Research and purchase of automatic polishing equipment
In recent years, with the rapid development of industrial technology and industrial automation, various automatic grinding equipment has been more and more widely used in casting. But in practical application, many automation equipment has a lack of rigidity, grinding process is not reasonable and other problems, leading to many enterprises to buy equipment practicability is reduced, and even appear as high as the artificial grinding efficiency of the embarrassing situation. In the face of the current situation of a wide variety of products and uneven quality in the market of automatic grinding equipment, do you really understand it enough?
If you're just getting started with automated polishing, there's a lot to learn and hopefully this article will help you through the automation process -- from understanding the mechanics of your equipment to choosing a system integrator, you'll also find answers to some of the most sensitive questions.
The mechanical structure
In order to truly understand the automation grinding equipment, first of all, we should know that the mechanical mechanism is the first standard to evaluate the rigidity and stability of a equipment. People in the industry know that the different mechanical structure will affect the grinding efficiency and grinding accuracy of the equipment. In the design of the mechanical structure, integrated with the current market of various types of automation equipment, although the size is rich and diverse, but there are mainly the following two forms;
1. Structure of manipulator
The working principle of the manipulator is that the three-joint, six-joint and other mechanical arms are used for grinding. Its advantage is good flexibility, and it has a certain effect when grinding some small gray iron castings. The disadvantage is that the bearing capacity and rigidity are low, and the removal amount of grinding is low when dealing with high strength parts such as ductile iron or cast steel. Only 1-2mm can be removed by grinding at a time, and it will even cause the situation that the car can not be processed. Moreover, the long-term use of manipulator equipment will lead to the damage of the joint of the mechanical arm, the position of the joint shaft is often offset, the grinding accuracy will decrease, and even shorten the service life of the equipment.
The disadvantages of manipulator structure type equipment in casting grinding and cutting technology and application:
1) Poor rigidity: it is difficult to solve the grinding and cutting process of high strength, multi-dimensional, thick and large pouring riser.
2) Low efficiency: mechanical arm lifting structure, series transmission of motion, slow motion, low efficiency.
3) low accuracy: low structural strength, when the load fluctuation, vibration is large, the accuracy of ±0.05mm - ±0.1mm.
To sum up, we probably understand the working principle of manipulator structure equipment, as well as the technical shortcomings of this type of products, so what are the characteristics of other mechanical structures in grinding and processing? Compared with manipulator equipment, what are the advantages? Next, let's take a look at the light points of the machine tool structure equipment.
2. Machine structure
Speaking of the advantages of the structure of the machine tool, it is necessary to compare the structure of the manipulator. The machine structure can realize the linkage of five axis or six axis, and its flexibility is not inferior to the manipulator. And each axis of the equipment can move directly. Compared with the manipulator structure, the machine tool structure equipment can improve the grinding speed and accuracy significantly. Moreover, the structure of the machine tool itself is large, higher rigidity, to ensure that the vibration is small when grinding high strength castings, the tool always maintains the best cutting state, so as to obtain a longer tool life and a shorter grinding beat. However, manipulator type equipment can not meet the requirements of such casting processing technology.
The advantages of machine tool structure type equipment in casting grinding and cutting technology and application:
1) High rigidity: machine guide screw structure, self-weight, good stability, can realize the cast steel, ductile iron and other different materials of large parts of the grinding and cutting.
2) High efficiency: each axis direct movement, movement without transfer, fast movement rate, high grinding efficiency.
3) High precision: small grinding and cutting vibration, repeated positioning accuracy up to ±0.02mm, far beyond the industry average level.
Laser measuring system
Automating the grinding process is not easy, and dissecting the mechanical structure of a piece of equipment is only the beginning. It takes a lot of experimentation and technological innovation to make the automation equipment perform well in order to make the grinding job look easier. Next, let's take a look at the challenging technology of casting cleaning, laser measuring system, which has a profound impact on casting grinding.
Unlike manual work, the equipment cannot use the eyes to observe the workpiece and make judgments and adjustments as needed. Due to the different deviations of each workpiece, it is difficult to achieve consistent grinding results due to overcutting or failure to effectively remove metal residual amount in the machining process. At this time, we need the help of laser measurement technology.
Laser measurement technology, first through the use of laser range sensor, real-time access to current workpiece testing point and point distance deviation samples and gave the corresponding data real-time transmission control system, then apply for different artifacts developed software and compared calculation module, thus compensation program, to boot device for cutting grinding target artifact. The successful application of laser measurement technology has solved the acknowledged difficult problem of casting cleaning, namely cutting steel castings and grinding large castings.
This is why laser measurement techniques are so important in practice. Unfortunately, very few companies have mastered and applied this technology, and most have been on the road of technological exploration. Caused by a lack of technology, this kind of enterprise for a single casting grinding efficiency is low, and can meet the cleaning such as a large number of parts in production line, even if the individual companies completed lens group and the integration of laser interferometer, but because of its mechanical structure is not reasonable, equipment of the underlying algorithm is not perfect, resulting in practical applications, the rectifying effect is not ideal.
It is believed that many enterprises will encounter a price war between brands when inspecting all kinds of automation equipment. A responsible supplier should establish a global value chain cooperation network to integrate the appropriate equipment components, tools, etc., to achieve the best solution for grinding automation. Rather than mislead the market with products with obvious technical flaws in order to cut costs. For example, there are many problems with the grinding spindle used on the equipment.
1. Servo motor
Now the grinding spindle on the market is generally used to drive the cheap servo motor. The disadvantages of small load and small torque make it easy to cause overheating of the spindle when the servo electric is working for a long time. Moreover, in the processing of high strength castings, the shortcoming of insufficient rigidity of grinding spindle will lead to the difficult completion of workpiece cleaning at one time, and the remaining part often needs to be repaired manually, and the utilization rate of equipment is seriously insufficient. The enterprise input cost increases, but the output efficiency does not improve significantly.
Disadvantages of servo motor:
1) Small load, small torque and insufficient rigidity can be realized.
2) Insufficient protection, no positive pressure gas protection, only sealed protection.
3) Air cooling, long time work will lead to overheating of the spindle.
2. High-speed motorized spindle
Compared with servo motor and ordinary motorized spindle products, the use of high-speed motorized spindle equipment is more reliable, because of its large load, high speed advantages have been certified by the market for many years. When polishing medium and large castings such as engine cylinder block and cylinder head, the workpiece can be cleaned 100% without manual secondary work. High-speed motorized spindle is safe, reliable and durable, which meets the needs of stable operation of equipment in various harsh environments, and has been favored by many enterprises. Of course, the price will be much higher than the servo motor.
Advantages of high-speed motorized spindle:
1) Torque feedback system, large torque, high load, good rigidity.
2) With positive pressure gas protection, safe and reliable.
3) Closed-loop water cooling function can realize grinding application in harsh environment.
A few years ago, the news reported that a large state-owned enterprise on the cylinder cleaning line, due to the grinding equipment produced by a domestic factory and another foreign company's grinding robot does not match, there is a dispute, long-term can not be resolved, resulting in the long-term stagnation of the line failed to put into use, bringing serious economic losses to the enterprise.
Now the automation market, there are a lot of equipment manufacturers, insufficient technology, rashly put imitation of foreign and domestic equipment, without the actual test of the market, brought the ideology, resulting in equipment can not be integrated, after-sales maintenance, causing mutual harm.
Criteria for selecting suppliers:
1) Possess independent intellectual property rights and certain research and development capabilities.
2) It can realize the effective integration of robots and automatic grinding equipment in the production line.
3) There are many successful implementation cases.