Routing Aluminium Extrusion: How to Reduce Long Cutter Breakages and CNC Downtime

CNC machining aluminium window and door extrusion often involves more than simply routing the face of the profile.

Depending on the extrusion, holes, slots and other details may need to be machined well down inside the profile or through into the opposite wall. That creates an obvious problem: you need a small-diameter cutter, but you also need a lot of reach.

Traditionally, the answer has been to use a longer overall-length solid-tungsten cutter.

They work well, but there is a trade-off.

The longer and smaller in diameter the cutter becomes, the more vulnerable it is to breakage. For aluminium joiners regularly machining deep profiles, those broken cutters can become an expensive and frustrating part of production.

The challenge with long, small-diameter tungsten cutters

Solid tungsten is an excellent cutting material for aluminium. It holds a sharp cutting edge and performs well at the speeds required on CNC machining centres.

However, a long 3mm or 5mm solid-tungsten cutter for example are relatively vulnerable compared with a larger-diameter tool.

The further that small-diameter cutter has to extend from the toolholder, the greater the opportunity for movement and deflection while cutting. Add an interruption in the extrusion, a change in cutting load or a little extra vibration and breakages can become much more common.

This is something we have seen repeatedly with aluminium joinery customers using machining centres such as Emmegi and Mecal.

What does a broken cutter actually cost?

When a cutter snaps, production stops.

Someone has to remove the broken tool, replace it and get the machine running again. The extrusion may need to be checked, and if the breakage has damaged the profile, that component may need to be remade.

Across one cutter failure, the interruption may not look significant.

Repeated across a week or month, it adds up.

You have the replacement cutters, lost machine time, operator time and the disruption of stopping a production run that should have kept moving.

So the real question is How can we make this long-reach operation more reliable?

A stronger way to get the reach

This is where our CNC Extension Arbors for Small Diameter Cutters come in.

Instead of using long solid tungsten cutter to provide the full reach, the extension arbor uses a steel body to carry the small cutter down into the extrusion.

The cutting diameter stays small where it needs to be. The difference is that the long section of the tool is now a substantially larger steel arbor rather than a long, thin piece of tungsten.

Importantly, these arbors are designed and balanced specifically for use on CNC routers. That means they are made for the spindle speeds and machining conditions involved

That creates a much stronger setup for reaching into deep aluminium profiles.

Our current range includes 82mm and 100mm overall-length arbors for 3mm cutters, along with an 82mm version for 5mm cutters. They are specifically designed for this type of hard-to-reach aluminium machining and for use on machines including Emmegi and Mecal machining centres.

Less cutter hanging out where you don't need it

The important part of the system is that the small cutter only needs to provide the cutting section.

It does not also have to provide 80mm or 100mm of reach.

The arbor does that.

This allows you to keep the exposed small-diameter cutter much shorter while still reaching the same machining position inside the extrusion.

For workshops that have been regularly snapping long tungsten cutters, that can make these jobs considerably more dependable.

What difference can it make in production?

We already have a number of aluminium joinery customers using these extension arbors, and the reason they have stuck with them is fairly straightforward: they are breaking fewer cutters.

That has a flow-on effect through the job.

Fewer breakages mean fewer unplanned tool changes, less time with the CNC sitting idle and fewer interruptions for the operator.

It can also make job times more predictable. If the operator is no longer stopping part-way through a run to replace another broken long cutter, more of the available machine time is actually spent machining extrusion.

When is an extension arbor worth considering?

The extension arbor is not intended to replace every solid-tungsten cutter used on an aluminium CNC.

Where a normal-length cutter can comfortably reach the machining position, there is little reason to add the extra reach.

It becomes particularly useful when you are regularly using long cutters simply to reach a machining position inside a deep extrusion—and those cutters are becoming a weak point in the process.

That is exactly the problem these arbors were designed to solve.

Instead of continually replacing fragile long-reach cutters, you keep the small cutting diameter you need and let the stronger arbor provide the reach.

Regularly breaking long cutters on your aluminium CNC?

If long cutters are regularly snapping when you machine deep aluminium extrusion, talk to us about the profile and the reach you need.

We can help work out whether an extension arbor will give you a stronger setup and help reduce the cutter changes and downtime currently slowing the job down.

View our CNC Extension Arbors for Small Diameter Cutters or call the Tungsten & Tool team on 0800 488 647.