 The
purpose of the drilled through-hole is to make an opening through the printed
circuit board that: |
| |
 |
permits subsequent processes to make
an electrical connection between top, bottom, and all internal pathways,
and |
| |
|
allows through-hole components to be
located precisely and mounted with structural integrity. |
The quality of a through-hole drilled in
a circuit board is measured by its ability to support and accept the plating
and soldering operations required to form a highly reliable, non-degrading
electrical and mechanical connection. When circuit boards had traces on only
one side, the quality of the drilled hole was not very important. Later as
double-sided boards with plated through-holes became common, drilled hole
quality had to improve. Since today's multilayer boards require connections
to the inner layers as well as the surface pads, the quality of the drilled
hole is paramount in ensuring reliable connections. |
| Although it is painful to abandon familiar
practices, we must recognize when they no longer meet our needs. The circuit
board fabrication industry is experiencing rapid technological change. The
driving force behind these changes has been the increased use of surface
mount technology (SMT) and the consequent need for designers to maximize
the use of board real estate. Consequently, the industry has experienced
increases in the number of holes per square inch, smaller SMT pads, conventionally
drilled vias as small as .0039", increased layer counts, tighter annular
rings, as well as blind and buried vias. There is no manufacturing area
where these changes have had more of an impact than in the drill room. |
| James Block, President of
Laminating Company of America (LCOA), states that the root cause for as
many as 85 percent of all circuit board failures can be traced back to drilling
(1). When the entire board manufacturing process is examined, it becomes
apparent that many post-drilling operations are corrective measures designed
to overcome shortcomings in the drilling process. For example, the use of
mechanical scrubbing to remove burrs, chemicals to remove resin smear and
bonded debris, etch-back to expose glass fibers, and acid or alkaline cleaners
to remove contaminants all are methods for addressing problems that result
from the drilling process. Logic tells us that at some point it no longer
makes sense to compensate for drilling problems, and that we should shift
our focus to address the source of the problems. |
| Generic drilling practices are no longer
acceptable. Specific drilling processes must be developed and validated
for each unique type of board technology. A key concern in the change of
mindset from applying generic drilling practices to tailoring a specific
and unique process for each technology is the selection of consumables used
in the drill room. Historically, cost alone determined the selection of
supplies for the drill room. However, as technology continues to push the
drill room for improvements, the role of consumables can no longer be overlooked.
To survive, circuit board manufacturers have had to develop a unique set
of processing parameters for each type of printed circuit board. As is often
the case when conventional thinking is challenged, innovative fabricators
have been rewarded with greater efficiencies, improved yields and reduced
costs.
|
| Although there are many items on the consumables
list in the drill room, the three most important are: |
| |
|
drill bits, |
| |
|
entry materials and |
| |
|
backup materials. |
 |
| Choosing Drill Bits |
| The carbide drill bit is the most critical
of these three consumables. Drill bit manufacturers have developed numerous
styles and series of drill bits to help support the varied applications
in today's board manufacturing environment. Flute length, web thickness,
point geometry, and back taper all need to be considered when selecting
the right drill bit for the application. |
| Mr. Tech Dweeb
Tech Tip |
.jpg) |
Today's typical basic drill geometry
incorporates a 15 degree primary angle, a 30 degree secondary
angle, a high helix, polished flutes, relieved margins, a back
tapered body , and a fine grain tungsten carbide base. |
|
|
| The minimum flute length must equal the
total drilled hole depth plus at least .050" of unused drill flute. (The
drilled hole depth is the sum of the total laminate thickness, the entry
material thickness, and the exit material penetration.) The unused flute
measurement is made above the stack while at the bottom of the drill stroke.
This extra flute length is necessary to allow debris to be evacuated by
the vacuum system. Failure to remove debris from drill flutes can result
in degraded hole quality and even drill bit breakage. |
| To keep drill bits sharp and to avoid
breakage, they are generally used for 750 to 1,500 hits on multilayer circuit
boards and for 2,000 to 3,000 hits on double-sided boards. Hit counts greater
than 3,000 can be realized on single-sided boards. |
| Drill bits can be repointed from 1 to
5 times depending on the diameter of the bit. Typically from .002" to .005"
is removed by grinding during the repointing process. The smaller the bit,
the fewer times it can be repointed since smaller diameter holes are more
critical and require superior drilled hole quality. |
| Drill bit replacement and repointing represent
substantial expenditures for circuit board manufacturers. Depending on the
diameter and style of the drill bit, average prices range from just over
$1.00 to more than $20.00 per bit. Therefore proper storage, handling, and
inspection are critical to ensure maximum life span and optimum performance,
and to contain costs.
|
|
Drill Bit Geometry
Based on a figure in: Vandervelde, Hans. PCB
Handbook. McGraw-Hill, 2001.
|
|
|
| Determining the Best Entry Material |
| The second most important drilling consumable
is the entry material. The main purpose of the entry material is to prevent
drill breakage by centering the drill bit. In addition, the entry material
helps avoid copper burrs, reduce contamination in the hole and on the drill
bit, and prevent pressure foot marks from the drilling machine. |
| Many types and thickness of entry material
are available on the market today. Aluminum composite, solid aluminum, melamine
products, and aluminum-clad phenolics are the most common. |
| Selecting the right entry material requires
a thorough understanding of the drilling application for which it is to
be used. Although aluminum composites are typically the most expensive,
they do a tremendous job improving accuracy and dissipating heat. In addition,
they leave no hole contamination. Phenolic materials are less expensive,
but often warp and can contaminate the hole wall, possibly resulting in
problems during subsequent processes. Solid aluminum provides good burr
suppression and no contamination, but increases the risk of drill bit breakage
for small diameter bits. |
| A lot of work is being done to develop
a new generation of lubricated entry material to help further reduce heat
generated during the drilling process. Heat generated during the drilling
process destroys the optimal condition of the hole wall. When a hot drill
bit is extracted from a hole, there is a risk of smearing melted resin over
the inner layer attachment pads. Although the amount of heat generated during
drilling can be minimized by controlling infeed rates and drill speed, the
selection of proper supplies for the application is essential. |
| Proper selection of entry material for
a particular drilling application is very important due to the wide range
of cost for different materials. Costs can range from 33 cents per square
foot for a phenolic material to around $4.00 per square foot for a specialty
product.
|
|
| Selecting the Appropriate Backup
Material |
| The third most important drilling consumable
is the backup material. The purpose of the backup material is to prevent
exit copper burrs on the underside of the drilled stack and to provide adequate
space for drill stroke termination. An acceptable backup material does not
contaminate the hole and helps cool the drill bit, thereby improving hole
quality. |
| There is a great variety of backup materials
available on the market today. Selecting the appropriate "backer" requires
extensive testing and qualification since few of the products marketed as
backup material were engineered specifically for circuit board drilling.
Typical materials include aluminum-clad wood core composites, melamine-clad
wood core composites, solid phenolics, and even paper-resin hard board.
|
| The backer deemed appropriate for a particular
drilling process must also have a tight thickness and flatness tolerances.
It should contain no abrasives that would increase drill wear or contaminates
that could be evacuated through the drilled hole. The surface should be
smooth and hard to properly suppress exit burrs. |
| As with the choice of entry material,
it is important to match the backup material to the application since the
cost of backup materials ranges from about 25 cents per square foot for
hard board to around $6.00 per square foot for a specially engineered, lubricated
backer. |
|
| Finding the Right Combination |
| The great variety of materials available
and the wide range of their cost create a multi-dimensional matrix of possible
solutions to the dilemma of choosing the optimal combination of drill bits,
entry material and backup material for a particular application. Proper
selection can be made only through continuous testing, a thorough understanding
of the technology employed in the application, and an unswerving commitment
to quality. The drill room must keep up with the processing requirements
of today's circuit boards, and keep in touch with customers' demands regarding
quality, technology, and cost. |
| Future articles in the dsi
Quarterly Tech Review will examine other variables that affect the
quality and cost of the drilling process. |
| Sources: |
| |
1. |
Vandervelde, Hans. PCB Handbook. McGraw-Hill,
2001. |
| |
2. |
Goulet, David. Bare Board Drilling: Trends
and Developments in Printed Circuit Board Drilling. Miller Freeman Books,
1992. |
| How
clean is clean? Three test methods for determining cleanliness are commonly
used in the electronics industry: |
| |
|
visual examination, |
| |
|
solvent extraction, and |
| |
|
surface insulation resistance (SIR) measurement. |
|
| Visual Examination |
| This method entails inspection of circuit
boards under an optical microscope at 2X to 10X magnification in order to
identify flux residues and other contamination. The main limitation of this
method is that flux residues trapped under large components cannot be identified
microscopically. |
|
| Solvent Extraction |
| The solvent extraction method involves
immersing the circuit board in a test solution and then measuring the ionic
conductivity in terms of micrograms of NaCl equivalent per square unit of
the board area. For this method to be effective, the test solution, typically
isopropyl alcohol and deionized water, must remove the contamination from
under every component. Solvent extraction is commonly used to monitor the
cleanliness of conventional assemblies. J-STD-001 requires ionic contamination
to be less than 10.06 μg/in˛ (1.56 μg/cm˛). This
standard applies to all fluxes, including no-clean fluxes. |
|
| Mr. Tech Dweeb
Tech Tip |
|
The NaCl equivalent standard was developed
to allow one test measurement to yield a value with a common
meaning no matter what type of contaminant is present. The value
is a calculation of the amount of NaCl that, if dissolved in
the solution, would produce the same measured resistivity. The
value does not mean there is necessarily any NaCl in the solution.
dsi ’s standard for assemblies is less
than 0.5μg/cm˛. |
|
|
|
| The solvent extraction process is widely
employed primarily due to its simplicity. The equipment to perform this
test is inexpensive and does not require a highly skilled operator. Consequently,
this test is often used at the end of a process line to characterize the
cleanliness of a board. In itself, the figure (μg/cm˛ of NaCl) is not
directly translatable to a specific contaminant. However, if the process
has been approved for use with a NaCl equivalent cleanliness test, then
the number generated by the cleanliness test can be used as a process indicator
for total cleanliness and a range of acceptability can be established. |
|
| Surface Insulation Resistance Measurement |
| SIR measurement is widely used for determining
the insulation resistance of laminates, assessing the compatibility of fluxes
with circuit board material, and testing the cleanliness of circuit board
assemblies. The equipment used to measure SIR values consists of a high
resistance meter, generally referred to as a megohm meter, and a humidity
chamber. |
| The primary advantage of the SIR measurement
method is that it is direct and quantitative. It provides useful results
when applied to boards with an aggressive flux. SIR tests also flag problems
with adhesive curing. If an adhesive is cured rapidly, voids are generated
that may entrap flux. Inspection and extraction methods cannot adequately
detect flux entrapment, but SIR measurement can. |
| The major disadvantage of SIR measurement
is the need to design additional circuitry on the surface layers of the
circuit board to conduct the measurements effectively. Another limitation
of this approach is that the trace pattern must be standardized to either
a “Y” or a “comb” pattern. Differing component sizes on the board can make
it difficult to standardize one particular SIR pattern. Also, to obtain
a representative indication of the contamination under the components, the
selected SIR pattern must appear in all areas of the board. |
|
| Selecting the Right Method |
| The two test methods described in this
article can generate very useful results if they are interpreted properly.
The SIR approach yields a figure that can be correlated directly to the
concentration of a specific contaminant. However, the test equipment is
sophisticated and does not lend itself to the factory floor. Further, the
product must have been designed to accommodate this test. In contrast, the
solvent extraction method is a representation of total cleanliness and does
not give specific information. However, this test is ideally suited for
inclusion in a process line and does not require advance planning to test
the product. Failure of the solvent extraction test clearly indicates that
the process is out of control and the product should not be shipped. |
| Sources: |
| |
1. |
IPC. Post Solder Aqueous Cleaning Handbook.
IPC-AC-62A, 1996. |
| |
2. |
Prasad, Ray P. Surface Mount Technology:
Principles and Practice, Second Edition. Kluwer Academic Publishers, 1997. |
| The
base metal conductor used in the fabrication of printed circuit boards is
copper. Although copper is an excellent conductor of heat and electricity,
it is also a very active metal that quickly oxidizes in the presence of
air and water. If a copper surface is not coated or treated with a protective
agent, the exposed area rapidly becomes unsolderable using conventional
assembly processes. For this reason, all printed circuit boards use some
form of a surface finish on the exposed pads to which electronic components
will be soldered. |
| Current manufacturing processes typically
also require circuit traces to be protected with a masking material, called
soldermask. The soldermask is relieved only where a subsequent operation,
such as soldering of electrical components, requires electrical access to
the circuitry. The relieved areas, which are not covered with soldermask,
need to be protected with some form of a surface finish. |
| The role of the surface finish is to coat
the copper pads and exposed traces in order to protect them between the
time the board is manufactured and when it is assembled. By protecting the
copper from oxidation, the surface finish ensures that the board can be
soldered successfully later during the assembly process. |
| The three most prevalent surface finish
processes are: |
| |
|
hot air solder level (HASL) |
| |
|
immersion precious metal plating |
| |
|
organic surface protectant (OSP) coating. |
|
| Hot Air Solder Level |
| The hot air solder level (HASL) process
entails the application of tin/lead solder to exposed copper. The solder
and exposed copper form an intermetallic chemical bond that protects the
copper from oxidation. |
| To prepare circuit boards for solder coating,
the boards are first processed through a flux containing amine hydro-bromide
flux activators in a polyglycol carrier. A solder bath is prepared using
a tin/lead alloy, normally 63 percent tin and 37 percent lead, heated to
500°C. In a vertical process, the “fluxed” boards are immersed in the solder
bath. The solder coats the areas not covered by soldermask. The boards are
then withdrawn from the solder bath while hot air knives remove or level
the excess solder. |
| The resulting solder thickness can vary
due to gravity, surface tension, and the geometry of the circuit board pads.
The use of a vertical process results in some droop or meniscus of solder
on the bottom side of the pads. This meniscus can be a problem if the board
requires high density chip placement (pitch spacing below 20 mil).
|
| HASL is still the most common coating
applied to protect copper pads and exposed traces. It provides good solderability
and excellent shelf-life for the circuit board. |
| There has been much discussion in recent
years about banning the use of tin/lead coatings. However, at this time
regulatory agencies have granted specific exclusions from lead-free restrictions
for most high-reliability applications due to the lack of a proven alternative.
For this reason, HASL continues to be used far more extensively than the
coating alternatives described below. |
|
| Immersion Precious
Metal Plating |
| The immersion process uses ion displacement
reactions to plate the circuit board surface. When the surface metal finish
(nickel/gold, silver or tin) has been deposited, the source of electrons
is used up and the process is complete. The process is self-limiting because
the copper forms an intermetallic layer that inhibit the immersion reaction.
|
| Immersion coatings have become popular
as circuit densities have increased and the pitch of surface mount technology
(SMT) components has decreased. A flat attachment pad is paramount in achieving
a reliable solder joint with fine pitch parts. Although the solderability
of each coating is different, all immersion coatings provide a very flat
attachment surface. |
| The electroless nickel / immersion
gold (ENIG) finish is the most expensive and also the most solderable
over the widest range of conditions. This coating ensures minimal long-term
degradation of solderability prior to assembly and excellent immunity to
corrosion from environmental exposure in the field. The nickel/gold coating
ranges from 3 to 10 µin in thickness and costs about twice as much as HASL.
|
| Silver is the next most costly
metal finish and is only slightly less solderable than nickel/gold. Deposited
to a thickness of 5 µin, the cost of silver is only about one and a half
times the cost of HASL. |
| Immersion tin has gained popularity
because its cost is favorable compared to the cost of HASL. However, the
long-term solderability of immersion tin is questionable and highly dependent
on the process controls of the fabricator. The plating is a tin oxide formed
from stannous fluoborate in an acid suspension. About 50 µin thick, tin
plating costs about 1.3 times as much as HASL. |
|
| OSP Coating |
| The process for applying an organic surface
protectant (OSP) coating does not require electron exchanges since the circuit
board is coated upon submersion in a chemical bath. A nitrogen-bearing organic
compound allows adhesion to the exposed metal surfaces and is not absorbed
by the laminate or soldermask. Although coating adhesion levels vary according
to the type of organic compound, the process is self-limiting and results
in a typical coating thickness of .5 µin. Organic coatings are equivalent
in cost to HASL and provide relatively flat pad topography. However, these
coatings break down during thermal cycles in assembly and are not recommended
for double-sided circuit boards (boards with SMT components on both sides).
Furthermore, these coatings do not hold up very well to long-term storage.
Boards with an organic coating must be kept sealed in a stable environment
and used very shortly after application of the coating. |
| Mr. Tech Dweeb
Tech Tip |
.jpg) |
Although customer specifications
vary, typical coating thickness are shown in the table below.
| Coating |
Thickness
(microinches) |
| HASL |
200 to 300 µin |
| ENIG |
100 to 250 µin of nickel
3 to 10 µin of gold |
| Tab nickel/gold* |
100 µin of electroplated
nickel
30 to 50 µin of electroplated gold |
| Silver |
8 to 20 µin |
| Immersion tin |
30 to 70 µin |
| Organic surface
protectant |
0.4 to 0.6 µin |
|
* Tab nickel/gold plating is applied
using an electroplate process that results in a harder and
thicker coating than the ENIG process. Tab nickel/gold is
used only for areas of a circuit board that will be inserted
into a connector.
|
|
|
|
| The fabrication industry developed the
immersion process to address the anticipated environmental mandate to eliminate
lead, even in alloy form (tin/lead is an alloy and has no free lead), from
the manufacturing process. However, exclusions given to military hardware,
implanted medical devices and critical automotive systems have delayed the
lead ban until an unspecified future date. As a result, the need for flat
pad surfaces, rather than the need to eliminate lead, has become the driving
force behind the development of alternative coatings. |
| Mr. Tech Dweeb
Tech Tip |
|
Cost comparisons of various coating
options are difficult since two of the metals (gold and silver)
are sold by the troy ounce. However, for a typical board with
approximately 15 percent exposed soldering surfaces the following
table provides a good comparison, using HASL as the baseline.
| Coating |
Cost Factor |
| HASL |
1.00
|
| ENIG |
2.00
|
| Silver |
1.36
|
| Immersion tin |
1.30
|
| Organic surface protectant |
1.05
|
|
|
|
|
 The
process of attaching surface mount components entails a series of mechanical
(solder stenciling and component placement) and metallurgical (solder fusion)
operations. Consequently, it is possible for components to be misaligned
or missing upon completion of the process. While good process control can
reduce the incidence of these problems, some form of inspection is still
required. In a high-mix manufacturing environment, the availability of good
statistical data is limited since the entire output for a particular circuit
board often is assembled in one lot. Therefore, the use of Automated Optical
Inspection (AOI) systems is a very efficient way to supplement process control
and improve quality levels. |
| The advantages of AOI systems include: |
| |
|
AOI systems can identify process problems
resulting in missing and misplaced components. AOI Systems are ideally suited
for inspecting passive components (1206, 0805, 0603, and 0402 package types),
which generally have the highest defect rate. Use of an AOI system to inspect
such components can improve first-pass yields by 20 to 25 percent. |
| |
|
AOI systems can point out equipment problems
such as misaligned or insufficient board supports and bent nozzles. AOI
data can reveal patterns of problems that can be traced to particular pick-and-place
machines, indicating maintenance needs. |
| |
|
AOI data indicate areas for
process improvement. For example, based on measurement information obtained
from an AOI system, pick-and-place machines can be recalibrated to bring
component placements closer to computer-aided design (CAD) data. |
| |
|
Use of AOI systems can result in process
enhancements that reduce the time circuit boards spend in inspection and
minimize the volume of product requiring repair. Using component failure
information obtained from an AOI system, operators can more quickly track
missing parts, offset errors and polarity defects. Also, if quality levels
drop below a prescribed percentage or if multiple errors of the same type
are found on consecutive boards, the manufacturing process can be halted
immediately and corrective action taken. |
| |
|
AOI data can be used to establish a capability
baseline for the process. A typical baseline is defined by determining the
X, Y, and Z (theta) movement after reflow for: 1206, 0805, 0603, and 0402
passive components; 50 mil pitch small outline integrated circuits (SOICs);
and 20 mil pitch quad flat packs (QFPs). These package types can then be
placed on a test capability outline board (48 are required for a full DOE)
and inspected to create a capability baseline. |
| Mr. Tech Dweeb
Tech Tip |
|
The acronym “DOE” is often used in place
of Design of Experiments. DOE is a structured methodology for
establishing process variability and capability by tabulating
the data from successive passes through the process. Engineers
use this data to determine whether the process can meet the
customer’s requirements. |
|
|
|
| Selecting the AOI System Right
for You |
| When choosing an automated optical inspection
(AOI) system, it is important to first define and understand your company’s
manufacturing process needs. The system that you select should help to identify
deficiencies in your process and result in improved product quality. It
is best to begin with a survey of your current process. Focus on determining
the most common types of component placement defects resulting from your
process. When comparing AOI systems, evaluate which system has the imaging
technology and features best suited to identify and remedy problems with
your company’s manufacturing process. |
| Implementation of an AOI system should
focus on: |
| |
|
improving assembly line process control, |
| |
|
ensuring high first pass yields and |
| |
|
establishing measurable benchmarks across
all assembly lines. |
|
The level of inspection accuracy and repeatability provided by the AOI
system must be suited to your manufacturing process. Inspection accuracy
for resistor and capacitor chips is usually not as critical as for leaded
devices, and different systems offer different capabilities in this regard.
For example, some systems attempt to identify defects based on the use
of a “golden board.” These systems compare the circuit board that is being
inspected to the “golden board” and identify all differences, regardless
of whether the differences represent real defects or just harmless variations.
In contrast, AOI systems that provide position measurement data offer
superior defect detection and process control for component placement.
In addition, it is easier to verify that the performance of these AOI
machines meets industry measurement standards (i.e., IPC-A-610c and J
Standard 001).
|
| A critical aspect of any inspection system
is its robustness. Designs often have 500 or more components per board side.
If the inspection process results in too many false calls, line operators
will have to re-check the results too often and will quickly lose confidence
in the accuracy of the results. Poor robustness in the inspection of component
placement is often caused by cosmetic variations in the board or its components.
An AOI system that is sensitive to changes in the color or finish of a circuit
board, or that relies too heavily on special lighting techniques, may have
problems with variations in the board finish, lighting, and board or component
color. |
| False calls include defects identified
as good placements and good placements identified as defects.
|
|
|
|
At a minimum, an AOI system should measure the position of each component
along its X, Y and theta dimensions, and should check that the component’s
polarity is correct. Actual component positions should be compared to
computer-aided design (CAD) data to see whether each component position
is within acceptable tolerances. Components positioned outside of tolerances
should be identified and the measurements should be used to update statistical
process control (SPC) charts.
|
|
| Inspection Technology |
| There are two main types of
technology for performing automated optical inspection (AOI) for component
placement: |
| |
|
camera-based systems and |
| |
|
laser-based systems. |
| Most systems use either gray-scale or
color charge-coupled device (CCD) cameras. The cameras collect images of
the circuit board, and the images are analyzed to determine whether there
are any defects in each area of the board. Camera-based systems can be very
fast, but because they rely on the brightness of light reflected from the
board, they can be sensitive to changes in lighting conditions and materials.
Most systems that rely on cameras for image collection have a programmable
lighting feature for creating optimal images of each site or component.
However, as board complexity increases, problems with lighting contrast
or shadowing may arise. As images become more complex, the image processing
becomes more difficult and inspection cycle times can drop. |
| Laser-based inspection systems for component
placement use a laser scanner to create a 3-D image of the circuit board.
This 3-D image is based on the height of the board surface and its components,
and is much less sensitive to changes in component color. Laser scanning
systems also can create a 2-D gray-scale image, similar to the image from
a CCD camera. This image can be used to identify objects where there is
little height contrast, such as board fiducials, and to detect component
leads in solder paste. Laser scanning provides accurate position measurements
of components, resulting in fewer false calls and the type of information
needed for optimal process control. |
| Mr. Tech Dweeb
Tech Tip |
|
dsi uses AOI
to inspect all SMT assemblies. On a typical day over 250,000
components are scanned for acceptance. |
|
|
| Medical device manufacturing
represents approximately 30% of dsi’s revenue and
is one of five industry segments in which we operate. (Automotive, Telecom,
Military/Aerospace, and General Industrial are the others.) dsi
maintains the audited certifications for every industry segment in which
we participate. According to the IPC, dsi is the
only member holding all major quality certifications. |
| All medical device manufacturing companies
(including contractors) are required by the Food and Drug Administration
(FDA) to maintain a quality system that complies with its Current Good Manufacturing
Practice (CGMP). These requirements govern the methods and controls used
in the design, manufacture, packaging, labeling, storage, and shipment of
all medical devices intended for human use. Their purpose is to ensure that
these devices will be safe, effective, and in compliance with the Federal
Food, Drug, and Cosmetic Act as appropriate. |
| Medical device manufacturing companies
are required to renew their registration on a yearly basis. The registration
renewal process may involve an unannounced audit by FDA inspectors. The
FDA audit includes verification of CGMP compliance regarding document control,
production and process control, identification and traceability, purchasing
control, inspection, corrective and preventive action, labeling and packaging
control, nonconforming product control and other aspects of production.
Compliance with these comprehensive requirements promotes consistency in
quality, safety and efficacy of medical devices. |
| Through its strong commitment to quality,
dsi ’s management ensures the corporate-wide
implementation of these rigorous regulations. As part of our ongoing effort
to maintain the highest levels of customer satisfaction and to meet our
business goals, dsi renews its registration annually,
guaranteeing uninterrupted service to the medical device industry. Our most
recent registration renewal from the FDA covers dsi
through the year 2003. |
Stanley L. Bentley
