Calibration of crushing machines

Our laboratory is prepared for the full on-site calibration of testing equipment ((Bending equipment, CKT crushers, Marshall crushers, concrete crushers, etc.) used primarily in the construction industry. As part of such full calibrations, we offer the following services:

Our services related to testing according to the MSZ EN ISO 7500-1 standard:

• verification, calibration of force measuring system
• maintenance on demand
• adjustments on demand
• uniaxial static testing machines
• tension-compression direction testing machines
• concrete crushing machines
• bending devices
• CKT crushers
• etc.

Calibrating as per the MSZ EN ISO 12390-4 international standard includes the following inspections:

• Determination of the hardness value of the pressure plates of a crusher and of the inserts and washers used in the crushing procedure
• Determination of roughness values of crusher machine pressure plates and insert washers used in the crushing procedure
• Inspection of the self-adjustment of upper pressure plate
• Inspection of the inhibition of movement of the upper pressure plate
• Inspection of the concentrated force introduction of crushers
• Inspection of the planarity of crusher pressure plates
• Inspection of the crushing performance speed of crusher

WORTH KNOWING...

It is worth mentioning Point 5 of the MSZ EN ISO 12390-4 standard on the calibration process and the frequency of calibration, according to which:

Quote from the MSZ EN ISO 12390-4 standard:

„5. Calibration of the machine

5.1. Characteristics to be specified
The verification performed to ensure due operation of the testing machine shall include the following calibrations:

• accuracy of force indication;
• force introduction (constancy); (for new machines only, unless otherwise stipulated in the national standards);
• planarity of the plate surfaces;
• regulation of the introduction speed of forces.

5.2. Frequency of calibration
When the machine is first installed, it shall be calibrated as per section 5.1. It needs to be recalibrated at a frequency specified in the accredited quality assurance system or annually, and if:

• the machine is reset or
• after the exchange of any of its parts which probably influence the characteristics listed in section 5.1.”

A LITTLE THEORY...

What is the purpose of the compression test?
The purpose of the compression test is to determine the crushing strength.

What is compressive strength?
Compressive (or crushing) strength is the quotient of the crushing force and the original cross section:

What is the purpose of the bending test?
The purpose of the bending test is to determine the toughness.

What is bending strength?
Here the bending strength and the plastic work of bending is determined, which is the plastic proportion of the area under the force-travel diagram.
The strength calculation of rigid, low deformability materials is often based on the crushing strength. The ranking of toughness of materials with identical crushing strength is based on the bending strength, and even more frequently the plastic work of bending (e.g. cast irons, hardened tool steel, hard metals, ceramics etc.).