Medical manufacturing and measurement

When it comes to digital and pairing new hardware with existing machines, the trend of more modular, versatile designs comes into play for all applications, including those pertaining to medical devices.

Recent technologies such as stroboscopic illumination reduce the time it takes to measure an object, sometimes referred to as dwell time. Older systems needed to completely stop to eliminate vibration in the field of view to measure an edge without blurriness.

More modern mechanisms allow machines to measure toward an edge without slowing down or stopping. For example, strobe lights freeze the image so an accurate measurement can be obtained. However, to get the same effect, it’s possible to enhance the functionality of older machines by retrofitting them with new hardware.

Add-on, retrofit technology

Retrofittable technology and add-ons such as touch probes, strobe lights, RGB lighting, and optics can enhance measurement for new and existing machines. Strobe lights enhance nonstop motion during a measuring event, while optical sensors, such as laser or white light interferometry (WLI), are used for high accuracy Z measurements and complex profiles. Vision systems historically aren’t considered truly three dimensional (3D), but the use of these advanced sensors is changing that. With hardware and software add-ons, including auxiliary sensors, even standard accuracy machines can become 3D machines.

Another add-on, referred to as points from focus (PFF), allows an operator to create a 3D image from a single stack of images. Each image is analyzed for which pixels are in focus within that image stack. This type of 3D imaging is particularly useful from a medical perspective. For example, the shape of a knee replacement part has many contours associated with it, as well as a mirrored surface finish. A through-the-lens laser sensor can enable automatic tracking of the part’s surface, following contours while the machine moves, eliminating the need to stop the camera to re-focus.

To focus on shiny and mirrored surfaces, a projection system in the optical path creates a fringe effect and grid shape on the workpiece on which the machine can focus. This capability allows measuring many different medical parts. Adding WLI is also a possibility, allowing for the measurement of the thickness of contact lenses in a single pass, top and bottom, simultaneously.

Additional add-ons include chromatic point sensors (CPS), using a chromatic aberration to determine height differences. And there’s PFF, which can enable 300,000 points per field of view (FOV). If measuring the end of a serrated medical blade, a heart endoscope or multi-lumen tubing, PFF can build up a 3D image stack. This can obtain 3D data sets of the teeth on a blade, or threads of a bone screw, despite its unique flute geometry. And for a bone plate requiring texture in some places and smooth surfaces in others, this method of measurement accomplishes both.

Retrofit vs. new purchase

It all depends on the measurement needs and the manufacturer’s ability to retrofit. Newer machines are more modular, allowing for the selection of more sensors and newer technologies as they’re developed.

If 3D structure measurements will be required, add-ons may be needed. It comes down to factory-ordered vs. retrofitting in the field. Parts in the medical industry often require dimensional inspection, but may start requiring defect detection and surface attributes. With these added requirements, vision system capabilities can meet these higher demands in a single platform.

As minimally invasive procedures continue growing in popularity, accuracy requirements for medical devices used in precision circumstances are becoming more stringent. Cameras, lasers, cutting tools, implant mechanisms, and stents need to be manufactured and measured with great precision.

In medical manufacturing, some devices require 100% inspection for 100% of the part. Modern machines can accomplish this via higher throughput, flexibility, and versatility, but machines already in the field can accomplish the same if appropriate sensor technology can be retrofitted.

This means higher throughput, faster measurements, and the enhanced ability to visualize surface structure and texture, and shape or radius abnormalities. It also means a greater ability to detect defects – scratches, dents, and burrs – which could be detrimental to medical components.

Key takeaways

The big trend in manufacturing and measurement is digitization and automation, but not at the expense of the human element. It’s to support the human element with faster, more accurate results by having people and automation work together, delivering greater production and safety for medical manufacturers and patients. It also eliminates bottlenecks while enhancing measurement capabilities for hard-to-measure pieces and when there are multiple FOVs. In addition, automated output for measurement across many dimensions makes precise statistical analysis possible, cutting months and days down to hours.

Modern tools and machines allow for more prescriptive maintenance, helping eliminate unnecessary fixes and, in turn, saving money. Organizations can also more easily predict down time and plan accordingly for machine maintenance.

This is beneficial to the medical supply chain, where time and money can be costly downstream. Ensuring no flaws or defects make it out of the manufacturing process is crucial to successful manufacturing.

About the author: Allen J. Cius is a product group manager for Mitutoyo America Corp.

Mitutoyo America Corp.
https://www.mitutoyo.com