Selection of overhaul and reconstruction plan for

2022-10-23
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Selection of machine tool overhaul and transformation scheme

this work may be better and faster if it can win the technical support of overhaul and transformation enterprises

1. Preliminary project preparation work

(1) technical feasibility analysis is mainly aimed at the transformation target and processing object, and a comprehensive analysis of the structure, performance, accuracy and other technical status of the transformed machine tool. Including whether the original structural design of the machine tool is reasonable; Whether the basic components and structural parts of the machine tool are still intact; To change an ordinary machine tool into a numerical control machine tool, we should check whether the mechanical transmission structure of each coordinate axis and the form of guide rail pair are applicable; Measure whether there is a gap between the current accuracy of the machine tool and the factory accuracy

comprehensively summarize all faults existing in the machine tool at present and major faults in history. In view of the above problems, according to the transformation objectives and typical workpieces, compile the transformation task book, so that the transformed machine tool can achieve a certain degree of progressiveness and practicality

(2) economic feasibility analysis lists several situations that should be considered from the actual operability: considering the value of the machine tool itself, analyze whether the investment required to achieve the transformation goal is too high; Analyze the transformation value from the position and importance of the machine tool in the product manufacturing of the unit; From the input-output rate of the machine tool, whether it can recover the investment quickly and then produce better benefits quickly

after the transformation of the machine tool, the accuracy of the machine tool has been improved and its functions have been increased. Its main characteristics are: ① whether the adoption of a single 5V power supply can improve the level of the unit's products, or it can be conducive to the development of new products, so as to obtain additional benefits. The source of funds for the transformation is reliable

(3) it is a key problem to choose machine tool reformers. If you choose well, you can successfully complete the transformation task and achieve the transformation goal; Bad choice is not only the failure of machine tool transformation, but also a waste of money and time, affecting production. Users can choose carefully according to the conditions for machine tool transformation discussed later

2. Technical proposal preparation

(1) as the end user of machine tool, the manufacturer must first confirm the condition of the machine tool's mechanical and hydraulic system. For example, the current accuracy of the machine tool, the condition of the mechanical transmission chain, the condition of the lead screw and guide rail, and whether there are major faults, so as to determine whether the machine tool is overhaul or item repair. If a non NC machine tool needs to be changed to a NC machine tool,

first of all, the feasibility of mechanical modification should be considered, and the most important thing is the form of guide rail and the installation of ball screw. Another is whether the transmission clearance and transmission stiffness of the mechanical transmission mechanism meet the requirements of CNC machine tools

(2) when the electrical system is making the transformation plan of the NC machine tool, the user can choose the NC system according to the state and process requirements of the machine tool. One is to choose CNC manufacturers. At present, Siemens (Germany), FANUC (Japan), Mitsubishi (Japan), Num (France), FAGOR (Spain) and other companies with good performance and reputation in the world. Users can choose a more suitable CNC system with the engineering company implementing the transformation on the basis of a detailed understanding of the characteristics and performance price ratio of the CNC system of the above manufacturers

second, select the type of corresponding control system according to the functional requirements of the machine tool, so that it can meet all the functional requirements of the machine tool without raising the standard

we suggest that special attention should be paid to the selection of CNC system: first, try to be close to the model series of a famous manufacturer. This is not only conducive to maintenance and management, but also conducive to the purchase of spare parts. Never make the CNC system of an enterprise into a world brand. Second, we should be clear about the maintenance service status of the selected manufacturers in China, so as to avoid endless trouble in the future

after the CNC system is selected, the user decides to replace or not to replace the drive system according to the actual situation of the machine tool. If it is not replaced, it must be confirmed whether the old drive system can match the CNC system

for the machine tool measurement system, the current requirement of the CNC system is incremental pulse coding input, so the measuring elements such as the induction synchronous ruler or rotary transformer equipped with the old machine tool need to be replaced by incremental pulse encoder and grating ruler

for the peripheral circuit, there are two schemes that can be adopted for transformation: "interface transformation", that is, to retain the peripheral relay circuit, and only transform NC and PLC. The new PLC does not participate in the peripheral circuit control, but only processes the command signals required by NC. The reconstruction design and commissioning workload of this scheme is small. The other is "thorough transformation". Under the condition that the relay logic is complex, the failure rate is high, and the user can provide a clear logic diagram, Achala de Mel Bo found that 3D printing allows the creation of multiple combinations in the support (the traditional manufacturing method is difficult to achieve such efficiency and repeatability), the peripheral circuits can be completely transformed with the PLC brought by the new NC, simplifying the peripheral circuits, It also makes reasonable use of the control ability of PLC

this scheme can greatly simplify the hardware circuit and greatly improve the reliability, but the workload of transformation design and debugging is large

(3) determine the installation form of each part. First, the installation of control system is common and can be stored in suspension, cabinet, desk, etc. The selection of installation mode directly determines the routing mode and cable length of various connecting cables, and also relates to the convenience of operation and maintenance. Second, in principle, the installation of the drive system can only be carried out in the electrical cabinet. The factors that should be considered include ventilation and cooling, cable routing method and length, and

interference with other electrical appliances

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