The PPCM oxy-fuel cutting is a reliable and efficient technique used for many applications at plate thick of minimum #8 mm. Oxy-fuel cutting compared to plasma cutting is a more economical solution – initial investment costs, consumables and operating costs are all lower, therefore is more suitable in many cases up to #20 mm.
- small investment and operating cost
- additional fumes exhaust system is not necessary
- good for thicker metals
- not suitable for stainless steel, aluminum materials
Plasma cutting allows to cut in electrically conductive materials like steel, stainless steel, aluminum, brass or copper at minimum thickness of #4 mm. This high speed cutting technology is widely used in CNC machines. The PPCM machine can be equipped with plasma as an option. Plasma cutting method outperforms oxy-fuel cutting in the wall thickness range up to #25 mm. When oxy-fuel cutting speed is within the range of 300 and 800 mm/min., plasma pipe cutting can reach speeds of up to 2 500 – 3 000 mm/min. with smaller wall thicknesses. Moreover, plasma cutting does not require pre-heating, therefore it allows to save more time considering each individual cut. The starting investment costs are higher for plasma than for oxy-fuel and is caused by plasma equipment and necessary fume extraction system costs. Moreover, the monthly consumables cost is also more expensive than oxy fuel but this is compensated by the higher cutting speed increasing efficiency and productivity of the process.
- very fast cutting of thinner materials
- small heat-affected zone
- don’t require storing or handling explosive gases or dealing with an open flame.
- No preheating required
- high investment and consumables costs
The Production Process
The pipes cutting is only a part of the manufacturing process in heavy steel industry, however each step affects the final product. Promotech is fully aware that accurate 3D cutting preparation is essentially to ensure savings on fitting and welding costs. Keeping that in mind, Promotech propose reliable solution to design and prepare work-pieces for the next step in production process.
Promotech continuously develop its own, made in house software which allows to prepare the cutting using wide scope of macros available on the machine or optionally on PC, saving operator’s time and reducing the chance of errors. In case of advanced bevel preparation Promotech advice CAD/CAM connection using additional Lantek software and post-processor. All prepared files can be copied to USB-drive and then loaded to PPCM machine.
The high 3D quality cuts is the goal archived by PPCM design and PLC advanced control software. Main support including torch holder allows to compensate work-piece imperfections, also machine’s software automatically adjust the movement parameters according to the speed and trajectory of cutting. Due to such way of working we achieve perfect cutting shapes and minimum of usage of consumables.
The PPCM machine allows to bevel up to 45° oxy-fuel and plasma provides design freedom to cut typical and custom shapes.
Fitting and welding
PPCM machines provides best-fitted cuttings. Additional operation, like grinding time is minimized. It has major impact in whole production process, avoiding costly manual cutting and reducing labor load.
Cutting optimization on PPCM machine
Depends on Client’s choice of cutting technology, PPCM ensure to achieve the best cutting accuracy and quality.
Kerf width compensation applied to oxy-fuel and plasma cutting
The basic feature is kerf compensation. By the setting its value, PLC is able to compensate kerf’s width and ensure best accuracy.
Speed compensation applied to oxy-fuel and plasma cutting
The cutting speed is calculated for the external pipe surface, therefore in some situations the internal cutting speed is different that external speed. This effect is especially visible during the corners cutting and results in a loss of cutting smoothness. To minimize this negative effect, Promotech has developed made-in-house software function to avoid this type of cutting inaccuracy.
Additionally, to optimize cutting quality during oxy-fuel process, PPCM automatically compensates the cutting speed with regards to the actual torch tilting. The cutting speed is higher when the flame is ahead and lower when the flame is behind the torch depends to cutting direction
Optimized cutting direction applied plasma cutting
Some type of plasma are available with swirl technology to stabilize and protect the arc. The swirl gas creates a ‘good’ and a ‘bad’ side in the kerf. In order to get a straight cut the torch must travel in the proper direction to have the ‘good’ side on the part and the ‘bad’ side on the remnant material. The ‘good’ side is on the right relative to the torch’s movement direction. Taking this into account, PPCM machine adapts the cutting routines to maintain the most accurate cut. This is always applied during using macros. In case of Lantek software, the user has a choice about cutting direction.
Cut in&out shape optimization applied plasma cutting
The starting and ending point of cutting is always the same, therefore this area is exposed to a material’s shape deformation and material loss, which is dependable of factors, e.g. plasma cutting parameters or cutting trajectory. The PPCM machine has a function allowing to set the distance at which the cutting arc has to be turned off relative to the end of the cutting trajectory. By setting this parameter to approximate the kerf value, it is possible to eliminate the problem of material loss in the trajectory start / end area.