The design features of the body of the portable electrocardiograph «ECG-EXPRESS»

The sequence of the industrial product shaping is specified, the main modeling characteristics of the configuration and some of its parts are designated subject to the electrocardiograph design and the technologies used for the production of its body.


Introduction
Currently the industrial design is a fundamental tool for the development of the competitive product, while the manufacturers experience much difficulties to stand among the competitors and amaze the customers with the modern and esthetically attractive design of the industrial products.
The relevance and potential of this trend is confirmed by a variety of the industrial products configuration introduced to the market. The quality, usability and ergonomics of the designed product is largely caused by the consistent regular shaping, which is dependent on the advanced materials and technologies, relevant configuration, stylistic and color solutions, that in general excludes the design errors and defects at the various stages of design [1].

The process of the product development and use
The main process stages of the product development and use are presented in Figure 1, including the following product design stages: 1 In the configuration development of the industrial medical device, in particular electrocardiograph, it is important to know its working principle and the scope of application: the self-control of the heart rhythm disorder and the ECG data storage for the subsequent analysis and study. This device is operated by sensors, which receive and convert the incoming signals, and then register them as a curved line on the paper.
The portable electrocardiographs are the terminated devices being often equipped with the screen which allow making a rough analysis immediately after the measurement, as well as, if needed, sending the recording for the detailed interpretation. These devices are wireless, and the measurement is made using the body built-in electrodes. The standard application scheme requires putting both thumbs to the electrodes on the surface of the device and wait for 30 seconds.

The types of the portable electrocardiograph
A key advantage of the hand-held electrocardigraphs is their portability and the diagnosis ability wherever and whenever possible, that is particularly important for the people suffering from the heart disease. The hand-held electrocardigraphs became available only 2-3 years ago, and there are only a few analogues on the market. Their comparative analysis is given in Table 1.
Of these devices currently the cardiograph Armed only is certified and sold in Russia, while being a Chinese development of Easy ECG, certified and imported in Russia by Armed. There are also attempts to adapt HeartCheck PEN to Russia. The strengths of these analogues, in particular, of the device Armed are their low price, achieved due to a significant reduction in the technical characteristics, and the huge advertising campaign.
As compared to the analogues, at the current reasonable price the electrocardiograph ECG-Express offers a wider range of functions (not only the diagnosis of the heart rhythm disorder, but for other diseases as well). And its innovative features will allow maintaining its competitiveness and attractiveness for the customer during several years, required to enter the market (figure 2).    The weight of this device is about 108 grams, the length is 145 mm, the height is70 mm and the width is 20 mm ( figure 4). The cardiograph takes a little space in the bag and in spite of its small size the cardiograph is handily placed in the hand and does not slip. The required minimum number of buttons is located on the central part under the monitor, the plugs are on the lateral side. The electrodebuttons used to record the measurements are located on the front and lateral sides. The slot for convenient removal of the back cover, which is very tight to the body, is located on the rear side. The mini-USB plug, which is designed to charge the cardiograph or to PC connect, is located on the bottom. The extended round configuration of the device is caused by the ergonomics criteria, the working principle and the configuraton of the modern phones and gadgets used every day [4,5]. configuration reflects the characteristics of its construction, the force distribution, the material behavior, that is characterized by the phenomenon of tectonics. The cardiograph shape also communicates with the environment, in this case it can be referred to the one-piece structure with the built-in hidden mechanism [6]. The color scheme is determined based on the configuration composition of the industrial product and the product color matrix, established in 1994 by Weinberger, Campbell and Brodie, according to which the selected colors are referred to the low-risk group in connection with their dyeing. The main characteristics of the visual perception are given in Table 2 [7]. By physiological and psychophysiological effects on the humans the yellow color initiates the brain function, green and blue cause a sense of freshness, remove exitation, calm, reduce the blood pressure, slow down the pulsation. The green colour is disciplinary making people self-control. Blue, green, yellow have an overall positive psychoactivity effect, improving the working ability [5].  The body frame is made of the ABS plastic or two-component polyurethane plastic by casting method in a silicone mold under the ambient pressure (the autoclave molding), or by vacuum casting method, depending on the configuration, the dimensions of the component and the set task. The twocomponent plastics are not "standard" plastics, which are casted under pressure into the mold, and there are some restrictions on use, such as the wall thickness (the wall thickness of the piece can not be less than 1 mm), it is prohibitted to use the polyurethane plastic under temperatures above 100-120°C. Other characteristics are similar to the common thermoplastics.
All materials used for the manufacture of the products from plastic, are painted in a variety of colors and combinations by adding the dye (pigment). The technology of the plastics production with different colors has a small weak point, that is the colouring of the plastics requires the specific equipment, which only a few manufacturers possess, thus very often it turns out that the color shades of the plastics depend on the suppliers. The highly concentrated plastic granules are used to facilitate the technology and avoid the dependence on the pigments' suppliers. About 2% concentrated plastic granules are added in the uncolored plastic to produce the desired color. The choice of the available colors of the super concentrate is highly diverse, but still limited, that should be taken into account for the plastics molding. The superficial coloring is used to make the plastic parts of the body frame in the silver or metallic colors. It is the manual painting of the details with the standard spraygun followed by drying process in a special chamber. A layer of the protective varnish is applied on top of the paint, which increases the coating resistance and assures the extra shine of the surface. The major processing complexity of the superficial coloring is the requirement to work in the clean rooms with the minimum dust.

Conclusion
Thus, the modern portable devices for the diagnosis of the cardiac rhythm have become the most relevant means of the cardiovascular disease prevention and entered in our life, that generally affects their configuration and appearance. The ease of use, ergonomics, functionality and appearance of the cardiograph prevail in the development of its configuration.