Published 8/28/2012

Video: CT Scanning for Injection Molding

A mold maker discusses its experience with computed tomography scanning for inside and outside inspection of delicate molded parts.

Edited by: MMS Editorial Team

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The proof of any injection mold is the quality of the part it produces. However, for plastic parts that are particularly small and precise, determining that the mold is making these parts accurately can be an engineering challenge in its own right. Moldmaker NyproMold of Clinton, Massachusetts recently addressed that challenge by implementing a computed tomography scanner from Carl Zeiss Industrial Metrology for precise 3D inspection of small, delicate molded parts. In a new video on MMSOnline, various employees of NyproMold discuss how the company uses this scanning and how the technology works.

Computed tomography or “CT” scanning is routinely used in medical settings, where the scanner moves around the patient. In industrial CT scanning, the inspected part moves between the X-ray emitter and sensor. Software makes sense of the point cloud generated in this way, so fixturing the part requires nothing more than placing the part into a foam support.

Measuring a part through CT scanning and processing the data take around two hours, NyproMold personnel say. With the resulting data cloud, the company can make a precise comparison between the actual part and the CAD model, but that’s just the beginning. Software tools also permit assembly analysis using the geometrical data of the actual part, as well part-to-part comparisons for measuring the mold’s consistency over time and consistency from cavity to cavity.

Perhaps the most powerful advantage of CT scanning is its ability to measure inside the part just as easily as outside. With this capability, NyproMold personnel now are able to discover surface distortions, not to mention voids and inclusions, without having to destroy the part in search of them.

Company president Bill Muldoon compares this to having x-ray vision. “Imagine being able to look all through your parts with an accuracy of 5 to 7 microns,” he says, “and, at that level of precision, to really understand what you’re making.” Watch the video to hear more from him and others at NyproMold and to see CT inspection in use.