Sunday, 17 October 2021

تاریخ بروزرسانی 1400/01/30

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Dimensional calibration laboratory

Calibration Laboratory of Soil Technical and Soil Mechanics Laboratory of Ministry of Roads and Urban Planning, using expert and experienced experts, modern machines and obtaining official certification from National Standards Organization and National Center of Certification of Iran in February 2011 began its activities. The main goal of the establishment of the calibration laboratory as one of the most specialized sections in the collection of the Soil Mechanics and Laboratory of the company is to meet the needs of internal and external customers in the field of calibration of laboratory equipment and quality control of related projects in the Ministry of Roads and Urban Development. The laboratory provides services in calibration services in various quantities including force, temperature, mass, volume, dimensions, pressure, loading and chemical quantities. The calibration of the equipment in the laboratory of mechanical and technical soil is carried out in accordance with regional, national or international standards.

Dimensional calibration laboratory

1-Dimensional  calibration  laboratory
In the dimensional calibration  laboratory ,the amount of deviation and  expanded  uncertainty are read at controlled temperature 20°C (centigrade) and the calibration of the equipment is by one or combination of several standard Gauge blocks, at least at a precision level of Grade 1 have been valuated  and determined.
 For measuring instruments calibration   with sensitive calibrators, the installation location of the calibrator devices should be insulated to vibration and the vibration relevant to the System and calibrator devices are  less  than  the  amount  specified be in the relevant manual. Also for the effect of temperature and variations temperature with length of calibration and dimensional quantities, the laboratory temperature  should be kept to 20 °C with a range of oscillations a constant degree.
Also, the amount of humidity, airborne dust and carbon dioxide changes should be carefully controlled for their impact on the accuracy of the equipment.
Dimensional calibration laboratory of the company: to the reason for the need of accurate measurements (at 0.5 micrometers), the temperature precise control and
 isolation from the point of view the vibration and other environmental influences from specific techniques and advanced equipment that automatically creates and maintains the vital environmental in the laboratory.

1-1-Laboratory sieves calibration
Test sieves are often used to grade or separate the aggregates of various sizes.
The accuracy of the sieve test depends on the accuracy of the size of the sieves apertures. The sieves are deformed for the continuous use or overweight of the screened material, and their aperture dimensions change.
The test sieves are calibrated according to the national standard 5002, equivalent to the international standard ISO 3310 and ASTM E11.
 In the report of the calibration results, the apertures average, the standard deviation and the wire average diameter are expressed in longitudinal and transverse (texture) directions.  
Finally, if the dimensions of apertures the  are out of the specified standard range, the sieve will be rejected and must be replaced with a new sieve.
Sieves calibration is done according to the standard by the video measuring
machine (VMS), which determines the size of the wire apertures , based on
the sieve nominal size of the using video measuring machine (VMS) .

Video measurement machine capabilities
-Possibility to install a 3D probe to measure the dimensions of the internal
sections and other user needs.
-Accurate calibration, very fast and reliable.
-Small space and workability even in non-test environments.
-Possibility to measure with high light or prophylactic light.
-Adjustability of light system by software.
No limitations on the dimensions of the parts to be measured.
-Possibility of providing cloud points of a piece for reverse engineering and
rebuild in the modeling of software applications
- Lens changer for maximum viewing angle
1-2 Calibration of caliper types
The caliper is used to measure internal and external dimensions of objects.
Measuring external thicknesses such as the diameter and length of a piece and
measuring  internal distances, such as the inner diameter or interior spaces inside
the pieces, as well as the height of the parts with the device done .Depending on the type, the calipers have the ability to measure one, two with all three internal,
external, and depth dimensions, and their display can be in vernier                                                       , analog, or digital forms.
For vernier calipers calibration at a temperature of 20 ° C (Celsius) with amaximum variation temperature up to +-1 C ° (centigrade), the caliper calibration
error is, by one or a combination of Gauge Blocks are evaluated and
determined at least in the precision level of 2 Grade.