Peridot News

Custom Made RFI / EMI Shielding

Since Peridot Corporation first opened in 1996, we have processed a lot of  custom RFI (Radio-frequency interference) and EMI (Electro-magnetic interference) shielding. The theory is simple: if a hole is cut in an electronics box, it leaks. This makes the FCC unhappy.  Unruly chips on RF boards attempt to talk over their neighboring brothers and sisters creating general chaos for the harried RF engineer. Filling holes in electronics cases and entombing board level chips & circuits with little metal boxes and strips proves to be a cost effective solution to prevent this interference. Nerdy PHD EMI voodoo gurus command stiff salaries because if you do not pass EMI testing, you can not sell your product.

Customers who are unable to find off the shelf catalog solutions to these applications or those who won’t tolerate the glacial pace of the East Coast cabal of catalog shielding vendors often wind up at Peridot. These customers are pleased to discover a willingness to innovate and lead times that suit the critical time to market issues being faced. Peridot excels at small and large volume manufacturing of metal shielding products. The delicate forming often required for these items is not something traditional “sheet metal” vendors can handle due to the thin and springy metals often required.

Let’s take a look at a few applications Peridot has nailed:

Busy enough for you?

The shield above has a 304 stainless top and bottom with beryllium copper spring fingers sandwiched in between. Operations include:

  • Laser cutting
  • CNC press brake forming
  • Tapping
  • Resistance welding
  • Silk Screening

Here are a couple more examples from that same family of shields:



The above examples were all fitted on the back plane of refrigerator sized super-computers (think Cray!). Volumes ranged from a few dozen to several hundred per order.

Here are a couple of examples of board level shielding.

Fence and cover

These are laser cut from pre-tinned cold rolled steel and then formed on small CNC press brakes. The small tabs on the “fence” are soldered into holes in the circuit board. The top is snapped on and stays in place by virtue of spring force. This allows access to the chip for rework purposes. Here is a picture of the two installed together:

Here are examples of finger strips that are typically fastened to doors.

These repeat finger strips can be shipped with Z axis conductive decals applied to the bottoms with a release liner.  This allows for the strip to be affixed to the chassis without fasteners.

The next example is a tin plated beryllium copper shield that gets over-molded onto a cable end for robotic surgery. Tough part! That’s a lot of bends in a VERY small space.

Lots of forms in a small package

Here is a 7 slot PCI interface shield:

This PCI shield (shown above) was laser cut from 301 half hard stainless. The forming was done in one shot on a hydraulic press with a special die designed and built in house at Peridot. We do not have to buy tooling outside as we have our own in house tool and die capability.

This next example is being stamped on a progressive punch press die on a 60 ton Straight side punch press. Material is 304 stainless. Die cost was around $30,000 and part cost in volumes are around $.18 each. This die has produced several hundred thousand shields and has a lot of life left.

Bunches of Punches

Folded and spot welded boxes are commonly used to isolate circuits. This example was made from 5052 H32 temper aluminum and received a clear anodized finish.

Pre-tinned cold rolled steel is an excellent low cost shielding material. It laser cuts beutifully with minimal dross and solders well. Here is a shield made from this material.

.015 inch thick material. approx 12"L X 6"W X 1 inch high

Next part is .003″ thick beryllium copper that started as a chemically etched blank and was formed in a dedicated stamping die. Following forming we heat treated and bright tin plated this shield.

This little guy goes into a GPS unit

Please consider Peridot Corporation for you next shielding project!