Press Fit Rework

Project

Project Update

HDPUG Meeting

Düren, Germany 06/05/14

© 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

Background

• 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 for new components, boards and designs.

© HDP User Group International,

Inc.

Background cont.

Project Goals

• The goal with this project is to understand and to

document how rework affects press fit connection

strength and hole wall deformation 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

© HDP User Group International,

Inc.

Expected 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

© HDP User Group International,

Inc.

Flow Chart

• Basic work

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Inc.

Flow Chart cont. version 1

• Work for each chosen component,

surface finish and hole size

1x

or

2x

or

3x

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Inc.

Yes

No

Flow Chart cont. version 2

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Inc.

0x

1x

2x

3x

Flow Chart cont.

• Analyze

– Activities after 0x, 1x, 2x and 3x rework

© HDP User Group International,

Inc.

Test 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

© HDP User Group International,

Inc.

• The backplane connectors in the following series

will be used:

DIN 41612 reference pin (Molex) ZDHD (Erni)

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

Components

Operations per Package

• If two different surface finishes are chosen and min,

nom and max hole diameters are used for each

component:

– 20 x 6 = 120 components (a few extra are needed for

incoming inspection and measurement)

• Amount of press-in operations

– 120

• Amount of removals

– 16 x 6 = 96

© HDP User Group International,

Inc.

Need 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 give 24 boards

• Altogether 30 boards are needed

© HDP User Group International,

Inc.

Connector Header Drill Hole Size

Requirement Less than Nominal

Drill Nominal Drill Greater than Nominal

Drill

FCI ExaMax 0.0177" .425mm

0.01673" .45mm

0.01771" #77

0.0180"

Molex Impel 0.0177" .425mm

0.01673" .45mm

0.01771" #77

0.0180"

TE Strada

Whisper 0.42mm+/-0.013mm

(0.0165”) #78

0.0160" .425mm

0.01673" .45mm

0.01771"

Erni ZDHD 0.55mm +/-0.02mm

(0.02165”) #75

0.0210" .55mm

0.02165" #74

0.0225

Molex DIN41612 1.15mm +/-0.025mm

(0.0452”) 1.125mm

0.0433" 1.15mm

0.0453" #56

0.0465"

• Decided drill sizes:

Drill Sizes

• Suggested PCB parameters:

– Surface metallizations: ENIG and imSn

– Base material: Isola 370HR

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

– Amount of layers: 2

– Board thickness 1.8mm

– Outer copper layer thickness: 0.050mm

(±0.020mm)

– Max size 6”x 6” (~150mm x 150mm)

PCB Parameters

Impel, Molex ExaMezz, FCI

ZDHD, Erni

Hole Pattern Drawings

• 2 hole pattern

drawings still

missing!

• Max board size 6”x 6” in

order to fit in sealed

container

• Perform prior to cross

sectioning

• Which equipment to

use?

• How to probe when

there is no lead

protrusion?

Gas Tight Test

• Component and hole pattern drawing

for Strada Whisper

• Hole pattern drawing for DIN 41612

Needed in order to be able to design

test board!

Immediate Need

• Preliminary design of test board

– Performed at Ericsson

• Decide how to connect the leads for resistance

measurements for each component type’s gas

tight test

• Decide how to measure retention force after

rework for each component type

– EIA-364, TP05 (used in Molex test)

Next Step

• Order test board

– After agreed design

• Collect all components

– For the actual test there will be a need of at least

120 components of each type

• Collect all needed information about press parameters

and tooling

– Borrow some of the tooling?

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

test

Next Step Cont.

Plans for the Nearest Future

• Last hole pattern drawings and agreement

of all PCB parameters

– June 2014

• Finalized Design of Test Board

– July 2014

• Received all necessary rework information

and tools

– August 2014

• Start assembly and rework tests

– September 2014 © HDP User Group International,

Inc.

Test Questions

• Can we get all the tooling/components?

– Pay for some of the tooling?

– Pay for some of the components?

• Who shall manufacture the test board?

• Where shall the rework tests be performed?

• Who shall do the cross-sectioning?

• Who shall do the analysis?

© HDP User Group International,

Inc.

Team 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

Tentative Schedule

• Kick off - San José 2012

• Idea Stage - Q2 2012

• Definition - Q2 2014

• Implementation - Q3 2014

• Publish Report - Q1 2015

© HDP User Group International,

Inc.