A wireform interconnect component is an electrical contact, spring, clip or terminal made by bending and cutting wire into a shape, instead of stamping it from sheet metal or machining it from bar stock. The family covers parts that make an electrical connection, parts that ground or shield, and parts that simply hold something in place.
In short:
- Wireform parts are made on wire-forming machines from round or flat wire in a copper alloy, stainless steel or a similar spring material, and are usually plated afterward.
- Typical parts are connector contacts, spring contacts, PCB test points, terminals, jumpers, retaining clips, ground and shielding clips, and battery contacts.
- They often suit custom shapes and low to mid volumes, where the cost of a stamping die is hard to justify.
- The choices that decide performance are the wire material, the contact force and deflection, the plating, and how the part attaches to the board or housing.
What Wireform Components Are Used For
Manufacturers of wire-formed parts describe a fairly consistent product range:
- PCB test points. A looped or post-style piece of wire soldered to a board so a probe or clip has something to grab. See our guide to test point and probe compatible connector design.
- Spring contacts and battery contacts. A formed spring that presses against a pad or terminal and keeps a steady contact force.
- Connector contacts. Pins and socket contacts for small or custom connectors.
- Ground and shielding clips. Clips that tie a board, shield can or enclosure to ground.
- Jumpers and preformed links. Formed wire that links two points on a board.
- Retaining clips and hardware. Parts that hold other components in position.
How Wireform Differs from Stamped and Machined Contacts
The same contact function can be made in three ways, and the best choice depends on shape, volume and tolerance.
- Wire-formed. Made from wire, so the cross-section starts round unless it is flattened. Tooling is usually simpler than a stamping die, which makes it practical for short runs, custom geometry and quick design changes.
- Stamped. Cut and formed from flat strip. This is the usual route for very high volumes and flat, complex contact shapes, but the die is a significant up-front cost.
- Machined (turned). Cut from bar stock on a lathe. It gives tight control of pins and sockets, but the cost per part is generally higher.
Which one costs least depends on your real quantity and shape, so ask for quotes at the volume you actually expect.
Materials
A contact wire has to be both conductive and springy, and the usual alloys trade one against the other.
- Beryllium copper. A precipitation-hardened copper alloy with high strength and good fatigue behavior. It is commonly formed in a soft state and then age hardened by heat treatment to raise its strength. It is widely used for precision spring and RF contacts.
- Phosphor bronze. A general-purpose spring copper alloy. It is usually lower in strength than beryllium copper, but it is a common and economical choice.
- Brass. Easy to form and a good conductor, but with less spring strength. It suits fixed terminals and test points more than contacts that flex repeatedly.
- Stainless steel. Strong and corrosion resistant, but much lower in conductivity. It is used where strength or corrosion resistance matters more than carrying current, such as retaining clips.
Beryllium copper needs one extra note. Finished solid parts are generally considered safe to handle, but dust or fume from machining and grinding is a recognized hazard. Ask your supplier how they control it, and check which regulations apply to you. For restricted substances in general, see RoHS and REACH compliant connectors.
Plating
Plating sets contact resistance, wear and corrosion behavior. Common systems are a nickel underplate with gold for low-level signals, and tin for cost and solderability. Two points matter for formed wire: ask whether the part is plated after forming, so bends and cut ends are covered, and match the plating on both sides of the mating pair. Mixing finishes can cause fretting corrosion and rising contact resistance, as covered in can you mix gold and tin plated contacts and in our guides to connector plating technology and galvanic corrosion and plating incompatibility.
What to Specify
Give the supplier enough to quote and build the part you actually need:
- Wire material, diameter and temper (spring or formed).
- Contact force and deflection range, and the number of mating cycles required. See connector mating cycles explained.
- Current per contact and the temperature rise you can accept. See how to read connector thermal derating curves.
- Plating system and thickness, and what it will mate against.
- How it attaches: solder, press-fit, clip, or weld to a tab.
- Tolerances on the formed shape, and how the supplier inspects small parts.
- Packaging for automated placement, such as tape and reel, if a machine will assemble it.
- RoHS and REACH declarations for the exact part.
- Contact resistance targets. See connector contact resistance explained.
Wireform or Something Else?
- Choose wireform when the shape is custom, the volume is low to mid, and the geometry is a simple spring, clip or terminal.
- Consider stamped parts when the volume is very high and the shape is flat and complex.
- Consider spring-loaded (pogo) pins when you need a long stroke or very many cycles.
- Consider a standard catalog connector when one meets the need. A custom part adds sourcing risk, because only one supplier may be able to make it. See second-sourcing connectors in the supply chain.
Whichever route you choose, test samples in the real assembly, and check the exact figures on the supplier's current drawing and datasheet before you freeze the design.