Figure 1: Visual comparison . Steppers (Left) are dense and simple. Servos (Right) are longer and include a visible feedback encoder housing on the rear. The Million Dollar Question: "Which Motor Do I Need?" If you are designing a CNC machine, a packaging robot, or a conveyor system, you face the same dilemma every time: Stepper or Servo? Make the wrong choice, and you face two disasters: The Stepper Trap: Your machine "loses steps" (positional error) without knowing it, scrapping parts. The Servo Trap: You spend $5,000 on a system that could have been done for $500, blowing your budget. This guide bridges the gap between mechanical requirements and electrical reality. 1. The Stepper Motor: The "Digital Ratchet" Think of a Stepper Motor like a very strong, magnetic ratchet. It divides a full rotation into equal steps (typically 200 steps per revolution, or 1.8°). Pros: Incredible Holding Torque: Ste...
Tool Steels
As the designation implies, tool steels serve primarily for making tools used in manufacturing and in the trades for the working and forming of metals, wood, plastics, and other industrial materials.
Tools must withstand high specific loads, often concentrated at exposed areas, may have to operate at elevated or rapidly changing temperatures and in continual contact with abrasive types of work materials, and are often subjected to shocks, or may have to perform under other varieties of adverse conditions. Nevertheless, when employed under circumstances that are regarded as normal operating conditions, the tool should not suffer major damage, untimely wear resulting in the dulling of the edges, or be susceptible to detrimental metallurgical changes.
Tools for less demanding uses, such as ordinary handtools, including hammers, chisels, files, mining bits, etc., are often made of standard AISI steels that are not considered as belonging to any of the tool steel categories.
Heat Treatment and Composition
The steel for most types of tools must be used in a heat-treated state, generally hardened and tempered, to provide the properties needed for the particular application. The adaptability to heat treatment with a minimum of harmful effects, which dependably results in the intended beneficial changes in material properties, is still another requirement that tool steels must satisfy.
To meet such varied requirements, steel types of different chemical composition, often produced by special metallurgical processes, have been developed. Due to the large number of tool steel types produced by the steel mills, which generally are made available with proprietary designations, it is rather difficult for the user to select those types that are most suitable for any specific application, unless the recommendations of a particular steel producer or producers are obtained.
The Properties of Tool Steels
Tool steels must possess certain properties to a higher than ordinary degree to make them adaptable for uses that require the ability to sustain heavy loads and perform dependably even under adverse conditions.
Tool and die design tips to reduce breakage in heat treatment
The extent and the types of loads, the characteristics of the operating conditions, and the expected performance with regard to both the duration and the level of consistency are the principal considerations, in combination with the aspects of cost, that govern the selection of tool steels for specific applications.
Although it is not possible to define and apply exact parameters for measuring significant tool steel characteristics, certain properties can be determined that may greatly assist in appraising the suitability of various types of tool steels for specific uses. For detailed data, refer to the Machinery's Handbook.
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