Welding stitch

The underside of fabricated baseplates beneath pump and driver supports shall be welded to reinforcing cross members, and the members shall be shaped to lock positively into the grout. All welding shall be continuous. Stitch welding, top or bottom, is unacceptable. 

While welding branch fittings in pipes and vessels, the weld projections and rubber lining projections should be outwards. Stitch welding from outside is preferred as shown in figure 6.2. 

Figure 6.2 Outward rubber lining projection and stitch welding. Rubber lining is shown in dotted lines.

Similarly, fabric-supported materials can be welded vinyl sides together, and plain welds can be made over stitched seams in such materials when, as in the protective garment trade, it is required to make the seams waterproof. 

Simple electrodes may be engraved with patterns of stitching or other designs (including trade names, logotypes, etc.) and in the course of welding also emboss permanently the design in the area of the weld. 

Figure 5.6 Through wall penetrators in ERW weld3 Figure 5.7 Stitch weld (intermittent fusion) in ERW weld4...

There exists another variant of FSSW where the FSSW tool is traversed a short distance. This may be referred to as stitch FSSW. However, it eliminates the fixturing benefits that would normally be accompaiued by FSSW, but if the weld is long enough, a stitch FSSW will have higher strength than an FSSW. 

Figure 12.9 shows the tool movement of various FSW processes and a corresponding top view of the welds. In the FSSW process, the rotating tool is plunged, momentarily held, and then extracted. In this process, the squeezed material is lumped around the shoulder indentation. Stitch FSW and swing FSW result in short-... 

Fig. 1 2.9 Tool movement and top view of variant of friction stir welding (FSW). (a) Friction stir spot welding, (b) Stitch FSW. (c) Swing FSW. Source Ref 5...

Fig. 12.31 Failed lap-shear specimens and as-welded micrograph of (a) friction stir spot welding and (b) stitch friction stir welding joints. Arrows show fracture path. Source Ref 5...

F. Hunt, H. Badarinarayan, and K. Oka-moto, Design of Experiments for Friction Stir Stitch Welding of Aluminum Alloy 6022-T4, Paper 2006-01-0970, 2006 SAE World Congress (Detroit, MI), Society of Automotive Engineers, 2006... 

Seam strength does not only apply to stitched seams but also to non-stitched seams whether they are bonded or welded. In a research paper by Hayes and McLoughlin (2007), the relationship between welded and stitched seams is examined and statistical analysis is used to compare their properties. 

Woven textile belts stitched or welded along the perimeter... 

A welded seam is formed where two pieces of material are fused together by heat and pressure alone, creating an adequate bond on thermoplastic coatings such as polyvinylchloride, polyurethane, polyethylene and polypropylene. Welded seams are also being used increasingly for women s bras and babies pants and nappies, as they are comfortable. The finished seams mb the skin less, as they are flatter and lighter than the conventional seams. Chemical protective clothing is another area where welded seams provide improved penetration resistance, as there are no stitch holes for the chemicals to penetrate. 

However, adhesive bonding and thermal welding do have certain limitations. Seams made with these processes tend to be noticeably stiffer than seams that have been joined using traditional stitching methods. Seams cannot be thermally welded when the fabric is predominantly made from natural fibres although adhesive bonding is possible on all types of fabric. 

We are already familiar with a portable solar charger, described in WO 2004/077577. This charger includes a flexible photovoltaic panel that is permanently fixed onto a flexible textile material. The said solar or photovoltaic panel can be stitched along its inactive edges to the flexible textile sheet, glued or even welded by the application of heat or ultrasound. 

As well as the foam replacements described in 15.3.3.1 in relation to mattresses for beds, multiknit fabrics, based on stitch-bonding technologies and nonwoven composites, can be used as foam replacements within furniture. Multiknit fabrics have excellent compressibility, low area and bulk density, heat, noise and vibration insulation, excellent mouldabUity, and the potential to be welded if they contain predominantly... 

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