Etching and forming RFI Shielding

Features of RFI Products through Chemical Milling

• Solder Joints – Butt jointed corners with tin plate finish, allows corners to be soldered for increased screening.
• Spot Welding – Overlapping joint corners with tin plate finish are spot welded for increased screening.
• Locking Tabs / Locating Holes – an alternative to soldering, allowing greater rigidity.
• Dividers – provide discreet screening within the frame.
• Holes / Cut Outs – can be incorporated as requested.
• Anti Solder Migration Barrier – prevents solder creepage up the sides of its PCB mounting screening enclosures during automated and reflow soldering processes.
• Spring Fingered Lids – easy access and excellent attenuation.
• Push Fit Lids – easy access and good attenuation.
• PCB Locations – lancings or brackets can be specified to act as guides or supports.
• Locking Pins – for exact positioning and retention, deal for reflow soldering applications.
• Half Etch Pins – pins that are easily bent, to lock the shielding can into place.
• Common Metal Types – Copper, Brass, Mild Steel, Stainless Steel and Nickel Silver.
• Common Plating Types – Tin plate (Bright and Electrolytic) and Nickel plate.
• RoHs Compliance – All standard metal used for shielding cans are RoHS compliant. The types of plating we offer will always be RoHS compliant, unless you state otherwise. Please note that Hot Tin Dip is not RoHS compliant.

The Benefits of Shielding at PCB Level

Sheilding at PCB Board Level – A deceptively simple technique for controlling EMC (Electro-Magnetic Compatibility). Perhaps the most common technique to keep harmful interference out and also unwanted emission in.

Solutions at Product Enclosure Level – Why This is Unadvisable
Practical EMC shielding requires considerable engineering skill to give good results. However, at product enclosure level, it can be complex and expensive when taking into account both additional material and assembly costs. Also, effective enclosure shielding usually requires substantial filtering of all cables, which pass out of the product right at the point where they penetrate the enclosure shield.

Why Use Shielding at PCB Level?
Shielding at PCB level, however, is simple and low cost. Board level shielding solutions can be used to achieve an EMC performance that would be far more difficult and costly at product enclosure level.

At board level, shielding cans can be used selectively on problem areas of a circuit, directly tackling components with emissions that are too high or are too sensitive.

In brief, PCB shielding cans are simple metal boxes that are easily soldered in place. Dealing with EMC problems at this level, ensures component and assembly costs are low and the appearance and ease of maintenance of the product are not compromised.

Effect on Emissions
With this method of execution, the circuit board tracking and wiring is shielded inside the can solution. Due to space, contained tracks and wires are consequently very short and not very efficient as aerial radiating RFI or EMI. Furthermore, filtering to reduce overall emissions to an acceptable level, may be minimal if required at all.

For bespoke RFI Shielding products the manufacturing technique of choice is Chemical Milling, let us illustrate this in more detail: