Before the CNC transformation of old machine tools, the price of CNC lathes with the same performance in the market should be investigated, and the price of the two should be compared while the delivery time should be considered.
For small CNC lathes and milling machines that are not expensive, It is recommended to update and purchase new machine tools instead of retrofitting old machine tools, because the cost of the two is similar and saves less money.
The machine tool transformation time is about 2 months. For small CNC lathes and milling machines, machine tool manufacturers generally have stocks. It is a better choice for a more expensive machine tool to perform CNC transformation, which not only saves more money, but also shortens the purchase time. For example, a table with a size of 2000×1800mm, three-axis linkage, and horizontal machining with 60 tools The center comparison is as follows.
Investigate the status quo of CNC lathe parts that need to be modified
Not all old machine tools are suitable for numerical control transformation. A comprehensive understanding of the machine tools that need to be transformed must be carried out. The mechanical system of the machine tool must be surveyed and mapped to make correct judgments. Good mechanical performance is the basic condition for successful numerical control transformation of machine tools. Otherwise, , No matter how good the CNC system is, it can't play its due performance. Therefore, the mechanical accuracy of the machine tool should be tested before the CNC transformation of the machine tool, and the problem can be repaired during the implementation of the machine tool transformation. If there are many problems in the mechanical system of the machine tool, such as defects in the mechanical structure design and manufacturing of the old machine tool, the CNC transformation of the machine tool will not be of much significance.
The electrical system of the old machine tool is the key work of machine tool transformation due to the aging and failure of components. It is necessary to understand the manufacturer model of the old machine tool numerical control system, the number of control axes, the drive configuration of the spindle and feed axis, the power of the spindle motor, and the power of the feed axis motor. Torque etc. Check whether the random technical information is complete and complete. Complete technical information can shorten the technical preparation time for machine tool transformation. Among them, electrical schematic diagrams, PLC programs, machine tool maintenance manuals, hydraulic, pneumatic, lubrication schematic diagrams, mechanical assembly drawings, etc., must be carefully studied. Special attention should be paid to the fact that the content provided in the technical data may be wrong and not consistent with the actual machine tool. This is because some machine tool manufacturers provide general drawings of series models, and the electrical hardware changes of individual machine tools are not marked in the electrical data. This requires us to compare the actual machine tool and carefully check to avoid mistakes.
The determination of the CNC transformation plan of the machine tool
On the basis of machine tool surveying and mapping, according to user requirements, determine the overall machine tool transformation plan.
1. Modification plan of CNC system
The transformation of the machine tool is first of all the transformation of the numerical control system. According to the existing control level of the machine tool, the workpiece processing requirements, and the capital status of the enterprise, the corresponding low, medium and high-end numerical control systems are selected. When choosing a numerical control system, you need to consider the products of mainstream manufacturers. For example, foreign numerical control systems can choose FANUC, Siemens systems, etc., and domestic numerical control systems can choose Huazhong and Kanedi systems. It should also be as consistent as possible with the CNC system selection of other CNC machine tools for machine tool users. The advantage of this is that it is convenient for maintenance personnel to maintain the machine tool; the more centralized CNC system also facilitates the reduction of the types of spare parts. The selection of the CNC system is based on the principle of practicality, and there is no need to waste money in pursuit of a higher level.
2. The transformation plan of the spindle servo system
The spindle control of old CNC machine tools generally adopts DC servo or AC analog servo drive system. According to the needs of use, the original drive device and spindle motor can be used instead of AC digital servo drive system or inverter control. The original drive system can also be retained, such as a good AC analog servo drive system; the DC servo drive system can retain a good DC motor and use a new DC servo control device to replace the old drive device.
3. The reform plan of the feed servo system
Similar to the reconstruction plan of the spindle servo system, according to the needs of use, the original drive device and motor can be replaced by an AC digital servo drive system; the original drive system, such as an AC analog servo drive system in good condition, can also be retained.
4. Modification plan of closed-loop control detection device
For the inductive synchronizer/ruler of the old machine tool, it can be replaced by circular grating and grating ruler. When selecting the model, pay attention to the consistency of the interface signal between the detection element and the system, square wave signal or voltage signal. If you retain the old current signal grating ruler, you need to install a current signal to voltage signal conversion device to match the new system, because most of the new systems do not support current signals.
