Fasteners ASIA May/July 2020

Manufacturing Technology

“FUL” speed ahead in spring production The FUL series of spring coiling machines from Wafios are designed for maximum productivity and quality. The range previously consisted of seven models covering spring wires ranging from 0.12 to 8mm. With the addition of the FUL 166 for wires from 6.1 to 16mm, Wafios is expanding the upper end of the range. The features are mostly identical to those of the smaller models.

The feed rollers are fixed to their shaft in two ways: via positive locking with three driving pins and via force locking with a preloaded central nut. In the event of wear or if the spring wire thickness is changed, it is easy to carry out the necessary modifications. Keeping the (dis)assembly work to a minimum is a design principle that runs through the entire machine. This also applies to the slip control, for example, which only needs to be moved out of the work area rather than being dismantled. In addition to the new FUL 166, other Wafios models for the production of suspension springs are the FUL 175 (up to 17mm), the FUL 183 (up to 18mm), and the FUL 203 – the largest suspension spring machine for up to 20mm oil hardened and tempered wire. Wafios AG www.wafios.com

possible to achieve feed speeds of up to 220m/min. The lack of hydraulic systems offers an advantage, as pneumatic components require less maintenance. As a result, the cutting and coiling unit has also been designed without hydraulics. The FUL 166 is the first Wafios spring coiling machine with six pairs of feed rollers. However, all six pairs are only required for wires with a thickness greater than 14mm. For thinner wires, the machine fitter equips the machine with fewer rollers. “There are two possibilities as far as the number and design of the feed rollers are concerned,” explained Andreas Sigg from the design department at Wafios. “Either fewer pairs with a large diameter, or more with a smaller diameter. Large rollers are heavy. In order to make handling as easy as possible, we decided on six pairs of rollers that were smaller in diameter.”

Wire is transported via feed rollers with pneumatic clamping for all machines; the FUL 16 is the only model where the operator carries out clamping manually using spring assemblies. The larger the machine or wire diameter, the more feed rollers are used – FUL 16 to FUL 46 use two pairs, while FUL 56 to FUL 86 use four pairs. The pneumatic contact pressure can be adjusted on-screen for each pair of rollers. This concept makes it

The turning of the screw in metal pre-treatment for cold forming operations

reduced CO 2 impact and less water usage. Bonderite L-FM FL is a non-reactive, water-based polymeric coating that adheres to the surface physically without any reaction, so the only evaporates produced in the subsequent drying step prior to cold deformation are aqueous. As a one-step process, it eliminates all rinsing steps, which saves water, and also has a reduced energy demand with appropriately lower CO 2 emissions. When the cold formed screws are dephosphatised for final heat treatment, the polymeric coating is easier to remove, which permits the use of a dephosphating cleaner in lower concentration, which means less consumption. In addition to the environmental benefits, the Bonderite L-FM FL technology is characterised by its reduced complexity over zinc phosphating. As a single-bath process, it minimises equipment footprint and maintenance. Raw material surface properties require initial sand blasting or pickling and neutralising, but the conversion cycle is simplified to a single step and operates at a temperature between 40°C and 50°C, providing time and energy savings. Overall productivity is enhanced by the lubricity and pressure resistance, in comparison with traditional zinc phosphating processes, which results in longer extrusion die life, and has been confirmed in industrial-scale applications.

Henkel Adhesive Technologies has enhanced the market fit of its Bonderite L-FM FL portfolio of polymeric coatings for the surface conversion of metals used in cold forming operations. The optimised Bonderite L-FM FL process reduces the number of treatment steps, from as many as ten, to one or two, and is an alternative in the production of high-performance automotive bolts and screws. Medium carbon or alloy steel grades designed for cold formed threaded fasteners in property classes such as 8.8, 9.8, 10.9 and 12.9 require a prior surface conversion process to create a thin, adherent coating that will facilitate deformation and ensure the quality of the final product. In the automotive industry, these cold formed screws and bolts are used in a wide range of engine, powertrain, suspension, wells and other demanding applications. Traditional zinc phosphating and reactive soap processes, although well established in metal pre-treatment for cold deformation, are associated with a number of potential drawbacks, including high acidity, high energy consumption and phosphate sludge. They can also involve up to ten individual steps, from initial degreasing and pickling to activation, phosphating and soaping, with frequent intermediate rinsing. With Bonderite L-FM FL, Henkel has developed a solution to these issues that provides a flexible one-step process,

Henkel Italia Srl www.henkel.com

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Fasteners ASIA – May/July 2020

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