double sewing machine

In the realm of sewing and garment construction, various techniques and stitches play an integral role in determining the durability and aesthetic quality of a finished product. Among these, the overlock chain stitch stands out for its unique application and functionality. This article delves into the characteristics, benefits, and applications of the overlock chain stitch, providing insights for both novice and seasoned seamstresses.

5. Additional Accessories Some overlock machines come bundled with accessories such as foot pedals, thread kits, and extra sewing feet. While these accessories can add to the initial cost, they can save you money in the long run by reducing the need for additional purchases.

1. Strength and Durability Lock stitches are known for their robustness. The interlocking of two threads creates a seam that can withstand significant tension, making it an excellent choice for seams that experience stress.

DIN    

Rubber type

Requirements of the shaft
Even more important than a correct interference fit of the Oil Seal is a perfectly smooth shaft in the region of the seal, particularly if shaft surface speed is high and the medium to be sealed is under a certain amount of excess pressure. The surface roughness of the shaft depends on the average profile depth Ra of the tool marks caused by the machining process. Oil Seals made of PTFE require, independent of the surface speed, a surface roughness of between 0,1 to 0,2 mm, because PTFE has less wear resistance than rubber seals. For normal circumstances, the shaft in the region of the seal must have a surface roughness of approximately:  To summarize, the surface of the shaft in the region of the seal should not have noticeable machining marks. For pivoting shafts and other difficult or critical sealing applications, it is recommended that Oil Seals with a helical groove hydrodynamic pattern, which has a pumping effect, be used. When grinding and polishing, an axial movement of the grindstone along the shaft must be avoided in order to prevent machine lay. 

Early engines used O-rings (also called packing rings or toric joints) as seals (first patented in 1896). These are just mechanical gaskets in the shape of a torus (a circular ring--like a lifesaver), seated in a groove and compressed during assembly between two or more parts. It creates a seal at the interface. However, O-rings require a fluid film to lubricate them. They have limited usefulness in vacuum application and at extremes of temperature. The modern oil seal represents a significant improvement over the simple O-ring because it effectively seals in lubrication and prevents contamination from outside under a wide range of pressures and temperatures.

3) Metal case and spring material

Pour-point depressants: This additive has nothing to do the actual pouring of your oil. In fact, pour-point depressants help prevent the wax particles in the oil from hardening in cold conditions. As a result, the motor oil flows freely even in low, cold temperatures and the engine doesn’t need to work any harder to pump it.

Almost every lip seal is constructed to have a flexible inner part that creates a dynamic seal on the moving shaft, as well as a hard outer casing that statically matches the machine-end cover. The flexible part is made from different grades of rubber, while the hard part is made of light-gauge metal or strong plastic.

Air side face The oil seal surface vertical to the center line of the shaft on the side that does not come in contact with substances to be sealed is called the back face.

Aflas is created from fluoroelastomers (FKM), providing the following benefits: