MICRO MACHINING VALIDATION USING CT SCANNING
11/19/12 Ct Scanning (X-Ray Scanning) has come a long way in the last few years. This technology was originally developed for use in healthcare facilities whereby a person lays flat on a table while a CT scans specific parts of the body, however CT scanning is now being used for inspecting ultra-high precision micro components and assemblies.
These critical components, along with many others requiring micro features and surface finish are ultimately validated using many metrology methods. Validation time lines for Phase 1 clinical trials can be lengthy but shortened with extremely fast CT scanning equipment. This equipment can measure a 3-dimensional part or assembly in <3 hours and compares the fully 3D model to the actual scanned part or assembly (see Figure 1.1).
The CT Scanning (Xray Scan) scans the entire part in 3D (see Figure 1.2), creates point cloud data which with software turns the scan into a 3d CAD model. This model can then be compared to the original part solid model, which when drawn at nominal can be used as a fast, and accurate comparison from planned to actual part geometry.
In fact, the smaller the part, the more accurate the CT scan can be due to the pixel sizes of the scan.
• Actual CT Scan vs. CAD Nominal Model Comparison
• Surface finish imperfection recognition
• Accuracy of non-contact metrology between sub-micron to ten nanometers
• Metrology fixtures simplified (Save time and money on multiple fixtures to “present” parts to vision source)
• Feature inspection and recognition
• Bonding surface inspection and analysis
• Accurate Volume calculation for costly materials
• 100% 3d component and assembly scanned in hours vs. days or weeks
• Micro Machining, Micro Molding, Micro Assembly Defect Analysis
CT scans a singular part or an entire assembly, showing the bond surfaces, the tiny interactive surfaces, and separate thin walls designed into surgical instruments, implants, and pharmaceutical devices.
Figure 1.1 CT Scanned Endoscope Micro Machined Component (Tan) compared Metal Injection Molded Component (Blue)
Figure 1.2 3d Scanned Endoscope component, scanned once from the top down, showing top and bottom scans
Validating with First Article Inspections is tedious, time consuming, and costly. CT scanning, whicle not cost effective for all parts, is a no-brainer when it comes to critical, high value components and assemblies such as implants and pharmaceutical devices.
Micro milling, grinding, and swiss turning are micro machining methods that create critical components for implants and pharmaceutical components such as:
• Cardiac Implants
• Trauma fixation Implants
• Orthobiologics
• Reconstructive join replacements
• Insulin Delivery Pumps
• Neuro stimulation Devices
• Glucose Monitors
• Ophthalmic Instruments
Medical and Pharmaceutical device companies can speed up the clinical trial process with validation and metrology methods such as CT scanning. Three hours to part and assembly CAD data compares to most first article inspections that can take days and weeks because of the fixturing necessary to view the entire part and assembly in many different planes, using many different datums. It is then not possible to stitch all of this data together in a visual way for engineers and research scientists to determine how far off the parts are from their original models.
It is also physically impossible to look inside orifices, tubes, and inside geometry without cutting parts in half or sectioning them. This can produce distortion of the actual parts and split the features needed for full metrology and validation. Guesswork such as datum re-establishing and solid model stitching is taken out of the equation when CT scanning is used.
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