Carbide vs. HSS End Mills for Aluminum Machining Which to Choose?

**howida** · 2 Weeks Ago

Hello,

I am currently working on a project that involves CNC machining aluminum parts; and I'm trying to decide between carbide and high-speed steel (HSS) end mills.

I have read that carbide can provide better surface finishes and higher cutting speeds; but they are also more expensive. On the other hand; HSS end mills are more affordable and easier to re-sharpen.

Could anyone share their experience or advice on which type would be more cost-effective and efficient in the long run for aluminum machining?
Are there specific scenarios where one outperforms the other? I have referred https://www.mycncuk.com/forums/11-Tool-Tooling-Technology- guide but still need help .

Additionally; any recommendations on specific coatings ; brands that have worked well for you would be appreciated!

Thank you

**JohnHaine** · 2 Weeks Ago

A UK supplier appears to recommend uncoated HSS for aluminium.

**Chaz** · 2 Weeks Ago

For milling, HSS is fine. If you can find a tool with a carbide insert, it can work faster / harder but it is less forgiving, brittle and more expensive.

For turning, HSS is generally a waste of time.

**Muzzer** · 2 Weeks Ago

I prefer uncoated carbide with honed or "lapped" edges (= razer sharp!) and the only issue I've had has been when using high material removal rates rates - failure to clear the swarf can result in chips being dragged back into the cutting zone ("recutting"). This usually ends with the chips becoming welded to the tool, with a breakage following quickly afterwards. If you supply enough coolant and/or air to clear the chips, the material removal rate and surface finish are impressive.

I like the YG-1 Alu Power cutters https://www.cutwel.co.uk/milling-too...e51-yg-1-e5e51 and tend to buy them when they are on offer (buy 2 get one free etc) but there are similar ones available from Ali Express if you look carefully eg https://www.yuzemachinery.com/.

Many coated cutters actually stick to aluminium, so it's good to avoid them. And the cutting angles are different for aluminium and steel.

Here - have a laugh at this. Shows what happens when you fail to clear the chips (working into a corner like this was asking for recutting). I wouldn't attempt this now without using coolant and air.

And again:

**Chaz** · 2 Weeks Ago

Originally Posted by Muzzer

I prefer uncoated carbide with honed or "lapped" edges (= razer sharp!) and the only issue I've had has been when using high material removal rates rates - failure to clear the swarf can result in chips being dragged back into the cutting zone ("recutting"). This usually ends with the chips becoming welded to the tool, with a breakage following quickly afterwards. If you supply enough coolant and/or air to clear the chips, the material removal rate and surface finish are impressive.

I like the YG-1 Alu Power cutters https://www.cutwel.co.uk/milling-too...e51-yg-1-e5e51 and tend to buy them when they are on offer (buy 2 get one free etc) but there are similar ones available from Ali Express if you look carefully eg https://www.yuzemachinery.com/.

Many coated cutters actually stick to aluminium, so it's good to avoid them. And the cutting angles are different for aluminium and steel.

Here - have a laugh at this. Shows what happens when you fail to clear the chips (working into a corner like this was asking for recutting). I wouldn't attempt this now without using coolant and air.

And again:

Nice cutting on what looks to be slowish Speed (due to machine). Whats your DOC and Feed Rate please?

**Muzzer** · 2 Weeks Ago

Sorry I don't recall the F&S but probably close to what the mfr recommended. I have about 4kW available at the spindle but it's not often I can get close to that. That machine is 40 years old but with modern tools and tool paths, you can shift some swarf. The skill is to clear the swarf - and perhaps wear rubber underwear!

**Chaz** · 2 Weeks Ago

Yep, know the feeling. I think for Alu, Air plays almost more of a part than lube. Get them chips out ...

**Muzzer** · 2 Weeks Ago

Perhaps best solution for machining time and surface finish would be a single flute, lapped cutter at max spindle speed (5000rpm for me), with full length engagement and the feed dialled up to a decent spindle load - and coolant with a strong air blast of course. That would shift some mean chips.

**Chaz** · 2 Weeks Ago

Yep. 5K is decent for what you have there. My 5 Axis Bridgeport clone has 4.2K however Im only getting around 3.9K at 50 Hz. Temped to take the head off and fit my HSD 24K RPM spindle, get the quick release tool changer then too.