Keywords:
Currently in the metal processing industry, the hot topics that people are most interested in are high speed and high precision machining. However, a decade ago, scientists focused their attention on a topic of special significance - how to reduce the vibration generated by the machine during machining.
The scientific and technical personnel's main focus on reducing the vibration theme is that every machine tool designer in the design of vertical and horizontal machining centers, the first consideration is how to go beyond the machine tools designed by the predecessors, so that It has made a big breakthrough in solving the technical problem of vibration reduction.
This is the latest NV4000 DCG vertical machining developed by Mori Seiki. It is designed to drive the machine Z and Y axes to be DCG driven by two ball screws, and the X axis is driven by a ball screw.
The designers and engineers of Mori Seiki in Japan have been predictively proposed from the very beginning. In metal processing systems, the vibration sources that cause severe vibration are mainly from the basic structural configuration of the machine itself. Unreasonable. This is the conclusion that they have focused on the research and analysis of the relationship between the linear motion axes and how the cutting forces are quickly and separately applied to the high-weight, high-rigidity machine tool moving components that move at high speeds.
They believe that the driving force is not very accurately applied to the center of gravity of the moving parts during the machining process. Thus, at high cutting speeds, especially at large feed rates, there is a tendency to produce torsional motion. This inevitable torsional motion and the inertia caused by the moving parts cause vibration of the machine tool and bending and deformation of machine components such as castings such as machine bed or column.
But people don't know enough about this, and they don't solve this technical problem that has long plagued manufacturing. It is obvious that a fundamental solution to the problem is to design the machine structure to apply the driving force to the center of gravity of the moving part, that is, the center of gravity drive (DCG).
But in reality, there is another problem. We can't pass a ball screw directly through its center of gravity (there are machine parts in the middle, there is no space). For example, in a horizontal machining center, the fourth axis table is located at the center of gravity of the Z axis, so the ball screw cannot be installed in this optimal position.
The designer of Mori Seiki Co., Ltd. placed the Z-axis and Y-axis motion components between the two ball screws in the newly developed DCG-driven vertical machining center to form an ideal but virtual center of gravity. But it can produce exactly the same effect as the actual driving force through the center of gravity. The vibration and bending generated when each shaft is driven are excellently suppressed, and even if the moving assembly is moving at a high speed, the center of gravity does not change, thereby achieving stable driving.
According to Mori Seiki Co., Ltd., they have made DCG drivers from both theory and practice. They specifically embodied this design principle in the trademark of DCG.
Up to now, the company has three machining centers that use the DCG trademark: one is the NV4000 DCG vertical machining center and the NH4000 DCG and NH6300 DCG two horizontal machining centers. The main feature is of course the design using the DCG design principle and the following two design principles:
All forces in the machining must be transmitted to the machine bed through the column to form a closed force transmission circuit.
Under the premise of ensuring that the main components of the machine tool have sufficient strength, rigidity and good vibration damping characteristics, the main components of the machine tool must be digitally analyzed to minimize the weight of the moving parts.
Through the bold design of the machine tool, the machine can reduce the vibration more than 10 times, and significantly increase the acceleration/deceleration speed of the linear feed motion during machining without reducing the surface roughness and geometric accuracy. At the same time improve tool life.
Among them, the NV4000 DCG vertical machining center, from the overall design of the whole machine, is indeed superior to the ordinary vertical machining center. The first is the arch of the arched structure and the DCG drive of the Y and Z axes. The arched column has the characteristics of high rigidity. Two deep holes are machined from above the arched column to symmetrically install two sets of ball screws, which is a typical DCG drive structure. Therefore, the Z axis (spindle) of the machine tool is kept from zero theoretically and practically.
The dual ball screw DCG drive solution is applied on the Y-axis (slide lateral), which is to install two sets of ball screws symmetrically on both sides of the machine bed casting. The center of the drive unit, which is mainly composed of two sets of ball screws, coincides with the center of the Y-axis slide to form a DCG drive. The X-axis (table longitudinal) is designed to be centered on the table and is driven by a set of ball screws. This set of ball screws is designed to be very close to the center of the Y-axis ball screw. This is due to the fact that there are no other machine parts at the center of gravity of the X-axis.
According to the manufacturer, they provide five sets of VMCs for ball screws according to the machine price of three sets of ball screws, and it is excellent in preventing vibration, improving product quality and greatly improving production efficiency.
The two horizontal machining centers of this series are characterized by the design of the latest box-in-box structure in which the headstock is placed in the sports box, making it smooth and rigid. The dual ball screw DCG drive scheme is applied to the X-axis and Z-axis (standard). To reduce the weight of the moving parts, the Y-axis is designed to be driven by a set of ball screws.
According to the development engineer, this configuration allows the machine to achieve both high acceleration machining and the best match of the high machining accuracy of the part. The two ball screws on the X-axis are designed to be located above and below the X-axis slide, respectively, and coincide with the center of gravity of the slide, which has the dual effects of significant vibration reduction and high production efficiency.
According to the manufacturer, this series of products are mainly used in production workshops that require high processing precision and small batch size. Manufacturers of cutting-edge products such as molds, medical devices and the aerospace industry will be buyers of processing equipment for the system.
Mirror is a smooth,highly polished surface covered a thin coating.Mirror is usually a thin coating of metal or dielectrics.
Precision Optical Flats are ideal for a variety of applications including interferometry, imaging systems, laser applications, optical path folding, and auto collimation.
China star optics designs and manufactures a great choice of various high and partially reflecting mirrors for the spectral range:UV,visible,near infrared,and infrared regions.Fused Silica substrates, is optically clear and features excellent resistance to abrasion and high durability, making it the best choice for applications in harsh environments. Metallic coatings Options, Protected Gold, and Protected Silver Coatings available. Wide Variety of Shapes and Sizes available in circular, square, and rectangular dimensions.
Specifications of our Optical mirrors as follow:
*Material:BK7 A glass, Fused silica, Quartz, CaF2,ZnSe,Optical crystals or other glass materials
*Parallelism:1 Arc min
*Clear Apenture:90%
*Squares/Rectangles:1mm to110mm+/-0.2mm
*Center thickness tolerance:+/-0.1mm
*Surface quality:60-40 to 20/10 Scratch/Dig
*Surface flatness:lambda/10 at 632.8nm
Protective Gold Mirror,Au Reflective Coating Mirror,Au Protective Coating Mirror,Protected Gold Mirror
China Star Optics Technology Co.,Ltd. , https://www.realpoooptics.com