There is an Exactalloy™ preform in the rightshape and size to improve your assembly operation, product reliability and quality. Get Technical support from Krayden Regarding Alpha product and its proper application method.

1. A L P H A
Exactalloy
™
Solder preforms
for product and process
improvement

2. There is an
Exactalloy™
preform in
the right
shape and
size to
improve
your
assembly
operation,
product
reliability
and quality.
2

3. C O O K S O N E L E C T R O N I C S
Each batch of Exactalloy™ preforms
is carefully examined under
magnification to assure compliance
with dimensional requirements.
Improved quality
and performance
Cookson Electronics Assembly
Materials’ experienced repre-
sentatives are ready to work
directly with your designers
Exactalloy™ solder preforms to recommend solder preforms
are the ideal solution to high- to provide maximum assembly
volume, precision-soldering efficiency, product quality, and
processes in electronic assem- improve your manufacturing
blies, sealed lighting, filtered processes.
connectors, multiple leaded
connectors, component manu- We can furnish Exactalloy™
facturing and the plumbing preforms in discs, rectangles,
industry. squares, rings, washers, sleeves
and washer arrays (linked A wide range of Cookson Electronics' unique
What are preforms? preforms). Your Cookson design choices flux coating process offers two
Electronics technical repre- distinct advantages over flux
Preforms are precisely formed sentative can help you specify Exactalloy™ preforms are avail- filled preforms: a flux-coated
pieces of solder, produced in the size and shape to achieve able in sizes from 0.020" to Exactalloy™ preform delivers
large quantities with very tight the maximum benefit for your 2.00" (squares, discs or washer flux to the area to be soldered
tolerances. There are almost soldering process. OD). Thickness can range from when it is needed most — just
unlimited combinations of .004" to 0.25". Generally, flux before the solder is melted, and
different preform shapes, Custom shapes can also be add-on represents .5% to 2.5% flux-coated solder is protected
sizes, combinations of solder produced to match specific by weight of the preform. from oxidation. Oxide-free
alloys and flux delivery systems. applications. Tooling charges solder yields better wetting
may apply to custom shapes and joint strength, and can
Preforms are commonly formed and sizes. eliminate the formation of
in 63/37 tin/lead solder. Both cold solder joints that can
lower melting point and higher have a severe impact on prod-
melting point alloys are also uct reliability. Flux coating is
available. See the Soft Solder limited to preforms at least
Alloys table on page 10 for a .007" (0.18 mm) thick. Thinner
list of the most common alloys preforms may lose their shape
used to produce Exactalloy™ in the fluxing process. See
preforms. Some solder alloys chart for available flux options.
cannot be used to produce
some preform shapes. High Available Flux Types
bismuth alloys, for example, FLUX TYPE INTERNAL EXTERNAL
can be very brittle, and cannot RMA (ROL1) yes yes
withstand rolling and stamp- RA (ROM1) no yes
ing processes required to form NC (ROL0) yes yes
some shapes. RSA (ROH1) no yes
WS (ORL0) yes no
Opposite: Exactalloy™ preforms can
be produced in thousands of shapes
and sizes, solving even the most
Both X-ray diffraction and wet analysis methods are
difficult soldering design challenge.
used to assure that every lot of Exactalloy™ preforms
meets or exceeds the metallurgical requirements of the
IPC and the customer. 3

4. There are numerous examples
where the use of Exactalloy™
preforms can optimize one
or both of the common mass
soldering techniques.
Eliminate hand
soldering
The use of preforms can pro-
vide a more consistent quality
alternative to repetitive hand
soldering applications. If core
wire is being used to hand
solder multiple leaded connec-
tors, or to solder a non-planar
area in a circuit assembly,
preforms often offer a better
solution.
Exactalloy™ preforms deliver
the exact volume of solder
required. They can be placed
exactly where needed, and
multiple solder joints can be
reflowed simultaneously using
a heat gun, or a reflow oven.
Low melting temperature
preforms are commonly used
to eliminate disturbance of
other solder joints already
formed on the assembly.
High-temperature preforms can
be used if the hand soldering
assembly is being performed
before conventional SMT or
wave soldering processes.
10/88/2 (Tin/Lead/Silver) or
96/4 (Tin/Silver) are common
choices for this application.
See the Soft Solder Alloys
table on page 10.
Precise control of foil thickness is a critical
step in providing the exact volume of solder
required. Here, linked arrays are used to
eliminate hand soldering on multiple-row
connector sets. Preforms also provide
more solder volume, eliminating
4 inefficient paste-in thru-hole processes.

5. C O O K S O N E L E C T R O N I C S
Exactalloy™ preform solutions provide a wide range of
advantages in electronic circuit assembly applications.
Step stenciling
Problem: In some SMT assem-
blies, larger volumes of solder
are required on one or more
surface mount pads. Traditional
co-planar paste stenciling will
not yield the solder volume
required. In this case, the
process engineer has two
choices, neither of which may
be acceptable: stencil more
paste onto the required pads
or use a second dispensing
process. The dispensing option
is often impossible in fine
pitch applications.
Paste-in thru-hole next consideration is the
diameter of the thru-hole or Solution: Place an Exactalloy™
Problem: In an attempt to via. The OD of the Exactalloy™ solder preform segment
eliminate wave soldering, washer must be at least .005" (square or rectangle) into the
many assembly processes use greater than the diameter of stenciled paste. Exactalloy™
solder paste to solder thru-hole the hole. The limit of the OD preforms are available in tape
components. The goal is to is usually the diameter of the and reel packaging. The pre-
eliminate wave soldering, and pad surrounding the plated form is sequenced in your
subsequent thermal stress thru-hole. pick and place process to be
resulting from multiple solder positioned prior to placement
reflow cycles. Given the ID and the OD, of the SMT component desig-
Cookson Electronics can man- nated for that pad.
Solder paste is very difficult to ufacture the washer to any
stencil over an open hole, and thickness from .004" to a limit Simply sequence the preform
dispensing adequate volumes of 110% of the ID. Using this placement prior to the compo-
of paste can be just as chal- technique, Exactalloy™ preforms nent requiring the additional
lenging. Thick, multiple layer can be engineered to meet or solder volume.
boards also make paste in exceed the IPC standard.
thru-hole processes more Above left: Cladded discs provide
difficult. Per IPC Standard B a simple method of soldering very
610, at least 75% of the space large components from the opposite
between the lead pin and the side of the board.
hole must be filled with solder.
Top right: Cookson Electronics can
Solution: The use of Exactalloy™ package preforms on tape and reel
washers or linked washer for use with common pick and
arrays eliminates the inherent place equipment.
problems of delivering enough
solder to meet the IPC standard. Left: Our extensive engineering
The design of the preform capabilities can turn your ideas into
begins with the inner diameter high-production reality. Bimetallic
of the washer. It should be solder sleeves are but one example
0.002" to 0.005" larger than of Cookson Electronics’ ability to
the OD of the lead pin. The engineer solder fabrication. 5

6. Flux-filled and flux-coated lead-free Reduce or eliminate
solder preforms are used by the wave soldering
major automobile lighting producers
to deliver the exact amount of solder, Problem: The primary assembly
in exactly the right shape, exactly process used is SMT. There
where it is needed. are still one or more thru-hole
components on the assembly
where the board must be run
through the wave to assure
a complete solder joint. The
second thermal cycle may
damage some of the paste joints.
Eliminating wave soldering
will reduce the cycle time of
each assembly.
Solution: After the paste has
been stenciled, and all of the
SMT components have been
placed, use a semi-automatic
technique to position flux-
coated preform solder washers
on the thru-hole component
leads. This completely elimi-
nates the wave soldering step,
increasing the production rate
and reducing rejects. (See the
connector jig schematic, on
opposite page.)
Sealed beam lighting
As the leader in lead (Pb) free
soldering, Cookson Electronics
has developed several alloys
that exceed today’s require-
ments for the elimination of
lead, which is the trend in this
industry. Both flux-coated
washers and flux-cored seg-
ments are used to automate
the placement of solder in
sealed beam lighting.
6

7. C O O K S O N E L E C T R O N I C S
See how Exactalloy™ preforms are providing innovative
solutions in actual applications.
provide an unlimited number Component TOP VIEW
OF FIXTURE
of beneficial solutions for the manufacturing
connector manufacturer.
CROSS SECTION
Capacitors OF FIXTURE
Pre-Soldered Connectors Preforms are used in both Ø Hole = Ø Washer
+0.15mm
Length hole = Washer
Exactalloy™ preforms can be surface mount and thru-hole thickness +25%
Preform washers are
automatically placed on con- component manufacturing. dropped into fixture.
nector leads, and the resulting Both axial and radial leaded Connector is placed in
fixture allowing preforms
to attach to connector
connector requires no addi- capacitors are manufactured pins.
tional paste or thru-hole sol- using solder preforms. A high
dering by the connector user. temperature alloy (Sn 95/Ag 5,
Your Cookson Electronics Sn 10/Pb 88/Ag2, Sn 5/Pb 85/
technical representative can Sb 10) is typical, to eliminate Hundreds of solder washers can
show you several methods of solder reflow when the capaci- be placed automatically by using
applying preforms to multiple tor is soldered to the final fixtures. Your Cookson Electronics
pin connectors. circuit assembly. High temper- technical representative can help
Exactalloy™ preforms deliver ature alloys allow for the use you design a fixture for rapid place-
exactly the right amount of Attaching Coaxial Connectors of thermal curing encapsulents ment of flux-coated washers on
solder, in the exact alloy, every Hand soldering can be elimi- as well. multiple-pin assemblies.
time. Consistent, reproducible nated as a high volume method
soldering is the real benefit to of soldering coaxial connectors Soldering lead frames to
the lighting industry. to cable ends. Several unique ceramic capacitor bodies with
solutions have been developed flux-coated Exactalloy™ pre-
Connectors by Cookson Electronics for forms can eliminate problems
attaching solder sleeves to bare associated with the use of
Filtered and Shielded wire ends. Coaxial connectors solder paste. Preforms also
Connectors can be slid over the preform offer the additional advantages
Exactalloy™ preform washers ring, followed by induction of delivering reproducible
are made in both a single alloy, reflow of the solder. Flux- volume, eliminating flux
and in laminated layers of a coated sleeves make this residue, increasing production
base metal and solder. A typical process highly efficient and speed and producing faster
application is attaching a ferrite reproducible. reflow cycle times.
EMI shield to a connector pin.
The pin is suspended in the
middle of the ferrite tube by Automatic placement of preforms
the unmelted base metal. The is often the key in reaping the
solder layers on either side of efficiency offered by automatic
the base metal form the solder soldering. In this application, a
joint. Similar technology is bowl feeder dispenses flux-coated
used to produce RFI shielded washers for subsequent placement
connector leads. Cookson and reflow.
Electronics’ lead-free alloys
and flux-coating processes
7

8. Using a solder preform to coat
the surface mount contacts
with solder in chip scale
capacitors eliminates dipping
heat-sensitive ceramics into
high melting point solder baths.
Thyristors
Exactalloy™ preforms are the
ideal metal to metal, and metal
to diode joining material. High
temperature alloys are used to
eliminate solder reflow during
the coating and curing of epoxy
encapsulents. Flux-coated
Exactalloy™ preforms (discs,
rectangles or squares) are
ideal for this application.
Rectifiers
Diode attachment with the
suitable preform alloy choice
makes high volume production
possible.
8

9. C O O K S O N E L E C T R O N I C S
Precise solder shapes can be used
as counterweights in analog
instruments.
Total Quality Management
Our is the driving force in the
design and manufacture of
ISO 9001 Cookson Electronics precision
Exactalloy™ preforms. Cookson
Electronics has earned ISO
certified 9001 certification for its
Exactalloy™ production facili-
Optoelectronics tin/lead/silver alloys, stamped
Indium-based alloys afford
into horseshoe-shaped pre-
forms, are used in automotive
quality ties. Comprehensive quality
controls include SPC (statisti-
cal process control), non-
excellent ductility, gold scav-
enging resistance, and low
rheostats and other hybrid
circuits to prevent catastrophic
program, destructive tests and random
sample analysis.
temperature soldering (where failures from excess heat.
needed) in this rapidly evolv-
ing market. Indium’s ductility
along with All incoming metals are exam-
Plumbing ined by spectrographic analysis
allows for soldering material
with large differences in their Lead-free Exactalloy™ preform
extensive and all alloy materials are
analyzed for content and purity
coefficient of thermal expansion. rings and washers are used to
Cookson Electronics’ technical
service personnel will help
solder internal plumbing joints,
and to automate the joining
tool making prior to in-house molten state
processing. Cookson Electronics
unique post-alloying batch
you specify the best alloy and
preform to improve your
of brass, copper, bronze and
tin plate materials. Cookson
capabilities analysis is used to identify
preforms by date, time, and
application. Electronics has several IAPMO
certified alloys for use in these have made materials used in manufactur-
ing. All materials, including
Hybrid Circuits applications. Washers up to
fluxes, are examined using
Solder based fuses are used
2" in diameter are available.
Larger rings can also be pro-
Cookson emission spectrography, X-ray
defraction, gas chromatography,
to protect high temperature duced flux-coated, flux-filled
circuits. Tin/lead and or plain. Electronics atomic absorption and classical
wet chemistry techniques.
the first The physical characteristics of
precision preforms, including
choice of dimensions, weight and uni-
formity, are checked meticu-
lously to ensure conformance
solder with customer specifications
and Cookson Electronics’ rigid
preform in-house standards.
users.
Connector manufacturers can attach
Exactalloy™ preform sets, providing
customers with ready-to-solder
assemblies. 9

10. Soft Solder Alloys Tin/Lead Phase Diagram
ALLOY MELTING TEMPERATURE RANGE
°F °C
TIN/LEAD
63Sn/37Pb 361 183 WETTING
RECO
MMEND URING
ED ALLOY TEMPERATURE D
60Sn/40Pb 361-379 183-190
50Sn/50Pb 361-421 183-216
40Sn/60Pb 361-460 183-238
10Sn/90Pb 514-576 268-299
5Sn/95Pb 581-594 305-312
SILVER BEARING
62Sn/36Pb/2Ag 355 179
96.5Sn/3.5Ag 430 221
95Sn/5Ag 430-473 221-245
10Sn/88Pb/2Ag 514-517 268-299
5Sn/92.5Pb/2.5Ag
92.5Pb/2.5Ag/5 In
549-565
572
287-296
300
Standard
97.5Pb/2.5Ag 579 304 Dimensional Tolerances
1Sn/97.5Pb/1.5Ag 588 309
DIMENSION TOLERANCE
SAC 305 Diameter ±0.002” (±0.051mm)
96.5Sn/3Ag/.5Cu 422 217 Length and Width ±0.005” (±0.127mm)
TIN/ANTIMONY Thickness
Up to 0.005” (0.127mm) ±0.0005 in (±0.0127mm)
100Sn 450 232 0.006 to 0.010” (0.152 to 0.254mm) ±10% of thickness
95Sn/5Sb 450-464 232-240 Greater than 0.010” (0.254mm) ±15% of thickness
99Sn/1Sb 453 234 Thickness (flux-filled)
LOW-TEMPERATURE Up to 0.010” (0.254mm) ±0.0015” (0.0381mm)
0.011 to 0.030” (0.279 to 0.762mm) ±15% of thickness
16Sn/32Pb/52Bi 204 96 Greater than 0.030” (0.762mm) ±10% of thickness but
48Sn/52In 244 118 not less than 0.0045”
50Sn/40Pb/10Bi 248-332 120-167 (0.1143mm)
43Sn/43Pb/14Bi 291-32 144-163 Horizontal Burr 0.005” (0.127mm) maximum
37.5Sn/37.5Pb/25In 274-358 134-181 Vertical Burr
50Sn/32Pb/18Cd 293 145 Up to 0.010” (0.254mm) 0.003” (0.0762mm) maximum
Greater than 0.010” (0.254mm) 3% but not to exceed
3Ag/97In 295 146
0.005” (0.127mm)
15Pb/5Ag/80In 298-300 148-149
GOLD BEARING
20Sn/80Au 536 280
10

11. C O O K S O N E L E C T R O N I C S
Use these drawings
to help specify
Exactalloy™ solder
preforms
OD
Min = .020” (0.508mm) The size ranges indicated
Max = 3.00” (76.2mm) on these drawings represent
ID the dimensions in which
Min = .008” (0.203mm) Exactalloy™ solder preforms
Max = OD – .010” (0.254mm)
are available. For information
T (Thickness) on preforms outside of these
Min = .002” (0.0508mm)
dimensions to meet your
Max = .110” (2.794mm)
specific application needs,
please contact your Cookson
Electronics Sales Representative
at 1-800-289-3797. You may
also fax drawings to us at:
S (Side) 1-814-944-8094, or contact
Min = .020” (0.508mm) us on our web site at:
Max = 2.30” (58.42mm)
www.alphametals.com
T (Thickness)
Min = .002” (0.0508mm)
Max = .200” (5.08mm) Cookson Electronics
Assembly Materials
is a member of
Cookson Electronics.
The power behind
the process.
D (Diameter) As a member of Cookson
Min = .020” (0.508mm) Electronics, Cookson Electronics
Max = 2.10” (53.34mm) Assembly Materials shares
T (Thickness) Cookson’s goal: To create total
Min = .001” (0.0254mm) process solutions that will
Max = .200” (5.08mm) power our customers to greater
productivity. We are committed
to optimizing every element
of our customers’ production
capabilities by providing
OD advanced process development,
Min = .057” (1.4478mm) comprehensive consulting
Max = 1.05” (26.67mm) and world-class training. Our
ID people aim to deliver real
Min = .049” (1.2446mm) results. To share their know-
Max = 1.024” (26.01mm)
ledge in ways that improve
H (Height) performance and productivity,
Min = .024” (0.61mm)
Max = .472” (11.99mm) and help our customers achieve
their goals. Cookson Electronics.
The Power Behind The Process.
11

12. The Power Behind The Process
Cookson Electronics Assembly Materials Cookson Electronics Assembly Materials
4100 Sixth Avenue Energiestraat 21
Altoona, PA 16602 USA 1411 AR Naarden
Order Hotline 800-289-3797 ext. 1685 Telephone +31 35 695-5411
Technical Services Hotline 814-941-1690 Fax +31 35 694-8451
www.alphametals.com www.alphametals.com
©2002 Cookson Electronics Assembly Materials