Presentazione di PowerPoint - INFN · design, control of tools , materials and work environments , and careful workmanship • basic deign concepts : – stress relief shall be inherent

.

Materials and Processes related to Space Electronic. . PerugiaPerugia 1414--99--20042004

Francesco Petroni

Materials and Processes related to Space Electronic

.


Francesco Petroni

INTRODUCTION

One question frequently asked is “Why does ESA, NASA etc not have a preferred materials list whereas such a list does exist for electronic components?”The reason for this is best summarised by the relationship:

In other words a material can only be considered together with the associatedprocess and the final application. To complicate matters further the effects of theenvironment (manned or unmanned, LEO or GEO etc.) have to be considered sincethese can significantly affect the suitability of the application

.


Francesco Petroni

Example 1Example 1

For example:

This combination is widely used in spacecraft application.However for manned space applications this cannot be used since solithane,in common with most polyurethanes, is flammable

.


Francesco Petroni

Example 2Example 2

.


Francesco Petroni

.


Francesco Petroni

The following section presents the requirements for PMP. However the actual

requirements for a particular project depend on several factors, e.g.

1. Type of spacecraft (manned or unmanned)

2. Spacecraft orbit (LEO, GEO, polar etc.)

3. Complexity (satellite, payload, etc.)

4. Duration of space exposure (x years, y days, etc.)

The requirements will therefore be specified as part of the contract either in the

statement of work or in the PA plan.

.


Francesco Petroni

ECSS ECSS Specifications Related toSpecifications Related to PMPPMP

ECSS-Q-70A-April 96 Space Product Assurance - Materials, Mechanical Parts andProcesses.

The purpose of this standard is to define the requirements and statements applicable toMaterials, Mechanical Parts and Processes to satisfy the mission performance requir.This standard also provides details concerning the documentation requirements and theprocedures relevant to obtaining approval for the use of PMP in the fabrication of SpaceSystems and associated equipment.

This documentation is currently under revision and issue B will include thedocumentation Requirements presently given in PSS-01-700.

In addition many of the lower level PSS Specification (PSS-01-7XXX series) are beingreplaced by ECCS Specification (ECSS-Q-70-XX series).

(http://www.ecss.nl)

.


Francesco Petroni

EuropeanEuropean CoCo--operation for operation for Space Space Standardisation Standardisation (ECSS) (1)(ECSS) (1)

For materials and processes the situation is presently as follows:

1. ESA PSS-01-70 has been replaced by ECSS Specification ECCS-Q-70A 2. An additional 26 specifications, based on the PSS-01-7xx Series, have been issued as

ECSS Specifications

• ECSS-Q-70-01A Contamination and cleanliness control• ECSS-Q-70-02 Outgassing Testing of Materials• ECSS-Q-70-04A Thermal Cycling test for the Screening of space materials and processes• ECSS-Q-70-07A Automatic machine wave soldering• ECSS-Q-70-08A The manual soldering of high reliability electrical connections• ECSS-Q-70-09A Measurements of thermo-optical properties of thermal control materials• ECSS-Q-70-10A Qualification of printed circuit boards• ECSS-Q-70-11A Procurement of printed circuit boards• ECSS-Q-70-13A The Peel and Pull Off Strength of Adhesives• ECSS-Q-70-18A Preparation, assembly and mounting of RF coaxial cables• ECSS-Q-70-21A Flammability testing for the screening of space materials

.


Francesco Petroni

EuropeanEuropean CoCo--operation for operation for SpaceSpaceStandardisationStandardisation (ECSS) (2)(ECSS) (2)

• ECSS-Q-70-20A Determination of the susceptibility of silver-plated copper wire and cableto .red-plague. corrosion

• ECSS-Q-70-22A The control of limited shelf-life materials• ECSS-Q-70-25A The Application of Aeroglaze Z306• ECSS-Q-70-26A Crimping of high-reliability electrical connections• ECSS-Q-70-28A The repair and modification of printed circuit board assemblies• ECSS-Q-70-29A Offgassing Testing of Materials• ECSS-Q-70-30A Wire-wrapping of high reliability electrical connections• ECSS-Q-70-33A The Application of Thermal Coating PSG120FD• ECSS-Q-70-34A The Application of Aeroglaze H322• ECSS-Q-70-35A The Application of Aeroglaze L300• ECSS-Q-70-36A Materials selection for controlling stress corrosion• ECSS-Q-70-37A Test method for stress corrosion cracking• ECSS-Q-70-38A High reliability soldering for surface mount and mixed technology PCBs• ECSS-Q-70-45A Standard methods for mechanical testing of metallic materials• ECSS-Q-70-46A Requirements for manufacturing and procurement of threaded fasteners• ECSS-Q-70-71A Data for selection of space materials and processes

.


Francesco Petroni

The The RequirementsRequirements

PMP which cannot be considered either space proven or standard/established shall besubjected to an evaluation programme in order to assess their suitability for the intendedapplication. This programme and subsequently its result shall be submitted to ESA.

1. Thermal Vacuum Products considered for use in space systems shall have theiroutgassing properties assessed by thermal vacuum tests according toPSS-01-702 (to be superceded by ECSS-Q-70-02).

2. Thermal Cycling Products which are likely to be subjected to thermal stresses shall havetheir thermal cycling properties assessed as per ECSS-Q-70-04A.

.


Francesco Petroni

The The Requirements Requirements ((ContinuedContinued))

3. Radiation Products which will be exposed to particle/UV radiation shall be assessedto determine their ability to withstand the type and degree of radiationdosage expected during the mission. Tests are specified in PSS-01-706.

4. Stress Corrosion Products intended for structural applications and likely to be exposed tolong term terrestial storage, or flown on the STS, or used in launchers shall possess a high resistance to SCC. Structural products of a metallicnature shall be selected from the preferred list in Table 1 ofECSS-Q-70-36A.Where no data exists testing shall be performed as per ECCS-Q-70-37A.

.


Francesco Petroni

The The Requirements Requirements ((ContinuedContinued))

5. Flammability Products considered for use in unmanned spacecraft to be launched bythe STS and manned spacecraft (including those of the spacecraft itself,stored equipment or payload/experiments) shall be evaluated forflammability resistance in the most hazardous environment.Flammability testing is described in PSS-01-721 (to be superceded byECSS-Q-70-21A).

6. Offgassing and Toxic analysis

All products considered for use in the crew compartment of mannedspacecraft shall be evaluated for offgassing and odour. Samples of eachproduct shall be tested according to ECSS-Q-70-29A.

.


Francesco Petroni

The The ExceptionExceptionECSS-Q-70-71A Data for selection of space materials and processes

Aluminium and Al-alloys

Copper and Cu-alloys

Ni-alloys

Titanium and Ti-alloys

Stainless steels

materials: welding, brazing and soldering

Miscellaneous metallic materials

Optical materials

Adhesives, coatings and varnishes

Annex C (informative) Material data sheets

C.11 Adhesive tapes and films

C.12 Paints and inks

C.13 Lubricants

C.14 Potting compounds, sealants and foams

C.15 Reinforced plastics

C.16 Rubbers and elastomers

C.17 Thermoplastics

C.18 Thermoset plastics

C.19 Miscellaneous non-metallic materials

C.1

C.2

C.3 Nickel and

C.4

C.5 Steels

C.6

C.7 Filler

C.8

C.9

C.10

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

• specifications

• pcb’s manufacturing

• soldering processes

• crimping

• wire wrapping

• Repair and modification of PCB assemblies

• cleaning

• quality evaluations

• good solderjoints

• failure modes

.


Francesco Petroni

• ECSS -Q-70-08A

– Space product assurance - manual soldering of

high-reliability electrical connections

• ECSS -Q-70-10– Space product assurance - qualification and

procurement of multilayer printed circuit boards

(gold plated or tin-lead finish)

• ESA PSS -01-718– the preparation, assembly and mounting of RF

coaxial cables

• ECSS -Q-70-26– Space product assurance - the crimping of high reliability

electrical connections

• ECSS -Q-70-28– Space product assurance - repair and modification

of printed circuit board assemblies

• ECSS -Q-70-30A– Space product assurance - wire-wrapping of high reliability

electrical connections

• ECSS -Q-70-38– Space product assurance - high-reliability soldering

for surface mount and mixed technology printed

circuit boards

.


Francesco Petroni

.


Francesco Petroni

• BOSCH Telecom GmbH, Germany

• CIT (ALCATEL), France

• LABTECH Ltd, England

• PRINTCA AS , Denmark

• SEXTANT Avionique, France

• SPEMCO Group Ltd, England

• STRASCHU Leiterplatten GmbH, Germany

• SYSTRONIC S.A.L, France

• VIASYSTEMS , div. CSI, Italy

.


Francesco Petroni

• Soldering processes

• Solder flux

• solder alloys

• cleaning

• accept/reject criteria

• conformal coatings

• thermal cycling

• operator training and certification

.


Francesco Petroni

• Hand soldering

• qualification

• machine wave soldering

• verification and approval

• surface mounting

• verification and approval

.


Francesco Petroni

• solder flux– rosin-based

• pretinning: mildly activated (fully activated in cases of poor solderability)

• assembly: pure rosin flux

– water-soluble acid flux

• only for pretinning when rosin-based fluxes are inadequate. (immediate cleaning after

use is required)

• solder alloy– 63 tin solder (63 Sn, 37 Pb)

– 62 tin silver-loaded solder (62 Sn, 2 Ag, 36 Pb)

– 60 tin solder (60 Sn, 40 Pb)

– 96 tin silver solder (96 Sn, 4 Ag)

.


Francesco Petroni

.


Francesco Petroni

• Cleaning– solvents shall be non-corrosive and non-conductive and shall not degrade parts or

materials .

• Acceptable solvents are:– ethyl alcohol (99.5% or 95% pure by volume)

– isopropyl alcohol (best commercial grade, 99% pure)

– deionized water at 40 °C maximum for certain fluxes (dry after use)

– any mixture of the above

.


Francesco Petroni

• Reliable soldered connections result from proper

design, control of tools , materials and work

environments , and careful workmanship

• basic deign concepts :– stress relief shall be inherent in the design

– where adequate stress relief is not possible, solder-joint reinforcement is necessary

– materials shall be so selected that the mismatch of thermal expansion coefficient is minimal

– materials and processes which the formation of brittle intermetallic shall be avoided

– the design shall permit inspection of the soldered joints

.


Francesco Petroni

• Clean, smooth, bright undisturbed surface

• solder fillets between conductor and termination

areas as illustrated

• contour of wire sufficiently visible to determine

presence of wire

• complete wetting as evidenced by a low contact

angle

• proper amount and distribution of solder

• absence of defects as mentioned in the next sheet

.


Francesco Petroni

– Charred, burned, or melted insulation of

parts

– conductor pattern separation for board

– burns on base material

– discoloration which is continuous between

two conductors

– excessive solder (peaks , bridging)

– flux residue, solder spatter, or other

foreign matter

– dewetting

– insufficient solder

– pits, holes or voids , or exposed base metal

in the solder connection

– granular or disturbed solder joints

– fractured or cracked solder connections

– cut, nicked, gouged, or scraped

conductors or conductor pattern

– improper conductor length or direction of

clinch and lap termination

– repaired or damaged conductor

pattern(rework if applicable)

– bare copper or base metal (except end of

cut wire or leads )

– soldered joints made directly to goldplated

terminals and conductors

– cold solder joints

– component moulding with solder fillet

.


Francesco Petroni

• Order of merit of conformal coating tested evaluated by:

• Cost, Process , Repair, Solvent resistance, humidity, life test, resistance to thermal cycling,

outgassing, micro-vcm, flammability, offgassing, toxicity

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

• Trained and competent personnel shall be employed for all

soldering operations and inspections

• Trained personnel performing soldering operations and

inspection shall be certified at a soldering school– ZVE , Oberpfaffenhofen, Germany

– Highbury College, Portsmouth, England

– Italian Institute of welding (IIS ), Genova, Italy

– IFE , Oberpfaffenhofen, Germany

– Hytek, Aalborg, Denmark

– Institute de soudure, Paris , France

.


Francesco Petroni

• Hand soldering to ESA PSS -01-708

• inspection of solder joints

• repair and modification of pcb’s to ESA PSS-01-728

• RF cable assembly to ESA PSS-01-718

• crimping and wire wrapping to ESA PSS-01-726/730

• surface mounting techn. Ass. To ESA PSS-01-738

• Instructor cat 1 to ESA PSS-01-748

• fiber optic terminations to ESA-draft/NASA-std-8739.5

.


Francesco Petroni

ESA PS S -01-738

• Request for verification

• technology sample

• process identification document and process control sheet

• audit of assembly line

• verification programme

• smd assembly approval

.


Francesco Petroni

• Request for verification– The verification of any SMD assembly line will be restricted to those companies which have

been selected for the fabrication of ESA sponsored projects.

• Technology sample– the contractor will supply one sample from his SMD assembly process to ESTEC. This sample

will be examined at ESTEC or a recognised test house

• no conformal coating

• workmanship

• cleanliness

• metallography of soldered interconnections

• Audit of assembly process line– following acceptance of the technology sample the manufacturing facility will be audited by ESA

– findings of the audit remain as confidential to ESA

.


Francesco Petroni

• Verification programme– Details of verification programme will be discussed at the time of the audit

• acc. To ESA PSS-01-738

• thermal cycling (500: -55 to +100 oC)

• vibration

• visual, electrical test, cleanlines s test, microsection control

– the verification programme shall be established and approved by E S A

– the verification programme shall be funded and performed by the contractor or one or more

independent test houses (test house require approval by ESA)

– summary table for SMD verified to ESA PSS-01-738 shall be compiled

• SMD assembly approval– following the successful completion of the verification programme a letter of approval will be is sued by

ESA. ESA project approval by means of Project Declared Process List

– The summary table for SMD’s will be attached to this letter

– The validation period is indefinite until change to PID

– history of supply, manufacturing defects and unauthorised change of materials and or manufacturing

methods will require new verification

.


Francesco Petroni

• ECSS-Q-70-07A

• verification tests to establish confidence in all

automatic machine soldering lines

• technology samples– technology samples , cleanliness , documentation

– examination by recognised test house

• line audit

• verification testing– testing according to ECSS-Q-70-70A: visual inspection, electrical tes ts , thermal cycling,

vibration when design deviates from ECSS-Q-70-08

– microsectioning

– pull testing of leads on board surface

.


Francesco Petroni

• CRIMPING

– Forms of crimps

– Crimping optimisation

– Workmanship examples

• WIRE WRAPPING

– wire types

– recommended insulations

– terminal posts

– examples

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

• Wire used for wrapped connections shall conform to ESA/SCC No. 3903 or other approved national wire specification intended for wire wrapping

– the wire shall be a single solid round conductor. Stranded conductors shall not be used

– Conductor size shall be between AWG 24 and AWG 30

• soft annealed high-conductivity copper for AWG 28 and AWG 30

• high strength high-conductivity copper for wire gauges AWG 28 and AWG 30

– copper shall be silver plated (>2 micron)

• Recommended wire insulations– outgassing according to ECSS-Q-70-02

– ETFE (Tefzel), PFA (Perfluoroalkoxy), PVDF (Kynar), and Kapton poluimide over extruded PTFE

• Terminal post– suitable grades of copper or nickel alloys (Copper-Z inc, Phosphor-bronze, copper-nickel-zinc, beryllium-copper,

nickel-copper(Monel) and nickel-cclad copper(Kulgrid)

– 1 to 3 microns of Gold over min. 1 micron of copper or nickel (barrier plating). No Silver undeplating

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

• Good quality solderjoints

• Good quality SMT solderjoints

• Cross section of smd devices

• Soldering to gold

• No pretinning

• After thermal cycling

• Whisker growth on Tin-plated brass

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

.


Francesco Petroni

Fine

Documents

Presentazione di PowerPoint - INFN · design, control of tools , materials and work environments , and careful workmanship • basic deign concepts : – stress relief shall be inherent