Top three tips on measuring medical parts

Medical Plastics News attended OGP’s Metrology Day where Colby Finn, VP of marketing and Dave O’Connor, director of sales and marketing, OGP, highlight why non-contact measuring is optimal for medical plastics.

There are multiple things to consider when measuring parts, especially when it comes to measuring medical parts. 

Colby Finn, VP of marketing and Dave O’Connor, director of sales and marketing share their top tips on measuring parts: 

1. Video measurement. The main advantage of video measuring is throughput, it means things can be measured faster. It’s not only the measurement process itself, but it’s also easier to set up the programme meaning there’s a lot of time saving involved. 

Measuring with video is non-contact, which is optimal for measuring medical parts, as there may be parts that cannot or should not be touched.  

“Non-contact measurement is highly suitable for medical parts that might be fragile or made of plastic, and you don’t necessarily want to touch them with force.” says Finn. “With non-contact measurement, not only is it very quick, but also, it doesn't disrupt the part. It doesn't move the part. You can look inside parts. Say they are plastic; you can look through the surface to go to the bottom surface. There's a lot of advantages of using video and other optical technologies on medical parts; from orthopaedic implants to plastic tubing for various kinds of medical applications across the board.” 

You can get high resolution, precision, and accuracy with video measuring, especially if you’re doing a measurement in one field of view, where you’re not moving your transport. You can easily get submicron accuracy on a video system. 

2. Automatic programming. This software can help with easily navigating around the part and easily generate findings through the measurements. Automatic programming, such as Zone3 from OGP, means you can import the CAD model and the tolerances and have it create the routine for you.  

The first thing is to import a Quality Information Framework file (GIF) into Zone3, which is an international standard for a CAD model and its tolerances. The software will find features and tolerances in the file and then ask if you would like it to create measurement steps. 

The software then allows you to choose the measuring features. In the QIF format, you can store how you want the features measured, meaning a measurement strategy will be made, which includes what tool you’ll be using, what point density, what scan strategy is wanted, and this will all be stored in the CAD model. 

3. 3D scanning. 3D scanning is very easy to use and can get you a lot of information. The ShapeGrabber, OGP’s latest 3D measurement technology, has a lot of benefits in comparison to conventional measuring. 

If a conventional measuring system were to measure something, you would pull-out information on specific features, and it would give you the measurements and beneath those measurements would be the actual points that are used to define those measurements. Whereas with the ShapeGrabber, it would show you the whole thing rather than just a few points. 

This does have a lot of benefits, for example, the whole image will always be archived for if something else needs measuring further down the line. 

Another huge advantage is a colour map, which is unique to 3D scanning. To get a reliable colour map, you need all these data points covering the surface.  

“Colour maps are a great diagnostical tool, but it is also a communication tool.” says O’Connor. “With the conventional measurement, you’re typically looking at a table of results and you’re trying to relate that back to a drawing. With 3D scanning, you can quickly see the results and determine where we should be looking.”