A Connection for Life: Crimping

Crimping is a joining technique used to connect two components through plastic deformation, for example by flanging, pinching, or folding. Detaching a crimp connection is only possible to a limited extent. Crimping is often used for the creation of electrical connections.

In this two-part blog series, we will explain the technique and process in more detail and will answer some key questions.

What you should know about crimping

Crimping is used to create a mechanically stable electrical connection between conductor and connecting element – or in simple terms: A connector is attached to a cable. This connection type is prevalent in HF electronics and telecommunications because it offers connection security and simplifies handling significantly. The connection is made by applying pressure. Here, the crimp dies are precisely adjusted to the connector and the wire cross-section to achieve the desired and defined deformation of the connecting element and the conductor. When performed correctly, crimping creates a virtually gas-tight connection. Deformation of the crimp barrel and the fine-wired conductor creates a structure that restricts the penetration of oxygen and thus is protected against corrosion. Principally there are two types of crimp connections: open and closed. Open crimp connections are suitable for fully automated processing.

Different materials for different connections

What types of cable are there?

• Single conductor: suitable for large quantities for semi- and fully automated processing with crimp connections

• Round conductor: only suitable for semi-automated processing with crimp connections

• Flat ribbon cable or flat flex cable (FFC): preferred choice for internal cabling

Illustration 1: kabelforum.de

Crimping preparation

Terminology you should know:

• Wire: several wire strands compose one wire (also referred to as Litz wire)

• Cable: compound of several wires/wire strands in a joint insulation (also referred to as cable)

• Crimp edge: the part of the connector to be deformed

  • Insulation crimp: crimp edge for the insulation area
  • Wire crimp: crimp edge for the wire area

During preparation, the following three things must be observed:

• The right cross-section: The cross-section of the wire strands and the insulation diameter must be suitable for the size of the contact to be processed.

• Cutting: After cutting, the single wire end must be almost round. If the single wire end is flattened during cutting, wire strands might get torn off during the subsequent stripping.

Tip: If possible, use cable scissors for cutting, not wire shears.

• Stripping: The stripping knife cuts into the insulation but must not damage the individual wire strands. Next, the insulation is stripped off.

Tip: If possible, use V-knives, not flat knives

Our next blog about quality control will highlight what could go wrong during the crimping process. What is very clear already is that you need the right tools to achieve the right crimp connection.

Naturally the required tools are offered by Würth Elektronik:

Manual Crimping Tool: We offer manual crimping tools with die and positioning aid, where rolling of the crimp edge is done by the crimp die.

Automatic Crimping Tool: We also offer fully automatic crimping tools. Here, the crimp height is directly set and there is an integrated knife for cutting the crimp connector from the contact strip.

IDC Press for flat ribbon cable: Crimping flat ribbon cables requires a different approach. It is called IDC (insulation displacement connection). For this insulation displacement connection, the cable is simply placed into the device and then pressed. The cable cross-section should not be too large making it suitable for signals, but not for higher currents.

More Service Than You Expect from Würth Elektronik

Do you want to buy a manual crimping tool or an IDC press and would like to test it first? Do you require tools for just a short term to complete prototype production in-house? Do you want to run a small batch production or perform repair works that are too small a job for your usual cable assembler? Simply rent the manual crimping tool or IDC press for two weeks! Würth Elektronik offers a leasing service: Rent a Tool: quick – straightforward – free

If you already know which cable you require, then simply browse our pre-crimped cable solutions from Würth Elektronik.

Alternatively you could outsource your cable assembly. For this Würth Elektronik provides support as well. Our assembler pool helps you find and select the right partner. The assembler will then undertake manual, semi- or fully automated cable assembly as well as final inspection for you.

Please read the next part of our blog to learn more about the actual crimping process and quality control.