Tumbling (mechanical surface cleaning method) (Better)
Tumbling (also known as
tumble polishing) is a technique of polishing or smoothing a rough surface.
Different substances like stone, metal, glass etc. are used in tumbling process
depending on the final requirements. We can achieve the outer edge radius on
metal parts such as castings and stampings using this tumbling process. The
radius may not be very exact but it is sufficient to avoid the sharp edges.
In this process, a plastic or rubber barrel is loaded with tumbling material such as stone. All these elements have similar or same hardness. They also add some abrasive grit to the barrel along with a lubricant. Silicon carbide is commonly used as grit and water as a universal lubricant. The barrel is then placed on a slowly rotating guide rails for rotation. The speed or rotation depends on various factors like geometry of parts being finished, tumbling material, degree of finish needed etc.
The parts to be finished are added to the above loaded barrel and allow the barrel to rotate. It will take out most of the sharp edges and other burrs from the parts. Time needed for tumbling also depend on several factors like degree of finish required, base material, tumbling material etc. It may range from few minutes to few days to complete the tumbling process.
Sometimes, shape of the tumbling material is changed to achieve a better control on final finish. There pre-shaped materials are called "preforms".
Tumbling is an economical process as large batches of parts can be finished with little or no supervision.
In this process, a plastic or rubber barrel is loaded with tumbling material such as stone. All these elements have similar or same hardness. They also add some abrasive grit to the barrel along with a lubricant. Silicon carbide is commonly used as grit and water as a universal lubricant. The barrel is then placed on a slowly rotating guide rails for rotation. The speed or rotation depends on various factors like geometry of parts being finished, tumbling material, degree of finish needed etc.
The parts to be finished are added to the above loaded barrel and allow the barrel to rotate. It will take out most of the sharp edges and other burrs from the parts. Time needed for tumbling also depend on several factors like degree of finish required, base material, tumbling material etc. It may range from few minutes to few days to complete the tumbling process.
Sometimes, shape of the tumbling material is changed to achieve a better control on final finish. There pre-shaped materials are called "preforms".
Tumbling is an economical process as large batches of parts can be finished with little or no supervision.
Krish ,Jythra Engineering Services Mechanical Engineering Blog by Jytra
Tumbling (previous)
Tumbling (also called barrel finishing and tumbling barrel finishing) involves the use of a horizontally oriented barrel of hexagonal or octagonal cross-section in which parts are mixed by rotating the barrel at speed of 10-50 rev/min. Finishing is performed by a “landslide” action of the media and parts as the barrel revolves. As pictured in Figure 28.1, the contents rise in the barrel due to rotation, followed by a tumbling down of the top layer due to gravity. This cycle of rising and tumbling occurs continuously and, over time, subjects all of the parts to the same desired finishing operation. However, because only the top layer of parts is being finished at any moment, barrel finishing is a relatively slow process compared to other mass finishing methods. It often takes several hours of tumbling to complete the processing. Other drawbacks of barrel finishing include high noise levels and large floor space requirements. (Groover M.P., Fundamentals of Modern Manufacturing: Materials, Processes, and Systems 3rd Edition, page 663-664)
Human-machine interface ( HMI ) (new)
Descriptions of HMI can be broad. Although it can refer to any type of
interface device, the term HMI usually refers to the display, computer, and
software that serve as the operator’s interface to a controller or control
system. More precise definitions are provided by Baumann and Lanz (1998) as
well as by Charwat . They describe HMI as the part of an electronic machine or
device which serves for the information exchange between the operator/user and
the machine/device. HMI consists of three parts which are operating
elements, displays,and an inner
structure. The inner structure compasses hardware and software
(electronic circuits and computer programmes). Displays show and transfer
information about the machine to the user (for instance by means of graphical
displays) and operating elements transfer information from the operator to the
machine via for instance push buttons, switches, adjusting knobs, etc..
(The human machine interface as an emerging risk p.9)
Human-machine interface (previous)
The design of human machine interfaces for the use of computer and information systems is still more of an art form than a science. Because humans are so adaptable that they can cope with awidw range of a situations, there has not been asmuch experimentation on and evaluation of interfaces as might be expected. Most of this generation`s designer of terminals and software interfaces were trained when computer hardwere was expensive relative to people costs. Many user communities represented captive audiences, such as employees who had to use whatever system was provided. As a result, human factors and optimization of the human interface were often sacricificed for machine efficiency.
(Hiltz S. R.,Turoff M.,The network nation: human communication via computer,page 313)
The design of human machine interfaces for the use of computer and information systems is still more of an art form than a science. Because humans are so adaptable that they can cope with awidw range of a situations, there has not been asmuch experimentation on and evaluation of interfaces as might be expected. Most of this generation`s designer of terminals and software interfaces were trained when computer hardwere was expensive relative to people costs. Many user communities represented captive audiences, such as employees who had to use whatever system was provided. As a result, human factors and optimization of the human interface were often sacricificed for machine efficiency.
(Hiltz S. R.,Turoff M.,The network nation: human communication via computer,page 313)
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