CNC Aluminium The biggest myth on CNC Machining.

[@TheCNCDen]

By the way folks, if you ever have used the wrong bit, such as a generic carbide, on 1000 series, or indeed any other flavour of aluminium, and you've welded the aluminium to it, do not chip it off or throw the bit away! It's very easy to remove and the bit will be as good as it was before you started. Simply soak overnight in a Sodium Hydroxide or Caustic Soda here in the UK, you only need it deep enough to cover the affected part of the bit. The aluminium will dissolve away. Obviously if you do, handle with care and wear gloves, discard the solution when finished by pouring carefully onto a weed in your garden, it's a great natural weed killer too!

[@m9workshop]

Great tip!

[@arbjful]

3:49 , try to avoid that from happening. The flying metal piece can break the end mill. This happened to me once. The end mill broke the instant it touched the break away piece…😂😂 To avoid this you can add dog tags (Freecad terminology) in the cam file, the tags stop the metal from flying away

[@TheCNCDen]

Thank you for your comment. Yes there are places where tabs are required, there places where they are not. It's also true that when cutting large thin flat sheet that tabs don't always work, if the part picks up vibrations, which is itself also a bigger killer of endmills. Unless you're using very thin endmills or fail to monitor the machine as it's cutting, it's very rare that small parts flying off damage them. If they don't fly off clear on their own, they need brushing out of the way of the cutting area. When cutting in volume, it isn't always possible to spend the time cleaning up parts that you can as a hobby or low volume, hence needing a clean, straight off the machine cut that requires minimum deburring. It's therefore the very powerful vacuum bed that holds the parts, but the counters however are so small, they are free to release and are more of a risk to me if I don't wear PPE.

[@freedomforever9166]

I cut out a bracket for a motor from 3/4 aluminum using a 1/16 nano blue endmill, no problem at all. But I did cut 1/8 deep with each pass. If your doing metals, you NEED a vac running to keep the chips from building up

[@TheCNCDen]

You don't really need a vac tbh as most vacs can't lift the volume of metal fast enough unless you're holding the original vac tube over the slot getting in the way. I personally have more issues with MDF in terms of build up in the slots, vacs struggle to lift that dust out of the slot and it's a lot finer and lighter than the chips from metal. You do need something to help reduce the chips though, which a vac does or indeed as I do a blower, - personal choice on that one. With a decent upcut bit, the bit should also lift the chips up and out of the slot anyway.

[@m9workshop]

Have you ever thought about adding a vacuum "scoop" opposite the air blower to suck the chips up as they fly? I've always thought it'd be trivial to 3d print one and for this work just a standard shop vac should be plenty because the chip volume is quite low. I don't envy your cleanup after these jobs is all 😄

[@TheCNCDen]

There is one available for the machine, when videoing it covers the entire cutting view so less interesting to watch and see what's happening. I'm still finding the HDPE chips from some work I did weeks ago, on that other video. But they don't suck up to well so again no point attaching the boot. I tend to use it now only when cutting wood & MDF which is very messy, I prefer sweeping the aluminium chips up and putting them to one side for recycling, ditto some plastic chips. It only takes a moment to sweep up the chips, but it is a workshop not a garage, basement etc so it affords me more lattitude for making a mess. The tube I move in the video is for the vacuum, I have it hanging there so I can suck up the remnants I can't sweep, plus it reaches to some of the floor area.

[@Ichoros]

hello, did u mention diameter of the bit and the rpm you were using for this FEED and DOC? i cant go more than 1000mm/min because of many curves and the jitter i get, so im trying to find the proper formula since i get fairy dust instead of chips. No welding or hot endmill but still.. I have to contour cut 3mm sheets, tried 0.5 - 0.75 - 1 - 1.5 DOC but still.. i think ill go full cut with 15000 - 16000rpm dunno why but they gave me 1050 to start with and learn to cut aluminum. its a nightmare

[@TheCNCDen]

Hi Thanks for commenting. I may not have done, clearly every machine will be a bit different. Typically those fitted with a router spin slower than the spindle I have. As standard I use 3mm diameter bits on sheet up to 5mm thickness as this gives me a wider level of detail, especially on smaller parts. At 3mm diameter I do cut to 3mm DOC sometimes, but I would normally go no deeper than 2mm DOC day to day, in 3mm stock I prefer 2 passes at 1.5mm. With the bits I mention, inexpensive single flute DLC bits, you run them at maximum speed for your machine, in my case 24,000 RPM. These bits do like to advance at speed too, so whatever the fastest feed is. The secret really is that type of bit.