Various cutting defects often arise during the operation of CNC flame cutting machines. To improve cutting quality, here is a brief overview of key control points for different cutting scenarios:
1. Key points for cutting forgings
Forgings often have a thick layer of surface scale. Since the ignition point of this scale is higher than its melting point, the cutting process is prone to interruption, resulting in reduced cutting quality and lower efficiency. Therefore, before cutting forgings, the scale on both the top and bottom surfaces of the cutting area should be removed to enhance cutting speed and quality.
2. Key points for preventing deformation when cutting rolled square billet cooling bed tooth plates
Controlling workpiece deformation during cutting is crucial. Conventional cutting path arrangements can lead to deformation and dimensional deviations; even with subsequent straightening, it is often difficult to meet specifications, ultimately resulting in product scrap. Thus, a rational arrangement of the gas cutting path is vital.
3. Key points for cutting thick plates
When cutting thick steel plates, the temperature decreases from the top surface downwards. At the start of the cut, oxygen pressure increases gradually before stabilizing across the plate's thickness. This causes uneven combustion through the thickness at the starting point, leading to defects at the cut's initiation end.
To avoid such defects, the following methods can be used:
① Use an arc-shaped lead-in to extend the length of the approach path, avoiding a direct entry point. This method is effective and widely used in production, though it does result in some material waste.
② Use an ignition bar. This involves placing an extra piece of steel tightly against the edge of the plate at the entry point, ensuring there is no gap between them. The cutting torch enters through the ignition bar, which guides the flame to the bottom of the plate, equalizing the combustion rate across the thickness and producing an optimal cut surface. Scrap offcuts from previous operations can serve as ignition bars. This method reduces the distance between the workpiece and the plate edge, minimizes scrap generation, and effectively improves material utilization. Ignition bars are particularly practical when cutting extra-thick steel plates.
