Recent Images - Digiray - Composites and Honeycomb

THE MOTIONLESS LAMINOGRAPHY X-RAY™ SYSTEM (MLX^® )

Overview
MLX^® operation
Step wedge images
Laminography of Composites
Laminography of Cracks in Composites
Porosity in Composite Adhesive

Overview

Laminography is the "layer-by-layer" imaging of an object. Whereas conventional transmission x-ray images are affected by features at all depths, the Digiray's MLX^® system can isolate the features on either side of a coin (or any depth in the middle).

Digiray's Motionless Laminography X-ray^® (MLX^®)

Looks through an object layer-by-layer
Detects the location of defects at record speed
Produces fog-free, high-resolution digital images
Captures 1000 x-ray slices, each 1 mil thick, with a single quick exposure
Set up is quick because alignment of tube and detectors is easy
Contrast sensitivity <0.3% - contrast ratio is 1500-to-1

Compare to conventional computed tomography (CT)

	MLX^®	Conventional CT
Resolution in 3rd dimension	8 mils	N/A
Spatial resolution	12 microns
Set-up time	Quick - 45 degree "freedom of alignment"	Slower, due to need for precise alignment
Size and weight	600 lbs	Uses large heavy arm and motors
Portability	Yes - as well as cabinet, robot, and gantry models	Not for top-quality images
Effects of mechanical motion on interpretation	No moving parts to cause artifacts in image	Mechanical motion does not cause artifacts
Image clarity	Exceptional - because small distant detectors get primary beam, not scattered x-rays	Scattered x-rays fog the image
First-generation image quality	Yes	No - Image intensifier or vidicon degrade first-generation quality

For more information, call 925-838-1510

Trademark and copyright information

The MLX^® system was invented by Digiray Corporation, a company formed in 1981 to develop state-of-the-art x-ray devices. Among its unique advantages are eliminating the need for physical motion and for critical alignment. It has one of the smallest footprints in the x-ray inspection market.

The system has many advantages:

ability to isolate features at any depth, thereby eliminating obstructions to the discovery of flaws
excellent spatial resolution and contrast resolution, even with low density materials, such as composites
portable
sturdy and reliable
first-generation digital data
no mechanical parts because the x-ray source is a tube with the raster-scanning electron beam
performs large-area inspection without physical motion of the object, dectors, or x-ray source
does not require critical alignment because the large source provides ample flux to the detectors

The primary function of MLXä laminography is to look through an object, layer-by-layer, in order to detect and pinpoint the location of a feature at record speed without moving either the object or the x-ray source. We have observed the following defects in low Z objects:

3-5% irregularities and tiny cracks in foam insulation.
1/2T penetrameter resolution.
wall separations due to impact damage in composite honeycomb
porosity in composite material
3D impact damage in composite material
adhesive defects in honeycomb sandwich to composite bonds
voids, cracks and porosities in thermal protection tiles
3D crack in Space Shuttle leading-edge RCC material from foam impact (simulation)

Currently NASA Ames is using it to help design their latest thermal-protection tiles for the X37 program for unmanned aircraft (drones).

The MLX^® system has been:

manufactured in small quantities and delivered to large customers — NASA Langley (3 systems), U.S. Air Force, British Defense Ministry, Kobe Steel, Saudi Aramco, and a classified U.S. Government agency.
used to evaluate structural integrity of aircraft by detecting corrosion, cracks and fatigue.
successful in portable field inspections including:
- Northrop Grumman’s aging aircraft program on F-14s and 707s
- Boeing's research on NASA's Space Shuttle
used for national security applications by two customers

MLX^® operation

The object is placed close to the x-ray source and a beam of x-rays goes through it. An image is produced by using an array of detectors, each viewing the object from a different angle. Then each image is shifted with respect to every other image and all are added together. This generates slices, giving a layer-by-layer view of the object There are no moving parts to degrade the image resolution.. In a single short x-ray exposure it captures 1000 x-ray slices that are 8 mils thick. These slices can be displayed individually or in a consecutive layer-by-layer motion picture.

A single short x-ray exposure provides enough information to strip away all obstructing layers and reveal all of the layers of interest.

The laminographic system can use 8, 16, 32, or 64 detectors. Each detector captures data from a unique view.
Laminographic software can then paint isolated layers to the visual display.

MLX^® provides zoom magnification capability with highest resolution by electronically compressing the raster into a smaller area. The reduced size raster can then be panned over the area of the display.

The result of these features is:

2D spatial resolution is 12 microns
Depth resolution is 8 mils

Step Wedge Images

Laminography of Composites

Because of its unusual contrast sensitivity (0.3%), MLX^® is particularly adaptable to inspection of low atomic number materials such as foam-composite sandwiches, foam insulation, and thermal protection tiles.

Laminography of Cracks in Composites

Leading edge prototype for NASA's Space Shuttle with a crack.

Laminography isolates crack as it wraps around both sides of the leading edge. Each "slice" shows the "ghost" of the crack on the opposite side of the edge.

T-Connector that connects leading edge sections. The reinforced carbon-carbon (RCC) piece has strain gauges. One slice shows the crack section near the strain gauges. The other slice shows the crack section on the opposite side.