Hot Topics in the NASA Workmanship Standards Program · 2019. 8. 31. · IPC/WHMA-A-620AS published and meets or exceeds NASA- STD-8739.4 requirements. IPC/WHMA-A-620B published. - [PDF Document] (2024)

Hot Topics in the NASA Workmanship Standards Program

Jeannette Plante, Program Manager NASA GSFC, Code 300, SMA

Quality Leadership Forum March 2013

https://ntrs.nasa.gov/search.jsp?R=201300134292019-08-31T00:58:07+00:00Z

• Standard of Standards Training

• Printed Circuit Boards

• Soldering • Cables and Harnesses • Polymeric

Applications • ESD Control

Agenda

• NASA-STD-8739.6, Implementation Requirements for NASAWorkmanship Standards

• Published September 5, 2012

• Fill requirements gap between VCS and NASA needs

Standards of Standards

• Covers global requirements which apply to all Workmanshipstandards: applicability, visual acuity, facility temperature andhumidity, training

• Codify Training Center policies JPL’s Mid-Infrared Instrument(MIRI) for JWST

“1.2.3 The workmanship requirements of this document do notapply to suppliers of commercial-off-the-shelf

(COTS) items. Projects which use COTS hardware for applicationsdescribed in 1.2.2 above are responsible

for identifying and managing risk associated with hardware thatwas built without material controls, production

methods, and/or quality inspections defined by the workmanshipstandards.”

COTS suppliers are retailers, not contractors building tospec.

Performance and reliability must be assured. (per Mission RiskClassification)

Standard, proven, low-cost assurance methods may not beavailable for printed wiring assembly (PWA) and cable harnessassembly quality assurance.

Custom assurance methods must address relevant defect types andfailure modes. For low-risk missions overall cost may behigher.

Example 1: Applicability to COTS

6.1.1 Temperature and relative humidity (RH) shall be monitoredin the processing area and

maintained within the following limits (Requirement):

a) For temperature: 18° - 30° C (65° - 85° F).

b) Maximum relative humidity: 70 percent RH

c) For ESD-sensitive hardware, minimum humidity: 30 percentRH.

d) For ESD-sensitive hardware, HBM Class 0, minimum humidity: 40percent RH.

6.1.2 For instances where maintaining an RH level shown in c. ord. above is not practical,

special methods, procedures, equipment, and assurancerequirements designed to

overcome the risks of relative humidity levels below 30% RHshall be used and documented

in the applicable ESD Control Program Plan.

Fixes confusion with old text/graphic. Addresses lack ofhumidity requirements for ESD control during operations (ANSI/ESDS20.20).

Example 2: Lab Operating Conditions

Extensive Appendix on Training. Important policies on: • NASALevel B Training Centers: JSC, MSFC Can train any operator orinspector (not Level B

instructor): industry, NASA, DCMA, etc. • NASA personnelcertification: Training is part of certification Personnel do notself-certify Trainers do not certify NASA certification is morethan IPC certification NASA certification is not portableSupervisor is accountable for personnel’s certification

status

Standards of Standards – Training Policy

• Consistent use of training variations: Initial, Retraining,Partial, On-line.

• Consistent use of curricula and grading • Solidified 3-monthgrace period. Training

credentials valid for 27 months. Certification still needs to berenewed after 24 months.

• Shorter retraining class shall be offered if within 27 monthwindow, regardless of prior school. After 27 months, schooldetermines class that can be taken.

Standards of Standards – Training Policy

• Treating NASA instruction of Workmanship courses as ITAR.Technical Assistance Agreement (TAA) required for foreignnationals.

• Policy for certifying Level A Instructors: • How to staycurrent? • How to share lessons learned? • How to encourage unifiedtraining product?

• How to include 8739.6 content in training classes?

Standards of Standards – Training Policy

Founded in 1989, the RITF is a critical support facility at NASAJohnson Space Center in the Safety and Mission AssuranceDirectorate. The RITF is operated for NASA by SAIC and providestesting and evaluation, screening services, and training to thetechnical community. The RITF has established control programs forElectrostatic Discharge (ESD) and Counterfeit Parts Avoidance. TheRITF is a AS9100-registered laboratory and holds an ISO/IEC17025accreditation.

Overview of the RITF Receiving, Inspection and Test Facility

• Chemical analysis • Environmental testing • Failure analysis •Mechanical testing • Metallographic analysis • Radiographicanalysis

Testing and Evaluation

• Counterfeit parts identification • Electronic componentscreening • Fastener acceptance screening • FOD and loose particlescreening • Wire and cable acceptance screening

Screening Services

•The RITF is a NASA Level B Workmanship Standards TrainingCenter.

Training

Available Workmanship Training Courses Course Duration (hours)Through–hole Soldering 40 Cable, Harness & CrimpTraining/Inspection 40 Conformal Coating & StakingTraining/Inspection 24 Electrostatic Discharge Control - Levels 1,2, 3 [i/a/w JSC’s Control Plan]

4 per level

Surface Mount Soldering Training/Inspection 40 Fiber OpticTerminations Training 24 Lithium Battery Handling Familiarization 2Wire Wrapping 8 NASA Workmanship Standards Familiarization 8Requirement for Soldered Electrical and Electronic Assemblies (IPCJ-STD-001 ES)

40

Course List

Shorter versions of most courses are available forretraining

Contact Information

Via a Space Act Agreement with Bay Area Houston AdvancedTechnology Consortium (BayTech), organizations can establish asimple contract with BayTech and enroll their employees in RITFTraining Classes. BayTech is a 501(c)(3) non-profitorganization.

NASA Johnson Space Center RITF: B15/R2001 2101 NASA ParkwayHouston, Texas 77058 http://ritf-sma.jsc.nasa.gov/Resources.htmlwww.nasa.gov/centers/johnson/ritf/

NASA Point of Contact: Cheryl Corbin JSC Safety and MissionAssurance Directorate [emailprotected] 281-244-8423

BayTech Point of Contact: Kim Morris 832-536-3260[emailprotected]

Transitioning into J-STD-001ES for Soldering • OnlyIPC-certified Trainers

allowed

• Class can be IPC standard course (either modular ornon-modular) or “home-grown”

• Establishes NASA certification requirements still apply (NASAcert > IPC cert)

• Old Projects may allow J-STD-001ES certified operators orinspectors at any stage of production: Manufacturing to drawingInspecting hardware Modifying or repairing hardware

Standards of Standards

Printed Circuit Boards

Source: Draft, IPC-6012D

• Printed Circuit Boards (PCBs) span across the EEE Parts andWorkmanship disciplines

• Design and Quality standards used by NASA are generally IPCthough not required at the Agency level.

• NEPP program supported improvements by adding a Space sectionto the rigid board standard, IPC-6012, circa 2006.

• Changes to IPC-STD-6012C in 2007 changed requirements in theSpace section that may have reliability impact to NASAmissions.

• Disconnect between requirement spec and delivery spec (want6012B, get 6012C, mil-spec, ESA spec).

• High lot rejection rate (at GSFC). Is lot verification testingbe performed? If so, why the delta?

Printed Circuit Boards

• Annular Ring (AR) • Ensures traces on layers (top, internal,bottom) connect electrically to entire barrel surface. • Drillholes must be very precise with low AR to avoid reduced connectionarea or misaligned

installed parts.

• Etchback - Negative • Drilled hole walls must be cleared ofresin smear and glass fibers with etchant followed by

cleaning prior to plating • Negative etchback over-etches thecopper, recessing it from the wall inner diameter. Residues

can be left in recess negatively affecting plating. Hole platingcan fold over near recess trapping residue.

• Desired limit: No negative etchback; IPC-6012C 3/A allows 0.5mil maximum • Study of residue entrapment can show risk isacceptable. Interconnect Stress Test (IST) may

also be a risk assessment test.

• Etchback - Positive • Excessive positive etchback risks foilcracks developing after thermal stress • Knowledge of dimension ofpositive etchback relative to trace geometry can reduce risk.

Interconnect Stress Test (IST) may also be a risk assessmenttest.

Printed Circuit Boards

• Interconnect Stress Testing (IST)

• An accelerated interconnect reliability assessment using a DCcurrent to simulate thermal stressing (Hrs vs Weeks)

• Gives more accurate failure analysis in pinpointing the siteof the failure without further propagation

• Requires special IST coupon – board house capability question• Technology owned solely by PWB company; IPC recently negotiatedto buy equipment • IPC currently conducting validation testing fornew IST Test Method to update TM-650 2.6.26

Printed Circuit Boards

Source: PWB Corp.

Soldering

J-STD-001ES Adopted for all Programs and Projects October2011.

“New Items” analysis nearly finished to help suppliers updateinternal procedures to match from NASA-STD to J-STD-001ES.

Important new areas: Red Plague control for silver-plated wireTime between and then between

is not limited to a maximum time. Recognizes small filletheights for smaller SMT packages (was 50%, now 25%) Ball grid arrayand column grid array now standard interconnect types Points tomoisture control characterization methods used for plastic

encapsulated microcircuits

Soldering

Important new areas in J-STD001ES: Better traceability to IPCstandards for flux, solder, paste Recognizes that cooling portionof soldering heat cycle must be controlled for ceramiccapacitors

Soldering

Leadless Chip Carrier (LCC) and Land Grid Array

(LGA) packages require customer approval to use. Dimension forLCC height off of the board is now

subjective rather than dimensioned “Parts shall be mounted withsufficient clearances between the body and the PCB to assureadequate cleaning and cleanliness testing”

LCC overhang allowed (25% max)

Solder fill of through-hole joints: Minimum of 75% including enddepressions, no void criteria

Solder joints which are thermal connections require

customer approved accept/reject criteria Ultrasonic cleaning OKwith data

Important new areas in J-STD001ES: Polymeric ApplicationsSection: NASA will not use (see

NPD 8730.5 and NASA-STD-8739.6) Requirements on PCB quality:

•Emphasizes that some imperfections on boards “as received” arenot defects •Names unacceptable defects caused by poor soldering•NASA re-engaging with IPC on IPC-A-600 series (6012, 6013, etc).•J-STD-001xS will have to keep pace to not contradict. •Assumptionis that a “known good” board was used.

Soldering

FLATSAT Harness

Cables and Harnesses

IPC/WHMA-A-620AS published and meets or exceeds NASA-STD-8739.4requirements.

IPC/WHMA-A-620B published. Companion training not finalized. IPCtending toward two-week course to cover “base” document and

then to teach the hands-on portion. This will be a significantimpact to NASA supply chain though no

alternative is defined. Historically this has not been ahands-on class for IPC Historically this has been a hands-on classfor NASA Base spec is very large. IPC wants to “touch” everyrequirement in base training IPC testing hands-on class withexperts. NASA lesson learned is that this class

takes longer to teach to newbies so beta approach may not bevalid.

Cables and Harnesses

NASA-STD-8739.4 due for revalidation in 2013. No major changesplanned other than synchronization with 8739.6

Polymeric Applications

Will be revalidated in 2013. Changes being considered:

Remove “test specimen” requirement for all except conformalcoating: Requirement is confused with material qualification Testmethod does not “test as you fly”. Uses a material

qualification test method (thus the confusion) Increased use ofpre-mixed, frozen, small-portion staking material.

Test sample size is much, much larger than amount used. Somehistory with conformal coating that looks good initially and

then degrades later

NASA-STD-8739.1

ESD Control

Gene Monroe, LaRC: - Hosting monthly Agency knowledge-sharingwebex

- Acting as Agency representative at ESDA meetings

ESD Control

Agency Self-help Group • Better understanding of technicalrequirements and measurement techniques • Approaches for setting uptraining programs • Approaches for Center-level ESD ControlPrograms • Recommendations for Agency-level policy •Recommendations for ESDA requirements

ESDA Changes to ANSI/ESD S20.20

NASA Center ESD Control

Programs

Informs NASA QA for Prime

and Subcontracts

New Workmanship

Processes & Changes to

NASA-STD-8739.6

Document Sharing

nsckn.grc.nasa.gov/ workmanship

ESDA

ANSI/ESD S20.21

ANSI/ESD S20.20

ESD Control

• 2008: NASA Workmanship begins suggesting to the ESDA to have aSpace-focused standard. • September 2012: ESDA accepts NASA’sformal proposal to make an Aerospace Standard that

would include S20.20 requirements • Over 20 aerospaceorganizations invited to participate • Feedback indicateswidespread grassroots support for approach • February 2013: Firstface-to-face meeting at the ESDA Working Group meeting series(DoD

participation limited by sequestration)

• Using NASA-HDBK-8739.21, Workmanship Manual for ElectrostaticDischarge Control (Excluding Electrically Initiated ExplosiveDevices) as a guide for capturing all critical assurancerequirements.

• Regular committee webex schedule being coordinated.

Example of ESD assurance requirement: NASA-STD-8739.6, Paragraph7.2.3: “ESD wrist straps and heel strap systems shall be verifiedto be functional each time they are put on prior to entry into anElectrostatic Protected Area (EPA) or prior to coming within onemeter of an ESD sensitive item (Requirement).”

New Workmanship Standard: • VCS risk reduction • Codifiestraining requirements • Expands NASA Training Centers

Summary Soldering: • NASA will not use Polymeric Applicationssection.

• BGA and CGA interconnects now standard

Printed Circuit Boards: • Workmanship adopting new

discipline area. • Particular concern around

annular ring and etchback requirements.

• Opportunities in IST testing

Cable and Harness: • IPC/WHMA-A-620AS.1 “meets

or exceeds” NASA-STD-8739.4 on a requirements basis.

• Training program doubles in length.

Polymeric Applications: • 5-yr review this year • Seeking tomodify test specimen

requirement for staking, bonding.

Hot Topics in the NASA Workmanship Standards ProgramSlide Number2Slide Number 3Example 1: Applicability to COTSExample 2: LabOperating ConditionsSlide Number 6Slide Number 7Slide Number8Overview of the RITF�Receiving, Inspection and Test FacilityCourseListContact InformationSlide Number 12Slide Number 13Slide Number14Slide Number 15Slide Number 16Slide Number 17Slide Number 18SlideNumber 19Slide Number 20Slide Number 21Slide Number 22Slide Number23Slide Number 24Slide Number 25Slide Number 26Slide Number 27SlideNumber 28Slide Number 29