In order to prevent the occurrence of defects, enterprises need to carry out inspections in accordance with the standards recognized and accepted by the state, such as ISO 230 standards or ASME B5.54 standards. Therefore, the enterprise must have the ability to edit the process file and the ability to ensure the process accuracy of the machine tool. Both standards require the use of ball bars and laser interferometers to check the accuracy of machine tools in accordance with recommended procedures. The purpose of adopting these standards is not to stipulate that the machine tool must meet a certain accuracy, but to find out what level of accuracy the machine tool can achieve. The written information of the parts stipulates that the accuracy of the machine tool of the enterprise must be able to produce qualified parts and set a benchmark for accuracy in this place. The test can let you know how high your machine tool can reach. As long as the machine tool can reach that accuracy benchmark, it has the ability to process.
Modern machine tools are equipped with testing and calibration technology, and can also provide this technology, so that the workshop can ensure the accuracy of the machine tool and normal operation. More and more factories and large workshops have their own laser interferometers and electronic equipment, while small factories can use various channels and commercial methods to obtain equipment and testing services through rental at competitive prices .
In fact, it is now possible to provide telescopic cue detectors for any workshop for the rapid detection of machine tools. It can complete the detection task in only 15 minutes to maintain the machining accuracy of the machine tool. Using club detection can accurately evaluate the machine tool’s geometric accuracy, roundness and stick / slip error, servo gain mismatch, vibration, backlash, repeat accuracy and scale mismatch. Some club software can provide specific error diagnosis according to ISO 230-4 and ASME B5.54 and B5.57 standards, and then provide a common English list, listing the various errors in order of overall impact on the accuracy of the machine tool source. This allows machine tool maintenance personnel to deal directly with problem areas.
The staged club test can keep up with the performance development trend of machine tools. Preventive maintenance is helpful for planning in advance before the machine deviates from the process capability. Industry generally tends to calibrate machine tools as needed rather than time. There is no reason to maintain a good machine in production for calibration. When something abnormal is found, let the club and the produced parts be determined. Production can continue during the inspection. Spot welding
On-board probe detection
The accuracy and repeatability that can be achieved with standard machine tools today are close to the levels that only CMM coordinate measuring machines could achieve in the past. This function enables the machine tool itself to automatically detect the workpiece with a probe at a critical machining stage. Once the measuring instrument is installed on the machine tool, the measuring probe becomes the operator’s CNC gauge. The inspection program can be programmed as part of the machining process and automatically run at various points to check the size and position and provide the necessary compensation. In this way, operators can avoid the use of dial gauges and plug gauges for measurement, and eliminate errors caused by human factors caused by the offset of fixtures, parts and tools in the control system. On-board inspection has become a part of the process. This is an improved and powerful process tool that can produce qualified parts for the first time in the shortest production time.
It can be used to automatically determine the position of parts, and then establish a working coordinate system. On-board detection can reduce the setting time, improve the utilization rate of the spindle, reduce the cost of fixtures and eliminate non-production machining transit time. In the machining of complex parts, it used to take 45 minutes to debug the fixtures. Now it takes only 45 seconds to apply the inspection device and it is all done automatically by CNC. When starting to process castings or forgings, the detection device can determine the shape of the workpiece, which can avoid wasting time due to empty cutting, and can help determine the optimal cutting angle of the tool. The control in the process is to use the detection device to monitor the characteristics, dimensions and position of the machine tool during the cutting process, and at the same time verify the precise dimensional relationship between the various features of each machining process to avoid problems. You can program the probe and check the actual machining results at each stage according to the program, and then automatically implement tool compensation, especially after roughing or semi-finishing.
Reference testing is to compare the characteristics of a part with a size model or a reference surface of known position and size. It enables the CNC to determine the positioning gap and then generate an offset to compensate for the gap. Before the critical machining, by detecting the fake model, the CNC can check its own positioning against the known size of the model, and then program the offset. If the size model is installed on the machine and exposed to the same environmental conditions, then the reference test can be used to monitor and compensate for the coefficient of thermal expansion. The result is a closed loop process that will not be affected by the operator.
Each machine tool has many inherent small errors during its movement and in its structure. Therefore, there is always a slight gap between the programmed position of the CNC and the true position of the tool tip, even between the two After the laser compensation is adjusted to be quite consistent. Programmable artificial model detection is a good way to further compensate the remaining errors of the machine tool. It can provide feedback for process control, and can make positioning accuracy close to the specification requirements of machine tool repeatability. This closed circuit process control can make the machining accuracy of the machining center reach the machining level of boring and milling machines and other precision machine tools.
Many probe detection operations are accomplished through the use of memory-resident macros. The update of working coordinates, the change of tool geometry and the measurement of parts are automatically determined by the CNC after successfully completing the probe detection cycle. This can eliminate serious errors caused by incorrect information links or incorrect calculations. For inspection of parts after machining, the length and complexity of offline inspection can be reduced through probe inspection, and in some cases, it can even be eliminated. Because large and expensive workpieces are very difficult to move and time-consuming, on-board inspection is particularly beneficial for large and expensive workpieces.
Here you can also use two methods to complete the reference test, that is, the machine tool correlation test method, compare the data measured on the machine with the previous CMM measuring machine data; or use the fake model test method, the machine data and the known size The traceability of the imitation model is compared. In making this comparison, the CNC can determine whether the machine tool has actually reached the specified machining tolerance. Based on these results, a wise decision can be made to adopt the correct machining method for the workpieces that remain on the machine.
Non-contact laser tool setting
The laser tool setting instrument provides a fast automated method for verifying the size of the tool. Especially in the mold manufacturing, it plays a key role in checking the tool wear after long-term machining. Laser tool setting instrument is an effective method for high-speed, high-precision tool adjustment and detection of tool breakage. It has good cost-effectiveness. In the working state, when the tool is indexed by the laser beam or rotated at a normal speed, it can quickly measure Its length and diameter. The laser detection working with the spindle speed can identify the errors caused by the uncoordinated clamping and radial vibration of the spindle, tool and tool holder. This function is impossible to achieve with a static tool setting system. Some NC CNC tool setters can detect breaks at the highest lateral stroke.
When the knife moves through the laser beam, the system electronics will detect the interruption of the laser beam and send an output signal to the controller. The NC control system can accurately measure tools with a minimum diameter of 0.2 mm anywhere in the laser beam. When the laser beam exceeds the 50% threshold and is blocked by the detected tool, the system is triggered. The non-contact tool setting system uses a red visible light diode laser that is reliable under machining conditions.
Advanced electronic components and simplified design make non-contact tool setting replace the contact system. Since there are no moving parts, it can actually make the NC control system maintenance-free. This design does not have the framework and actuator required for contact systems. Some NC numerical control laser tool setters have a protection system and are installed in a solid stainless steel device, which is filled with uninterrupted compressed air. Even during the measurement process, it can prevent pollutants, chips, graphite and coolant Intrusion. These systems can also be installed on machines of various sizes and shapes without affecting the work of the machine.
The mature application of these technologies and the controllability of powerful tools such as powerful tools to improve the process level are of great benefit to improve the automation level of mold machining and achieve better process control. They enable mold makers to produce molds faster with higher geometric and dimensional accuracy, requiring little operator involvement, rework, or manual finishing operations.