EN 50390:2004

Introduction
1 Scope
2 Normative references
3 Terms, definitions and abbreviated terms
   3.1 Terms and definitions
   3.2 Abbreviated terms
4 Principles and prerequisites of reliable soldered
   connections
   4.1 Principles
   4.2 Prerequisites
5 Preparatory conditions
   5.1 Facility cleanliness
   5.2 Environmental conditions
   5.3 Precautions against static charges
   5.4 Lighting requirements
   5.5 Equipment and tools
        5.5.1 Brushes
        5.5.2 Files
        5.5.3 Cutters and pliers
        5.5.4 Bending tools
        5.5.5 Clinching tools
        5.5.6 Insulation strippers
        5.5.7 Soldering irons and resistance soldering
               equipment
        5.5.8 Non-contact heat sources
        5.5.9 Soldering tools
        5.5.10 Defective or uncalibrated equipment or
               tools
6 Materials selection
   6.1 Solder
        6.1.1 Form
        6.1.2 Composition
        6.1.3 Melting temperatures and choice
   6.2 Flux
        6.2.1 Rosin-based fluxes
        6.2.2 Corrosive acid fluxes
   6.3 Solvents
        6.3.1 Acceptable solvents
        6.3.2 Drying
   6.4 Flexible insulation materials
   6.5 Terminals
        6.5.1 Preferred terminals
        6.5.2 Tin-, silver- and gold-plated terminals
        6.5.3 Shape of terminals
   6.6 Wires
   6.7 PCBs
        6.7.1 Boards
        6.7.2 Plated-through holes
        6.7.3 Tin-lead finish on conductors
        6.7.4 Gold finish on conductors
   6.8 Conformal coating, staking compounds and potting
        materials
7 Preparation for soldering
   7.1 Preparation of conductors, terminals and solder
        cups
        7.1.1 Insulation removal
        7.1.2 Damage to insulation
        7.1.3 Damage to conductors
        7.1.4 Insulation clearance
        7.1.5 Surface to be soldered
        7.1.6 De-golding and pre-tinning of conductors
   7.2 Preparation of the soldering bit
        7.2.1 Inspection
        7.2.2 Maintenance
        7.2.3 Copper bits for special soldering applications
        7.2.4 Plated bits
        7.2.5 Tip in operation
   7.3 Maintenance of resistance-type soldering electrodes
   7.4 Handling (work station)
   7.5 Storage (work station)
        7.5.1 Components
        7.5.2 PCBs
        7.5.3 Materials requiring segregation
        7.5.4 Traceability
   7.6 Baking of PCBs
8 Mounting of components
   8.1 General requirements
        8.1.1 Introduction
        8.1.2 Heavy components
        8.1.3 Metal-case components
        8.1.4 Glass-encased components
        8.1.5 Stress relief
        8.1.6 Reinforced plated-through holes
        8.1.7 Lead and conductor cutting
        8.1.8 Heat-generating components
        8.1.9 Moulded components
        8.1.10 Hook-up wire
        8.1.11 Location
        8.1.12 Conformal coating, cementing and encapsulation
   8.2 Lead bending requirements
        8.2.1 General
        8.2.2 Components with leads terminating on the
               opposite side of a PCB
        8.2.3 Components with leads terminating on the
               same side of a PCB
        8.2.4 Conductors terminating on both sides of a
               non-plated-through hole
        8.2.5 Non-bendable leads
   8.3 Mounting of terminals to PCB
        8.3.1 General
        8.3.2 Methods of attachment
   8.4 Lead attachment to PCBs
        8.4.1 General
        8.4.2 Lead access holes
        8.4.3 Clinched leads
        8.4.4 Stud leads
        8.4.5 Lapped round leads
        8.4.6 Lapped ribbon leads
        8.4.7 Lapped round- and ribbon-lead parts with
               solder connection on same side
   8.5 Mounting of components to terminals
        8.5.1 General
        8.5.2 Special constraints
   8.6 Cordwood modules
   8.7 Mounting of connectors to PCBs
        8.7.1 General
        8.7.2 Special constraints
9 Attachment of conductors to terminals, solder cups
   and cables
   9.1 General
        9.1.1 Conductors
        9.1.2 Terminals
        9.1.3 Component leads
   9.2 Wire termination
        9.2.1 Breakouts from cables
        9.2.2 Minimum and maximum insulation clearance
        9.2.3 Multiple parallel entry
        9.2.4 Variations
        9.2.5 Solid hook-up wire
        9.2.6 Stress relief
        9.2.7 Mechanical support
   9.3 Turret and straight pin terminals
        9.3.1 Side route
        9.3.2 Bottom route
   9.4 Bifurcated terminals
        9.4.1 General
        9.4.2 Bottom route
        9.4.3 Side route
        9.4.4 Top route
        9.4.5 Combination of top and bottom routes
        9.4.6 Combination of side and bottom routes
   9.5 Hook terminals
   9.6 Pierced terminals
   9.7 Solder cups (connector type)
   9.8 Insulation tubing application
   9.9 Wire and cable interconnections
        9.9.1 General
        9.9.2 Preparation of wires
        9.9.3 Preparation of shielded wires and cables
        9.9.4 Pre-assembly
        9.9.5 Soldering procedures
        9.9.6 Cleaning
        9.9.7 Inspection
        9.9.8 Workmanship
        9.9.9 Sleeving of interconnection
   9.10 Connection of stranded wires to PCBs
10 Soldering to terminals and PCBs
   10.1 General
        10.1.1 Securing conductors
        10.1.2 Insulation sleeving, potting or coating
        10.1.3 Thermal shunts
        10.1.4 High-voltage connections
   10.2 Solder application to terminals
        10.2.1 Soldering of swaged terminals onto PCBs
        10.2.2 Soldering of conductors onto terminals
               (except cup)
        10.2.3 Soldering of conductors onto cup terminals
   10.3 Solder application to PCB
        10.3.1 Solder coverage
        10.3.2 Solder fillets
        10.3.3 Soldering of component leads to plated-through
               holes
        10.3.4 Solder application
   10.4 Wicking
   10.5 Solder rework
11 Cleaning of PCB assemblies
   11.1 General
   11.2 Ultrasonic cleaning
   11.3 Monitoring for cleanliness
        11.3.1 Cleanliness testing
        11.3.2 Testing frequency
        11.3.3 Test limits
        11.3.4 Test methods
12 Final inspection
   12.1 General
   12.2 Acceptance criteria
   12.3 Rejection criteria
13 Verification
   13.1 General
   13.2 Temperature cycling
   13.3 Vibration
14 Quality assurance
   14.1 General
   14.2 Data
   14.3 Non-conformance
   14.4 Calibration
   14.5 Traceability
   14.6 Workmanship standards
   14.7 Inspection
   14.8 Operator and inspector training and certification
Annex A (informative) Typical satisfactory and
        unsatisfactory solder connections

This standard defines the technical requirements and quality assurance provisions for the manual soldering of high­reliability electrical connections intended for use in spacecraft and associated equipment.The rigorous requirements set by this standard ensure the high reliability of hand­soldered electrical connections intended to withstand normal terrestrial conditions and the vibrational G­loads and environment imposed by space flight. The proper tools, correct materials, design and workmanship are covered by this standard. Acceptance and rejection criteria are stated and some workmanship standards are included to discriminate between proper and improper work.Wave­soldering processes and surface mount technologies are specified in separate documents, and those processes require to be verified as prescribed in the respective standard.