SprutCAM enables you to create CLData for oxygen, plasma, waterjet and laser cutting. This cutting strategy provides for control of the sequence of the parts being cut out. In order to diminish thermal deformations, crosspieces are created.
1. Types of cutting of the sheet metal
SprutCAM enables creation of CLData for 2, 3, 4 and 5 axis machines for laser, plasma and water jet cutting. The sequence of how the parts are cut out is controlled, which prevents cutting out of the external contour containing uncut parts. In this operation first the internal contours are machined followed by the external contours.
Oxygen cutting is based on the ability of metal to burn down in a flow of a pure oxygen. This same flow takes away the ensuing combustion products. Acetylene, propane or natural gas is commonly used as the fuel source.
The plasma cutting process is based on the use of air-plasma or an arc of constant current of direct application (cathode is the electrode, the metal being cut is the anod). The process consists of the local melting and blowing out of the melted metal with creation of the cut cavity when the plasma cutter is moved on the metal.
Water Jet Cutting
The tool for the water jet cutting is a specially formed liquid flow, coming out from a special nozzle with diameter 0.08 – 0.5 mm at a supersonic speed (1000 meter/second and more) which provides a working pressure of 400 Mpa or more on the work piece. When the distance between the nozzle section and the material is a few millimeters, the flow pressure exceeds the material resistance limit and this is how the cutting is done.
SprutCAM supports both types of the water jet cutting:
- waterjet cutting;
- abrasive waterjet cutting.
Adding an abrasive material in the flow increases its cutting capacity, the abrasive liquid can cut hard materials of considerable thickness.
Laser cutting implies no mechanical contact with the treated material. The focused laser radiation allows cutting and engraving of almost any material, regardless of its thermophysical properties. The precision of the laser head is around 0.08 mm. This permits a high precision of the reciprocal position of the workpiece elements. Laser cutting can be applied to the easily deformed and not rigid workpieces. The laser beam has a diameter around 0.2 mm, which allows creation of holes with diameter 1 mm.
The high power of the laser radiation guarantees a high efficiency when working with laser cutting. Laser cutting enables cutting almost any type of sheet material even with a complex contour.
2. Technology choice
When writing for numerical control programs, the choice of the exact cutting method does not have a crucial importance. For instance, the command for turning off of the plasma (M53), when working with the plasma equipment, and the command for turning off the alternator (M73), when working with the laser cutting is pretty much the same when it is realized in the CAM system. So the NC program writing for laser, oxygen, plasma and waterjet cutting can all be done in the same module of the CAM system provided that the post processors in question are available.
3. Requirements for CAD system
CAD systems are used to form the profile of the parts being cut out and form a cutting sheet on that basis. The requirements for such systems are set depending on the character of the parts being cut out, their number, and profile complexity. For instance, if a plasma cutting machine is used in making of a large number of parts of various complexity, one of the top requirements is to have an optimal lay out of the parts on the sheet. This will provide maximum coefficient for the material being used.
On the other hand, when the sheet doesn’t need to be filled in completely with parts, the emphasis is on the geometry editor and sophisticated imports methods from the modeling systems (CorelDraw, RhinoCeros).
4. Writing of NC programs in SprutCAM
Contour cutting uses sequence optimization according to the lengths of the passes, taking into consideration the inner contours.
The contour cutting sequence is determined automatically, taking into consideration the inner contours. This has to be done in order to avoid the untimely cutting out of a part with uncut parts inside. Besides that, the system provides the optimization of the machining sequence taking into account the length of the passes between parts.
Automatic detection of the optimal approach points to the work piece contour with a simultaneous control of the approaching and withdrawal of the cut of the neighboring parts.
Depending on the approach chosen, the system has an automatic creation of positioning for the tool penetration, avoiding a cutting of the neighboring parts.
Automatic schemes for angle passing
In order to avoid a bad angle cutting of the part, the system has several methods of forming of tool path in the angles. The passing of the angles can be set automatically or manually, depending on the angle.
In order to not loose the cut out pieces from the sheet, you can leave several crosspieces on their contours. After the cutting, the cross pieces are cut and the parts are taken out from the sheet.
SprutCAM has the following modes for detecting crosspieces:
- machining without crosspieces;
- a definite number of crosspieces is set, hence we get an even number of crosspieces for all the curves;
- number of crosspieces for each curve is variable and depends on its length;
- number of crosspieces for each curve is variable and depends on its surface area.
Avoiding passes over already machined zones
Often, the machined piece will bend because of the thermo treatment and it can break when the cutter head is moved above it. In order to avoid such situations, the passes between cutting in points can be done above the unmachined zones of the sheet. When the function is turned off, the passes will be made following the shortest distance between the points. When the function is turned on, the passes are made in such a way, that the cutter head avoids passing above the already cut out contours.
3D cutting simulation
The CLData is checked in the machining simulation mode. The cutting simulation assures visual control of the quality of the CLData.