SN 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

Covers the technical requirements and quality assurance provisions for the manual soldering of high-reliability electrical connections intended for use in spacecraft and associated equipment.