UPGRADE YOUR CNC MACHINE TO A FSW MACHINE
By adding 4 functions to your CNC machine through our FSW head, you will be able to assemble aluminium parts by friction stir welding.
It is not possible for a classic CNC machine to perform a quality friction stir weld given …
The lack of control
that could results as defects into the welded part.
The absence of control
over the pressure on the part when performing FSW.
The impossibility of cooling
the tool without also cooling the workpiece.
Possible damages to the CNC machine
because of the forces and vibrations produces during the FSW process.
Moreover, using a classic CNC, FSW is not a repeatable process. Therefore, this technique may be useful for students with academic or research objectives, but it is impossible to get quality welds for an industrial application.
Nevertheless, now the Stirweld FSW head can bring to your CNC machine these 4 missing functions, that will allow you to produce quality weld aluminium parts by friction stir welding.
Whatever type of CNC machine you have, our compatible equipment could provide it with:
1. FORCE CONTROL
FORCE CONTROL to apply constant pressure on the workpiece and to assure a constant contact between FSW tool shoulder and parts to weld.
The CNC machine already has position control for milling. This allows the tool to be positioned at a constant altitude. But, in order to carry out friction stir welding, it is mandatory that tool applies a constant pressure on the workpiece. Consequently, the Stirweld FSW head has a piston inside the system, which moves up and down to apply that constant force on the part and achieves the correct quality weld.
Stirweld force control outcomes in similar results and performance than any other FSW machines (special gantry or robots). This performance has been proven many times on aerospace and automotive application.
2. TOOL COOLING
TOOL COOLING that protects the machine from the temperature
Tool cooling is substantially important, to avoid the overheating of the machine that could damage it. However, we must not forget that in order to carry out defect-free welding it is necessary to reach at lears 70 percent of the melting point of the alloys to weld. For aluminium alloys, that represents a temperature between 400 and 500 degrees Celsius. This is owing to the weld is made in the pasty state, in other words: the solid state of the joining process.
Therefore, it is not possible to cool down as it is done during milling, by spraying water onto the tool. The reason is that the water would fall on the parts being welded and reduce their temperature. That is why Stirweld installed a closed loop system inside the FSW head that allows water to go up and down cooling the tool, but never over the piece.
3. FORCE RECORDING
FORCE RECORDING for quality control
As mentioned above, constant force on the workpiece is essential for quality welding. Consequently, it is necessary to guarantee this constancy in order to be sure that the part is free of defects. At Stirweld, we carry out this quality control by incorporating a sensor to measure and record the force which is exerted during the friction stir welding process. As long as the force exerted lies between the minimum and maximum defined for the specific weld, we can ensure that the welded part meets the quality criteria and is free of defects.
Our software permits to control the force in real time, being observed directly on the screen during the friction stir welding procedure. Additionally, as the force control is recorded, it can be analysed afterwards.
4. FORCES AND VIBRATIONS MANAGEMENT
FSW FORCES AND VIBRATIONS MANAGEMENT to protect your CNC
During friction stir welding forces and vibrations are produced which, if not prevented, are transmitted to the CNC spindle. These can damage it when they are too high. In order to protect your CNC machines, the Stirweld FSW head offers a special protection. This allows, firstly, to cut all the possible vibrations produced during the process. And, secondly, the protection system transmits the force directly to the gantry instead of the spindle, which is strong enough to withstand the produced force without problems.
The FSW head has been mounted to date on more than 30 machine models for 3 years with high production rate with absolute spindle protection.
Thanks to these 4 functions added to your CNC machine – whether it is a 3, 4 or 5 axis machine – you will…
Perform high volumes of production with constant quality.
Be able to carry out aluminium and copper welding or bimaterial assemblies without damaging your milling machine at all.
Greatly reduce the investment cost of an FSW machine, obtaining the same performance as with a special one.
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