Definition
The ring pressure sampler is a special equipment for preparing standard-size round specimens, which is mainly used in the pretreatment process of physical property testing of cardboard, corrugated cardboard and similar materials. The equipment obtains round samples with flat edges and accurate dimensions through precision punching and cutting actions to meet the strict consistency requirements of specimen specifications for subsequent ring compression strength and other tests.
How it works:
The core working principle of the ring pressure sampler is based on mechanical stamping. The equipment usually consists of a base, a punching die and a force application mechanism. During operation, the material to be measured is placed flat on the base, and the upper ring knife die moves vertically downward through manual or automatic drive, exerting pressure on the material that exceeds its shear strength, so as to neatly cut out a disc-shaped specimen that meets the standard diameter. The process ensures that the specimen edges are free of burrs and compression deformation, maintaining the structural integrity of the original material.
Measurement methods and standards
Specimen preparation using a ring pressure sampler is the first step in performing ring pressure strength testing. Standard methods typically require multiple samples to be randomly flushed from a representative sample. The operation process includes: placing the material on a flat substrate, aligning the tool die, applying pressure smoothly to complete punching, removing the specimen and checking the edge quality. Relevant domestic and foreign standards, such as ISO 12192, TAPPI T 822 and GB/T 2679.8, etc., all clearly stipulate the diameter, quantity and preparation method of specimens. For example, a common specimen diameter is (formula: d = 49.5 ± 0.2 mm). The prepared specimens need to be balanced under standard temperature and humidity conditions before subsequent compression tests can be carried out.
Influencing factors
The quality of the sampling directly affects the accuracy of the final test data. The main influencing factors include: the sharpness and concentricity of the knife die, and the passivated knife die may lead to delamination or crushing of the edge of the specimen; The uniformity of punching speed, too fast impact may cause edge microdamage; The flatness and horizontality of the substrate, and the uneven support will cause the specimen to deform; The way the operator exerts force, non-vertical punching will produce non-circular or dimensional deviations. In addition, ambient temperature and humidity also have an indirect impact on the physical state of the material itself.
Applications:
Ring pressure samplers are widely used in the packaging materials, papermaking, printing and quality inspection industries. Its primary use is to provide standard pretreatment for evaluating the edge compressive properties (ring strength) of materials such as cardboard and corrugated paper. This performance is a key indicator to measure the compressive resistance and stacking stability of the packaging box. Therefore, from raw material inspection, production process control to final product quality determination, ring pressure sampling is an indispensable link in the supply chain.
Key points of selection
When selecting a ring pressure sampler, multiple technical parameters need to be taken into account. At the heart is the die size, which must meet the specimen diameter specified by the target test standard. The rigidity, guiding accuracy and stability of the equipment construction are the basis for long-term repeatability. Depending on the laboratory throughput, different drive modes such as manual lever or electro-hydraulic can be selected. Safety designs, such as accidental fall protection devices, also need to be taken into account. In addition, the ease of maintenance of the equipment, the versatility and replacement cost of accessories (such as tool molds), and the technical support and calibration services provided by the manufacturer are all important factors in ensuring the continuous compliance of the laboratory.