Creation of 3D STL models for CNC machine tool

If during the work on a cutting tool the main role stays with the operator, then the use of CNC tool means that the whole production process is based upon the creation of the 3D STL model. Further operations will be conducted automatically in full accordance with built-in information.

It is fair to say that 3D STL models are used not only in such fields as engraving and cutting. No digital equipment, intended to automatic processing of different materials can be without it. Actually, such a model represents a three-dimensional picture of an object that must be received

For its creation, the software is used. However, deep down there is a mathematic, as well as 2d drawing of the object.

3D STL models for the CNC machine tool allows us to get a variety of undeniable advantages and among them are:

1. Perfect reverse engineering (under initial parameters)
2. Flexibility, allowing to use the same model with the different equipment types
3. Ability to manage the process remotely
4. Cost reduction and time-saving thanks to the removal of manual work

Varieties of 3D STL models

Nowadays a lot of varieties are used that can be significantly different by several criteria. Even though the purpose of such 3D STL models comes down to the creation of three-dimensional products it is still necessary to choose intentionally to get an optimal result.

The most common and simple is a monometric image. The question is about well-known drafts representing the object in three dimensions. This allows us to get an idea of how it must look like, but to read similar drafts and respectively set out final results is reduced to specialists.

Thanks to modern software (firstly this refers to CAD apps) the ability to transform 2d drawing into the 3D STL drawing appears. Firstly they relay geometrics of upcoming object but also can contain other information about it, including properties of the material that is about to use. Tracking of all these parameters allows us to determine not only the configuration of the upcoming product but also its volume, mass, etc.

Another approach for 3D STL models creation proposes the use of 3D STL scanner. However, in such a case you should have a finished sample.

But if there is no need in creating something unique, it is possible to use an out-of-the-box solution. In that context, 3D STL libraries are a great help. Nowadays they contain a huge amount of elements, that differ by complexity and other parameters. This allows producing a wide array of standard production, saving a lot of strength and resources during 3D STL models creation.

Varieties of 3D STL models for CNC machine tools

It is usual to divide it in some varieties

•  carcass;
•  surface;
•  solid.

The carcass is the simplest 3D STL model variety. For its creation, different types of lines are used: arcs, circles, lengths, etc. Thanks to this approach it is possible to get a general idea about how the end product will look like. The main disadvantage of carcass models is that they do not capture their inner properties. However even such a primitive at first glimpse visualization is appeared to be highly useful, because thanks to it, it is possible to get directions, that the tool will use while moving over the surface of a draft and by this means to create a program control.

Surface models, as you can figure out by its name, are concentrating on the properties of the surface, considering it as some kind of a shell and dividing it of the inner part of the object. Besides, surface models contain data of product edges.

Solid models are the most difficult variety. In reality, they represent an exact copy of the product that must be received at the end. They also contain information on its intrinsic properties that therefore allow us to explore real properties of different objects and also predict how complex construction elements will cooperate between them.

3D STL models building for CNC machine tools

Above we have already mentioned that AutoCAD and similar products allow us to create 3D STL models based on 2d drawings that transfer in digital form. However such an approach is deemed not so optimal – nowadays pride of place goes to front-line creation of objects upon which, when necessary, 2d drafts can be created.

When developing 3D STL models for CNC machine tools, relating to a given type, another software is used: Autodesk Inventor CATIA, Pro/Engineer, etc. They are created especially for the creation of a solid type 3D STL model.

Such a variety of programs leads to the fact that not often the final result that alike an image file is a cross-functional, in other words, can be used with different CNC machine tools. To prevent this, stipulate this important moment with the developer in advance. Let’s only add that cross-functional files are those, that have the following extensions *.igs,*.iges, *.sat,*.step, *.stl and *.stp.

Like that 3D STL model, creation is the most important, but not the only operation. More like it creates a foundation and mistakes, made during this step will tremendously affect the final result. However, for its achievement, it will be necessary to initiate some more activity.

An important step is a comparison of the available 3D STL model with the surface of the workpiece. After that slopes and stocks for a plane surface are set. One more crucial step is establishing the depth of cutting and definition of the area where the workpiece will be mounted.

Pretty much cutting is a sequence that consists of several steps. For each of it, the cutting feature is set, the movement of a cutting tool is aligned. To make an optimal result the whole range of parameters should be taken into account, including the quality of using material and when necessary even a tool change.

It is necessary not to forget about the so-called control stage where the visualization of the whole cutting process is made. It allows us to guarantee the high quality of the final result. Some beginners neglect this stage, thinking of it as of some waste of time. However, more experienced specialists know that additional control helps to bring to light possible mistakes (if they are not dismissed on time, the final result will be defect product).

After you make sure that all parameters, which are responsible for cutting work are okay, the final step is coming. CNC machine tools start-up preceded by the export of program control in the so-called command format (the special software is used for it), that firstly depends on the CNC machine tool model. In that form, the program control is downloaded in the electronic unit of the machine tool, and in the time following fully operates its work. All that is left to do for the operator is just fit a cutter and push the “start” button. All further operations will be automatic. When the process is finished it will be just necessary to check the final result.