First of all, on the premise of aluminum materials, the following aspects need to be considered:
One, irresistible factors:
1. The stability of the CNC machine tool itself.
If it is not a new CNC machining machine or the CNC machining machine has not been debugged after a lot of processing, there will be dimensional errors caused by the CNC machining machine itself. There are several factors that cause the error of the machine tool itself:
Mechanical aspects:
a. Looseness between the servo motor and the lead screw.
b. Ball screw bearing or nut wear.
c. Insufficient lubrication between the screw and the nut.
Electrical:
a. Servo motor failure.
b. There is dirt inside the grating ruler.
c. Servo amplifier failure. In terms of system parameters, PMC recovery can be performed, so it is omitted.
2. The parts are cooled and deformed after CNC machining.
This is basically unavoidable. Try to pay attention to the use of coolant during CNC machining, and pay attention to the deformation of CNC machined parts after cooling when performing in-situ measurements.
Two: Avoidable factors:
1. CNC machining process
In fact, most of the actual machining errors are caused by the unreasonable CNC machining process. When ensuring the basic CNC machining process (such as “roughing first, then fine, first face and then hole, first large face and then small face” in milling CNC machining or the use of fixtures On the basis of basic CNC machining process details such as “reducing the number of clamping times and using combined fixtures as much as possible”), try to reduce the error caused by iron filings to aluminum CNC machining parts, because aluminum parts are very soft, and the iron filings that are excluded are easy to make aluminum CNC machining parts cause errors. For example, in FANUC or Huazhong machining center, use G83 command as far as possible to make deep holes, so that iron chips can be discharged instead of G73 command.
2. Three cutting elements: cutting speed vc, feed f, cutting depth ap and tool compensation. It is really difficult to elaborate on this aspect. To put it simply, on the premise of ensuring the quality of CNC machining and tool wear, the parameters are adjusted to give full play to the cutting performance of the tool, so that the cutting efficiency is the highest and the cost of CNC machining is the lowest. In CNC lathes, there are also elements such as tool head wear compensation.
3. Numerical calculation in manual programming and automatic programming. Errors in calculations are also common in manual programming, but most production is now automated.
4. Tool setting and inaccurate tool setting are also factors that cause dimensional errors of CNC machined parts. Therefore, try to choose a good edge finder. It would be better if the machine tool has an automatic tool setter. If there is no edge finder, then Just try to cut.
The above is my summary. In the process of aluminum CNC machining parts, there are several factors that are easy to cause errors in the accuracy of CNC machining parts. If there are any omissions or errors, please point out!