Clinching technology is fast becoming the manufacturing superhero as a sustainable fastening solution. The clinching process, a breakthrough in industrial engineering, uses punch and die tooling to create leak-proof joints in a single press stroke. Implemented on a large scale by Audi in 1985, clinching technology has accelerated in recent years because of public and industry demand for more sustainable ways of manufacturing. Here is an overview of the clinching process, applications, and economic and green benefits.
What is Clinching Technology?
Clinching is a simple method of assembling sheet metal without welding or fasteners. It’s a cold-forming process that involves using a special tool called a clinching machine or press that presses a punch into the layers of metal. The movement causes the material to flow and form a mechanical interlock. There are several types of tooling available including Tog-L-Loc®, Lance-N-Loc®, Oval-Loc® and V-Lock® for aluminium alloys, multi-material combinations (e.g. aluminium and steel), pre-coated, painted, and galvanised metals.
The patented Tog-L-Loc®, from BTM for example, produces a round, button-shaped extrusion on the die side of the assembly, and a small cylindrical cavity on the punch side which are leak-proof. See the innovative BTM Tog-L-Loc® in action here.
Clinching Compared to Traditional Methods
In modern manufacturing, spot welding and riveting are well-established metal fastening methods. With the increasing availability of lightweight materials and the demand for sustainable manufacturing, clinching technology opens new environmentally friendly possibilities.
Clinching replaces resistance spot welding which fuses two or more parts by high heat or pressure to form a join as the parts cool. The heat source is usually an electrical arc flame. Other forms include gas metal arc welding (MIG) and tungsten inert gas (TIG) welding. The environmental impact of welding has become increasingly evident in recent years. Welding can burn pre-painted surfaces, and emit harmful hot metal and flying sparks, toxic fumes, and gases.
Another popular method of joining materials that has been used for decades is riveting. Rivets are mechanical fasteners consisting of a cylindrical shaft with a head on one end. The riveting process involves inserting the shaft through aligned holes in the materials to be joined and then deforming or “setting” the other end to create a second head, securing the materials together. While durable, the riveting process is time-consuming and costly as holes need to be drilled, rivets inserted, set, and trimmed. Clinching eliminates drilling, the use of materials, and excess shavings that contaminate the environment.
Clinching Quality and Performance
Real-world applications including automotive, aerospace and electronics provide practical evidence of clinching performance and effectiveness. High-stakes industries need to prove the method can meet quality standards and use force placement testing to verify joints. In some industries, clinched joints must be evaluated to withstand environmental conditions such as sea air, salt water, and extreme variations in temperature, wind, and altitude.
Quality control methods to test joint strength include tensile testing, shear testing and peel testing. Cliched joints can also be visually inspected to assess joint quality. The punch side needs to be the correct shape and size as per the tooling used. No cracks, perforations, or distortion. The die side should be symmetrical with the right shape and dimension and without signs of structural stress. Other important measurements are the thickness of the base indentation to determine sheet compression and the diameter of the button on the die side for the radial expansion of sheets.
Clinching Sustainability Benefits
Material Efficiency: Clinching minimises material waste because it doesn’t need additional fasteners like screws, nuts, or rivets and eliminates slugs and shavings. This reduces the consumption of materials, which is environmentally friendly and cost-effective.
Energy Efficiency: Since it’s a cold-forming process, clinching doesn’t need the high temperatures associated with welding or the energy-intensive manufacturing of threaded fasteners. This results in lower energy consumption and reduced greenhouse gas emissions.
No Consumables: Unlike processes that use adhesives or welding consumables such as stick electrodes, flux, solid and saw wires, rod electrodes and gases, clinching doesn’t rely on consumables that can harm the environment.
No Toxic Emissions: Welding produces visible smoke that contains harmful metal fumes and gas by-products. Workers exposed to prolonged welding fumes can develop respiratory problems and lung damage. The clinching assembly process is a green and clean workspace.
Low Noise Emissions: The welding process can be very loud. Arc welding noise is the loudest and along with weld fume can contribute to operator hearing loss over a long period.
Clinching For Green Industries
Clinching technology has been used on a large scale in the automotive industry for years to join a variety of parts including petrol tanks, engine components, airbags etc. Clinching has also proven to be beneficial for industries such as white goods manufacturing, building supplies, and electronics.
Among the fastest-growing green industries, solar panel manufacturing has found success with the clinching process. Norwegian company, Sunlit Sea, partnered with BTM Scandinavia to manufacture floats for offshore floating solar panels. The floats are constructed from two aluminium sheets clinched together using the BTM V-Loc 5.5®, producing a strong, vibration-resistant, leak-proof joint. Aluminium is perfect for marine applications as it is resistant to corrosion and is lightweight. The pre-assembled floats are topped with solar panels and deployed in the sea.
As solar cells and other renewable industries continue to evolve, manufacturing processes and assembly will need re-thinking. As Sunlit Sea have shown, the clinching method of fastening is an environmentally friendly process that manufacturers can adopt.
Clinching Technology and the Renewable Future
Overall, Clinching is a sustainable manufacturing process that aligns with the principles of reducing waste, energy consumption, and environmental impact while maintaining high-quality and durable assemblies across varied industries. Unlike other green processes that are typically more expensive than traditional methods, clinching is a very cost-effective solution. It’s particularly relevant in industries aiming to improve their sustainability practices and reduce their carbon footprint.
Hawker Richardson is the exclusive supplier of BTM products in Australia and New Zealand. Is clinching technology suitable for your industry application? Contact our team for more information about clinching technology.