 2812:2008 (E) Particular care is necessary during the use of rotating blades, and their depth shall be adjustable to adapt the cutting diameter to the need. 3.4 3.5 4.1 Laser stripping 3.4.1 Use Laser wire stripping can be carried out on wires an
23、d cables of any gauge and on jackets. This process is particularly suitable for use in applications where damage of any sort to the conductor or the screen is unacceptable and when the external geometry of the cable to strip is incompatible with mechanical processes. For illustration, see Annex C (I
24、nformative). 3.4.2 Application Carbon Dioxide (CO2) lasers are normally used, but other laser types may be applicable for certain applications. Beam power shall be adjustable to be able to cut properly all various types of insulation and shapes. Thermal stripping 3.5.1 Use Thermal wire stripping can
25、 be carried out on wires and cables of any gauge and on jackets. This process is particularly suitable for use in applications where damage of any sort to the conductor or the screen is unacceptable, when the external geometry of the cable to strip is incompatible with mechanical process and when th
26、e size of tooling equipment investment must be limited. This process may not be suitable for all types of insulation or in particular environmental conditions such as where flammable vapours may be present. For illustration, see Annex D (Informative). 3.5.2 Application Generally the tool is in two p
27、arts, a generator to control the required temperature and a hand unit. The hand unit can be equipped with various shape of blades. 4 Identification, inspection and calibration Manual stripping tools 4.1.1 Identification An identification number marked on the main body is recommended in order to faci
28、litate the follow-up of the inspection of the cutting blade. 4.1.2 Inspection The inspection of cutting area is carried out visually at regular intervals. The inspection shall be completed by inspection of samples of stripped cable ends, see 5.3.1. 5 prEN 2812:2008 (E) 4.2 4.3 Mechanical stripping t
29、ools 4.2.1 Identification An identification number shall be permanently marked on the main body of the tool and on the blade. In addition, each stripping tool shall have an individual inspection sheet including: its identification number; date of first commissioning; dates of successive inspections;
30、 dates of rectification or repair; numbers of associated blades. 4.2.2 Inspection The inspection of blades is carried out with the aid of measuring gauges, shadowgraph, calipers or other means permitting confirmation that the cavities are in accordance with the dimensions specified. The inspection s
31、hall be completed by checking the mechanical condition of the manual tool or power tool and by stripping tests, followed by inspection of samples of stripped cable ends, see 5.3.2. For the routine inspection of production tools, the gauging of blades may be omitted, provided double stripping is used
32、 for the inspection of stripped cable ends. Stripping tools shall be inspected at least every 90 days. If a worn blade requires replacement, the complete blade assembly shall always be replaced together. 4.2.3 Calibration Some particular tools, for coaxial cables for example, may require calibration
33、 to obtain the necessary diameter to strip. Laser stripping tools 4.3.1 Identification An identification number shall be permanently marked on the main body of the tool. In addition, each tool shall have an individual inspection sheet including: its identification number; date of first commissioning
34、; dates of successive inspections; dates of rectification or repair; numbers of associated parts. 6 prEN 2812:2008 (E) 4.3.2 Inspection The inspection shall be completed by checking the general behaviour of the laser tool accordingly to the laser tool manufacturer instructions and by stripping tests
35、, followed by inspection of samples of stripped cable ends, see 5.3.3. Laser tools shall be inspected at least every 90 days. 4.3.3 Calibration Periodic laser power checks shall be made to ensure power levels remain within the limits as defined by the manufacturers specification. 4.4 5.1 General The
36、rmal stripping tools 4.4.1 Identification An identification number shall be permanently marked on the main body of the tool. In addition, each stripping tool shall have an individual inspection sheet including: its identification number; date of first commissioning dates of successive inspections; d
37、ates of rectification or repair; numbers of associated parts 4.4.2 Inspection The inspection shall be completed by checking the general behaviour of the thermal tool according to the thermal tool manufacturer instructions and by stripping tests, followed by inspection of samples of stripped cable en
38、ds, see 5.3.4. Thermal tools shall be inspected at least every 90 days. 4.4.3 Calibration Periodic calibration checks of the tool shall be made to ensure power levels, and consequently temperature at the tip of the respective blade remain within the limits as defined by the manufacturers specificati
39、on. 5 Qualification Wires and cables must be strippable as normally defined in their technical specification or product standard. The test method generally used to assess this is EN 3475-701. The stripping operation must remove the insulator from the conductor over a length defined with tolerances,
40、to allow correct connection of cables, without damaging the core strands or the screen or the insulator and without reducing the original performances of the cable as defined in its technical specification. The stripping length depends on the length required to connect the conductor into the end com
41、ponent. Each process must be applied by trained operators. 7 prEN 2812:2008 (E) For qualification to a wire and cable standard, there must be an agreement between the wire and cable manufacturer and the qualifying authority on exact tool reference to use. The exact reference of this tool must be wri
42、tten in the associated test report. 5.2 Method 5.3 Requirements Qualification of a dedicated tool to strip a cable type will be performed by stripping of samples coming from at least two different batches (ideally for manual stripping pliers used for single wires, batches shall have conductors not c
43、oming from the same conductor batch, and if possible one at the maximum conductor diameter and the other at the minimum). The inspection of stripped cable ends, for which the tool will be used, shall be carried out on 10 samples coming from the same manufacturing batch for each cable size. Five samp
44、les will have one stripping at each extremity and the other 5 samples a double stripping at each extremity. The first strip shall be made approx. 10 mm from end of the cable and the second strip approx. 20 mm from end of cable. All slugs of insulation shall be cut cleanly, with no residual insulatio
45、n remaining on the conductor (see Figure A.6). Using a 10 times magnification aid, the conductor of the cable shall be examined for damage, at the position of the first strip. 5.3.1 Manual stripping As this process is of high risk to damage conductors or screen, particular care will have to be taken
46、 for the visual examination of possible defects mentioned in Annex A (Normative), see Table A. 5.3.2 Mechanical stripping The geometrical configuration of the blade assembly shall allow automatic centring of the cables without damaging or cutting the strands. During the stripping, the cable shall be
47、 maintained at 90 in relation to the blade and the separation of the insulation shall be made parallel to the cable. Each blade profile shall be calibrated in relation to the dimensions of the cable, as shown in Annex B (Informative) (Figure B.1). For stripping with power tools, the rotating of the
48、blade(s) shall be in the same plane and form a cutting circumference whose diameter is greater than the maximum diameter of the conductor of the cable to be stripped. After stripping, the conductor shall show no damage to or untwisting of the strands according to Annex A (Normative). Taking into acc
49、ount expansion of conductor cross-sections larger than 2 mm2, some marks on the strands are permissible (see Figure A.4), however the material of the conductor beneath the plating shall not be visible. The insulation remaining on the wire or cable shall show no damage due to the tooling, however light marks may be tolerated (see Figure A.9). 5.3.3 Laser stripping During the stripping, the wire insulation or cable jacket shall be maintained at the focal point of the laser beam. The rotating of the cutting beam shall be in
