Thread: Hogging Aluminium on the mill - what is the best tool?

Whats the largest endmill you have?
Can you get it closer to size on a bandsaw?


Cant help with how much a HM46 can take as I've never used one.


Stuart

Hi Maybe you should use a shaper to remove 90 percent , then use the mill to finish off

Originally Posted by Stustoys

Whats the largest endmill you have?
Can you get it closer to size on a bandsaw?


Cant help with how much a HM46 can take as I've never used one.


Stuart

Stuart, I have a 16mm rippa, but using it would shake the hell out of the machine. Any decent depth of cut with a 12mm and it lets out some wonderful harmonic tunes. I have an indexable fly cutter (Tormach Superfly) and it is pretty good. That said, I do not have the courage to push it deeper than 1.5mm. At 1.5mm with the superfly I have to take it real slow! I thought maybe some "rougher face mill" type of thing might be the go?

I thought it was absurd when I saw people epoxy/granite filling the base etc on the RF45. Then I got one and now I see why. It is not really all that rigid especially dry cutting aluminum using a poor mans misting (squirter bottle!) coolant of wd40. I am actually beginning to think that I should have gone for the HM50!

Edit: Morrisman - I have severe space limitations.. I literally have no room for a shaper or the like unfortunately.

variant22 I use one of these https://www.machineryhouse.com.au/Face-Mill-Cutter, tiz pretty pricey tho by the time you buy the indexable tips and the arbour, when I bought it it was marketed towards smaller milling machines, mine is 1650 kg and 3 hp, but this thing doesn't seem to need
much power to remove metal, I have used it on al and it cuts it like butter.
I'm sure you could buy similar, cheeeper tho.

Here is a bit of a picture of an angle plate I made not long ago, out of steel plate, it's face cut and then side cut on the edges, the finish looks a bit rough in the pic but its actually not a bad finish.

At 1.5-2mm the rippa's won't be actually working, you will just be cutting with the tip. They like to be buried in the job, and taking a decent chip. I know this comes down to the rigidity of the machine, but my HM50 with take a 12mm deep cut with a 12mm rippa in steel no worries. Try taking a full width cut too, having material on both sides, not a half width that the tool will want to deflect out of. The other thing is the difference between hand and power feed. As the power feed is constant it will tend to create less vibrations than even the best hand feeding. The rippa's are the best thing i have used for roughing any material, i am only new to them but i think they are great.

I have a DM 45 and it doesnt like deep cuts, the column tends to shake and oscillate . I just limit the cuts to about 2mm and take my time Mike.........maybe the rigidity would improve with a more sturdy cabinet/stand . The supplied stand is not really heavy enough I reckon.......... I havent tried the ripper cutters yet .

Originally Posted by variant22

Stuart, I have a 16mm rippa, but using it would shake the hell out of the machine. Any decent depth of cut with a 12mm and it lets out some wonderful harmonic tunes. I have an indexable fly cutter (Tormach Superfly) and it is pretty good. That said, I do not have the courage to push it deeper than 1.5mm. At 1.5mm with the superfly I have to take it real slow! I thought maybe some "rougher face mill" type of thing might be the go?

I thought it was absurd when I saw people epoxy/granite filling the base etc on the RF45. Then I got one and now I see why. It is not really all that rigid especially dry cutting aluminum using a poor mans misting (squirter bottle!) coolant of wd40. I am actually beginning to think that I should have gone for the HM50!

Edit: Morrisman - I have severe space limitations.. I literally have no room for a shaper or the like unfortunately.

I would have thought HM46 should be capable of reasonable cuts with a 12mm 'rippa' - incidentally, those endmills ARE designed to be buried in the work to a depth equal to their diameter, and run hard, at the cost of surface finish... Perhaps its an issue of speed and feed? What spindle rpms are you running? Off the top of my head, a 12mm endmill in aluminium should be running around 2500rpm (fair bit higher than your max, I suspect!)... Have you tried feeding faster? I find often if I'm getting chatter, either on the lathe or mill, its actually that I'm not being aggressive enough.

How much work has the endmill done, are the cutting edges all in good condition?

Have you actually tried the 16mm 'rippa'? It should flex less for a given depth of cut than the 12mm, which will help reduce chatter, not to mention its ideal speed is closer to the max on your machine (assuming you have a max of 1600rpm). Plus you're cutting an extra 4mm width in a pass....

Flood coolant would likely help too, I tend to find Inox/WD40 aren't that useful when running the machine harder. I seem to need the chip clearing and workpiece/cutter cooling that you get from flood coolant.

How about a slitting saw? My little Hercus with it's half horse motor can turn a 6" x 1/16" saw comfortably. I've used it to chomp through a lot of cast iron. I imagine aluminium would be like cutting butter. What's more you can use the offcuts.

BT

+1 on the saw
I've been doing similar things with steel and find that the quickest way to remove stock is with the bandsaw (for partial cuts I have to finish with a hacksaw though). If you are cutting dry on a bandsaw the teeth will tend to clog with Al and I've discovered that by putting a backing piece of steel behind the Al when cutting it will tend to clean the blade. Doesn't have to be much - 3mm flat is fine but it helps keep the teeth & gullets clear. If you use a slitting saw try applying candle wax (the bog standard white ones are fine). As a solid lubricant it seems to help stop the teeth getting a build up on the teeth.
Below is a picture of my mill with a diameter 32 segmented mill and a 14mm DOC into steel. As you can guess from that I have no need to cut the excess away because I could hog with that but as Bob suggests you don't get offcuts that way and the saw is quicker. (It's also a hell of a lot quieter)

Michael

P1010480 (Medium).JPG

As said earlier Speed and Feed will play a part in your process,most of the tipped face cutters should be able to remove at least 5mm depth of cut over the full width of the job on a machine like you have,you may find that you would need to use tips that are made for machining ali rather than general purpose.

If cost is a factor have you considered using the largest roughing cutter or End mill that will fit your collets,cutting flute length would need to be longer than the width of your work piece. Mount your work piece on a parallel/s so it is clear of you table and machine along the length of it with the cutter,as long as you have it clamped securely you should be able to get half cutter depth of cut,if you dont use cutters for ali you may need to use air to blow the chips from the cutting edges to stop them from clogging up,if you machine it this way don't climb mill.

Thanks for the tips on how to use the ripper correctly. I will have to give a much deeper DOC a try. I will keep in mind the feeds and speeds. Generally speaking with aluminum I run the mill at top speed which is about 1,600 rpm. I will also give a slitting saw a try. I have one due to arrive any day now, so it will be interesting to see how it goes. Hopefully my next post does not start with "how to repair a ripper end mill".