introduction Micromachines or MEMS (microelectromechanical systems) are an edge, cross-cutting high-tech research field emerging in the 1980s. Since the 1980s, miniaturization and miniaturization have become one of the main directions of mechanical evolution. Therefore, micromachinery has been listed as a key development discipline in the 21st century by developed countries such as the United States, Japan, and Germany. At present, research on micromachinery at home and abroad is mainly focused on the theory of micromechanics, structural design, microfabrication technology, and application of micromechanics [2-3]. Compared with the commonly used microfabrication method shown in Table 1, since the resolution of optical molding can reach about 2μm, and it has features such as high degree of freedom of processing and the parts can be of any complicated shape, it is suitable for machining of small machines. In this study, Lai uses a spot-curing light-molding method that corresponds to a photo-curing unit and uses a UV laser as the light source. The free liquid surface illuminates the light from top to bottom and the workpiece grows upward. Because the liquid surface is not constrained, after the first layer is processed, a special liquid leveling device is required. The workpiece will be affected by the surface tension of the liquid surface, so that the thickness of the liquid in the vertical direction should not be controlled, thereby reducing the resolution of the direction; and Each layer is exposed to the atmosphere, easy to enter the dust, but also reduce the resolution. The constrained liquid surface type confines the work piece between the substrate and the light window. The light beam irradiates from the bottom to the top, and the work piece grows downward. (3 Because it eliminates the influence of the surface tension of the liquid surface, it is conducive to the improvement of the vertical resolution, which is suitable for tiny Mechanical production, but this also brings about the problem that each molded part is not easily separated from the light window and that the light window absorbs a part of light energy (the solution of these problems will be described in 2.2 Composition and Commissioning of Experimental System). . 2.2 experimental system composition and debugging The block diagram of the micromechanical optical molding experimental system is shown in Fig. 3. Fig. 4 shows the whole picture of the experimental system. Fig. 5 shows the laser, worktable, light path system and resin tank. The composition, functions and specifications of the various components of the experimental system are shown in Table 4. The experimental system debugging mainly solves the following problems: This article discusses the possibilities of light-molding for micromachined manufacturing. Based on the study of micro-mechanical light-shaping microfabrication technology, system construction and commissioning, and light-molding process experiments, the first micromechanical photomolding experimental system in China was produced. All the components used in the system are made in China, and the way to manufacture a low-cost micro-light shaping system is explored. Construction machine service. Construction machine Service,Construction machine,Construction machine Manufacturers Xinxiang Anlian Crane Construction Machinery Co.,Ltd. , https://www.electrical-hoist.com
Semiconductor technology is commonly used in micromachine manufacturing. Semiconductor technology exists: The parts that can be produced are mainly planar, and it is difficult to form a three-dimensional complex structure. It is difficult to realize the production of space agencies and can not meet the manufacturing requirements of micro-robots and other advanced micromachines; equipment investment Large; single-piece, small batch production costs and other issues. Therefore, all countries are exploring new ways to manufacture three-dimensional complex parts.
Rapid Prototyping & Manufacturing (RPM) is a rapid design and processing technology developed in the late 1980s [1]. The core idea of ​​rapid prototyping is to decompose two-dimensional entities into two-dimensions, process them layer by layer, and build them up to form prototypes. The biggest advantage of this kind of manufacturing technology is that it can quickly manufacture 3D complex parts and it can precisely make up for the shortcomings of silicon technology. In recent years, Japan and other countries have begun to discuss the rapid prototyping technology as a micro-mechanical micro-machining process [4]. However, research on the application of light-shaping technology in micro-machining has not yet been reported.
This article reports the conclusions about the possibility of light-molding technology for machining micro-machines, and the progress of research on the following issues of micromechanical light-shaping systems [5]:
(1) Special process problems such as light shaping method, slicing method and data format, beam scanning method, and liquid level control method;
(2) system configuration and debugging; (3) optical molding process experiment.
1 The possibility of micro-machined light forming and its special process problems
1.1 Possibility of Micro-Mechanical Light Forming Processing The micro-machinery used in this paper is defined as a machine that has an overall size of about 1 cubic centimeter or less, a minimum length of about 10 micrometers, and a highly integrated structure that is intelligently controlled by computers. Compared with ordinary machines, the micromachinery is characterized by its small size, high processing resolution (minimum distance between two points that can be independently processed) and large machining freedom (shape of the machinable parts). Complexity).
The following table summarizes the resolutions, machinable shapes, and major problems that are commonly used in microfabrication techniques. 
1.2 The special process problems of micro-machined light forming
(1) Forming resolution and curing unit An important indicator in micromachining is resolution. In rapid prototyping, we differentiate it into scanning resolution and forming resolution. Molding resolution refers to the minimum unit of molding; scanning resolution refers to the minimum distance the scanning mechanism moves. Introduction of the concept of a light-curing unit in a micromechanical light forming system: A light-curing unit refers to a resin volume that is cured by a laser spot on a photosensitive resin. The smaller the curing unit, the higher the molding resolution.
(2) Light shaping and beam scanning methods Beam scanning methods are generally divided into two types: raster scanning and vector scanning. The vector scan is line forming, and the forming resolution is low. The c raster scan is a point forming. The laser beam is scanned in a set of parallel light, and the light beam is controlled in an open and closed manner to obtain an arbitrary three-dimensional shape. Raster scanning method is easy to control and improve the resolution of molding, but the time for producing large-scale moldings will be greatly increased. In order to improve the resolution of the forming and overcome the shortcomings of long scanning time, the system adopts an improved raster scanning method, which is characterized in that: since the scanning time of the raster scanning type is roughly proportional to the scanning area, in order to shorten the processing time, the scanning path is only Internal scan design of the workpiece; to eliminate the SACKRASH of the scanner. Take the same direction raster scan as shown in Figure 1. The photo-molding method also includes mask surface curing. The author summarizes the optical molding methods, characteristics, and spectral light sources used, as shown in Table 2. 
(3) Slicing method and data format The general RPM system adopts STL data format: First, it applies a discrete grid approximation of a small-diagonal surface model to a CAD model to generate a series of small triangular data STL files similar to the original three-dimensional entity. , and then slicing the STL file. Since the small dihedral cannot completely express the actual surface, it will produce an unacceptable loss of precision. In addition, when the S.D.L format is converted, partial defects may occur, and some of the defects are more difficult to repair. The system directly slices the CAD model by slices, and uses the BMP (bitmap: bitmap) data format. Due to the direct slicing, approximation errors and description defects similar to the STL method can be avoided; and the BMP data format directly corresponds to the curing unit and the raster scanning method, which is advantageous for improving the accuracy of the curing unit.
(4) Liquid level control method Liquid level control is divided into two types: free liquid surface type (general RPM system uses free liquid surface type) and constrained liquid surface type, as shown in Figure 2. 
2 Micromachined Light Forming System
2.1 Light Forming Process System
In this paper, on the basis of the research on the special process problems of micro-mechanical light forming, a process system suitable for micro mechanical light forming is proposed. Compared with the general RPM system, this process system has the characteristics shown in Table 3. 
The design of the micromechanical optical molding experimental system is based on the following principles: the equipment construction is to be simplified; all molding equipment components including lasers are made of national products, which helps to reduce the development cost and create a way for localization of micro-scale light-shaping systems. 
(1) Separation of the molded part from the light window The method of coating the resin on the surface of the light window was adopted, and the type of the coating material on the surface of the light window and the experiment of coating the split type were performed. Coating materials include fluorides and silicides; coating methods include resin coating, resin tape, or film (collectively referred to as tape). Coating materials should have transparency, separation, heat resistance and other comprehensive performance indicators, coating methods should be simple and easy. After a comparative experiment, the optimum solution for attaching Teflon tape to the surface of the light window was determined. This paste scheme has the advantages of good overall performance, uniform resin paste, good effect, and easy use.
(2) Comparison of optical window adhesive materials A comparative experiment was conducted between Japan-made (3MScotckTM) and domestic (Taizhou Organic Fluorine Materials Factory) Teflon films, and it was concluded that the domestically produced Tcflon film could also be used as a window adhesive material.
(3) Light window material and light transmission experimental light window material should have high transmittance for light of wavelength required for photochemical reaction. After transparence contrast experiment between ordinary glass and quartz glass, it is decided to select good transmission to ultraviolet light. Quartz glass for light window material.
(4) High-frequency interference analysis and anti-jamming measures The high-frequency interference generated by pulsed nitrogen molecular lasers was analyzed. The characteristics of this interference source were diagnosed as: Interference frequency of nearly 100 Mb, instantaneous amplitude up to 100 V. Take the appropriate countermeasures shown below; isolate with a targeted shielding measure—eliminate the source of interference; use a reasonable grounding method to cut off and obstruct the interference pan channel: set the filter, use a shielded wire, etc. to reduce the receiver circuit pair The sensitivity of the interference, etc., has achieved a good anti-jamming effect.
2.3 Experimental research of light forming process
Through experimental modeling, we have mastered the relatively reasonable scale of micro-mechanical light forming process, and summed it into the following steps:
(1) Reference alignment The base plate is provided with a number of reference holes for alignment; the elevating table (Z-direction table) is moved so that the substrate is slightly higher than the light window, and the exposure head is moved to coincide with the reference hole on the substrate.
(2) The base part is machined so that the lift table is as close as possible to the resin slot light window. The entire resin in the gap between the substrate and the light window is cured. With a large exposure amount, the horizontal dimension of the base portion is larger than the horizontal dimension of the workpiece, so that the base portion and the substrate have a larger contact area, so that the molded object can be firmly fixed on the substrate.
In order to prevent the surface treatment layer of the optical window and the resin from absorbing excessive heat and causing damages such as burns and deterioration, the condenser lens leaves the material fat at the discretion, and improves the heat dissipation conditions to suppress the temperature rise.
Due to the large contact area between the base part and the light window, the adhesive force is also large, and when the two are separated, the surface treatment layer of the light window is easily damaged. To this end, the base section raises and lowers the elevating table once it cures a certain area, so that the adhesive force at each separation is not excessive. In the processing of the basic part, the operator should frequently interrupt the processing and determine the processing state so as to avoid accidents in which the workpiece and the light window cannot be separated.
(3) Processing of the shape part Compared to the processing of the base part, a small exposure spot and a small exposure amount are used to increase the resolution.
The exposure conditions inside the workpiece are made uniform, so that the deformation during the secondary curing is only a simple similar deformation.
With improved raster scanning and pulse exposure methods, the scanner can be moved directly to the curing unit position.
When the lifting platform descends, the resin between the workpiece and the light window is squeezed. When the pressure rises, the surface treatment layer or the work piece of the light window may be damaged. Therefore, there should be a period of buffering at the beginning of the rise and the end of the decline, which takes about several seconds.
(4) Ultrasonic acetone cleaning
(5) UV curing
The experimental system has been successfully debugged and a micro test piece has been prototyped. The purpose of the trial machining is to verify whether the scanning system can be scanned according to the set number of curing units (including the usability of the BMP data format); confirm the Z direction layer. Thickness; verify the separability of the molded part and the light window; observe the state of solidification, confirm the presence of uncured resin in the solidified layer, and the regularity of the shape of the molded article. The shape of the micro test piece is a cylinder, an elliptic cylinder, a triangular column type and a parallelepiped, and the surface dimension is about 2-3 mm2.
The results of trial machining show that the experimental system can operate normally, X-Y plane scanning and Z-direction layer thickness control meet the design requirements, the resin is cured uniformly, the molded parts can be well separated from the light window, and the shape of the molded article is regular. However, this is only a preliminary test. The shape of the micro test piece is still simple. The more complicated shape micro parts and the experimental work of directly manufacturing the micro machine using the micro-mechanical scale effect are in progress. In addition, the forming resolution and the scanning resolution are still not high enough. The reason for this is that due to the selection of the laser, the design of the optical path system, and the design and manufacture of the workbench, the research funding has been limited. At present, we are carrying out the following work: reduce the spot size of laser beam to obtain high forming resolution. Improve table accuracy to improve scan resolution.
3 Conclusion
The experimental system has passed the acceptance of the “863 Program†expert group.
Construction machine services,fault analysis and troubleshooting, the current Construction machine is generally electromechanical-hydraulic integration,the focus is on the three major blocks of machinery,electrical appliances, and hydraulics.
1.Construction machine.The failure rate is actually low, so it is enough to be familiar with the structure and mechanical working principle of the product.Such as the main components,how to complete the specified action,important parameters of the work,etc.
2.Electrical appliances.Familiar with the role of various electrical appliances on the machine,common faults and processing methods,such as:batteries,electromagnetic switches,generators,relays,instruments,etc.,
3.Hydraulic.It is relatively complex and must be familiar with the various components of the hydraulic system of the machine,such as hydraulic pumps, hydraulic motors,control valves,etc.Focus on the hydraulic working principle diagram,familiar with the oil direction and control process to realize each action,which is the basis for future analysis and troubleshooting.
Another is the engine,which is the heart of the machine,and should focus on study and research.
In addition to technical aspects,after-sales service of Construction machine has to deal with customers,so interpersonal communication skills must be cultivated.Work experience needs to be accumulated slowly,and more seniors should be consulted for methods and procedures for dealing with faults and complaints.