Stretchforming - Sheet
Contract Manufacturing

Sheet stretchformed parts The forming department has the ability to undertake and solve forming of sheets in a variety of types of materials and thickness. Sheets are stretch formed beyond their yield points while maintaining near machining tolerance accuracy. The sheet stretch forming process provides consistent parts, which are formed under stretch (work hardened). Parts hold their shapes, and remain wrinkle free.  700 ton vtl sheet forming press with positionable carriages Cyril Bath Company has been dedicated to providing quality parts and impeccable customer service. The implementation of such philosophy has been the core of this company. Today it is represented in many industries, such as automotive, trucking, motorcycle, aerospace, appliance, railroad, material handling equipment, satellite dishes and aeronautical.  Cyril Bath Company develops special stretch/compression forming machines that are used in house to form parts for our customer base.

Stress Strain Curve

YIELD CONDITION ANALYZER (available for presses with tension cylinders) Our Cyril Bath Company Control contains a yield condition analyzer mode of operation. This mode will sense, and display graphically to the operator the yield condition of the material being formed. This condition is known as plastic, or yield forming range of the material. The yield condition is found by continuously monitoring the ratio of the magnitude of transverse strain to the magnitude of the uniaxial state of stress momentarily existing in the forming material. Once the desired forming condition has been achieved, the control maintains this stress on the part throughout the forming sequence. The following is a brief explanation of the concept of elastic (recoverable) and plastic (permanent) strain (elongation). Plastic Deformation or Permanent Set (elongation) is any lateral elongation that remains in the formed part after the load has been removed. All elongation is composed of plastic and elastic elongation. Both conditions must be considered in order to achieve the permanent percent of elongation desired. Figure I illustrates this. If the material is stressed to Level 1 and then released, the strain (% elongation) will return to zero. If the material is stressed to Level 2 and then released, the material will recover the amount  E2 - E2P, where E2P is the plastic strain (% elongation) remaining after the load is released. Similarly, for Level 3 the permanent elongation will be E3P. As can be seen for stress levels above the elastic and plastic elongations, the total elongation is composed of both elastic and plastic elongations. By entering the amount of permanent elongation desired into the control system and initiating the yield cycle, the system will automatically achieve the desired part condition for forming. It will notify operator that the proper yield condition has been achieved and forming cycle has been initiated.