Cheap Large CNC cutting machine design

Cheap Large CNC cutting machine design Guo Yongping, Dong Qinghua, JIANG De (Chengde Petroleum College, Chengde, Hebei 067000) machine. Designed machine is simple, low cost, high reliability and easy maintenance. Child heart design CNC system, using IPC as control platform to overcome the electromagnetic compatibility in its design, production, system reliability, high cost of production problems, to the design object, and through the identification of new products.
At present, China’s machinery processing industry under the steel material commonly used oxyacetylene cutting, while foreign companies cutting process is mostly CNC oxyacetylene or CNC plasma arc cutting method, not only can improve material utilization, but also improve the quality of products, optimize the working environment, improve work efficiency. CNC Cutting why not spread in China, mainly due to: funding, equipment failure maintenance issues, operational problems. Domestic CNC cutting machine control systems are produced abroad, the operation is more complex, requiring the operator to have a high quality and specially trained. The survey found that, for the user, and its products are not updated frequently, cutting part shape, relatively limited size, the machine requires simple and reliable. Therefore, the existing CNC cutting machine does not make customer satisfaction. For this reason, most decide to design a user-oriented, large-scale economic conditions for the CNC cutting machine.
1 design requirements design includes: parts mechanical parts, CNC parts, cutting devices.
Applicable direction: requirement applies to a wide range, both for large enterprises under the plant material, batch cutting of large parts; but also for small-scale machinery plant, carry out minor parts of the small batch production.
Technical level: its comprehensive technical level exceeding domestic requirements of such products, close to the world advanced level.
Production costs: comprehensive cost less than existing similar domestic cutting machine.
Precision: precision than current national standards.
Application materials: carbon steel, stainless steel, non-ferrous metals.
Failure rate: the average time is greater than 3000h no barrier workpiece size: more than 50mx30b, is greater than the maximum radius circular interpolation programming mode: Automatic Programming Manual ISO code editor f.
Cutting speed range: the overall design to achieve the above object design, the choice of the program emphasizes design optimization, system modularity, simplified processing. To this end, in each part of the design of the cutter we have carried out several sets of design, machining and alignment and preliminary tests, the final choice of the optimal design. CNC cutting machine mainly consists of the following sections: mechanical part and its main role is to support the torch 1 = 6 daphne into!
– Plane linkage, and capable of moving independently of each torch cutting to adjust the distance between the nozzle and the steel plate in the direction. At the same time, also supports the installation and the necessary means and with numerical control movement of the gas line.
To achieve the above effect, while ease of processing, control and installation, decided to implement gantry structure, namely two longitudinal rails on the left and right to walk through a support car beam mounted on the beam 1 = 6 can cut a lateral movement torch the car by two longitudinal rails running car on the drive to move in the longitudinal beam. At the same time, the torch beam on the car driven by the torch along the beam do lateral movement. Thus, for the torch, its vertical and horizontal movement of the composite motion, it can be any plane curve coriander into motion in the horizontal plane, see. Daphne torch into the sport, you need to rotational movement of the servo motor car and walk into the linear motion of the torch trolley on the beam, the optional program has a hint parent screw kinematic pair, toothed belt, a rack gear movement deputy, rollers, linear motors. After weighing and final comprehensive performance test, select a gear rack kinematic pair of drive, walk between the car and the track combined with the use of ball bearings, culminating in the car and walking two longitudinal lateral walk several cars.
CNC part CNC machine for cutting part of automatic ignition, automatic drilling, torch motion interpolation operation, plasma arc ignition off and back to working state display, man-machine dialogue. This part is the core of the cutting machine, its performance has a decisive influence on the success of the final design. So it was carried out to test and refine the repeated demonstration, and ultimately achieve the design requirements. First, display and control, to achieve compliance with most of the domestic consumer behavior, make the operation more simple, intuitive, and decided to adopt the Chinese menu plus 1: 964 Guo Yongping, a man I Welding Equipment and Materials Lam Yik Hong CNC machine tool technology and its application. Beijing: Mechanical Industry Press, graphic display, speed development time, improve system reliability, reduce production costs, human-computer interaction is an ordinary part of the IPC. The advantage is reliable, strong anti-jamming capability, software, versatility, and low prices. On advanced language platform can easily develop after the IPC software human-computer interaction, the control, the display interface is simple and easy, but also greatly accelerate the speed of development of the system. For low-level hardware control, in order to increase the characteristics of the development system, improve the flexibility of control, we have decided to develop the controller. The controller can have a single-chip microprocessor, DSP, MPU, etc., considering the performance, development costs, and ultimately choose INTEL company 8XC196KC family of microcontrollers.
Cutting means 23 for implementing the final part of the plate cutting, key indicators will determine the type of material, thickness, and processing quality cutting machine processable. Daphne can to cut and can achieve a variety of cutting methods design requirements are: oxyacetylene flame, high current plasma arc, oxy-propane flame, high-power laser, ultrasonic beams, high-pressure water. Taking into account the factors of investment in equipment and operating costs and business equipment production habits, and decided to use oxyacetylene flame cutting method as thick carbon steel plate, high current plasma arc cutting method as non-ferrous metals and thin steel plate. High current plasma arc cutting machine CNC system interference selection of small, light weight, small size inverter air plasma arc cutting machine, not only reduces the cost and ease of installation flexibility. Oxyacetylene flame cutting system mainly mainframes torch, a sub-air gas, flow control, pneumatic control, automatic ignition of several components. ! Difficulties and solutions design large-scale CNC cutting machine is a complex system, which combines computer technology, precision machinery manufacturing, motor drive, digital control, thermal processing and other subjects, so the design, production, testing, installation, maintenance, etc. each link will encounter difficulties, through the work of many hands, overcome all difficulties and make the prototype meet the design requirements. Now design difficulties encountered and solutions to make the following summary.
Control operation speed and precision cutting machines in real time, complexity is high the torch of interpolation motion control, interpolation is divided into circular interpolation and linear interpolation, wherein the degree of computational complexity than the circular interpolation high. In 80C196KC double word precision circular interpolation operation takes about 280 steps per cycle status at 16MHz crystal case takes about 35 that is about 28,000 times per second can be the difference complement operator. Operation and have an impact on the accuracy of the torch motion pulse equivalent, ie interpolation operation torch moving distance of each CPU. By design, the highest analog speed should be 100mm / s, this time to achieve a minimum pulse equivalent: 100/28000> 0.00357 << taking into account the degree of control other operations take pulse equivalent to 000625mm test proved possible. to achieve the required precision.
Data pulse weight, and size of the workpiece during cutting cutting, work often contains a large radius arc size, such as crane beams, hanging owners beams, bridges and the like. The design requirements for the maximum arc radius 1000m. When the pulse equivalent 000625mm, the maximum word length for a binary bit 29bit, take practice 4 bit, so, in the computation of the degree of control 80C196KC double word operator program.
The complexity of the work and storage space because the controller uses a separate controller, storage space is limited, it 80C196KC, the Harvard architecture of the program and data spaces separate ways, and through the data pin spare room for further expansion of the case next, you can achieve a more realistic set of data space is 64KB each workpiece arc and line 50H, plus signs and check word line, a line needs 10 bit, -. arcs need 18 bit, average 14biE. Thus, the maximum number of lines 64KB data space can be stored as: 64×1024 / 14> section 4681. According to statistics, the average number of lines at about 1030 steel parts feed segment, calculated according to paragraph 30, the controller may be arranged workpiece machining time about 100, to meet most machining requirements.
CNC system jamming the cutting machine is mainly used for factory welding workshop, these workshops mostly with mainframe processing and welding equipment, can produce strong electromagnetic radiation spectrum competition. Meanwhile, the cutting machine itself has a plurality of system components, can produce a strong interference, especially easy to interfere with the normal operation of the NC system, causing the system to crash, malfunction, so the anti-jamming capability CNC system has a very important significance. Measures taken by the main design are: electromagnetic shielding, CNC System in the upcoming strong shielding housing; purifying power, there is a lot of interference from the power cord into the machine, so the introduction of the power supply with multiple levels filter to eliminate power supply noise; electromagnetic isolation, all inputs in the controller, the output of optical isolation measures are completely cut off from the CNC system and other portions of the electromagnetic contact, greatly improved anti-jamming capability; computers and controllers a digital processing device, the work has a certain level of electromagnetic radiation, if the traditional method, the controller will make a card inserted in the computer’s bus structure is inserted and hard to ensure electromagnetic compatibility, so in this design uses a computer and a controller isolated way, with the isolation measures external communication contact, the reliability is further improved.
When the oxyacetylene flame cutting automatic cutting perforated reliability more artifacts, each cut coriander a closed contour cutting machines need to perforate the next contour cutting. In the case of a thicker plate, perforation will have more splatter, ranging from the cutting nozzle of life, reduce the cutting quality, cutting nozzle can cause severe blockage caused by tempering. Therefore, when the automatic perforation must take certain measures to prevent splatter. There are two main measures: First, reduce the cutting oxygen pressure during piercing, cutting oxygen supply circuit has two low pressure all the way, dedicated to the perforation, the higher the pressure the other way, for normal cutting. Another measure is to improve the perforated torch height so that the height between the cutting nozzle and the steel sheet when the punch is greater than normal height, so easily damaged or clogged splashing cutting nozzle. When piercing, the controller first cutting oxygen pressure switch to lower perforated pressure while driving motor is rotated to lift the torch torch elevated direction, open cutting oxygen automatically start the process of perforation, after a certain time, steel was beaten wear, cutting oxygen is switched to the normal pressure, while improving electrical torch down to normal height and started cutting parts. Practice has proved that, through these measures, the reliability of drilling significantly improved, greatly extending the life of the cutting tip.
4 According to the design requirements for different requirements adopted different measures, and finally the actual product inspection, have reached the design requirements, the design is successful, now the device has been put into actual production, and sales of more than one. In actual use, for enterprises to save a lot of manpower, material resources, to achieve good results, while production costs are significantly lower than similar products, it is suitable for China’s national conditions, there is a certain competitive advantage.

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