Micro-CT scanning allows us to inspect small components like stainless mesh filters for porosity, gaps, and overmold conditions.
Continue readingIndustrial CT Scanning Micro Filters
Geometric Magnification Explained – 40um vs 8um CT Scan of Sensor
WHY RESOLUTION MATTERS
For x-ray & CT imaging there is a dynamic called Geometric Magnification. GeoMag (Mg) is the calculation of the distance between the x-ray source to test object and detector (Source to Object Distance, SOd) & (Source to Detector Distance, SDd).
If the detector remains stationary, the closer the object moves to the x-ray source the higher the resolution becomes. However, the further the object moves from the detector, the smaller the field of view. Put simply, the higher the resolution, the smaller the area of interest to be imaged.
A proper understanding of the project requirements determines the appropriate resolution and field of view. If a client needs to check for hairline fractures or micro-porosity, maximum resolution is necessary. If these defects are smaller than the resolution of the data they may not be resolved.
The below sensor is being scanned to evaluate potential leak paths in the soldered tip. The advantage of the 40um scan is that the entire part is characterized. However, the fine details of the area of interest are best resolved in an area of interest scan at 5x that resolution. At this resolution we can see micro-porosity not seen in the larger GeoMag scan.
40um Full Part Scan
8um Area of Interest Scan
X-Ray Repeatability of PCB Components
HIGH RESOLUTION X-RAY REPEATABILITY
High resolution x-ray is used to characterize PCB components for failure avoidance and analysis. With electrostatic discharge mechanisms in place, we image and sort safety and mission critical PCBs against customer specified metrics like porosity percentage, FOD size and location, bond wire straightness, general failure points, and many other indication types.
With programmable part manipulators and low density custom fixturing solutions, we guarantee the highest quality digital x-ray solutions.
The below image set is an example of our resolution, contrast, and positioning capabilities.
CAN YOU CAN SPOT THE FAILED SAMPLE?
Failure in the Field – Medical Instrument Carrier
Failure in the Field
This vessel is designed to hold and suspend implant screws in sterile liquid. The slots allow for various sizes to be carried using the same vessel. The vessel came to us because a screw was out of place inside the vessel prior to opening. Because of the occurrence the entire unit was quarantined for investigation.
The blue arrows point to a crack found in the seat of the carrier. The most probable explanation is that because some force is applied to hold the screw upright the seat cracked during loading. Then, during transit or handling the screw dislodged.
Versatility of CT Data
While this investigation was completed quickly, there is much more that can be learned from this dataset. For example, a common application for Industrial CT Scanning is seal and thread engagement analysis. This data can be exported to .STL for dimensional inspection, CAD comparison, and wall thickness calculations.
CAD comparison is useful to understand why the seat may have cracked. Perhaps the seat is accurate to CAD but the slots are out of position, causing stress fractures.
Shrink & Porosity near Fan Blades
Pre-to-Post Use Evaluation using Industrial CT Scanning
High Resolution part evaluation
Industrial CT Scanning is used to characterize a variety of products including multi-material plastic assemblies like this wall anchor.
Some practical uses include:
> Fitment analysis - clearance & interference
>> Dimensional inspection - concentricity & wall thickness
>>> Porosity, inclusion, and fiber orientation evaluation
>>>> Pre-to-Post Use Comparison
Pre-to-Post Use Evaluation
Pre-to-Post use evaluation is particularly useful for understanding how a part changes over time. For example, in the below comparison slider we can see the threads created from a screw. We can measure the wall thickness where the expansion wings bend. We can also see how the the interface between the two components changes. Lastly, we can measure damage caused by insertion and removal.
CT Scan of Shaver – Blade Wear Analysis
Evaluating an Electric Shaver
Industrial CT scanning can be used to investigate components and assemblies for proper part placement, failure analysis, and wear. This Norelco shaver is a great demonstration sample because of how complex it is:
- Multiple materials including plastic & metal
- Intricate gears & interfaces
- Small features like sharp blades
- Motor with copper winding
- Rechargeable cylindrical battery
Blade wear comparison
New and used blades were scanned at higher resolution to understand how the part changes and becomes less effective over time. First, the blades were aligned on top of each other for a direct visual comparison.
The top view shows a cylindrical unroll of the blade. This allows us to simultaneously view all nine blades. From this view we can hypothesize that the lower performance of the used blade is caused by the blades being bent downward over time.
measuring the hypothesis
By exporting the blades into .STL scan file format we can use PolyWorks dimensional software to produce a part to part profile comparison. This map confirms that most of the blades are approximately 50 microns lower than the new blade.
CROSS SECTION COMPARISON
A 2D cross-section is placed across “best-fit” aligned blades. The used blade was then manually shifted to the left to help visualize the samples. Then, arcs were defined on each blade with an approximate deviation of .006mm between nominal (new blade) to measured (used blade.)
