Delcam’s FeatureCAM supports shielding specialists

At VTI, PVC masks machined with FeatureCAM protect parts as they are metallised

Delcam’s FeatureCAM feature-based machining software plays a major part in helping Vacuum Technologies Inc. to supply the highest-quality electromagnetic shielding on a wide range of plastic enclosures.  The software is used both to make components for VTI’s unique metallising process and to manufacture fixtures for the company’s cured-in-place gasketing service.

For over fifteen years, VTI, which is located in Reedsburg, Wisconsin, has specialised in providing shielding for plastic enclosures, mainly for highly-demanding military and medical applications.  The company uses a unique vacuum process to apply a thin aluminium film to the surface of the part.  This coating provides the excellent electrical conductivity that is required and also gives good design versatility at a competitive cost.  In fact, the results can be so good that a coated plastic enclosure can sometimes give even better protection that a metal casing.

An increasing number of the enclosures now come with display windows that are moulded into the part.  These need to be covered with masks during the metallising process to ensure that no metal gets onto the window.  Some years ago, VTI switched from metal masks to PVC.  The benefits are that the material is lighter, cheaper and can be machined more easily with no need for cutting oils.  At around the same time, the company started using FeatureCAM to program the machining of the masks.

The ease of use of the software was the most important attribute when it was chosen.  Scott Nicholson, Fixture and Tool Design Engineer, has been using FeatureCAM for three years.  Even though he didn’t know much about machining, and nothing about the software, when he first started using the system, he was proficient in its use within three months.

The accuracy of the software is also essential.  "The masks need to be very precise to ensure metal doesn’t get onto the window,” explained VTI President Wil Fernandez.  "A lot of cleaning up is needed if you get the metallising where you don’t want it.”

The programming speed that is possible with FeatureCAM is also important.  "Every customer wants something different so we need to make new masks for every project,” claimed Mr. Fernandez.  "They also want a quick service, especially because the metallising usually comes towards the end of the manufacturing process.”

Some of the components need multiple masks to cover over holes or caps on several tools for a larger run of parts.  In these cases, it is easier to mould the masks in an air-cured silicone resin than to machine them all individually.  FeatureCAM is again an important part of the process as all the moulds are machined in PVC using programs generated in the software.

More recently, VTI added a gasketing service for its clients.  "One of our metallising customers was sending our parts out for gasketing,” remembered Mr. Fernandez.  "I thought ‘Why can’t we do that?’ and decided to set up a sealing unit in-house.  We use a special silicone filled with nickel to create the seals.  This material is applied onto the parts by robot.  We need fixtures to hold the parts exactly in position during this process.  These are all produced with FeatureCAM.”