Early Defect Containment Medium to high complexity products High reliability/quality requirements by end users Products with coverage gaps unfilled by other test technologies: Lack of access Products that require functional test to verify product functionality but lack functional diagnostics Can reduce manufacturing cost if properly implemented Partner with other test technologies No single technique provides complete coverage ICT/Functional will not be replaced
Where does manufacturing test fit
Multiple manufacturing test strategies, driven by: Complexity of product Complexity of repair End user quality/reliability Cost of the product Acceptable manufacturing risk Volume of product to be built Deliver the product at the lowest possible cost with acceptable level of quality. Test is there primarily to ensure end user quality by: Defect Prevention Defect Containment
X-rays are one of the most used apparatus in hospitals, clinics,
and other medical facilities worldwide. It is used to visibly see a bone
fracture, a swallowed object, if there's liquid in your lungs, and any
other parts of your body without having the doctors open your body up
right away. It is an indispensable apparatus which saves doctors time
and effort and saves you some money from major surgical operation costs.
But, we all know, as a rule of life that everything comes with its pros
and cons. So with all of these benefits we get from using X-rays in
helping diagnose patients, is exposure to X-ray machines bring
disadvantages, too?
Are X-Rays Harmful?
X-ray machines release electromagnetic energy
that lets you see your bones, and organs without surgery. This light
energy released in the machine is known to be high in radiation. The
X-ray is a form of an ionizing radiation which causes chemical reactions
to cells when these cells are exposed to the energy emitted by the
X-ray machine. You see, when the X-ray hits an atom, the electron of an
atom changed into a charged ion that can cause the harmful chemical
reactions.
For one, an electrically charged ion can break DNA
chains in the body. This can either kill a lot of the living cells
inside your body or can cause a mutation. If the number of cells that
dies inside you is more than what your body can handle, you may develop
diseases and other conditions. On the other hand, if these cells mutate,
these can form cancerous tumors that may later on spread on the other
parts of the body.
Furthermore, if the cells that mutate are
include sperm or egg cells; you may have children with birth defects
later on in life. Lastly, X-rays can also have an effect on your bone
marrow damaging the cells found on it therefore affecting your hair
follicles and skin which causes rashes, hair loss, and other harmful
effects.
Because of the risks X-rays can cause due to prolonged or
repeated exposures, doctors, dentists and other health care
professionals use X-ray machines with a lot of caution and concern.
Patients and other people who are being exposed with X-ray machines are
asked to wear protective gears just to be safe. X-rays should not be
taken unless they are deemed to be necessary or as advice by a doctor as each exposure is harmful to the body.
X-rays are one of those things that people tend to be wary of.
The radiation involved in taking one is a concern. Dentists understand
this, and strive to minimize a patient's exposure to the radiation, but
they continue to take x-rays because risks of radiation exposure are
outweighed by the benefit of what is learned.
X-rays are the best
way for a dentist to check a patient's dental health. A dentist can
locate cavities in a tooth, show dental abscesses, impacted or extra
teeth and even cysts and tumors. Fillings, crowns, bridges and root
canals are all facilitated by the use of x-rays. Bone-loss, hidden
tartar build-up, and foreign bodies that may be creating dental issues
can also be detected by the use of x-rays. Anywhere between two and
eighteen may be needed, depending on each patient's situation. Eighteen
are needed for a full check-up. Follow ups to check a specific issue
require either two or four x-rays. These are referred to as "bite
wings." And yet, for all of their benefits patients are still concerned
about the radiation levels incurred during an x-ray session.
Dentists,
too, are concerned about a patient's exposure to radiation, and so use a
high-speed film, and lay a heavy lead vest over the patient before the
images are shot. Pregnant women are not given standard x-rays due to the
danger to the unborn child, yet dentals are deemed safe due to the
relatively low dose of radiation that is received. Dental test send out
58,000 times less radiation than an upper GI, 8,000 times less than a
chest and forty times less than the daily radiation that we all
experience sitting in front of our televisions or computers, or even
just walking around. These figures should go a long way in relieving
people of their concerns regarding dental x-rays.
New dental
technology now allows for digital x-rays to be taken. The benefits of
digital are noteworthy. To start, digital x-rays deliver 80% less
radiation than their traditional cousins. That's an 80% reduction to the
already low doses of radiation dental x-rays deliver. In addition to
lower radiation levels, digitals are almost instantaneous, and the
dentist has the advantage of color contrast, since the digital is more
like a photo than the traditional black and white. Digital x-rays also
eliminate the need for processing chemicals and the cost of film the
downside is that the digital technology is more expensive, and the
quality of the image is not necessarily any better than a traditional,
so not all dentists feel digital x-rays are right for their practice.
• For devices on the focal plane:
− A device on the focal plane will be stationary.
− The beam will pass through the device at every angle as it rotates,
creating a three-dimensional, composite image of the device.
− Because the image is a composite of a rotated X-ray beam, the image is
always going to appear slightly fuzzy.
− The advantage, a single composite image represents all aspects of a
solder joint. Therefore, one battery of tests can judge the joints integrity.
− One rotation of the x-ray beam is required to create an image.
(In certain circumstances, up to four rotations of the beam can be used to
create a single image.)
• For devices off the focal plane:
− As the beam rotates, it intersects a device that is off the focal plane at
different points.
− These different points form a circle, the diameter defined by the distance
from the focal plane.
− The image is collected from one rotation of the beam. During that
rotation, the device is "smeared" in the corresponding circle and becomes
simply a shadow.
The 5DX allows you to move the panel on the Z Axis to examine devices on the top of
the panel, the bottom of the panel or internal to the panel.
• The deflection angle of the x-ray beam from 28 to 35 degrees.
Basic 3DX Concept
A Stationary Beam is a “Transmission X-ray”.
Basic 3DX x-ray Concept
X-Ray Concepts
There are two basic ways to image an X-Ray.
• Transmission X-Ray
• Laminography
transmission x-ray
Transmission X-Ray: The X-ray beam that most people are familiar with is the kind used by a doctor or dentist. These are "transmission" X-rays and regardless of the layering of the objects being xrayed produce an image of all features. In the example shown: • The printed circuit board is positioned between the X-ray source and the Detector (film). • There are devices on the top of the panel and • There are devices on the bottom of the panel. • The X-rays pass through the devices and the printed circuit board. • Solder, being a heavy metal, absorbs most of the x-ray energy hitting it. • The fiberglass of the panel attenuate very little energy. • The energy that makes it through the panel is collected by the detector. • This produces an image showing top and bottom devices together, but at slightly different magnifications.
basic 3d x-ray laminography
Basic 3DX Concept A rotating beam is a “Laminography X-ray”.
Laminography X-ray Beam The Agilent 5DX uses X-ray Laminography. The X-ray beam is rotating. Deflection coils in the tube cause the photon stream to pass through the panel at a rotated angle. Above, four locations are shown, during test, the image is being collected during the entire 360degree sweep, but examine these four locations: • The X-rays leave the X-ray tube at position 1 - The beam passes through the device on top of the panel. - The beam passes through the panel - The beam passes through devices on the bottom of the panel. - The image is collected by a detector at its position 1. • This is repeated at positions 2, 3 and 4. What is going to be visible? • All devices on the plane of focus. • None of the devices above or below the plane of focus.
Learning Objectives
When you have completed this module of training, you will be able to:
• Correctly explain the basic concepts of the 5DX X-Ray Inspection System
including the Theory of Operation.
• Correctly describe the steps in the 5DX application development process.
• Correctly describe the Laminography process and describe the anatomy of
the 5DX system.
• Correctly explain how and why a panel can be tested with x-ray.
• Correctly list and explain the safety procedures of the 5DX system.
The Inspection Process An Overview
The Inspection Process - an Overview
• An X-ray beam passes through a printed circuit board.
- As the beam emerges from the X-ray tube, it is deflected. A series of
deflected x-rays form the circular pattern described earlier.
• Dense metals absorb more of the X-ray's energy than less dense materials.
- A large quantity of solder will appear dark gray, almost black.
- A segment of printed circuit board, without traces or ground plane will
appear light gray, almost white.
- Traces can be seen as slightly darker gray lines.
- Some device packages produce a slightly darker gray area too.
• The X-ray beam reaches the Rotary Scintillator. The Scintillator converts the
X-ray energy into a gray scale image of a solder joint.
- The "Scintillator" has a cesium iodide surface that emits light when
struck by X-rays. (Similar to the phosphors in a picture tube.)
- The X-ray beam is synchronized at 180 degrees following the Rotary
Scintillator. Thus, the beam is rotated through the device being tested.
- During test, the x-ray beam is on continuously. The image is being
collected continuously. Thus, the image is actually a composite, 360
degree view of the solder joint. This is Laminography.
