The movement of the various moving parts of the desktop 3d milling machine is completed under the control of the numerical control device. Each moving part can reach a certain accuracy under the control of the program instructions. It is the achievable accuracy that directly reflects the processing parts. What is the accuracy achieved by the desktop 3d milling machine?
1. Desktop 3d milling machine linear motion positioning accuracy detection
Linear motion positioning accuracy is generally carried out under no-load conditions on the machine tool and worktable.
In accordance with the national standards and the provisions of the International Organization for Standardization (ISO standards), for the inspection of CNC machine tools, we should use laser measurement as the standard. In the absence of a laser interferometer, it is also possible for general users to use a standard scale with an optical reading microscope for comparative measurement. However, the accuracy of the measuring instrument must be 1 to 2 levels higher than the accuracy of the measurement.
In order to reflect all the errors in multiple positioning, the ISO standard stipulates that each positioning point is calculated based on the five measurement data and the positioning point dispersion band composed of the average value and the dispersion difference -3 dispersion band.
2. Detection of repeat positioning accuracy of desktop 3d milling machine linear motion
The instrument used for testing is the same as that used for testing positioning accuracy. The general detection method is to measure at any three positions close to the midpoint and both ends of each coordinate stroke, each position is positioned with rapid movement, and the positioning is repeated 7 times under the same conditions, the stop position value is measured and the reading difference is calculated . Take one-half of the difference between the three positions and attach the positive and negative signs as the repeat positioning accuracy of the coordinate, which is the basic index reflecting the stability of the axis motion accuracy.
3. Detection of the return accuracy of the origin of the desktop 3d milling machine linear motion
The origin return accuracy is essentially the repeated positioning accuracy of a special point on the coordinate axis, so its detection method is the same as the repeated positioning accuracy.
4. Reverse error detection of desktop 3d milling machine linear motion
The reverse error of linear motion is also called loss of momentum, which includes the reverse dead zone of the driving part (such as servo motor, servo hydraulic motor and stepping motor, etc.) on the coordinate axis feed transmission chain, and the mechanical motion transmission pair A comprehensive reflection of errors such as backlash and elastic deformation. The greater the error, the lower the positioning accuracy and repeat positioning accuracy.
The detection method of the reverse error is to move a distance in the forward or reverse direction in advance within the stroke of the measured coordinate axis and use the stop position as the reference, and then give a certain movement command value in the same direction to make it move a certain distance. Then move the same distance in the opposite direction, and measure the difference between the stop position and the reference position. Perform multiple measurements (generally 7 times) at three positions near the midpoint and both ends of the stroke, find the average value at each position, and take the larger value of the average value obtained as the reverse error value.
5. Detection of positioning accuracy of desktop 3d milling machine rotary table
Measuring tools include standard turntable, angle polyhedron, circular grating and collimator (collimator), etc., which can be selected according to specific conditions. The measuring method is to make the worktable rotate an angle forward (or reverse), stop, lock, and locate, use this position as the reference, and then quickly rotate the worktable in the same direction, lock the positioning every 30, and measure. The forward rotation and the reverse rotation are measured one round each, and the difference between the actual rotation angle and the theoretical value (command value) of each positioning position is the indexing error. If it is a CNC rotary table, it should take every 30 as a target position. For each target position, fast positioning is performed 7 times from the forward and reverse directions. The difference between the actual reached position and the target position is the position deviation, and then press GB10931- The method specified in 89 "Digital Control Machine Tool Position Accuracy Evaluation Method" calculates the average position deviation and standard deviation, the difference between the large value of all the average position deviation and the standard deviation and the sum of the small value of all the average position deviation and the standard deviation , Is the positioning accuracy error of the CNC rotary table.
6. Repeated indexing accuracy detection of desktop 3d milling machine rotary table
The measurement method is to repeat positioning at any three positions within a circle of the rotary table for 3 times, and perform detection under rotation in the forward and reverse directions respectively. The large indexing accuracy of the difference between all readings and the theoretical value of the corresponding position. If it is a CNC rotary table, take one measuring point every 30 as the target position, and perform 5 rapid positioning of each target position from the forward and reverse directions respectively, and measure the difference between the actual reached position and the target position. That is, the position deviation, and then calculate the standard deviation according to the method specified in GB10931-89. The standard deviation of each measuring point is 6 times the maximum value, which is the repeat indexing accuracy of the CNC rotary table.
7. Detection of the return-to-origin accuracy of the desktop 3d milling machine rotary table
The measurement method is to perform a return-to-origin from 7 arbitrary positions, measure the stop position, and use the large difference read out as the precision of the return-to-origin.
In mechanical manufacturing, it refers to the gap between the actual position of parts or tools and the standard position (theoretical position, ideal position). The smaller the gap, the higher the accuracy. It is the prerequisite to ensure the accuracy of parts processing. Mechanical Seiko has very high requirements for accuracy, and subtle differences will cause serious consequences. We must pay attention to the detection of positioning accuracy.
desktop 3d milling machine
The above are 7 aspects of the detection of the positioning accuracy of the desktop 3d milling machine.
