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Mad Professor
04-05-2013, 07:36 PM
Good day all.

I am looking for some help and advice with some aluminium engraving that I am trying to get done.

I have a small bunch of extruded aluminium cases in black, and I want to do some basic engraving on them.

The only small engraving tools I have are 0.5mm, 0.2mm, 0.0mm v-groove carbide.

I don't need to engrave deep as the cases are black, and as such my DOC is only 0.1mm.

My 1st try I used a 0.5mm cutter, spindle at max (24k), feed 300mm/min, DOC 0.1mm.

I got just over half way then snapped the tip of the cutter.

And that happened to be my last 0.5mm cutter

So tried again with the 0.2mm cutters this time back the feed rate down to 150mm/min, this time I got about 90% done before snapping the tip.

I don't want to keep snapping bits, so moved onto trying a shape point v-groove cutter, this finished a new case without damging the tip, but the cut and finish is s**t.

What am I doing so wrong here?

Can you please help and advice.

Thanks for your time.

Best Regards.

John S
04-05-2013, 08:00 PM
Fück the carbide.
They always break the tips off and tease you by nearly doing the job before doing so.
Carbide for anyone that doesn't know is a sintered powder, pressed up and heated so no matter which way you look at it that tiny tip that doing all the work is just a grain or two of powder. - bound to snap off.

Long short is do your self a favour and learn to grind engraving cutters by hand. It's not that hard, you can normally spot a trained engraving cutter grinder by the cauliflower ear from being smacked round it by his apprentice master whilst being trained.

I only use HSS cutters nowadays, OK they won't last as long as carbide in the wearing stakes but they don't chip unless you do something stupid and because they don't chip they will allow you to finish a job.

If you have to use the Vee cutters than you need just a tiny flat on the tip, think about it a very sharp point revolving round a centre point is stationary so it has no clearance to allow it to cut.

Hold the cutter tip upwards, flat pointing towards you and the bit that will be doing the cutting is the left hand side so you need to take a swipe with the finish diamond file you have going right to left and with the file tipped up at a couple of degrees.
Add to this it also needs to be tipped a couple of degrees from front to back.

The idea is to make that tiny flat on the left hand side higher than the rest. You only need one or two swipes, any more means you have wide letters

phill05
04-05-2013, 11:02 PM
With carbide it's all about not going to fast and lube it, drip on some wd40, around 15K cutter speed on ally and you'll cut all day without braking, I'm cutting stone with carbide engraving cutters and wearing them down but never broke one.

Phill