Tablets that can replace smartphones: the choice of ZOOM. Tablets that can replace smartphones: ZOOM choice Best Android GSM tablets

1. Installing the part directly on the machine table (or in a universal fixture) with alignment of its position relative to the machine table and tool. This method is time consuming and is used in single and small sizes produced from the A-A surface, which in this case is mass production, when it is not economically feasible to manufacture special fixtures due to a small production program.

2. Installing the part on the machine table for marking. Marking is the application of axes and lines to the workpiece that determine the position of the surfaces to be machined. When marking, the workpiece is pre-coated with chalk paint; after it dries, the workpiece is placed on a marking plate, in a prism or on a square, and lines are applied to the surface using a gauge, compass, square, caliper with sharp jaws and other tools. In order for the lines to be visible if the paint is removed, points are applied with a core along the lines at some intervals. The marking is intended to indicate on the workpiece such a position of the machined surfaces so that the allowances for all surfaces are sufficient.

Marking requires a significant investment of time by a highly qualified marking specialist, whose individual qualities determine the accuracy of marking. Installation by marking does not provide high accuracy of processing. This installation method is used when processing large castings of complex shape and large forgings in single-piece and small-scale production (mainly in heavy engineering).

3. Installing the part in a special fixture. This method of installation provides for giving and fixing a certain position of the part for processing (moreover, the part is oriented relative to the cutting tool) with a sufficiently high accuracy and with a small expenditure of time.

When processing parts using special devices, there is no need to mark the workpieces and reconcile their position on the machine; thus, an expensive and time-consuming operation is eliminated, which, moreover, introduces errors in dimensions, depending on the individual qualities of the scriber.

Installation and fastening of parts on machines with the help of special devices is much easier and faster than installation and fastening directly on the machines. The rational design of the fixture ensures minimal installation time and a completely reliable fixing of the part. The use of a special fixture provides the highest and most stable machining accuracy for all parts manufactured with it; due to this, the interchangeability of parts is ensured to the greatest extent. In addition, the use of devices allows processing at higher cutting conditions, significantly reduces auxiliary time, including the measurement of parts during processing, allows the combination of main and auxiliary time, provides the possibility of automation and mechanization of the machining process.

In order to obtain the proper dimensional accuracy of the part processed with the fixture, it is necessary that the fixture itself be made very accurately and that due to the inaccuracy of the individual elements of the fixture, there should be no increase in processing errors. In this regard, when determining the tolerances for the dimensions of fixtures, it is necessary to assign such limit deviations that they are two times less than the limit deviations of the workpiece. The necessary accuracy of processing the part in this case will be ensured.

The question of the advisability of using a fixture when processing a part usually arises in single-piece and small-scale production, since the manufacture of a fixture, especially a complex one, for processing a small number of parts is mostly uneconomical.

R 1, R 2, R 3- forces acting on the part during basing

Figure 3.5 - Part basing scheme (six point rule)

In single and small-scale production, mainly normalized fixtures are used; it is also possible to use specialized devices, in these types of production they are rarely used, only in cases where without them it is not possible to fulfill the requirements of the technical specifications for the processing of parts, since the costs of manufacturing devices are not compensated by the benefits they provide. The greater the output of parts, the more economically advantageous it is to use special devices, because. the cost of their manufacture is decomposed into a larger number of parts.

In large-scale and mass production, the use of fixtures is mandatory, and economically it is always beneficial. With the repetition of the same parts processed in large quantities, special devices give a technical and economic effect, which pays off the cost of them with significant benefits.

With these types of production, in each individual case, only the question of the design of the fixture and of how many simultaneously processed parts should be designed for the fixture is decided.

In special fixtures, mounting surfaces are provided for basing parts.

As is known from mechanics, a rigid body in space has six degrees of freedom: three possible displacements (I, II, III, Fig. 3.5) along three arbitrarily chosen mutually perpendicular coordinate axes X, Y And Z and three possible rotational movements about the same axes (IV, V, VI). You can deprive a part (body) of each of the six degrees of freedom by pressing the part to a correspondingly located fixed point of the fixture (or machine table), called a single-point support.

Each fixed single-point support deprives the part of one degree of freedom, i.e. the possibility of moving the body in the direction of the normal to the surface of the brow at the fulcrum. In order to deprive a part of all six degrees of freedom, it must be based on six fixed points. The rule of six points is that each body (part) must be based on six fixed points, while the body is deprived of all six degrees of freedom.

These six points must be located in three mutually perpendicular planes: three reference points (1, 2 and 3) in the plane XOZ two points (4 and 5) in the plane YOZ and one point (6) in the plane XOY.

Three coordinates (1, 2, 3) determine the position of the part relative to the plane YOZ:

Y;

b) deprive the part of the ability to rotate around the axes X And Z. Thus, three coordinates (1, 2, 3) deprive the part of three degrees of freedom.

Two coordinates (4, 5) determine the position of the part relative to the plane YOZ:

a) deprive the part of the ability to move in the direction of the axis X;

b) deprive the part of the ability to rotate around the axis Y.

Therefore, two coordinates (4, 5) deprive the part of two more degrees of freedom.

One coordinate (6) determines the position of the part relative to the plane XOY, depriving the part of the ability to move in the direction of the axis Z, i.e. one coordinate (6) deprives the part of one more - the last - degree of freedom.

Therefore, to determine the position of the part in space, it is necessary and sufficient to have six reference points: 1, 2 and 3 define the reference plane; 4 and 5 define the guide plane; 6 - thrust plane.

With a larger number of fixed supports, the part does not rest on all the supports, and if, nevertheless, it is artificially pressed (pulled) to all the fixed supports, then it will be deformed by the action of the clamps.

For reliable fastening during processing, the part must be pressed simultaneously to all six reference points.

When a cylindrical part is based on a prism (Fig. 3.6), it is deprived of four degrees of freedom by four fixed single-point supports (1. 2, 3 and 4) and the remaining two degrees of freedom - from moving the part along the prism and rotating the part around its axis - is deprived of single-point supports (5 and 6), for which purpose it is necessary to put a stop at point 5, and a key at point 6.

When processing parts with flat surfaces, especially black or pre-roughly processed, the locating surfaces of the fixture are replaced with support pins, since the surfaces of the workpiece and the surface of the fixture (or machine) due to manufacturing errors will not touch all points during installation, but only some.

1,2,3,4,5,6 - single point supports

Figure 3.6 - Basing a cylindrical part on a prism

Three support pins replace the support plane, two - the guide plane and one pin - the thrust plane; six dots in the form of pins determine the position of the part to be installed on flat surfaces.

Sometimes a part is installed for processing simultaneously on two surfaces - two flat or two cylindrical or one flat and one cylindrical. In this case, two flat surfaces can be mutually parallel or perpendicular. Two-surface installations use support pins instead of full surfaces, which can be fixed or adjustable.

The use of support pins instead of flat surfaces has several advantages, which include the following:

The bearing surface of the pin, due to its small size, is not clogged with chips,

The accuracy of processing the supporting (installation) surface of the pin is achieved more easily than the accuracy of processing a flat surface;

The correctness and accuracy of the installation of the part is ensured more easily than when installed on a flat surface;

In case of wear, the pins are easy to replace.

It should be noted that when using a precision-machined surface as a mounting base, scaled support plates are used instead of support pins, which eliminate the possibility of dents.

The following examples illustrate various cases of installing a part on two surfaces (Fig. 3.7).

Figure 3.7.a shows the installation of the part along two parallel planes. Part 5 is installed on one (of two parallel) planes (A), and the other plane (B) is supported by a self-aligning pin 1 with a spring 2. The position is fixed with a screw 3 through an insert 4. The arrows show the direction of the clamping forces.

Figure 3.7 - Schemes for installing parts on various surfaces

On fig. 3.7.b shows the installation of part 1 along two mutually perpendicular planes. One surface of the part rests on flat surface 2, and the other on surface 3.

The installation of the part on a plane and a cylindrical surface is shown in fig. 3.7.c.

On fig. 3.7.d shows the installation of the part on a cylindrical surface - a pin 1 and a flat surface 2, and the part is wedged with a wedge 3.

If the part is not wedged, then due to a processing error it will not fit snugly against surface 1, or will not be put on the finger.

When installing the part on the cut pin 1, as shown in fig. 3.7.d, the part rests on surface 2 without the aid of a wedge.

If part 1 has two holes and must be installed on two fingers 2 and 3, then one of them (2) must be cut off (Fig. 3.7, e), otherwise it will not be possible to accurately install the part due to the inevitable inaccuracy of processing; at the same time, to facilitate installation, one finger should be shorter than the other.

Cylindrical parts (rollers, bushings, etc.) during drilling and (milling) are usually based on their outer cylindrical surfaces on supporting prisms, which are manufactured mainly with an angle α \u003d 90 ° (see Fig. 3.6), although sometimes there are prisms with an angle of 60 and 120 °.

Stepped cylindrical parts cannot be mounted on two fixed prisms, because the inaccuracy of the dimensions of the diameters obtained during processing will change the position of the axis of the part in height; with such an installation, it is also difficult to achieve the exact position of the axis of the part in the horizontal plane.

Therefore, when installing a stepped cylindrical part (roller) fig. 3.7.g, one fixed prism (1) (and longer) should be used, and the other - adjustable (2).

Let there be two series of independent tests of homogeneous quantities X And at. In this case, the observed values x i And i give different values ​​of the averages (or detect different dispersions (). The question arises whether these discrepancies can be considered significant or are they random. For example, two current samples are taken from two machines configured to process the same parts. Averages and variances of these samples differ from each other.At the same time, the law of distribution of the general populations from which the samples are taken is unknown.It is required to check whether both machines provide the same processing accuracy.

The null hypothesis in this case would be that the distribution functions X And at are identical, i.e., the samples belong to the same general population. To test this null hypothesis, the Wilcoxon test based on the number of inversions can be used. In this case, inversions mean the following. Observed values X And at in two samples are arranged in a common sequence in ascending order, for example, in the form

where are the members of the first sample and are the members of the second sample.

If any value X preceded by some at, then this pair is said to give an inversion. If some value x m preceded n values at, then this means that x m It has n inversions. For example, in our sequence x 1 gives two inversions, x 2- the same two inversions, x 3 - five inversions and x 4 - six inversions. The total inversions in our sequence will be

The null hypothesis is accepted if the number u will lie within some limiting or critical values ​​calculated for the accepted confidence level. Calculation of critical values ​​for u is made for the following reasons. If the sample sizes n> 10 and m> 10, then the number of inversions u distributed approximately according to the normal law with an average value (expectation)

and dispersion

Therefore, the limit values u defined by boundaries

where t depends on the accepted confidence level q and calculated from the table of values Ф (t)(see Appendix 1) according to the formula

where

For example for q- 0,05

This value Ф (t) according to the table of appendix 1 corresponds t = 1,96.

Thus, if the observed value u will lie within the boundaries defined by inequality (130) or not go beyond the critical regions:

then the null hypothesis is accepted, otherwise it is rejected. Because u has an approximately normal distribution only for volume samples u> 10 and m> 10, then to use the Wilcoxon test, it is necessary to take samples of at least 12.

test questions:

1. What is statistical hypothesis testing and what role does it play in research?

2. What criteria are used to test the hypothesis about the law of distribution of a random variable?

It's done! The market defeated Apple's famous stubbornness and the company not only recognized the existence of "phablets" as such, but even harnessed itself to full-fledged competition in this market with two models at once. Meanwhile, the white flag on the towers in Cupertino raises the question of how far can one go in the expansion of the diagonal? And isn't it better to acknowledge the fact that now there are no smartphones, phablets, tablets, but only devices with and without a telephone module?

Tablets that can replace smartphones: choosing ZOOM

In fact, these classes of devices simply do not have any technical gap. They are all assembled from the same parts, run the same operating systems, use the same network services.

Of course, everyone can distinguish a smartphone with a screen diagonal of 3.5 inches from a 10-inch tablet. However, this does not allow us to turn a blind eye to obvious trends that say one thing - the diagonal is growing, and the GSM module is becoming more commonplace and in demand.

In fact, at least some conditional distinction between smartphones and phablets on the one hand and tablets with support for voice calls over cellular communications can be found only in one thing - the physical size of the case. If, when calling, the user holds the device in his hand near his ear, this is a smartphone or, in extreme cases, a phablet. If forced to conduct a conversation through a headset - a tablet. Having adopted such a fairly simple (albeit subjective - everyone's hands are different) rule of differentiation, we will empirically find a line of 6.5-7 inches of screen diagonal, after which the phablet "turns" into a tablet with support for the GSM communication standard.

Having defined the concepts, let's try to find out how common today are phablets (smartphones with a screen diagonal of 5-6 inches) and GSM tablets. The all-knowing "Market.Yandex" gives the following statistics:

At the same time, out of 3052 tablets with a screen diagonal of 6.5 inches, as many as 617 have a GSM module.

It turns out that if in percentage terms phablets are still more widely represented, absolute numbers are no longer on their side.

Of course, the overall quality of GSM tablets corresponds to the average quality level of modern mobile devices, where the PRC occupies the leading place in terms of the number of brands and names represented. However, looking among the tablets with support for the voice function, you can find very interesting instances.

The best GSM tablets for Android

As we said above, the greatest variety of modern gadgets can be obtained in the Chinese market. However, a significant part of the models presented here still does not deserve interest. This is due to the weak technical base of the devices, and poor software optimization and banal problems with localization for the European, American and Russian markets, as well as the lack of warranty and service.

However, it's no secret that some manufacturers from China have managed to go a long way towards recognition in the world, having established a completely competitive production of smartphones, phablets and tablets, which are not ashamed to be placed next to the best samples and their class. As a living example, we can point to Huawei, which relatively recently released a GSM tablet Huawei MediaPad X1 7.0.

The manufacturer immediately declares the high quality of Huawei MediaPad X1 7.0 - by the very design of the performance and the materials used in the construction of the case. At launch, the tablet was one of the world's thinnest and most compact 7-inch tablets. And although the aluminum chassis MediaPad X1 7.0 is not monolithic, the tablet looks very stylish.

The computing power of the MediaPad X1 7.0 is provided by the Kirin K910 quad-core processor, created by HiSilicon, a company closely associated with Huawei. Its cores on the ARM Cortex-A9 architecture operate at a frequency of 1.6 GHz and score 21.5-22 thousand points in the popular AnTuTu test. As a video accelerator, the tablet uses Mali-450MP4, the amount of RAM is 2 gigabytes, the programs are located in the working memory of 16 gigabytes and on microSD flash memory cards.

Huawei MediaPad X1 7.0

The Huawei MediaPad X1 7.0 screen uses a very good quality IPS matrix. Its resolution is 1920 by 1200, the display has excellent color reproduction and high brightness. The screen is covered with protective glass Gorilla Glass and supports 10-point touch input.

Sufficiently serious power consumption of the tablet provides a built-in non-replaceable battery with a capacity of 5000 mAh. Its charge lasts for two to four days of standard use.

The built-in cameras of the device have a fairly high resolution: the front one is 5 megapixels, and the rear one is as much as 13.

In general, Huawei MediaPad X1 7.0 is good in itself, it confidently holds its position against competitors. However, the presence of a GSM module makes this device almost universal: it has a large screen for comfortable content consumption, excellent battery life, modest dimensions and low weight. The last - not least allows us to recommend this tablet as a replacement for a smartphone or phablet.

If a diagonal size of 7 inches seems insufficient to you, and the presence of a GSM voice communication module in an overall tablet does not cause confusion, then as a real life example, you should take a closer look at.

Samsung Galaxy Note 10.1 2014 Edition Wifi+3G, despite the name, was released in 2013 (at the end of the year) and was the first tablet with an eight-core processor. This processor is a proprietary Samsung Exynos 5420 with four Cortex A15 cores running at 1.9 GHz and four Cortex A7 cores clocked at up to 1.3 GHz. A complex mechanism works sequentially - depending on the resource intensity of the task and the need to save energy. The synthetic performance level of the Samsung Exynos 5420 is estimated by AntuTu at 32-34 thousand points.

As Samsung's flagship tablet line-up, the Galaxy Note 10.1 2014 Edition is ready to inspire big-figure fans with its other features. The tablet comes with 3GB of RAM, with 16GB and 32GB versions available on the market, both of which support an additional MicroSD card.

Samsung Galaxy Note 10.1 2014 Edition Wifi+3G

The screen is another reason for the pride of the device. Its resolution is 2560x1600 pixels, the matrix is ​​made using Super Clear LCD technology. In addition to conventional finger touch input, the Galaxy Note 10.1 2014 Edition's display is trained to work with the included pen using technologies licensed from Wacom, a well-known graphics tablet manufacturer.

The good technical data of the display is enhanced by the TouchWiz graphical shell, which allows applications to function in multi-window mode. For a tablet oriented to use as a working tool, this is an important point.

Flagship appetites Samsung Galaxy Note 10.1 2014 Edition Wifi + 3G satisfies the battery capacity of 8220 mAh. He does it well - for the day his charge is enough completely.

In general, the Samsung Galaxy Note 10.1 2014 Edition is an excellent, although not cheap, solution due to its flagship class. The tablet is good in itself, however, if you need a device with good performance, a very high-quality display and support for voice communication according to the GSM standard, then this is perhaps the most obvious, if not the only, choice.

If 7 inches of screen seems to you insufficient for a tablet, and 10 is too redundant for a device that replaces a phone, then you should pay attention to the middle options. If the time of choice suffers, then it makes sense to wait for the new Sony tablet from the Xperia line to appear on the market -.

Sony Xperia Z3 Tablet Compact has an 8-inch screen with a sufficient, but not overly "gluttonous" resolution of 1920 by 1080 pixels. The edges of the screen have a rounded shape, which goes well with a light, thin metal body. Traditionally for Soty tablets, the new Xperia Z3 Tablet Compact has dust and moisture protection, so you can make a business call from it even while taking a bath or sitting by the pool.

Sony Xperia Z3 Tablet Compact

The computing heart of the tablet is the Qualcomm Snapdragon 801 chip, which has already proven itself in flagship smartphones and phablets, with four cores operating at a frequency of 2.5 gigahertz. The processor scores 33-35 thousand points in AnTuTu and does not experience problems with the most modern applications and games. The 3 gigabytes of RAM that are on board the Xperia Z3 Tablet Compact also contribute to the same. Built-in memory holds 16 gigabytes of data, which can be increased using microSD cards.

A 4500 mAh battery is responsible for the comfortable charging mode of the device by modern standards. Its energy is enough for a day and a half of dense use, however, some saving methods bring the autonomy to two full days.

All in all, the Sony Xperia Z3 Tablet Compact promises to be a good choice in the 8-inch tablet market. As a phone, only the Nvidia Shield Tablet LTE could compete with it. However, the fate of the latter's GSM module is rather ambiguous (according to the latest data, the Nvidia Shield Tablet LTE will be able to play the role of a smartphone only in the United States in the networks of certain operators) and is not favorable to the Russian user.

	CPU	Screen	Battery	Price
Huawei MediaPad X1 7.0	HiSilicon Kirin K910	1920x1200 pix.	5000 mAh	i 13 000
Samsung Galaxy Note 10.1 2014 Edition	Samsung Exynos 5420	Super Clear LCD 10.1" 2560x1600 pix.	8220 mAh	i 25 500
Sony Xperia Z3 Tablet Compact	Qualcomm Snapdragon 801	1920x1200 pix.	4500 mAh	i 23 000

Source: ZOOM.CNews

GSM tablets on the Windows platform

Speaking of phablets or tablets with a GSM module, we almost automatically mean a device running the Android operating system. This is understandable: the iOS platform is unlikely to ever be installed on a tablet with support for voice calls in the foreseeable future, and somehow Windows is not remembered at all.

And in fact - in vain. Although the circle of manufacturers of GSM-tablets for Windows is narrow, they themselves can offer quite interesting options. For example, not every modern tablet, in principle, can boast a screen with a diagonal of 11.6 inches. BUT iRU C1101W- maybe!

However, the hardware base of the tablet in the form of a dual-core Intel Celeron 1037U processor (Ivy Bridge architecture) with a frequency of 1.8 GHz and the included keyboard-case allow the device to be called a laptop.

As befits a computer based on an x86 chip, the iRU C1101W has a full-fledged Windows 8.1 as an operating system. The presence of 2 gigabytes of RAM and 64 gigabytes on a solid-state array allows the tablet to use a fairly wide range of applications from the vast software library of Windows-compatible programs. If the framework of 64 gigabytes will be the user, the device allows you to increase the amount of storage through microSD cards.

IRu C1101W

Although the iRU C1101W screen diagonal is large, the matrix resolution is very moderate - 1366 by 768 pixels. The display supports ten-point touch input, and the tablet comes with a stylus.

Since the Intel Celeron 1037U belongs to the ultra-mobile line of processors famous for low power consumption, and the screen detail is modest by modern standards, the 4800 mAh battery lasts for 5-7 hours.

In general, the very presence of a GSM module in a device that is equally a tablet and a laptop on Windows 8 is a plus. And people who, for some reason, decide to make calls from a computer, will obviously appreciate this "plus".

If you do not need a Windows 8 tablet with such a large screen as the iRU C1101W, then you can pay attention to.

Prestigio MultiPad PMP810TF 3G is a tablet that was released quite recently, and therefore has a completely modern configuration. Its basis was the ntel Atom Z3735F quad-core processor with a frequency of 1.83 GHz. Thanks to the new Bay Trail-T architecture, the CPU TDP is only 2.2 watts.

Like the iRU C1101W, the Prestigio MultiPad PMP810TF 3G has 2 gigabytes of RAM and 64 gigabytes of working memory on the SSD. However, PMP810TE 3G with 16 gigabytes and PMP810TD 3G with 32 gigabytes are also produced under the Prestigio brand. All of them, of course, have a slot for installing MicroSD cards.

Prestigio MultiPad PMP810TF 3G

The Prestigio MultiPad PMP810TF 3G display with a fairly standard 10.1-inch diagonal for tablets uses an IPS matrix with a resolution of 1280 by 800 pixels. The device does not pretend to be a professional tool, so the screen is glossy, with rich colors and good brightness.

Unlike the IRu C1101W, the Prestigio tablet does not come with a keyboard either in the form of a cover or in the form of a docking station. However, third-party devices - both wireless with Bluetooth interface and wired with USB - MultiPad PMP810TF 3G supports.

The battery of the Prestigio MultiPad PMP810TF 3G is quite capacious - 7000 mAh. This allows the manufacturer to guarantee battery life of the tablet for at least 6 hours. However, this is a rather pessimistic assessment, in reality the device works longer.

All in all, Prestigio MultiPad PMP810TF 3G is a good alternative to iRU C1101W. The model has a smaller diagonal, but a higher screen resolution. The kit does not include a keyboard or a stylus, but the price of the device is almost 10 thousand rubles lower.

IRu Pad Master B1002GW

True, IRu has an answer to the price war from Prestigio - iRU Pad Master B1002GW. This tablet is relatively inexpensive, its screen is identical to the Prestigio MultiPad PMP810TF 3G display, and it also runs on an Intel Atom processor. However, iRU Pad Master B1002GW has an undeniable advantage: two slots for SIM cards. An essential trump card when it comes to using the voice call function over the GSM network.

	CPU	Screen	Battery	Price
iRU C1101W	Intel Celeron 1037U	1366x768 pix.	4800 mAh	i 24 000
Prestigio MultiPad PMP810TF 3G	Intel Atom Z3735F	1280x800 pix.	7000 mAh	i 15 000
IRu Pad Master B1002GW	Intel Atom Z3740	1280x800 pix.	7900 mAh	i 16 000

Interchangeability the property of the same parts, units or assemblies of machines, etc., is called, which allows you to install parts (assemblies, assemblies) during the assembly process or replace them without prior adjustment while maintaining all the requirements for the operation of the unit, unit and structure as a whole . The specified properties of products arise as a result of the implementation of scientific and technical measures, united by the concept "principle of interchangeability".

The most widely used complete interchangeability, which provides the possibility of free assembly (or replacement during repair) of any independently manufactured with a given accuracy of the same type of parts into assembly units, and the latter into products, subject to the technical requirements for them (for assembly units or products) in all quality parameters. Compliance with the requirements for the accuracy of parts and assembly units of products is the most important initial condition for ensuring interchangeability. In addition, to ensure interchangeability, it is necessary to fulfill other conditions: to establish the optimal nominal values ​​of the parameters of parts and assembly units, to comply with the requirements for the material of parts, the technology of their manufacture and control, etc. Parts, assembly units and products as a whole can be interchangeable. First of all, these should be parts and assembly units, on which the reliability and other performance indicators of products depend. This requirement naturally also applies to spare parts.

With full interchangeability:

The assembly process is simplified - it comes down to a simple connection of parts by workers, mostly of low qualification;

It becomes possible to accurately normalize the assembly process in time, set the required pace of work and apply the in-line method;

Conditions are being created for automating the processes of manufacturing and assembling products, as well as for the wide specialization and cooperation of factories (in which the supplying plant manufactures unified products, assembly units and parts of a limited range and supplies them to the plant that produces the main products);

The repair of products is simplified, since any worn or broken part or assembly unit can be replaced with a new one (spare).

Sometimes, to meet operational requirements, it is necessary to manufacture parts and assembly units with small, economically unacceptable or technologically difficult to implement tolerances. In these cases, to obtain the required assembly accuracy, group selection of parts (selective assembly), compensators, regulation of the position of some parts of machines and devices, fitting and other additional technological measures are used, with the obligatory fulfillment of the requirements for the quality of assembly units and products. Such interchangeability is called incomplete (limited). It can be carried out not for all, but only for individual geometric or other parameters.

External interchangeability- this is the interchangeability of purchased and cooperating products (mounted in other more complex products) and assembly units in terms of performance, as well as in size and shape of connecting surfaces. For example, in electric motors, external interchangeability is provided by the shaft speed and power, as well as by the dimensions of the connecting surfaces; in rolling bearings - according to the outer diameter of the outer ring and the inner diameter of the inner ring.

Internal interchangeability applies to parts, assembly units and mechanisms included in the product. For example, in a rolling bearing, rolling elements and rings have internal group interchangeability.

The level of interchangeability of production can be characterized by the coefficient of interchangeability TO in , equal to the ratio of the complexity of manufacturing interchangeable parts and assembly units to the total labor intensity of manufacturing the product. The value of this coefficient may be different, but the degree of its approach to unity is an objective indicator of the technical level of production.

Compatibility- this is the property of objects to take their place in a complex finished product and perform the required functions during the joint or sequential operation of these objects and a complex product under specified operating conditions.

Functional interchangeability standard products - this is the property of independently manufactured parts to take their place in the product without additional processing. Functional interchangeability implies not only the possibility of normal assembly, but also the normal operation of the product after installing a new part or other component in it to replace the failed one.

functional are geometric, electrical, mechanical and other parameters that affect the performance of machines and other products or service functions of assembly units. For example, the gap between the piston and the cylinder (functional parameter) affects the power of the engines (operational indicator).

This chapter deals with interchangeability only in terms of geometric parameters.