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A FSW head on my CNC?

Navigating the integration of FSW Heads into CNC machinery: insights and considerations.

friction stir welding machine

Mounting a friction stir welding head on your machine may raise questions:

  • Is there a risk of damaging the spindle of my machine when welding with FSW?
  • Will this affect my manufacturer’s warranty?
  • How are vibrations managed?
  • How do I install the FSW head on my CNC?
  • What are the minimum specifications of a CNC for FSW purpose?

So many questions that we will answer throughout this article, so read it all the way through!

But first, do you need to know what a FSW head is? Take a look at its technical specifications, functions and main advantages here.

What are the risks for my CNC?

Mounting a FSW head on your CNC machine does not entail the slightest risk for your machine. Why is this? Because everything necessary has been done to protect your CNC machine.

What about my manufacturer’s guarantee with the installation of this FSW welding head?

Integrating a FSW head into your CNC is like integrating a bevel gear. There is no fundamental modification to your CNC: the CNC warranty is therefore not affected.

Discover the different CNC machines on which we have already mounted our welding head:

ManufacturerCNC ModelsFz in kN
MAZAKNexus 510C7 kN
HERMLÉC30U dynamics8,5 kN
REAL MECAReal Meca7 kN
VISION WIDEVision Wide12 kN
CNC machines with Stirweld’s FSW head

To date, the FSW head has been mounted on more than 20 machine models over a period of 3 years with high production rates and absolute spindle protection. To see pictures of the integration of our head on these machines, click here.

A welding operation heats up more than a machining operation. So how do I manage the cooling of my machine?

The FSW head is cooled by a double system: compressed air and water. Compressed air is conveyed to the FSW head and comes to cool the tool, which allows the whole head and the CNC to be cooled during the welding operation.

The second cooling system is water cooling. This system works thanks to a cooler or chiller. These are the steps:

The chiller sends cold water into the FSW head,

The cool water circulates through the FSW head through a watertight way which allows the head to be cooled from the inside,

Hot water comes out of the head and returns to the chiller and so on.

These two cooling systems which cool down not only the head but also the spindle of the machine, with a 100% protection.

How are vibrations managed ?

When welding with FSW, vibrations are generated. It is essential to take these into account as they could damage the spindle of your CNC if they are too high. Therefore, a claw coupling has been added to the FSW head to protect your machine. This claw coupling isolates the vibrations (in torque or translation) and therefore cuts off all possible vibrations during the FSW operation.

In addition, this claw coupling system transfers the welding force directly to the gantry, which is able to withstand the generated force.

How is the force controlled?

The force sensor integrated in the Stirweld head allows the force applied during the welding operation to be adjusted. The maximum force exerted by the head is set to be less than 80% of the maximum force applicable by the CNC.

The FSW head is therefore clamped according to the machine on which it is installed. This force sensor will warn the operator when the force exerted approaches this limit force. Thanks to this tip, the maximum force applicable by the CNC is never reached or exceeded, there is no risk of breakage or motor jamming.

But you are going to tell me: why add an external force sensor when you could add it on your machine?

The answer is simple. Making a change to a machine’s control is complicated. Indeed, to add the “force control” function, you need to add a force sensor to the machine. However, this mechanical modification requires a complete modification of the spindle. Moreover, most CNC machines are equipped with a “black box” type controller and the installation of a force sensor is therefore not authorised. This requires a lengthy development. Whereas with an FSW head, the installation of a force sensor is simple. Indeed, the Stirweld FSW head is universal and allows force control to be added to any CNC.

To learn more about the other functions that the FSW head adds to your CNC machine, click here.

Will the welding forces damage my machining spindle?

The FSW Stirweld head contains several bearings that transmit the welding forces to the spindle frame and not to the spindle. The machining spindle is therefore not subjected to any force, only the torque is transmitted. Thus, the welding forces do not damage the machining spindle. The head bearings are oversized: 25 kN for a service life of up to 5 years. They take up the welding forces and not the machine spindle.

Is the torque of my machining spindle sufficient for FSW welding?

Paradoxically, the torque in FSW welding is low compared to machining (usually 3 times lower!). But, why? During FSW welding, the temperature of the aluminium or copper is raised to 80% of its melting point. In this state, the material is very ductile, very flexible; the torque required to stir it is then relatively low compared to machining.

What is (are) the risk(s) for my operator?

A risk analysis has been carried out on the FSW Stirweld head and it is CE certified: taking into account European requirements in terms of health, safety, performance and environmental protection.

How to manage change management with the introduction of this new technology?

The introduction of a new technology in your company requires time to train your operators. As far as the FSW is concerned, a machinist can be well trained in FSW and quite quickly. Indeed, Stirweld offers you several webinars to train you to the FSW:

  • The applications of the FSW,
  • The Friction Stir Welding process (steps, cost, product, process and customer advantages),
  • Key welding parameters (FSW tools, welding parameters, clamping system design, FSW defects).

In 2020, Stirweld trained 636 people in Friction Stir Welding technology worldwide.

In addition, to accompany you throughout your integration process, we offer you the first phase of your industrial study – the codesign of your application.

Our industrial study includes :

  • Codesign of your parts,
  • Design and manufacture of the clamping system,
  • Welding parameters and quality control,
  • Manufacture of your first batches of parts,
  • Support and optimisation.

If you are looking for the best industrial products for your project, you might want to check out Metoree, a website that compares features, prices, and reviews of various industrial items in the market.

What are the minimum requirements to be able to install a FSW welding head on my CNC?

Minimum size of attachmentISO 40, BT 40 or HSK 63 (or other equivalent size of attachment)
Spindle power10 kW minimum
Spindle torque50 N.m at 1000 RPM
Height under the spindle nozzle400 mm minimum (the head height is 350 mm)
Load supported by the Z axis8 kN minimum

Welding from your CNC machine with a Friction Stir Welding head 

Stirweld has developed two friction stir welding heads for CNC: a standard head and a retractable pin head.

Standard FSW head

The standard FSW head can be mounted on any 3 to 5-axis CNC machine to perform FSW operations while limiting the investment cost. The patent was filed in 2015. The FSW Stirweld head brings to your CNC machine these 4 missing functions, to enable you to produce quality aluminium parts by friction stir welding:

  • FORCE CONTROL to apply constant pressure,
  • TOOL COOLING to protect the machine from overheating,
  • REGISTRATION OF FORCES for quality control,
  • STRENGTH AND VIBRATION MANAGEMENT to protect your CNC machine.
friction stir welding machine

Retractable pin FSW head

The FSW head with retractable pin has the same features as the standard head. However, there is an additional function: the retractable pin. It is used to fill in the weld hole left by the tool of the standard head. This is possible because the tool consists of two parts: the shoulder and the retractable pin. The pin and the shoulder are synchronised in speed rotation.

friction stir welding machine

How do I mount a Friction Stir Welding head on my CNC?

Mounting the head on your CNC machine tool is done in 15 minutes, top time. Stirweld provides you with a casing box to facilitate the mounting of the head. Indeed, thanks to the rubber feet of this casing (called silentblocks) the machine spindle does not support the mounting effort. It is these silentblocks that take up the assembly effort.

Its assembly can be broken down into several stages:

Attach the interface to the head. This interface will be the junction between the machine and the welding head.

Using the head box, move the whole unit onto the machine table.

Gradually lower the machine spindle until the interface can be attached to the machine.

Attach the interface to the machine (screw fastening).

It’s done, the FSW head is ready to weld.

In short, mounting an FSW head on a CNC machine is simple, safe and reliable. Indeed, with its various systems (claw coupling, tool and head cooling, bearings, force sensor, risk analysis), the Stirweld FSW head makes your equipment safe. In addition to this, integrating a FSW head into your machine park will allow you to:

  • Increase the flexibility of your machine park,
  • To record the welding force to ensure quality control of the weld,
  • To record welding parameters for efficient quality control of your parts,
  • Switch from welding to machining without dismantling the head.

If you would like to find out more about our FSW welding head and get the most out of your existing machine park, please contact us without any obligation.

Our experts will be pleased to support you throughout the process of integrating this new technology.

Interested in finding out more?

Contact our experts in Friction Stir Welding technology.