How to ensure the dimension when CNC machine tools are processing aluminum?
First of all, on the premise of aluminum, the following aspects should be considered:
Force majeure:
1. Stability of the machine tool itself. If it is not a new machine tool or the machine tool has undergone a lot of processing without debugging, the size error caused by the machine tool itself will occur. The error of the machine tool itself is caused by the following factors:
Mechanical:
a. Looseness between servo motor and lead screw.
b. The ball screw bearing or nut is worn.
c. Insufficient lubrication between lead screw and nut.
Electrical:
a. Servo motor fault.
b. There is dirt inside the grating ruler.
c. Servo amplifier fault.
The system parameters can be recovered by PMC, so they are omitted.
2. The workpiece is deformed after cooling. This is basically unavoidable. During processing, pay attention to the use of coolant as much as possible, and during in position measurement, pay attention to the deformation of the workpiece after cooling.
Avoidable factors:
1. Processing technology
In fact, most of the actual processing errors are caused by unreasonable processing technology. On the basis of ensuring the basic processing technology (such as "roughing first and then finishing, face first and then hole, large face first and then small face" in CNC milling, or "reducing the number of clamping times and using modular fixtures as much as possible" in the use of fixtures), try to reduce the processing errors caused by iron filings on aluminum parts, because aluminum parts are very soft, The iron scraps removed will easily cause machining errors for aluminum parts. For example, use the G83 command as much as possible to drill deep holes so that iron filings can be discharged, instead of the G73 command.
2. Three elements of cutting: cutting speed vc, feed rate f, cutting depth ap and tool compensation
It is hard to say in detail in this respect. To put it simply, on the premise of ensuring the processing quality and tool wear, adjust the parameters to give full play to the cutting performance of the tool, so that the cutting efficiency is the highest and the processing cost is the lowest. In CNC lathes, there are elements such as cutter head wear compensation.
3. Numerical calculation in manual programming and automatic programming
In manual programming, calculation errors are also common, but now most production is automatic programming.
4. Tool setting
Inaccurate tool setting is also a factor that causes dimensional error. Try to choose a good edge finder. It would be better if the machine tool has an automatic tool setting device. If there is no edge finder for trial cutting, this is the operating experience.