press fit rework project project update hdpug meeting kawasaki, japan 10/12/14

Press Fit ReworkProject

Project UpdateHDPUG MeetingKawasaki, Japan 10/12/14

© HDP User Group International, Inc.

• Since late 60’s or early 70’s

• First press fit was a square peg into a round hole using a fixed geometry solid pin construction, original pin designed for 1.5 mm diameter finished holes

• Recent years, compliant pins, finished holes just 0.22 mm diameter

Source: Tyco Electronics

BackgroundBackground

• When performing press fit component rework, the plated holes and their annular rings could easily get damaged. Questions that need to be answered are:– How much hole wall deformation does one, or several,

rework(s) cause?

– How is the pin insertion force affected by the rework(s)?

– How is the pin retention force affected by the rework(s)?

– Will the gas tight connections be intact?

• There is a need to evaluate press fit component rework, especially for new components, boards and designs.


Background cont.Background cont.

Project GoalsProject Goals

• The goal with this project is to understand and to document how rework affects press fit connection strength, hole wall deformation and gas tightness for new high-speed press fit connectors

• 0, 1x, 2x and 3x rework shall be performed on assemblies with:– Different, new, high-speed, small pin sizes, connectors

– Three different hole sizes for each component (minimum, nominal and maximum specified diameters )

– Hole plating, ENIG and ImSn

– Moreover, standard board materials and designs shall be used


Expected OutcomeExpected Outcome

• The outcome of this project shall be a document that specifies how press-fit rework affects– Pin insertion force

– Pin retention force

– Hole wall deformation

– Gas tight connection

• The project shall tell which pin and design combinations that work well to rework and what strength and hole wall deformations that could be expected


Flow ChartFlow Chart


• Basic Work

Connector rework testConnector rework test


0x

1x

2x

3x

Total insertions & retentionsTotal insertions & retentions

• 24 populated boards


ImSn, min holes ImSn, nom holes ImSn, max holes

ENIG, min holes ENIG, nom holes ENIG, max holes

Gas Tight TestGas Tight Test

• The activities in the flow chart below shall be performed on X pins per component/5 components per board/24 boards

• After the gas tight test cross sectioning shall be performed on these boards


Contact ResistanceContact Resistance

© HDP User Group International, Inc. David Wice, Ciena

Cross SectioningCross Sectioning

• Use the boards from gas tight test for cross sectioning


Pin retention testPin retention test


0x

1x

2x

3x

Total insertions & retentionsTotal insertions & retentions

• 24 boards


ImSn, min holes ImSn, nom holes ImSn, max holes

ENIG, min holes ENIG, nom holes ENIG, max holes

Test ProcessesTest Processes

• Initial mechanical measurements of all used materials

• Insertion/Retention test–Demand on retention and insertion force in Telcordia GR-1217-CORE

• Visual inspection according IPC-001, IPC-610, Telcordia GR-78 R4-10, GR-1217-CORE and IEC 60352-5 (hole deformation, delamination etc.)–Directly after insertion–After rework–After retention of pins

• Electrical contact resistance measurements after aging (gas tight test) shall be performed for all components


• The backplane connectors in the following series will be used:

DIN 41612 reference pin (Molex)ZDHD (Erni)

ExaMezz (FCI) Impel (Molex) Strada Whisper (TE)

ComponentsComponents

Need of Components Need of Components

• If two different surface finishes are chosen, one base materials and min, nom and max hole diameters are used for each component:– 0x rework, 1 x 1 x 2 x 3 = 6

– 1x rework, 2 x 1 x 2 x 3 = 12

– 2x rework, 3 x 1 x 2 x 3 = 18

– 3x rework, 4 x 1 x 2 x 3 = 24

– 0x rework, 0 x 1 x 2 x 3 = 0 (pin retention test)




• Total component needs = 96 (a few extra are needed for incoming inspection and measurement)


Test BoardTest Board

• Test board design suggestion exists

• 100mm x 100mm side lengths


• Suggested PCB parameters:– Surface metallizations: ENIG and ImSn

– Base material: Isola 370HR

– Hole sizes: Min, Nominal, Max (if possible)

– Amount of layers: 6

– Distances between layers: L1-L2: 0.1mm, L2-L3: 0.5mm,L3-L4: 0.6mm, L4-L5:0.5mm, L5-L6:0.1mm

– Board thickness 1.8mm

– Outer copper layer thickness: 0.050mm (±0.020mm)

– Inner copper layer thickness: 0.017mm (+0.003/-0.007mm)

– L2, a full ground layer

– Board size: 100mm x 100mm

PCB ParametersPCB Parameters

Connector HeaderDrill Hole Size Requirement

Less than Nominal Drill Nominal Drill

Greater than Nominal Drill

FCI ExaMax0.0177" .425mm

0.01673".45mm

0.01771"#77

0.0180"

Molex Impel0.0177" .425mm

0.01673".45mm

0.01771"#77

0.0180"TE Strada Whisper

0.42mm+/-0.013mm(0.0165”)

#780.0160"

.425mm0.01673"

.45mm0.01771"

Erni ZDHD 0.55mm +/-0.02mm(0.02165”)

#750.0210"

.55mm0.02165"

#740.0225

Molex DIN41612 1.15mm +/-0.025mm(0.0452”)

1.125mm0.0433"

1.15mm0.0453"

#560.0465"

• Decided drill sizes:

Drill SizesDrill Sizes

Need of BoardsNeed of Boards

• One board for each hole size (min, nom, max) and surface finish (ENIG, ImSn) is needed for incoming board hole inspection/measurement– 3 hole sizes and 2 surface finishes give 6 boards

• Four boards are needed for each hole size and surface finish for the rework test (i.e. for 0x, 1x, 2x and 3x rework)– 4 boards, 2 surface finishes, 3 hole sizes, 1 base material give 24 boards

• Four boards are needed for each hole size and surface finish for the pin retention test (i.e. for 0x, 1x, 2x and 3x rework)– 4 boards, 2 surface finishes and 3 hole sizes give 24 boards

• Altogether 54 boards are needed


• Order test board– After agreed design

– Each connector manufacturer check “their“ hole pattern

• Collect all components– For the actual test there will be a need of at least 120 components of

each type

– Need of extra single pins for each connector type

• Collect all needed information about press parameters and tooling– Borrow the tooling?

– Find suitable site(s) to perform the press fit rework test

Next Step Next Step

Plans for the Nearest FuturePlans for the Nearest Future

• Finalized and agreed design of test board– Dec 2014

• Order test boards– Jan 2014

• Received all necessary rework information and tools– Jan 2014

• Start assembly and rework tests– March 2015


Test QuestionsTest Questions

• Who shall manufacture the test board?

• Where shall the rework tests be performed?

• Where shall the gas-tight test be performed?– Contact Research

• Who shall do the cross-sectioning?

• Who shall do the analysis?


Team ListTeam List

• Team List:

• Participating Companies:– Dell

– Philips

– GE

– Delphi

– Curtis Wright

– PWB Corp

– Nihon Superior

– Ericsson

– Alcatel-Lucent

– Multek

– Cookson © HDP User Group International, Inc.

– TTM

– Juniper

– ASUS

– Oracle

– Flextronics

– Plexus

– Cisco

– Fujitsu

– Ciena

– Isola

– IBM

– ASE

– Continental

– Panasonic

– Emerson

– IST Group

– Boeing

– Fujitsu

– ZTE

– Sytech

Team List 2014-03-10

Tentative ScheduleTentative Schedule

• Kick off - San José 2012

• Idea Stage - Q2 2012

• Definition - Q4 2014

• Implementation - Q2 2015

• Publish Report - Q4 2015


press fit rework project project update hdpug meeting kawasaki, japan 10/12/14

Documents

press fit component

x rework

max holesenig

nom holesenig

original pin

nom holesimsn

gas tight connections

hole wall deformations