- The balance or scale: electronic or mechanical devices are being used in homes, industries, laboratories and companies to determine the weight, or, well, mass of an object, thing or substance. 
- catharometer: is an instrument that measures the concentration of small amounts of gas , comparing the thermal conductivity of gas against analyzed sample gas conductivity resulting in atomic mass, although obtaining the results is a little slower in comparison to the next instrument. - mass spectrometer: this instrument seeks to analyze the samples by determining the masses of its ions , analyzes with great precision composition of different chemical elements and isotopes atomic splitting atomic nuclei according to their mass ratio - charge (m / z). 
+ or vernier Vernier: + Interferometer: + dial indicator: 
- Calendar: is a systematic account of the time for the organization of human activities allows us to have an accurate measure of year months and days. - Clock: is a tool that allows us to measure the passage of time in years, hours, minutes and seconds . There are variety of watches such as sun, sand clock, analog, digital and more. - Timer: is an instrument used to measure fractions of time, usually short and accurately seconds, milliseconds, etc. .. - Atomic Clock: a clock whose operation is based on the frequency of atomic vibration . is a kind of clock that uses an atomic resonance frequency normal to feed its counter. 
| |
| gauge usually has three sections of measurement. Items measuring gauges. A = for measuring external dimensions. B = for measuring internal dimensions. C = to measure depth.
The strip (or major scale) is graduated in millimeters or 0.5 mm if the metric system is low or knockout fortieth of an inch or if it is under the English system. The Vernier (vernier or scale) in the cursor, allowing readings below the following decimals. Metric 1 / 20 mm or 1 / 50 mm The following lengths of gauges are widely used: This gauge is equipped with a button instead of the traditional screw brake. This type is equipped with a screw which is used to move the cursor slowly when used as a gauge fixed, this allows easy adjustment of the cursor. This guy called dial indicator is equipped with a dial indicator in place of a vernier to allow easy reading of the scale.
precautions when measuring.
If the gauge is often handled roughly, be rendered useless before completing its normal service life, to keep always useful not stop taking extreme care following 1) Before making measurements, clean dust and dirt surfaces measurement cursor and rail, particularly remove the dust of the sliding surfaces, and dust can often obstruct the sliding of the cursor. 2) Make sure that surfaces measurement of the jaws and the peaks are free of kinks or chipping. 3) Verify that the sliding surfaces of the strip are free from injury. For correct measurements, check the tool arranged as follows: 1) Be sure that when the cursor is completely closed, the zero on the scale and vernier strip are aligned with each other, also check the measuring surfaces of the jaws and the peaks as follows: - When light passes between the contact surfaces of the jaws, contact is correct. - Contact of the peaks is better when a uniform band of light passes through the measuring surfaces. 2) Place the gauge down on a flat surface with the depth gauge down and push the depth gauge, if the zero graduation on the strip and the vernier scale are misaligned, the meter depth is abnormal. 3) Verify that the cursor moves freely but not loosely along the strip.
Place the item on the bench and measure it, hold the gauge in both hands, place your thumb on the button and push the vernier jaws against the object to be measured, use only a gentle force. external measurement. If the measurement is made at the end of the jaws, the cursor could bend resulting in an inaccurate measurement. Hold the object square to the jaws as shown in (A) and (B), otherwise you will not get a correct measurement. internal measurement. This measure is to make mistakes unless carried out carefully u enter the peak entirely within the object to be measured, ensuring adequate contact with the measuring surfaces and take reading. By measuring the inside diameter of an object, take the maximum value (A-3) to measure the width of a groove to take the minimum value (B-3). is good practice to measure in both directions AA and BB in A-3 to ensure proper measurement. The measurement of small inner diameter is limited, we are exposed to confuse the apparent value "d" real value "D" The best value "B" in the figure or the lowest "D" is the error.
depth measurement. the measurement of depth, do not let the tip of the instrument tip, be sure to keep it level. corner of the object is more or less round, therefore, turn the bar resaque deep into the corner. Examples of methods of measurement,
When using the gauge, the surface of the scale is often played with his hand, so after use, wipe the tool clean with a cloth and apply oil to the sliding surfaces measurement before placing the instrument in its case. Be careful not to put any weight on the gauge, you could strain the power strip. not strike ends yu peaks of the jaws or use them as a hammer.
How to read the gauge (metric): Example 1. (Metric) Step 1. Step 2. Step longitudinal plane 43 + 0.6 = 43.6 mm Example 2. (Metric) Example 3. (Metric) Example4. (Metric) How to read the gauge (English system) Step I. The zero point of the vernier scale is located between 2 4 / 16 "., And 2 5 / 16 inch. On the scale of the strip. In this case, read 2 4 / 16 "., First 2 4 / 16". On the scale of a vernier, find the graduation which is in line with a graduation on the scale of the strip. This setting is "6", the 6 on the vernier indicates Final Step. Step I + Step II The correct reading is 2 19/64 inches.
Step I + Step II 4 3 / 16 + 4 / 128 = 4 24/128 + 4 / 128 = 4 28/128 The correct reading is 4 7 / 32 ". Step I read 2400 in., First Step II Graduation 18 on the vernier scale is in line with a graduation scale of the strip, this reading is 18 inches pulg./1000 or 0018. Step I + Step II The correct reading is 2,418 inches. step I + Step II = 4,450 + 0,016 = 4,466 inches. The correct reading is 4,466 inches. Information from: http://www.rolcar.com.mx/Mecanica% 20of% 20the% 20sabados/instrumentos_de_medicion.htm |
One of the instruments most often used in industry to measure the thickness of small objects, metal is the micrometer. The concept of measuring an object using a screw thread goes back to the era of James Watt. during the last century was achieved given the micrometer readings of 0.001 inches.
Figure 1. Examples of micrometers
The micrometer is a device that measures the displacement of the spindle when it is moved by turning a screw, which converts rotary motion into linear motion drum spindle. The displacement of this amplifies the rotation of the screw and barrel diameter. The graduations around the circumference of the drum can read a small change in the position of the spindle.
Micrometer Reading
standard micrometer to mm we refer to Figure 2. For readings in hundredths of a millimeter first take the reading of the cylinder (note that each rank corresponds to 0.5 mm) and then the drum, add the two to obtain the total reading.
Figure 2. reading of a conventional micrometer
a. Reading of the cylinder 4.0
b. Reading between 4 and 0.5
edge drumc. Drum line that coincides with the cylinder
Reading0.49 total: 4.99 mm
Note that the drum has stopped at a point beyond the line corresponding to 4mm.
Note also that an additional line (graduation of 0.5 mm) is visible between the line for the 4mm and the edge of the drum.
line 49 on the drum corresponds to the line and central cylinder:
micrometer screw.
micrometer for external action is a device consisting of a movable axis (c) with a threaded part (e), the end of which is mounted a scale drum (f) rotating the scale drum is obtained micrometer movement (e) and therefore the movable shaft (c), which will push the workpiece against the flat spot (b). On the fixed part (d), which is integral with the arc (a), is marked on the linear scale graduated in millimeters or inches. Unlike vernier micrometer is a unit for each system. The fundamental parts of a micrometer are
horseshoe arch.
Fixed point level.
mobile Axis, whose tip is flat and parallel to the fixed point. Main
graduate that is marked on a linear scale graduated in mm and ½ mm.
mobile screw integral with the shaft. Drum
graduate.
locking devices, which serve to fix the movable shaft in a pattern and be able to measure the micrometer gauge go / no go.
Clutch. The device consists of a thumb wheel which acts by friction. Serves to keep the pressure on the piece movable shaft exceeds the value of 1 kg / cm ², as excessive pressure against the workpiece can result in erroneous measurements.
Figure 3. The micrometer screw.
The micrometer has two graduations to read millimeter and hundredth of a millimeter. The micrometer screw thread has a pitch of 0.5 mm
. So with a full turn of the screw, the scale drum forward and back 0.5 mm.
The conical tip of the drum is divided into 50 parts another graduation. Therefore the assessment is done in this case by dividing the step from 50 parties, would be 0.5: 50 - 0.01 mm. Rotating cylinder, graduated in hundredths body, the movable shaft and the clutch are run by the graduated scale fixed. The millimeter and half a millimeter is read on the graduation line is fixed in correspondence with the graduation of the scale drum cone.
The depth micrometer
The depth micrometer is used to check the extent of the depth of the hole, grooves, etc. It differs from the micrometer to external measures to be replaced by a bridge arc applied a micrometer head.
The measuring range of this instrument is 25 mm and its approximation is 0.01 mm. The main parts are:
Steel Bridge. The width can vary from 50 to 100 mm. Plano
support. Axis
mobile.
locking device. Main
graduate. Drum
To increase readability, the available depth micrometer shafts of variable size that are interchangeable. Figure 4. measurement shows an example with my microns deep. To the extent sea correcta es indispensable que el plano del puente del micrómetro se adapte perfectamente a la superficie de la pieza, y con la mayor zona de contacto posible.
Micrómetro de interiores
El micrómetro para interiores sirve para medir el diámetro del agujero y otras cotas internas superiores a 50 mm. Está formado por una cabeza micrométrica sobre la que pueden ser montados uno o más ejes combinables de prolongamiento. La (figura. 5). muestra las partes principales del micrómetro:
Tambor graduado.
Graduate body.
micrometer screw.
locking device. Punta
fixed micrometer head. First
prolongation tube, screwed directly overhead.
Axis is screwed inside the first tube prolongation. Second
prolongation tube screwed onto the first tube. Axis
bolted inside the first tube.
spherical tip.
flat tip.
Figure 5. The internal micrometer
completely open with the drum head gives a length of 50 mm. The measuring range is about 13 mm. With only the head of the micrometer, measures can therefore be between 50 and 63 mm (Fig. 6).
To extend the measures may provide one or more axes of extension. A complete set consists of 5-axis measures are: 13, 25, 50, 100 and 150 mm. Combining
axes can be measured in different ways any distance between 50 and 400 mm.
For measurements above 400 mm axle failure makes additional 200 mm. (Fig 6), shows a example of measurements performed micrometer head mounted on two axes of prolongation.
Measurement Errors on the micrometer
Uncertainty
In a series of lectures on the same dimension constant, the inaccuracy or uncertainty is the difference between maximum and minimum values \u200b\u200bobtained .
Uncertainty = maximum value - minimum value
Absolute Error
absolute error is the difference between the reading and the value corresponding conventional true.
Absolute error = read value -
conventional true value
Relative Error
The relative error is the ratio of absolute error and the conventional true value
relative error = absolute error / conventional true value
As the absolute error is equal to reading less conventional true value, then:
relative error = (reading value - actual value) / actual value
often the relative error is expressed as a percentage error multiplying by one hundred:
Percentage of error = 100% relative error *
Example measurement error
Sea for example, a rivet whose length is 5.4 mm and measured five times in succession, obtaining the following readings :
5.5 mm, 5.6 mm, 5.5 mm, 5.6 mm, 5.3 mm
Uncertainty = 5.6 -5.3 = 0.3 mm
The absolute errors each reading would be:
| 5.5 - 5.4 = 0.1 mm |
| 5.6 - 5.4 = 0.2 mm |
| 5.5 - 5.4 = 0.1 mm |
| 5.6 - 5.4 = 0.2 mm |
| 5.3 - 5.4 = -0.1 mm |
The sign tells us if the reading is higher (sign +) or less (- sign) to conventional true value. The absolute error has the same units of reading.
The relative error and the error rate for each reading are:
| 0.1 / 5.4 = 0.0185 | = 1.85% |
| 0.2 / 5.4 = 0.037 | = 3.7% |
| 0.1 / 5.4 = | 0.0185 = 1.85%
|
| 0.2 / 5.4 = 0,037 | = 3.7% |
| -0.1 / 5.4 = 0.0185 | = -1.85% |
MITUTOYO micrometer: micrometer Foreign Archery
Cast Series 103
MITUTOYO: External Digital Micrometer
293 Series
MITUTOYO, Economic Affairs Digital Micrometer
293 Series
MITUTOYO: External Micrometer with interchangeable tips
104 Series
MITUTOYO: External Digital Micrometer with interchangeable tips
340 Series : SPC data output
MITUTOYO:
micrometer threads
Series 126
MITUTOYO: Digital Thread Micrometer
326 Series: With SPC data output
MITUTOYO: Tips Thread Micrometer Series 126
: 60 ° metric and Unified
MITUTOYO: depth micrometer with interchangeable tips
129 Series
MITUTOYO: Digital Depth Micrometer with Interchangeable Tips
329 Series : SPC data output
MITUTOYO: Internal Micrometer with Extension Rod
137 Series
MITUTOYO: Interiors with Digital Micrometer Extension Rod
337 Series: With SPC data output
MITUTOYO: Internal Micrometer with Interchangeable Rods
141 Series
Figure 4.
micrometer depths
Information from:
http://html.rincondelvago.com/metrologia_1.html
