AQA DIRECTIVE ON PCB SOLDERING PROCESS · ‘भभ’ भभभभभ, भभभ...

AQA DIRECTIVE ON PCB SOLDERING PROCESS

07/2020

भभभभ भभभभभ, भभभभभ भभभभभभभभ भभभभभभभ भभभभभभभभ भभभभभभभ भभभभभभभभभभभ / भभभभभभ भभभभभभ भभभभभभ

‘भभ’ भभभभभ, भभभ भभभभभभ -110011 GOVERNMENT OF INDIA, MINISTRY OF DEFENCE

DIRECTORATE GENERAL OF AERONAUTICAL QUALITY ASSURANCE ‘H’ BLOCK, NEW DELHI – 110011

TEL: 011-23011783, FAX: 011-23014395 www.dgaeroqa.gov.in, e-mail: [email protected]

AQA Directive 07/2020

DGAQA Directive on PCB Soldering Process Page 2

TABLE OF CONTENTS



Sl. No.

Contents Page No.

1. Introduction 04

2. Definitions and Brief Description 04

3. Safety & Handling Instructions and Assembly Preparation 06

4. PCB Soldering Process 08

5. Documentation / References 20

6. Conclusion 21

7. Annexure 22



INTRODUCTION

1. Printed circuit board assembly (PCBA), is the process of soldering or

assembly of electronic components to a printed circuit board (PCB). A

circuit board prior to assembly of electronic components is known as PCB.

Once electronic components are soldered, the board is called Printed

Circuit Assembly (PCA) or Printed Circuit Board Assembly (PCBA).

2. It has been observed during inspection, testing and

exploitationsoldering defect like dry solder, insufficient solder, bridging,

lumps solder, solder cracks etc. have been noticed. These

defects/inadequacies lead to the re-work of modules/boards which

reduces the reliability of the LRUs/equipmentsand affect the Quality and

reliability of the product. Hence, it is more important that controlling the

soldering processis a better method of Quality Assurance than post process

inspection (Assembly Inspection).This Directive is reference document

only the process can be modified depending on specific requirements.

DEFINITIONS AND BRIEF DESCRIPTION

3. Thru-Hole Electronic Components

Electronic componentsthat have leads coming out and are inserted through

tiny holes in the PCB or soldering are called thru-hole electronic components.

The assembly or soldering process for these components include wave

soldering and hand soldering

4. Wave Soldering

A PCB assembly process in which solder in the form of solder bar are put in

a high-temperature bath. This solder remains in the bath in molten form and

forms a wave at very high temperature. The range of temperature depends on

the type of solder.

Wave soldering process includes following steps:

Inserting of electronic components

Flux application

Preheat



Cleaning

Testing of assembled PCB as per the ATP

Once the wave soldering is done; the PCBA is cleaned and tested. If any

fault or solder joint is found, it is sent for rework, which is generally done

by hand.

5. Hand soldering

Hand soldering is performed in manufacturing units with less work load or in

rework / repair jobs. A good quality soldering station or soldering iron and

solder wire and flux are used in the process.

6. Surface Mount Technology (SMT)

Surface Mount Technology or SMT is a PCB as SMD components don’t have

leads or legs. They are mounted on the surface of the circuit board. The

equipment’s, electronic components and other soldering material used in this

assembly process are different from thru-hole soldering process.

7. Reflow Soldering

This is a process in which a solder paste (a sticky mixture of powdered solder

and flux) is used to temporarily attach one or several electrical components to

their contact pads, after which the entire assembly is subjected to controlled

heat, which melts the solder, permanently connecting the joint. Heating may

be accomplished by passing the assembly through a reflow oven or under an

infrared lamp or by soldering individual joints with a hot air pencil assembly

process for SMD electronic components.

8. Selective Soldering

This is the process ofsoldering components selectivelyin standalone

mode(leaded components) on existing populated printed circuit boards

(PCBs) and modules. Moreover,surface-mount technology (SMT) assembly

processmay damage adjacent component by heat of reflow oven. The selective

soldering process must be sufficiently precise to avoid the damage of existing

surrounding components.



SAFETY, HANDLING INSTRUCTIONS AND ASSEMBLY PREPARATION

9. For effective monitoring and uniform assembly process across all

assembly houses, reference template document has been prepared

(Annexure-E). The document has been prepared based on experience and

adopting the practices being followed by major electronics assembly

manufacturer.

10. All assembly and inspection operations are to be carried out by trained,

approved Operators as per JST-002 Standard and Inspectors as per IPC-610 D

Standard and DGAQA approval of Inspectors. The signature and stamp of the

operators and inspectors have to be affixed after completion of each

operation.

11. Assembly and other related processes to be carried out inassembly

areas where temperature is maintained at 24° C+/- 2° C & relative humidity

less than 60%.

Note: List of machinery and equipments indicated in the Production Route

Card (PRC) be in line with the production facility. The machine details are

indicative and may vary during actual production.

12. Verification of inputs as per part list &bom (kit inspection)

(a) Verify the parameters as per Kit Inspection Format (Annexure A to D).

(b) Verify the bare Printed Circuit Board (PCB) finish, Part No, Sl. No,

Group A and Group B certificates as per MIL-PRF-55110 or

equivalent standard.

(c)PCB manufacturing date to be indicated in the kit inspection report.

(d) Ensure all SMDs have been inspected as per AQL using 40X as part of

Inward Goods Inspection (IGI).



13. Collection of kit from stores

(a) All the electronic components to be packed in tubes or trays or

continuous strips and to be kept in Electro Static Device (ESD) covers.

(b) Integrated Circuits (IC’s) with formed Leads to be packed in ESD

Box.(To avoid Transit damage for Leads)

(c) For Moisture sensitive devices, details from the original pack (i.e.

Moisture Sensitive Level (MSL), Baking Details, Storage temperature and

humidity.) to be duplicated on the Moisture barrier bags used for

packing.

(d) ICs, which are moisture sensitive devices and should be packed in

moisture barrier bags and to be kept in de-humidifier.

(e) Verify for Shortage of Components.

(f) Verify for any Transit damage of components and PCB.

14. Storing of launched kit (if kit inspection is not taken up within

onehour)

(a) Store kit in de-humidifier (Relative humidity < 25%) placed in

temperature controlled room.

(b) Printed Circuit Boards (PCBs) and Moisture Sensitive Devices

(MSDs) should be kept in sealed dry packaging in de-

humidifier(Relative humidity 10%) placed in temperature controlled

room.

(c) Record the date of storing of kit.

15. Details of components with multiple batch codes

Enter the list of components having multiple batch codes.

(a) Part No. (b) Batch Codes

16. Identification & Listing of Components with Old Date Codes

(Greater Than 5 Years)



(a) List the components that are older than 5 years Leaded Components

Part No.Other types of components including chip components Part

No.

(b) Solderability test has to be carried out as per the J-STD 002

(solderability test for components leads, terminations, lugs and

wires) before assembly as per the approved documents by Assembly

department).

17. Collection of Items as per Part List (Pl)

Following parameters are to be verified: –

(a) Part Number of components

(b) Quantity

(c) Documents: Production order, General Assembly, Part List.

(d) Cleared kit offering letter/Memo/Inspection call slip& BOM

verification report

18. MOVEMENT OF MATERIALS TO ASSEMBLY HOUSE

Ensure the following: -

(a) PCBs are in sealed dry packing.

(b) All electronic components are packed in Electro Static Device

(ESD)bags/covers

(c) Moisture sensitive devices are in Moisture Barrier bags

(d) Formed ICs are kept in ESD sensitive transit boxes

PCB SOLDERING PROCESS

19. Marking Mark the module Sl. No. on the rear side of PCB using Epoxy

InkWhite (Part No.) and Catalyst (Part No.) or as per process stdPCB issue



level traceability has to be marked on the PCB as per Master Drawing Index

issue level.

(Note: Pot life of the mixture to be ensured).

The location of marking is indicated in the drawing.Curing time for the

mixture is 60 minutes at 930 C, Start time, End time, Shelf life expiry date of the

ink used, and Shelf life expiry date of catalyst used.

20. Storing of launched kit (If In case manufacturing not taken-up within

one hour)

Store the kit in de-humidifier (Relative humidity < 25%) placed in

temperature controlled room.PCBs and MSDs should be kept in sealed dry

packaging in de-humidifier (Relative humidity 10%) placed in temperature

controlled room. Endorse date of storing and date of assembly.

21. All assembly and inspection operations are to be carried out by trained

as per J-STD 002 or equivalent approved operators and inspectors having IPC

610 D or equivalent certificate holder only. The signature and stamp of the

operators and inspectors have to be affixed after completion of each

operation.

22. Assembly and other related processes have to be carried out in areas

where temperature is maintained at less than 26 ° C& relative humidity less

than 60%.

23. Pre-heating/baking of PCB

(a) Pre-heat the PCB (Part No.) 1000 C for 10 Hrs to remove moisture

and gaseous pollutants as per the process standard as defined in the

process document.

Note: Check for bow and twist (war page) on the PCB. The bow and

twist should be less than 0.75%. (Ensure prebaked PCBs are taken for

soldering within 3 days of pre-baking under storage condition 200 C and

30% RH).

(b) Date of Pre-Heating PCB shall be endorsed in PRC



24. Degolding of IC

ICs having gold plated leads are to be De-Gold for better Solderability as per

the process standard.

a) From at least 95% of the surfaces to be soldered of the through-

hole component leads with 2.54 µm [100 µin] or more of gold thickness.

b) From 95% of all surfaces to be soldered of surface mount

components regardless of gold thickness.

c) From the surfaces to be soldered of solder terminals plated with

2.54 µm [100 µin] or more of gold thickness.

25. A double tinning process or dynamic solder wave may be used for gold

removal prior to mounting the component on theassembly

26. Baking of moisture sensitive devices

IC which are having moisture sensitive, carryout the following baking

operation to dry the SMD packages as per J-STD-033801.

27. For different moisture level floor life is as mentioned in table below

shall be followed: -

Level Floor life 1 Unlimited at ≤ 300 C 85% RH

2 1 Year

Temp range 300 C 60% RH

2a 4 Weeks

3 7 Days

4 3 Days

5 2 Days

5a 1 Days

6 Mandatory bake before use. After bake, must be reflowed within the

specified time limit.

28. The moisture sensitive devices which floor life exceeded shall be baked

as per the process document.

29. Tinning of components and solderability test for components

which are more than 5 years old



(a) For leaded components. Carryout Solderability test for

leaded components as per Process Standard,prior to assembly.

(b) For other types of components. Carryout Solderability test as

per the process document for old components other than leaded

components which are more than 5 years old. If the component passes

the Solderability test, entire batch of component can be used for

production.

30. Mounting of SMD components on top side

(a) Solder paste details:

Use the solder paste as per the specification.

(i) Make:

(ii) Part No.

(iii) Shelf Life expiry date of Solder paste.

(b) Solder paste thawing and softening

Keep solder paste in solder paste softener machine and stir for 3

minutes.

(c) Screen Printing

Screen print the solder paste using stencil in the screen-printing

machine. Squeezing is done once in both forward and reverse direction.

Screen printing machine details are Make, Model and Location. Ensure

the PCB is taken up for reflow soldering within 8 hours of deposition of

solder paste.

(d) Solder paste height verification

Check for solder paste height using Z check meter or equivalent.Solder

paste height should be between 5 +/- 1.0 mil.

(e) Placement of SMD components

Place SMD components using automatic pick and place machine as per

the program detail. Component shall be mounted without obstructing

the terminations of the other components and parts.Ensure that polarity

and part marking is maintained while mounting thecomponent.

Components are to be mounted on PCB top side using pick and place

machine.



(i) Program number.

(ii) Version.

(iii) Date of carrying out the process:

(iv) Starting time:

(v) Ending time:

Machine details are Make, Model and Location.

Calibration status of (please tick)

Solder Paste softener machine : Yes/No

Screen printing machine : Yes/No

Screen print height measurement machine : Yes/No

Automatic Pick and place machine : Yes/No

Note: Clean the solder stencil using Isopropyl Alcohol (IPA) and blow

with high pressure compressed air before and after screen printing.

31. Visual inspection

Inspect the boards where components have been placed with40 X magnifier to

check for component missing, wrong value, and polarity reverse, extra

components, marking erased on the components and PCB.

32. Re-Flow Soldering

If the reflow soldering for the above board is to be carried out for the first

time, arrive at the reflow solder profile after carrying out trails on 3 boards on

different days and if it is already arrived, follow the steps indicated below,

Re-flow solder as per the Thermal profile indicated below:-

Program number:

Version:

Temp @ Zone 1:

Temp @ Zone 2:

Temp @ Zone 3:

Temp @ Zone 4:

Temp @ Zone 5:

Temp @ Zone 6:



Temp @ Zone 7:

Temp @ Zone 8:

Conveyer speed:

Reflow profile data will be arrived after conducting trails. Ensure reflow

soldering is carried out within 8 Hrs of deposition of solder paste.

Date and Time of carrying out Reflow soldering:

Reflow machine details are follows:-

Make:

Model:

Location:

Note: Thermal profiler to be used for each batch to validate the thermal

profile obtained during the approval of the above reflow profile.

Thermocouple point to be soldered at Top side and resister pack (R-

PACK) as per the work instruction.

Thermal profile obtained above should be compared with original

profile (reference board).

Re-flow profile used for soldering are to be attached to Production Root

Card (PRC) of each assembled PCBs.

33. Cleaning

Clean the PCB by dipping in Isopropyl Alcohol (IPA) with ESD brush to remove

flux residues and other contaminations within 30 minutes of soldering.

34. Automatic Optical Inspection (AOI)

AOI machine details are as follows: -

Make:

Model:

Location:



Following details to be checked in AOI:-

Component placement:

Component orientation:

Component marking as per BOM:

QM to maintain Assembly inspection report:

Work Instruction to be followed:

Assembly Inspection Report (AIR) No:

35. Mounting of SMD components on rear side

The procedure followed for mounting of SMD Components as per above para

No. ‘G’ should be followed for rear side also.

36. Manual Soldering (Rework)

Carryout rework manually asper the work instruction.

37. Re-Inspection

Verify whether rework has been carried out and parts can be released for next

operation.

38. Mounting of Connectors

(a) Pre Tin the leads of the connector by dipping in solder bath.

(b) Mount the Connectors. Apply torque on screw as per the GA and

clean the solder joints with IPA solution.

39. Lead forming of ICs

Form leads for IC using lead forming tool for IC, Use Tool No.----- and Work

Instruction------

40. Pre Baking Of ICs

The ICs which are to be soldered manually in isolation (which cannot be

carried out reflow soldering), following procedure to be followed:

Bake the IC No. -----

Time started --------



Time completed ------

41. Apply Loctite No

Apply Loctite No. --- where ICs is bonded to the PCB as per Work

Instruction No. --- .

Loctite No. ---- adhesive comes in 2 parts

Adhesive (P/N --- )

Activator for Adhesive (P/N ---- )

Apply Loctite by following instruction in the area between ICs and PCB.

(i) Bond surfaces should be clean and free from grease.

(ii) Use applicator to apply the activator to the surface to be bonded.

(iii) After the solvent evaporates, the active ingredients will appear

wet, and will remain active for up to 2 hours after application,

Contamination of the surface before bonding should be prevented.

(iv) Apply adhesive to the un-activated surface.

(v) Secure the assembly, and wait for the adhesive to fix

(approximately 5 minutes) before any further handling. Full cure occurs

in 24 hours.

(vi) The amount of adhesive applied to the part should ensure a

minimum coverage of 90% of the area under the device and should be in

contact with the bottom of the part.

(vii) The dispensing of application of the adhesive should be done as to

minimize air entrapment.

(viii) Ensure the adhesive should not interfere with the footprint pads

or the device leads.

(ix) Shelf life of Adhesive and Activator shall be ensured.

42. Potting of Vibration Sensitive Components

Pottingof vibration sensitive components to be carried out by using MIL

approved RTV compound as per the process document.

43. Alignment and Spot Soldering of ICs



Ensure curing time of 24 hours is completed for the adhesive before taking up

for soldering. Also, care should be taken so that the temperature on the

adhesive does not cross 1250 C while soldering.

44. Manual soldering

Manual soldering of ICs under 10X magnification as per the Process Standard

and Work Instruction.

45. Jumpers and Short Connections Zero Ohm Components

Solder the jumpersand Pads of Components as per General Assembly (GA) and

Work Instruction. Nos. of Jumpers will be decided by designer and will be

approved by RCMA with DGAQA consultation. The same will be reflected in GA

drawing.

46. Cleaning

Clean the boards with IPA solution using ESD brush within 30 minutes of

soldering and record soldering completion time&cleaningtime.

47. Physical Inspection

Verify the following under 40X magnification or as mentioned in

the process standard.

Soldering quality.

Soldering defects.

Component damage.

Foreign Object Debary (FOD).

QM to maintain Assembly Inspection Report.

48. Application of jet melt

Apply Jet Melt on to IC as per work instruction and record Start Time ; End

Time and Shelf life expiry period.

49. Mounting of card lock

(a) Mount the card lock on card lock slot.

(b) All screw should be mounted using Loctite.

(c) Apply Torque as specified in process standard.

(d) Record Shelf life expiry period of Loctite.



50. Test as per ATP

PCBA testing has to be carried out as per ATP.

51. Screening of assembled PCBs which are having; industrial grade

components

The PCBs/Modules having Industrial Grade Electronics Components shall be

screened as per the JSG 0667: 2005 (Reaffirmed 2011). Following screening

operation carried out:

(a) Stabilization bake at + 850 C for 24 Hrs.

(b) Thermal Shock.Thermal shock at - 400 C and + 850 C with 30

minutes dwell time. Carryout for 10 cycles and ensure transfer time is 2

minutes.

(c) Power-on Burning. PCB shall be maintained at maximum rated

operating temperature with tolerance +- 50C for 48 Hrs in power ON

condition and functional test to be carried out every five hours.

52. Rework

Carryout rework as per assembly inspection report.

53. Re-Inspection

Verify whether rework has been carried out and parts can be released for next

operation.

54. Cleaning

Clean the PCB using Iso Propyl Alcohol (IPA) as per Process Standard (PS).

The three tank cleaning system as detailed below:

(i) Dip the PCB assembly in ‘Tank-1’ for 5 minutes.

(ii) Wear antistatic gloves and clean the PCB using antistatic brush.

(iii) Shift the PCB assembly to ‘Tank-2’ which has in dipped condition

for 3 minutes.

(iv) Dip the PCB assembly in ‘Tank-3’ for 3 minutes.

(v) Dry the PCB in clean air circulated oven 55 (+/- 5)0 C.

Note: The solvent in Tank-1 has to be discarded when the boards failed

to meet the resistivity test of solvent extract or sodium chloride salt



equivalent ionic contamination test as specified in QS. Cleaning of the

PCBs also can be carried using De-Greasing Machine.

55. Resistivity check

Carry out the resistivity check on one representative sample of each printed

wiring board assembly type processed during each production shift.Check as

per Quality Standard (QS), QM department to maintain the report/record after

carrying out the test.

56. Conformal Coating Process

Mask the connectors and card lock mounting surface with masking tape and

carry out Conformal Coating as per Process Standard. Record the following

parameters:

Date of process;Start time;End time &Curing temperature

57. Removal of masking

Remove the masking done for conformal coating carefully without disturbing

the Coating.

58. Conformal coating inspection

Verify following parameters: -

(a) Coating coverage (This checked under UV lamp).

(b) Peel off, Blow Holes and Bubbles under 4X magnification.

(c) Coating Thickness using instrument.

(d) Masking area as indicated in drawing are not coated with the

coating material.

(e) Wavy pattern to be verified.

(f) QM department to maintain Inspection Report.

59. Functional testing

Module/PCB to be tested as per ATP and Testing department to maintain

Testing Reports / Records.

60. X-ray Inspection



Carry out X-ray inspection for checking the soldering quality and to verify any

shorts in the following devices.

Integrated Circuits (ICs) including BGAs.

Crystal Oscillator.

Resistor Network.

61. High resolution photo

High resolution photo to be taken and soft copy of the same to be maintained

by Quality Manager (Assembly Inspection) [QM (AI)] Department.

62. PCB handling and transportation

The following procedure has to be followed for handling the PCB assemblies

during transportation

(a) Each PCB assembly should be packed and vacuum sealed in

antistatic aluminium foil cover with desiccant.

(c) Antistatic box with partition for holding one PCB assembly per

partition with adequate antistatic foam or bubble sheet to give

cushioning effect.

DOCUMENTATION & REFERENCES

All the documents used for manufacturing of the above PCB assembly including PRC to be scanned and softcopy of the same to be maintained by QM (AI) Department. Check list Kit Inspection Document. Production Order, General Assembly (GA), Part List, ATP for Modules / LRUs BGA. Part No Process Standards List of documents that will be available as part of manufacturing the above PCB assembly (Data Pack) Kit Inspection Report. Screening Report of ICs.



Reflow profiles followed for component side and solder side. AOI report after reflow soldering on component side and solder Side. Report of visual inspection using 40X magnification. Inspection report after manual soldering of ICs and connectors. X-ray inspection report. Inspection report after thermal shock. Test reports for the tests conducted as per ATP. Acrylic conformal coating inspection report. Filled PRCs, with signature and seal of approved operators andinspectors. High resolution photos of assembled PCBs (both sides) onebefore conformal coating and other before dispatch. All AIRs pertaining to the non-conformities observed duringproduction. Consolidated List of all non-conformities (NCR No. / AIR No.)observed during Material Inspection, Assembly Inspection andtesting. Certificate from Head, Quality Manager (QM) for having verified the disposition on Non-Conformances (NCs).

CONCLUSION

The document has brought out systemic procedures / practices that will help

all the stakeholders to ensureQuality Assurance (QA) during Soldering Process

with documentary evidence that specified quality requirements have been

met. Though, the primary responsibility of ensuring the quality of the outgoing

product will continue to rest with the main contractor. These procedures will

enhance the quality of final product. Strict adherence to these procedures is

expected to further enhance the confidence of our esteemed customers of

Armed Forces for keeping our flying machines in the highest order of

operational readiness.

NOTE: Suggestions for further improvement/amendment in this document

are welcome and may be addressed to the following;



Directorate General of Aeronautical Quality Assurance

(Attention: Director / Tech Coord)

‘H’ Block, New Delhi-110 011

E-mail: [email protected]



Annexure ‘A’

KIT INSPECTION FORMAT (ELECTRICAL/ELECTRONICS)

REQUIREMENT AS PER BILL OF MATERIAL (BOM)

BOM Sl. No Part No. / Type No.

Description OEM /

Manufacturer Part No.

Qty. / Set Lead Finish

Component Category

(MIL / QML / QPL / LCSO /

Industrial / Automotive

Component grade /

Operational Temp and

Storage



Annexure ‘B’

KIT INSPECTION FORMAT FOR ELECTRONICS COMPONENTS

Data of received part

GR No

Manufacturer

Manufacturer

Part No. marking

on the item/ Pack/ COC

On item marking

Date code/ batch code

COC (OEM/ OEM

Franchises

Test reports/ Material Analysis Report

Qty. / offered/c

hecked

Expiry Date

ESD or

Non ESD

MSD of

Non MSD

ROHS or Non ROHS

Pack. Type

Lead Finish/ Solder

coated/Gold

plated / Surface Finish

and Thickne

ss

Nos. of

Pins

Visual Inspection / Testing at MI

Visual Inspection / Corrosion /

rust / pitting / scratches /

cracks

Dimension/Size

Remarks



Annexure ‘C’

KIT INSPECTION FORMAT (MECHANICAL)

Raw Material

Batch No.

Material Specification /

Material Code

Spectrometric

Verification of Material

Manufacturing

Process of Items

Heat Treatment/brazing

annealing/forging

etc. of the item,

Process and Batch

No.

Mechanical properties

test on samples

(heat treatment)

Non Destructive Testing on

the component

s

Micrometric Examination

Surface Treatment

Functional / Fitment

Test

Any special

test

Final acceptance / Itemization

/ Tag Generation

Preservation Details / Tag Endorsement

Visual Inspection

before assembly / detail part inspection

for assembly

Remarks



Annexure ‘D’

KIT INSPECTION FORMAT (CONSUMABLES) Raw

Material Batch No.

Material Specification / Material Code

Part No. Nomenclature

Date of Manufacturing

Shelf life/Date of Expiry

Qty per packing

Total packed Qty

Storage Conditions



Annexure ‘E’

PCB ASSEMBLY TEMPLATE

Sl. No.

Operation Number

OPERATION Assembly carried out by (sign & date with

apex approved

stamp)

Verified by QM

(AI) (sign & Date

with apex approved

stamp)

Remark

1. KIT INSPECTION (AQA Directive 06/2018) As per the Appendix A ; B ; C & D

2. STORING OF LAUNCHED KIT (IF IN CASE MANUFACTURING NOT TAKENUP WITHIN ONE HOUR)

Store kit in de-humidifier (Relative humidity < 25%) placed in temperature controlled room.

PCBs and MSDs should be kept in sealed dry packaging in de-humidifier (Relative humidity 10%) placed in temperature controlled room.

1. Date of storing : __________________

2. Date of assembly : __________________



Annexure ‘E’ Sl. No.

Operation Number


apex approved

stamp)

Verified by QM

(AI) (sign & Date

with apex approved

stamp)

Remark

3. DETAILS OF COMPONENTS WITH MULTIPLE BATCH CODES Enter the list of components that are offered to Kit Inspection with multiple batch

codes

1.P/n : …………………………………….

Batch Codes : …………………………………………..

1.P/n : …………………………………….

Batch Codes : ……………………………………………

1.P/n : …………………………………….

Batch Codes : …………………………………………

4. IDENTIFICATION AND LISTING OF COMPONENTS WITH OLD DATE CODES (GREATER THAN 5 YEARS)

List the components that are older than 5 years Leaded Components –

P/n :_______________________________

Other types of components including chip components

P/n :_______________________________

(Solderability test has to be carried out before assembly as per operation no: -

----- by Assembly department)



Annexure ‘E’

Sl. No.

Operation Number


apex approved

stamp)

Verified by QM

(AI) (sign & Date

with apex approved

stamp)

Remark

5. COLLECTION OF ITEMS AS PER PART LIST (PL)

Following parameters are to be verified,

1. Part Number of components

2.Quantity

3. Documents: Production order, General Assembly, Part List.

4.QA cleared kit inspection report

6. MOVEMENT OF MATERIALS TO ASSEMBLY HOUSE Ensure the following

a. PCBs are in sealed dry packing.

b. All electronic components are packed in ESD sensitive covers

c. Moisture sensitive devices are in Moisture Barrier bags

d. Formed ICs are kept in ESD sensitive transit boxes




Operation Number


apex approved

stamp)

Verified by QM

(AI) (sign & Date

with apex approved

stamp)

Remark

7. MARKING

Mark the module Sl. No. ________ on the rear side of PCB using Epoxy Ink white

(P/n------ ) and Catalyst )P/n ----- )

PCB issue level traceability has to be marked on the PCB as per Master Drawing

Index issue level.

(Note : Pot life of the mixture : 4 Hours )

The location of marking is indicated in the drawing.

Curing time for the mixture is 60 minutes at 93 Degree centigrade.

Start time : ______________ End time : _________________

Shelf life expiry date of the ink used : _______________

Shelf life expiry date of catalyst used : ______________

8. PRE-HEATING OF PCB

Pre-heat the PCB (Part No. ---- ) for 1000 C for 10 hours to remove moisture and gaseous pollutants as per process standard (PS) Quality notification no

Note : Check for bow and twist (war page) on the PCB. The bow and twist should be less than 0.75%. Ensure prebaked PCBs are taken for soldering within 3 days of pre-baking under storage condition 200 C and 30% RH. Date of Pre Heating PCB:



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9. DEGOLDING OF ICs ICs is having gold plated leads Carryout Manual De-Golding on IC as per the process standard

10. BAKING OF MOISTURE SENSITIVE DEVICES IC which are having moisture sensitive, carryout the following

Bake operation to dry the SMD packages as per J-STD-033B01

IC which are having moisture sensitive level 3 and has a floor life of 168 hours take

out of moisture barrier bag at factory ambient temperature 300 C / 60 RH.

Bake the IC to 1250 C for 7 hours, if the floor life has been exceeded by ≤ 72 hours

OR

Bake the IC to 1250 C for 96 hours, if the floor life has been exceeded by > 72 hours

Baking Start Time : -----

Baking End Time : ------




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11. TINNING OF COMPONENTS AND SOLDERABILITY TEST FOR COMPONENTS WHICH ARE MORE THAN 5 YEARS OLD For leaded components: Carryout Solderability test for leaded components as per process standard prior to assembly (Sample component can be assembled on a trial board also). If the components are unable to be soldered properly, they are to be tinned and soldered during assembly. A record of the tinning of these components to be maintained. For other types of components: Carryout Solderabilitytest for all components other than leaded components which are more than 5 years old. If the component passes the Solderability test, entire batch of component can be used for production.




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12 MOUNTING OF SMD COMPONENTS ON TOP & REAR SIDE

(a) Solder paste details: Use the following solder paste Make:- ---------------, part number ---------- (combination Sn63, Pb37 with no-clean formula) Flux content – 10%, type III Shelf life expiry date of Solder paste : _______________

(b) Solder paste thawing and softening: Keep solder paste in solder paste softener machine and stir for 3 minutes. Solder paste softener machine details are as follows,

Make : ---------------- , Model : ----------------, Location: ---------------

(c) Screen printing: Screen print the solder paste using stencil (stencil Part no: -----) in screen printing machine. The profile details are as indicated below,

Program number:………………………………. Squeeze pressure : ……………………………….




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Squeezing is done once in both forward and reverse direction. Screen printing machine details are as follows,

Make : ---------------- , Model : ----------------, Location: ---------------

Ensure the PCB is taken up for reflow soldering within 8 hours of deposition of solder paste

(d) Solder paste height verification: Check for solder paste height using Z check meter or equivalent . Solder paste height should be between 5 +/- 1.0 mil

Solder paste height measured is _____________________

(e) Placement of SMD components: Place SMD components using automatic pick and place machine. The program details as indicated below Component to be mounted without obstructing the terminations of the other components and parts. Ensure that polarity and part marking is maintained while mounting the component as per GA and Process standard. Components are to be mounted on PCB top side using pick and place machine. Program number : ----------------------------- Version :------------------------------- Date of carrying out the process : ------------------------

Starting time : --------------------------- Ending time : ---------------------------



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Pick and place machine details are as follows, Make : ---------------- , Model : ----------------, Location: -------------- Calibration status of (Please tick)

Solder Paste softener machine : YES / NO

Screen printing machine : YES / NO

Screen print height measurement machine : YES / NO

Automatic Pick and place machine : YES / NO

Note : Clean the solder stencil using Iso Profile Alcohol (IPA) and high pressure compressed air before and after screen printing .

13. VISUAL INSPECTION Inspect the boards where components have been placed with 40 x magnifier to

check for component missing, wrong value, polarity reverse, extra component

places, wrong orientation, damaged components, marking erased on the

components and PCB.




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14. RE-FLOW SOLDERING: If the reflow soldering for the above board is carried out for the first time, arrive at the reflow solder profile after carrying out trails on 3 boards on 3 different days and if it is already arrived, follow the steps indicated below Re-flow solder as per the Thermal profile indicated below , Program number : --------------------------- Version : ------------------------------- Temp @ Zone 1 : Temp @ Zone 2 : Temp @ Zone 3 : Temp @ Zone 4 : Temp @ Zone 5 : Temp @ Zone 6 : Temp @ Zone 7 : Temp @ Zone 8 : Conveyer speed :



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Reflow profile data will be arrived after conducting trials. Ensure reflow soldering is carried out within 8 hours of deposition of solder paste. Date & Time of carrying out Reflow soldering : _________ Reflow machine details are as follows, Make : ---------------- , Model : ----------------, Location: --------------- Note:- Thermal profiler to be used for each batch to validate the thermal profile obtained during the approval of the above reflow profile. Thermocouple point to be soldered at following locations Top side and R-PACKs Thermal profile obtained above should be compared with original profile. Re-flow profile used for soldering are to be attached to Production Root Card (PRC) of each assembled PCBs

15. CLEANING Clean the PCB by dipping in Iso- Propyl Alcohol with ESD brush toremove flux residues and other contaminants within 30 minutes ofsoldering.




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16. AUTOMATIC OPTICAL INSPECTION AOI machine details are as follows, Make : ---------------- , Model : ----------------, Location: --------------- Following details to be checked in AOI, 1. Component placement. 2. Component orientation 3. Component marking as per BOM QM to maintain Assembly inspection report

Work Instructions to be followed.

Assembly Inspection Report (AIR) No.-----------------------------

17. VISUAL INSPECTION

Inspect the boards where components have been placed with 40 x magnifier to

check for component missing, wrong value, polarity reverse, extra component

places, wrong orientation, damaged components, marking erased on the

components and PCB.

Assembly Inspection Report (AIR) No : _____________________



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18. MANUAL SOLDERING

Carryout rework as per assembly inspection report AIR No :_______________

19. RE-INSPECTION

Verify whether rework has been carried out and parts can be released

for next operation.

20. MOUNTING OF CONNECTORS

(a) Pre Tin the leads of the connector by dipping in solder bath

(b) Mount the connector by using Screws and Washers. Apply specified torque on screw as per GA/Process Standard/Work Instruction. Solder the connector on to the PCB as per GA/PS/WI and clean the solder joints with I P A solution.

21. PRE BAKING OF ICs

Bake the IC at 1250 C for 48 hours

Time started : __________________

Time completed : _________________



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22. LEAD FORMING OF ICs

Form leads for IC using lead forming tool

For IC , USE TOOL ( No : ------ ) and Work Instruction No.----------------------

23. ALIGNMENT AND SPOT SOLDERING OF IC

Ensure curing time of 24 hours is completed for the adhesive before taking up for

soldering. Also, care should be taken so that the temperature on the adhesive does

not cross 125 degree centigrade while soldering.

24. MANUAL SOLDERING OF under 10 x magnification IC

Manually solder ICs under 10 x magnification, and ICS used on to the

board using Item ( P/n : ----) and RMA flux ( P/n -----). Avoid swapping of ICs,

which are having same package and same part no. Mask the connectors which are

close to the ICs.

25. JUMPERS AND SHORT CONNECTIONS ZERO OHM COMPONENTS

Solder the wire of item no: (P/n:----) across the pads of components

Solder the wire of item no : (P/n: -----) manually as per General Assembly drawing

(GA).




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26. APPLY LOCTITE NO. ---------

Apply loctite No. ----- where ICs is bonded to the PCB as per Work Instruction. Loctite No. ----------- adhesive comes in 2 parts Adhesive (P/n : ---------------------) Activator for Adhesive ( P/n : ------------------------) Apply Loctite No.----- by following the below instruction in the area between ICs and the PCB a. Bond surfaces should be clean and free from grease. b. Use applicator to apply the activator to the surface to be bonded. c. After the solvent evaporates, the active ingredients will appear wet, and will remain active for up to 2 hours after application. Contamination of the surface before bonding should be prevented. d. Apply adhesive to the inactive surface. e. Secure the assembly, and wait for the adhesive to fix/bond (approximately 5 minutes) before any further handling. Full cure occurs in 24 hours. f. The amount of adhesive applied to the part should ensure a minimum coverage of 90 % of the area under the device and should be in contact with the bottom of the part. g. The dispensing or application of the adhesive should be done as to minimize air entrapment. h.Ensure the adhesive should not interfere with the footprint pads or the device leads . Shelf life of Adhesive : ________________________ Shelf life of activator : ________________________



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27. CLEANING

Clean the boards with IPA solution using ESD brush within 30 minutes of soldering.

Soldering completion time : __________________

Cleaning time : __________________

28. PHYSICAL INSPECTION

Verify the following under 40x magnification,

1. Soldering quality

2. Soldering defects.

3. Component damage.

4. Foreign Object Debary (FOD).

QM to maintain Assembly inspection report

AIR No : ___________

29. REWORK

Carryout rework as per assembly inspection report

30. RE-INSPECTION

Verify whether rework has been carried out and parts can be released for next operation.




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31. APPLICATION OF JET MELT

Apply Jet Melt on to IC as per work instruction: Starting time : ____________________ Ending Time : _____________________ Shelf life expiry period : ________________________

32. MOUNTING OF CARD LOCK

1. Mount the card lock on card lock slot.

2. All screws should be mounted using Loctite no.---- (Make: ----------).

3. Torque applied as specified in process standard.

Shelf life expiry period of Loctite : ______________________

33. REMOVAL OF MASKING Remove the masking done for conformal coating carefully without disturbing the coating.

34. X RAY INSPECTION

Carry out X-ray inspection for checking the soldering quality and to verify any

shorts in the following devices

Integrated Circuits

Crystal Oscillator

Resistor Network



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35. MOVEMENT OF PCB ASSY FROM ASSEMBLY HOUSE

The following procedure has to be followed for handling the PCB assemblies during

transportation

a. Each PCB assembly should be packed and vacuum sealed in antistatic aluminium

foil cover with desiccant.

b. Antistatic box with partitions for holding one PCB assembly per partition with

adequate antistatic foam or bubble sheet to givecushioning effect.

36. PHYSICAL INSPECTION

Following verifications done under 40x magnification,

1. Component damage.

2. FOD.

QM to maintain Assembly inspection report

AIR No : _______________

37. TEST AS PER ATP

To be verified by Testing personnel

Card testing has to be carried out as per ATP Document No. ; Issue No. and Date




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38. SCREENING OF assembled PCBs which are having; INDUSTRIAL GRADE components. Industrial Grade Electronics Components shall be screened as per the JSG 0667: 2005 (Reaffirmed 2011). Following screening operation carried out: (a) Stabilization bake at + 850 C for 24 Hrs.

(b) Thermal Shock: Thermal shock at - 400 C and + 850 C with 30 minutes dwell time. Carryout for 10 cycles and ensure transfer time is 2 minutes.

(c) Power-on Burning: PCB shall be maintained at maximum rated operating temperature with tolerance +- 50 C for 48 Hrs in power ON condition and functional test to be carried out every five hours.

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39. RESISTIVITY CHECK

Carry out the resistivity check on one representative sample of each printed wiring

board assembly type processed during each production shift.

Check as per Quality Standard (QS) / Process Standard (PS).

QM department to maintain the report / record after carrying out the test

40. CONFORMAL COATING PROCESS

Mask the connectors and card lock mounting surface with masking tape (P/n ---) as

per details given in the GA.

Setting :

Mix Coating material (Item no: ---) and thinner (Item no : ---) in the ratio 1:1.

Check for Viscosity. Ensure Viscosity 18 +/-4 Sec in Ford cup no 04 (100 ml).

Spray the mixture on a test sample / aluminium plate from a distance of 150 to 200

mm (Air pressure 7 psi).

Allow the board to air dry for 10 min and cure (@ 75 Deg +/- 3 Deg, 30 mins for

Humiseal material P/n : --- and 60 +/- 3 Deg, 45 mins for Conap material, P/n : -)

Spray to the other side and repeat.

Finish shall be smooth, homogeneous and free from defects like blisters, pin holes,

peeling etc. Only after obtaining satisfactory results, production part should be

taken up.




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41. CLEANING

Clean the PCB using Iso Propyl Alcohol (Part no ----) IR grade in three tank cleaning

system as detailed below.

1. Dip the PCB assembly in ‘Tank 1’ for 5 mins.

2. Wear antistatic gloves and clean the PCB using antistatic brush.

3. Shift the PCB assembly to ‘Tank-2’ which has in dipped condition for 3 mins.

4. Dip the PCB assembly in Tank-3 for 3 mins.

5. Dry the PCB in clean air circulated oven 55( +/-5 )deg ( As per Process Standard

(PS )

Note : The solvent in Tank 1 has to be discarded when the boards failed to

meet the resistivity test of solvent extract or sodium chloride salt equivalent

Ionic contamination test as specified in QS. Cleaning of the PCBs also can be carried

using De- Greasing Machine



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42. CONFORMAL COATING INSPECTION

Following verifications are to be done

1. Coating coverage (This checked under UV lamp)

2. Peel off, Blow holes and bubbles under 4x magnification.

3. Coating Thickness using instrument

4. Masking area as indicated in drawing are not coated with the coating material.

QM department to maintain Inspection report

43. FUNCTIONAL TESTING

Module is tested as per ATP No.---------------------------------

Testing department to maintain Testing reports / records

44. HIGH RESOLUTION PHOTO

High resolution photo to be taken and soft copy of the same to be maintained by

QM (AI) Dept.

All the documents used for manufacturing of the above PCB assembly including PRC

to be scanned and softcopy of the same to be maintained by QM (AI) Dept.

AQA DIRECTIVE ON PCB SOLDERING PROCESS · ‘भभ’ भभभभभ, भभभ...

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Transcript of AQA DIRECTIVE ON PCB SOLDERING PROCESS · ‘भभ’ भभभभभ, भभभ...