If you’ve ever wondered how metal sheets are joined together without welding or fasteners, chances are you’ve come across the process of clinching. Clinching, also known as press joining, is a cold-forming process used to join thin sheets of material by localized plastic deformation without the use of heat or filler material.
Learn what exactly clinching is, how the clinching process works to create a joint, the advantages over other joining techniques, the types of materials suitable for clinching, and the tools used in the clinching process.
What is Clincling?
Clinching is a mechanical process for joining two or more sheets of ductile materials by deforming them locally to create an interlocking joint. The materials remain solid during the joining and no heat or filler material is used.
The clinching process works by pressing the materials between a punch and die to cause controlled plastic deformation. This deformation interlocks the sheets being joined at a predetermined point. The result is a durable, leak-proof joint.
How the Clincling Process Works to Create a Joint
The clinching process utilizes a relatively simple press tooling setup consisting of a punch and die to create a clinched joint. Here are the basic steps involved:
The sheets to be joined are positioned between the punch and die. The sheets must be accessible from both sides.
The punch presses the sheets into an encapsulating die using a large force. This pressure causes the controlled plastic deformation that swages the materials together.
The final swaging of the materials forms an interlocking button on the opposite side, creating the joint. This is usually leak-proof due to the tight mechanical clinching of the two sheets.
The punch then retracts and the clinched part can be removed with a durable, sealed joint remaining.
What Are the Advantages of Clincling?
Several notable benefits make clinching an attractive joining option:
- Leak-proof and sealable joints – The mechanical interlock creates a sealed joint. This makes clinching suitable for liquid or gas containment applications.
- No heat affected zone (HAZ) – Since no heat is applied during clinching, there is no heat effected zone or chance compromising the base material properties near the joint.
- Weight savings – Clinched joints allow lightweight materials like aluminium and magnesium to be joined without adding fasteners or welding filler material. This helps reduce component weight.
- No surface prep needed – The sheets don’t need to be cleaned or prepared prior to clinching. The process works on raw material edges.
- Environmentally friendly – Clincling doesn’t require potentially hazardous chemicals, shielding gases, or welding fumes. It’s generally a very clean process.
- Visually appealing joints – The smooth clinched joints create no sharp edges and have an appealing industrial aesthetic.
- Automation capable – The clinching process lends itself very well to automation. Robotic arms can be leveraged to boost precision and throughput.
Suitable Materials for Clincling
Clinching is suitable for joining thin ductile sheet metals ranging in thickness from 0.5 mm to about 5 mm thick. The most commonly clinched materials include:
- Aluminium sheet alloys – 1000, 3000, 5000 and 6000 series aluminium can be clinched with good structural strength. This allows lightweight fabrications.
- Mild steel – Low carbon steel sheet metal is commonly clinched. The joints tolerate some material coating like galvanizing.
- Stainless steel – Austenitic and ferritic stainless steel sheets are also reasonable candidates for clinching.
- Copper alloys – Brass, copper and bronze sheeting can also be clinched effectively.
- Titanium – Grades 1-4 commercially pure titanium and alpha-beta alloys can be cold formed using clinching.
In addition to traditional metals, some plastics like PVC, ABS, Polycarbonate, Acrylic and Nylon may also be good candidates for clinching using modified parameters.
Tools Used for Clincling
There are two basic types of tooling used to perform clinching – fixed and adjustable tooling.
Fixed tooling consists of a punch and die with a fixed geometry and depth setting. This is the simplest and usually most cost effective clinching tooling. It’s best suited when clinching material thickness doesn’t vary.
Adjustable tooling uses a punch and die set that has incremental adjustments allowing the clinch depth to be varied. This accommodates different material thicknesses. Brands like Jurado Tools offer an adjustable clinching tool range.
Both tool types are commonly integrated into presses, stamping machines and CNC fabricating centers to automate clinching. Dedicated benchtop clinching machines are also available for manual clinching work.
Pneumatic clinching presses provide an affordable way to get started with in-house clinching capabilities.
Jurado Tools offers products like the MOUSE ALS system clinching machine.
For production scale runs, hydraulic clinching presses offer superior power and precision for repeatability. CNC integratable clinching units can provide that flexibility combined with robotic automation.
Final Thoughts
As we’ve covered here, clinching provides an innovative cold forming option for creating durable, air-tight sheet metal joints without welding. The clinching process interlocks and swages materials using punch and die tooling to deform the metals and plastics being joined.
Clinching delivers numerous advantages over traditional joining approaches – from being a fastener method to producing visually appealing joints. And it’s a green production process that reduces energy consumption and environmental impact.
With capabilities spanning from benchtop manual machines to fully automated robotic clinching cells, modern clinching equipment makes adoption simple. This allows smaller shops to integrate clinching in-house just as effectively as larger manufacturing facilities.
So if you’re exploring new ways to join sheet materials, clinching delivers a proven adhesive-free option to consider. The cold-forming approach may be just what your next project needs.
