The caliber of the plug is pass-through or non-pass-through. Control of calibers, their purpose, classification, rules of use
Inspection of smooth cylindrical products such as shafts and bushings in mass and large-scale production is carried out using limit gauges (for products with sizes from 1 to 360 mm).
Calibers intended to determine the suitability of parts with approval from IT6 ... IT17.
Calibers are used to check the dimensions of smooth cylindrical, conical, threaded and splined parts, the depths and heights of protrusions, as well as the location of surfaces and other parameters.
To control the shafts, staple gauges are used, and plug gauges are used for holes.
It is impossible to determine the actual size of a part using gauges. With their help, they find out whether the size being checked is beyond the upper or lower limit, or is between them.
For control use set of calibers: passing (PR) and non-passing (NOT).
By purpose calibers are divided:
- workers – used by inspectors or workers when monitoring parts during their manufacturing process ( PR and NOT).
- control – when monitoring working calibers during their manufacture ( K-PR and K-NOT), and operation ( K-I wear). Manufactured only for staples in the form of rings. They are not made for plugs (complex configuration, high accuracy). K-I - control the maximum wear of the pass-through gauge.
Rules for using calibers
Detail considered fit, if the pass-through gauge (the pass-through side of the gauge), under the influence of its own weight or force approximately equal to it, passes, and the non-go-through gauge does not pass along the controlled surface of the part.
If the PR caliber does not pass, it is a correctable defect; FAILS – irreparable marriage.
Caliber designs
Plug gauges
Gauge gauges
Rigid and adjustable brackets are used. Adjustable brackets can be adjusted to different sizes (up to 330mm), allowing you to compensate for wear and use one bracket to control sizes within a certain range. Used to control sizes of grade 8 and coarser. Less accurate and less reliable compared to rigid ones.
Caliber called a scaleless measuring instrument designed to control (check) the dimensions or shape and relative position of the surfaces of a part. Since the size of the part is limited by two maximum dimensions, to control them it is necessary to have two gauges, one of which controls the part according to its largest, and the other according to its smallest maximum dimensions. These calibers are called extreme. Unlike instruments and universal measuring instruments equipped with reading devices (scale), gauges do not determine the actual value of the controlled size, but only determine whether the controlled size is within the tolerance. When checking by limiting gauges, parts are sorted into three groups: suitable - with dimensions within the manufacturing tolerance range, final defects and correctable defects. Depending on the shape of the parts being controlled, gauges are divided into smooth, threaded, splined, etc. The most numerous are smooth gauges. They are divided into gauges for checking shafts (clips and rings) and gauges for checking holes (plugs).
Staples - gauges for checking shafts. Rings are rarely used, since they are less versatile and do not allow you to control parts on the machine, for example, the dimensions of the crankshaft journals. The staples have two sides: pass-through and non-pass-through. They differ not only in nominal dimensions, but also in appearance (the non-passing side of the bracket has chamfers on the measuring jaws).
The designs of staples are numerous and varied. The most common staples are single-sided, double-sided sheet, stamped and cast, and adjustable. Adjustable clamps can be adjusted to a different part size or restored to size as the gauge wears out. This increases the life of staples and reduces the cost of purchasing gauges. Adjustment of the size of the staple is achieved by moving one of the gauge inserts. Traffic jams are called gauges for checking holes.
The designs of plugs are quite diverse. They come in full and profiles, double-sided and single-sided, with inserts.
The gauges are marked with: the nominal size of the part, the conventional letter designation of the tolerance field of the part (the main deviation with the quality number), signs and digital values of the maximum deviations of the part (mm), the designation of the side of the gauge - PR (pass) and NOT (non-pass) and a trademark manufacturer's plant.
To control the wear of brackets (rings) and their sizes during the manufacturing process in grades from 1T6 to P77 with sizes up to 500 mm, three types of control gauges are provided:
K-PR- counter-caliber plug to control the size of the passage PR new working bracket; K-NOT- counter-caliber plug to control the size of the impassable NOT new working bracket; K-I- counter-caliber plug for monitoring the wear of the pass-through bracket PR according to the greatest wear limit. If the caliber K-I passes through the controlled bracket, then it is worn beyond the established tolerance and must be removed.
Caliber tolerances(GOST 24853 - 81). For the manufacture of all types of gauges, tolerances are established, designated in Latin letters: H - for plugs (Hs - for gauges with spherical measuring surfaces); Н1 for staples and Нр - for counter-calibers.
In grades from 1T6 to 1T10 inclusive, the tolerances for staples are approximately 50% greater than the tolerances for plugs, which is explained by the greater complexity of manufacturing staples. In grades 1T11 and coarser, the tolerances for brackets are equal to the tolerances for plugs.
Pass-through gauges PR wear out during operation. The amount of wear of PR gauges is limited by the tolerance field of the part, and for parts with tolerances up to the 8th grade, the size of the gauge - plug (staple) is allowed to exceed this limit by the value V (VI). With nominal sizes above 180 mm, the tolerance field of the HE caliber and the wear limit of the PR pass-through gauge shifts inside the tolerance field of the part by an additional value b or b1 - the so-called “safety zone”. Shifting the tolerance fields of gauges and the wear limits of their pass sides inside the tolerance field of the part by the value z or z1 eliminates the possibility of distortion of the nature of the fits and guarantees obtaining the dimensions of suitable parts within the established tolerance fields.
In mass and large-scale production, the suitability of parts with tolerances from IT6 to IT17 is checked using gauges. These gauges are used to check the dimensions of smooth cylindrical, conical, threaded and splined parts, the depths and heights of shoulder lengths, as well as the location of surfaces and other parameters.
Calipers are scaleless measuring instruments designed to control the size, shape and relative position of the surfaces of parts. Calibers are limited and normal. Limit gauges limit the largest and smallest limiting dimensions of parts and allow you to determine whether the size being checked is within the tolerance. Limit gauges have two sides: pass and non-pass. The control principle is as follows:
a) the gauge - ring and gauge - bracket of the pass-through PR must pass along the shaft under the influence of its own weight or force of at least 1N.
b) the gauge-ring and the gauge-bracket should NOT pass through.
c) caliber - the passage plug must pass freely through the hole under the influence of its own weight or with a force of at least 1N.
d) gauge - the no-go plug should NOT fit into the hole.
e) the product is considered suitable if the pass-through gauge PR passes, and the non-go-through gauge does NOT pass through the product.
A pass gauge PR is a gauge that controls the limiting size corresponding to the maximum material of the product being tested.
A no-go gauge is NOT a gauge that controls a size limit that corresponds to a minimum material.
A control gauge is a gauge used to control workers
caliber - staple.
1.2 Normal calibers.
Normal gauges are precise templates that are used to control complex profiles and are made according to the nominal size of the part.
Templates include angular, radius, fillet and other gauges.
To control the radii of concave and convex surfaces, sets of radius templates are used; to determine the nominal pitch of the thread and its profile, sets of thread gauges are used; To determine the size of the gap between the planes, a set of feeler gauges is used.
1.3 Limit calibers for depths of heights and ledges.
The depths and heights of benches with dimensions of 1 - 500 mm and tolerances of 11-17 qualifications are controlled by limit gauges, the maximum deviations of which are provided for in accordance with GOST 25344 - 77.
The limiting gauges for bench depths and heights are structurally represented by stepped plates of various shapes.
The side of the working caliber for the largest maximum size is designated by the letter B, the side of the smallest maximum size by the letter M.
1.4 Gauge - staples for length control.
Product lengths from 10 to 50 microns with 6 or more coarse grades are controlled by limit gauges - staples.
To control lengths from 10 to 360 mm, single-sided double-limit gauges are made - staples.
To control lengths over 300 and up to 500 mm: gauge - double-sided staples.
1.5 Design of smooth gauges.
Structurally, smooth gauges are made adjustable and non-adjustable: gauge - plugs and gauge - staples.
1.6. Technical requirements for the production of smooth gauges. Measuring parts caliber - plugs are made of steel grade X GOST 5950 - 73 or steel ШХ 15 GOST 801 78, it is allowed to be made of steel grade U10A or U12A according to GOST 1435-75.
Roughness of measuring surfaces of calibers:
6th grade R a =0.04 to 0.08 microns.
7-9 qualifications R a =0.08 - 0.16 microns.
10-12 quality K., = 0.16 microns.
13 and rougher grades R a =0.32 µm.
The hardness of the working surfaces of smooth calibers is in the range of 56 - 64 HRC.
1.7 Marking of calibers.
On each caliber it is marked on the handle:
Controlled nominal hole (shaft) size;
Designations of the tolerance field of the hole (shaft);
Numerical values of maximum deviations of the hole (shaft) in mm;
Caliber designation;
Trademark of the manufacturer;
1.8 Caliber tolerances.
According to GOST 24853 - 81, the following manufacturing tolerances are established for smooth calibers:
N - working gauge - plugs, HI - working gauge - staples, Hs - gauges with spherical measuring surfaces; HP control gauges for staples.
Pass-through working gauges PR wear out, as a result of which a wear tolerance has been introduced, upon reaching which the gauge is removed from use. The wear limit is located from the pass limit at a distance Y or Y1.
For all PR pass-through gauges, the H and HI tolerance fields are shifted inside the product tolerance field by the amount z - for plug gauges and zl - for staple gauges.
Work order:
1. Study of various designs of smooth gauges.
1.1. Familiarize yourself with all types of proposed calibers; plugs of various types and designs, rigid and adjustable brackets, to control the depths and heights of ledges, the location of surfaces.
1.2. Give a brief description of the design of the calibers, its name and purpose, and make a sketch.
1.3. Decipher the markings and determine what dimensions the gauges are intended to control, determine the nominal size, tolerance range and maximum deviations of the part dimensions.
2. Product control using smooth gauges.
2.1. Study the drawing of the controlled product, make a sketch of it, indicate the controlled size and tolerance range.
2.2. According to GOST 25347 - 82, determine the maximum deviations of the controlled size and indicate them on the product sketch.
2.3. Construct a control scheme for the product using PR and NOT calibers.
2.4. Select gauges to control the specified dimensions of the product, write down their names and markings.
2.5. Wipe gauges and instruments with a clean cloth.
2.6. Inspect the gauges carefully.
2.7. Check the product with calibers. Control of each size should be carried out consistently for all products.
2.8. Record the results of caliber control in the report table. For each controlled element of the product, indicate its suitability.
2.9. After checking all dimensions, give a general conclusion about the suitability of the product. A product is considered valid if all dimensions are made correctly.
When testing with smooth gauges, the size of the product is considered valid if the PR gauge passes, and the gauge does NOT pass into the product.
The marriage is final if the PR caliber passes and the caliber does NOT pass.
2.10. After finishing work, lubricate the measuring surfaces of gauges and products with anti-corrosion grease, and tidy up the work area.
Security questions:
1. What are calibers called?
2. What calibers are called limiting and normal?
3. What are control gauges used for?
4. List the types of smooth gauges for checking holes and shafts?
5. How is the suitability of a product determined when testing with smooth gauges?
6. Is it possible to determine the size of a product using a nasty gauge?
7. Marking of smooth calibers?
8. What are the requirements for the design and materials of calibers?
9. Measures to improve the durability of calibers?
10.How should the bore and shaft be checked with gauges?
11.How should a product be checked with normal gauges?
12.How is the depth and height of product ledges controlled?
13.What tolerances are established for the production of smooth gauges?
14.What deviations are established for the wear of smooth gauges?
15.What are the maximum dimensions that control the caliber - PR and NOT plugs?
16.What are the maximum dimensions that control the caliber - PR and NOT staples.
Figure 1.5 - Basic designs of gauges - plugs for checking holes and control gauges for staples:
a) double-sided plug with inserts (1 – 6 mm); b) double-sided plug with inserts (3 – 50 mm); c) one-way plug (52 – 75 mm); d) stamped plug with pass-through (non-pass-through) with nozzles (52 – 100 mm); e) pass-through (non-pass-through) incomplete stamped plug (102 – 160 mm); f) the plug is passable (non-passable) incomplete (102/75 – 300 mm); g) the plug is passable (non-passable) incomplete with linings (160 – 360 mm); h) single-sided sheet cork (52 – 360 mm); i) the washer is full (18 – 100 mm).
TO category:
Turning
Types of calibers and their scope
In mechanical engineering, the so-called alternative method of monitoring product shelf life is widely used. It allows you to divide products into good and defective. In this case, the actual values of the parameter being checked are not determined, but the fact of its compliance with the standard is established. When alternatively checking the geometric parameters of products, gauges are most often used.
Calibers are scaleless measuring instruments for checking linear dimensions, angles, shapes and relative positions of surfaces. There are several types of calibers.
Rice. 1. Smooth clamp gauge (a) and its tolerance range (b)
Smooth clamp gauges (Fig. 1) are used to control the lengths and diameters of the outer surfaces. They can be one-sided and two-sided, one-limit and two-limit. Single-determined staple gauges are made either passable or non-passable. To control the dimensions of the 8th accuracy class (and less accurate), clamp gauges with replaceable jaws are used. To control more precise products (up to 6th quality), the working surfaces of the gauges are equipped with a hard alloy. In small-scale and individual production, staple gauges are made from sheets, in large-scale and mass production - from forgings and castings.
Smooth plug gauges (Fig. 2) are used to control holes. Structurally, they are made in the form of a handle and a working part. The working part can be made integral with the handle or in the form of inserts and attachments. For plug gauges designed to control precise holes (6-12 grades), the inserts are made of hard alloy. Plug gauges can be single-sided or double-sided. One-sided ones are made passable or non-passable.
Smooth gauges allow you to control linear dimensions from 0.1 to 3150 mm. As the dimensions increase, the control error increases due to the increase in elastic deformations of the gauges.
For smooth plug gauges, the through side (PR) has the smallest limit size (i.e., it must pass into the hole), and the non-go through (NOT) side has the largest limit size (i.e., it must not pass into the hole). For smooth staple gauges, the through side (PR) has the largest maximum size, and the non-through side (NOT) has the smallest. According to their purpose, gauges are divided into working gauges (P), intended for checking parts by workers and quality control inspectors, receiving gauges (P), for checking parts by representatives of the customer, control gauges (K), for checking working and receiving gauges during the process of their manufacture and operation, and counter gauges ( K-I) - to control the wear of working calibers.
Rice. 2. Smooth plug gauge (a) and its tolerance range (b)
Rice. 3. Types of gauges: 1 - measuring plane, 2 - guide plane, 3 - product, 4 - marks
The gauges are marked with their type, the pass and fail sides, the controlled nominal size, the designation of the checked tolerance range, and the manufacturer's trademark.
Calibers for controlling dimensions in height and depth are varied both in design and principle of operation. The most commonly used calibers are those using the “light slit” method. The extreme sides of these calibers are designated by the letters B (large) and M (smaller).
Cone gauges are designed for testing smooth conical surfaces. Most often they control the conical shanks of tools (bushing gauges) and conical holes for their fastening (plug gauges). The limiting positions of the gauges relative to the controlled surface are determined by two marks marked on the gauge. Typically, such gauges are used in a set consisting of a plug gauge, a bushing gauge and a counter-plug gauge. The latter is designed to allow the bushing gauge to be fitted to the paint plug gauge.
Gauges for checking the shape and relative position of surfaces have a wide variety of designs. They can control the parallelism of planes, the alignment of holes, the symmetry of grooves, the parallelism of the plane and the axis of the hole, spline shafts and bushings, etc.
Thread gauges are used for comprehensive thread control. The external thread is controlled with a ring gauge, and the internal thread with a plug gauge. Thread gauges are manufactured and used in sets, which, in addition to the thread gauge, include control pass and no-go gauges. Along with unregulated calibers, adjustable ones are also used. The latter are adjusted using installation thread gauges, which in this case are also included in the kit.
Profile templates are flat gauges used to control the profile of shaped surfaces of a product. Control with such a template is carried out using the “light slit” method. The manufacturing accuracy of the profile template itself and its wear are checked using counter templates. The gauges are made from structural, tool and tool alloy steels. Equipping the working part of the caliber with hard alloy VK8 increases its durability several tens of times compared to calibers made of carbon tool steel.
They are called calibers scale-free measures that are designed to control the size, shape and location of the surfaces of parts. According to the control method, calibers are divided into normal and limit. Normal calibers copy the size and shape of products.
Limit gauges reproduce dimensions corresponding to the upper and lower tolerance limits for the product. During control, pass and non-pass are used. maximum calibers. By design, limit gauges are divided into unregulated and adjustable. Adjustable gauges allow you to compensate for their wear or set the caliber to a different size; limit gauges can be single-limit and double-limit, combining pass and no-go gauges. Both limit gauges can be located on the same side. In this case, the limiting gauges are called one-sided.
Complex calibers(Fig. 1.26) are designed to control several product dimensions (for example, spline joint parts).
Differential gauges (Fig. 1.27) allow you to control only one size (for example, a gauge for controlling the width of a keyway).
According to their purpose, working gauges are distinguished to control products during manufacturing; inspector calibers (for checking products by technical control service workers); receiving gauges for control of products by the customer; control gauges for checking the sizes of working and receiving gauges. Partially worn pass-through and unworn non-pass-through gauges are used as the controller gauge.
The calibers are marked with markings indicating the parameters of the parts being controlled: nominal size, tolerance zone designation and maximum deviations.
Normal caliber templates(Fig. 1.28) are used to control the size and shape of products with complex profiles. Templates 1 can be applied to the tested profile of product 2 (Fig. 1.28, a) or applied to product 2 with the profiles aligned (Fig. 1.28, b). In the first case, the deviation of the product profile from the template profile is determined by “paint” if the deviation is less than 3 µm, or by transmission if the deviation is more than 3 µm. When testing for “paint,” the surface of the template is covered with a thin layer of paint and applied to the product. The print of the paint on the surface of the product being tested is used to judge the tightness of the template.
When inspecting a product by combining profiles, the deviation of the profile is determined using an indicator (see Fig. 1.28, b). The indicator is used in cases where the deviation is no more than 5 microns upward or downward; if this value is greater, then the deviation is assessed visually.
To determine radii of curvatures from 1 to 25 mm, radius templates are used (Fig. 1.29), which are steel plates with a circular arc profile of the corresponding radius. They are assembled in sets consisting of plates with 1 convex or 3 concave profiles. The plates are assembled into a holder 2. During inspection, radius templates are usually applied to the product profile. If there is no gap in the mate, then the radii of the product and the template are equal.
Probes
A fairly common tool are probes, which are a set of plates of a certain thickness (Fig. 1.30). The probes are normal gauges when checking the gaps between surfaces, they are produced with nominal sizes of 0.02 ... 1.0 mm, with gradations of 0.01 and 0.05 mm. The length of the probes is divided into two versions: 200 and 100 mm. Probes with a length of 100 mm are manufactured both in the form of individual plates and in the form of sets, and with a length of 200 mm - only in the form of individual plates. When measuring the gap, a feeler gauge or set of feeler gauges is inserted into it. When measuring, the probe should move in the gap with little force, i.e. it should not fall into the gap and move freely.
When measuring gaps with a feeler gauge, a number of rules should be followed:
Before measuring the gap, make sure that the feeler plates move smoothly;
If the movement of the plates in the gap is difficult, then they should be lightly lubricated;
The size of the gap is determined by the total size of the set of probe plates that are completely included in the gap along its entire length;
When measuring the gap, do not apply great force to the feeler gauge to avoid breaking the plates or deforming them.
Gauge-staples
The most common limit calibers are gauge-staples for checking smooth shafts and a plug gauge for checking smooth holes.
Gauge staples have different designs(Fig. 1.31). They are made single- and double-sided from sheet material (Fig. 1.31, c, b). Such brackets are used for shafts with a diameter from 1 to 500 mm. To control shafts with a diameter from 3 to 100 mm, staples made from stamped blanks are used. Such staples have increased wear resistance and durability.
Stamped brackets are made, as a rule, one-sided (Fig. 1.31, c), and also with replaceable measuring jaws (Fig. 1.31, d).
The increased durability of these staples compared to staples made from sheet metal is due to their increased rigidity and wider measuring working surface.
Gauge plugs
Gauge plugs to control holes of small diameter (1 ... 3 mm), they are made double-sided with inserts made of calibrated wire (Fig. 1.32, a).
Double-sided gauge plugs, having inserts with conical shanks (Fig. 1.32, b), are used to control holes with a diameter of 3 to 50 mm. The length of the pass-through gauge for these plugs is greater than the length of the non-go-through gauge. For the same sizes, one-sided plugs are sometimes used, in which the go and no-go gauges are located on one side of the handle, however, such plugs are difficult to manufacture and do not allow control of shallow blind and long holes, so they are rarely used.
To control holes with a diameter of 50 to 100 mm, double-sided plugs with nozzles (Fig. 1.32, c) having a full profile are used. The use of such gauges is difficult due to their large mass, therefore, when checking large-diameter holes, plugs with incomplete profiles are often used. Gauge plugs with an incomplete profile are made double-sided from sheet blanks; they are used to control holes with sizes from 50 to 250 mm. Caliber plugs with an incomplete profile can also be made one-sided.
Control of holes with a diameter from 250 to 1000 mm is carried out using limit gauges or pin gauges. For bore gauges, the measuring surfaces are cylindrical, and for bore gauges, they are spherical. Calipers and bore gauges are used in the form of sets consisting of two gauges—go and no-go.