Cutting quality evaluation of the hottest CNC plas

Evaluation of cutting quality of NC plasma cutting machine

at present, there is no recommended national standard for the evaluation index of cutting quality of NC plasma cutting machine, only the industry standard: that is, thermal cutting, sub arc cutting, quality and dimensional deviation for equipment (jb/t 10045.). The evaluation of plasma arc cutting quality mainly includes the following aspects: it is mainly used to compare the hardness and softness of different minerals. First, the width of the incision: it is one of the most important characteristic values to evaluate the cutting quality of the cutting machine, and also reflects the half diameter dimension of the smallest circle that the cutting machine can cut. It is measured by the size of the widest part of the incision. The incision width of most plasma cutting machines is between 0.15~6mm. Effects: 1. Too wide incision will not only waste materials, but also reduce cutting speed and increase energy consumption. 2. The notch width is mainly related to the nozzle aperture. Generally speaking, the notch width is always 10% - 40% larger than the nozzle aperture. 3. When the cutting thickness increases, it is often necessary to use a larger nozzle aperture, and the incision will also be widened. 4. The increase of the width of the cut will increase the deformation of the cutting part

II. Surface roughness:

it is used to describe the appearance of the notch surface and determine whether it needs to be reprocessed after cutting. It is the Ra value on the cross-section at 2/3 of the measured incision depth. Due to the action of cutting air flow, longitudinal vibration is produced in the cutting direction, and the main form is cutting ripple. Generally, the surface roughness after oxyacetylene cutting is required: Grade 1 RA ≤ 30 m, grade 2 RA ≤ 50 m, and grade 1 RA ≤ 100 m. The kerf Ra value of plasma arc cutting usually exceeds the level of flame cutting, but is lower than the laser kerf Ra value (less than 50 m)

Third, the squareness of the kerf edge:

it is also an important parameter reflecting the cutting quality, which is related to the degree of reprocessing required after cutting. This index is usually expressed by perpendicularity u or angular tolerance. Generally speaking, the U value of plasma arc cutting is closely related to the plate thickness and process parameters, usually u ≤ (1%~4%) δ （ δ For this machine is digital display, frequency conversion speed regulation, automatic shutdown in case of fracture, and automatic return of plate thickness can be set), laser cutting u ≤ 0.5mm

IV. width of heat affected zone:

this index is very important for those low alloy or alloy steels that can be hardened or heat treated. Too wide width of heat affected zone will significantly change the properties near the notch. The width of the heat affected zone of air plasma arc cutting is about 0.3mm. When underwater plasma arc cutting, the width of the heat affected zone can be narrower

v. slag hanging amount:

describes the amount of oxide slag or re solidified material adhered to the lower edge of the incision after thermal cutting. The grade of slag hanging is usually determined by visual observation. The residual concave deformation after the experiment should not be greater than: Grade a 3.00mm, which is generally described in terms of none, slight, medium and serious

in addition, there should also be corresponding requirements for the straightness of the slit, the melting degree of the upper edge and the notch. (end)