What are the things that are included in the graphics preparation before CNC machining? What should I pay attention to?
1: Software selection
2: Format selection
3: bad face correction
4: The processing plan is determined, mainly the clamping, fixture selection, machine selection
1: CNC machining currently uses Mastercam, cimatron, powermill, ug, proe, solidworks, catia, etc., but the most commonly used are mc, cimit, pm.
However, our split model, copper removal, hand-piece disassembly, and many of them are still done in ug, proe, or other software.
For example, the author used to use proe + mc, proe + cimit, ug + mc, ug + cimit several combinations.
In many factories with relatively fine division of labor, parting and cnc are often separated. On the one hand, this improves efficiency; on the other hand, the price comparison is easy to control standardized operations!
In this case, the graphics that the cnc engineers get are provided by other software, so the file formats provided are generally step and iges. These two formats are the most commonly used.
2: iges and stp
The differences between the two formats are as follows:
Iges only stores the geometry of the model and the topological relationship of the dotted line; the stp format stores more content, in addition to the above, there are precision, materials and so on.
In addition, from the perspective of data structure, the igs file is slow to open, the topological relationship is easy to lose (broken surface) and other aspects are not as good as stp format files.
Usually, when a simple model is used for data exchange, the two formats are not much different. When the structure is complex, the surface shape is large, and the file size is large, the output igs may have unexpected problems.
There are three types of steps, AP203, AP214, AP242.
The suffix of step is sometimes step. Sometimes it is stp.
When you can’t find it in a software, please modify stp–“step. or step-->stp.
In practice, when the step file is not found by software, most of it is due to the problem of this suffix.
The IGS format file is an initial graphics exchange specification (IGES) type 2D/3D vector graphics file. It is a CAD (Computer Aided Design) software commonly used to save and export vector data standards based on ASCII text format. IGS files can store wireframe models, surface or solid objects, and schematics or other purposes. The suffix of IGS is igs.
3: When we convert the graphics into it, we may encounter the following problems, which are bad or have the parting surface left when there is a parting. At this time we need to communicate with the file provider. We can delete the parting surface.
Sometimes if you have a bad face, you need to fix it yourself.
Sometimes, this piece of work is no less than programming. This is the answer of the author’s 20 years of experience, and it is by no means a piece of paper.
4: When the problem of the bad face is solved.
It is the processing orientation of the part. In fact, this is the analysis of the processing technology.
Is it single-sided or multi-faceted, is 3-axis or 4-axis, 5-axis CNC machining.
You need to know whether your company’s machine tools or external processing extra beds have these 4-axis or 5-axis functions. These must be well understood in advance, so as not to need to modify the program, delay time
If it is a simple multi-station. Then we first process which orientation, and then use the graphics rotation to get the 2nd orientation.
That is, using a 3-axis machine tool to do the 4-axis machine tool.
In this case, you need to do a good job in document management and you need to communicate with the machine operator.