Thread: First cuts on new HM-46 - aluminium - what should I try?

Hi I got a HM-46 the other day, I've just trammed it in, and picked up some aluminium blocks.

Are there any users out there who could suggest some cuts to try? I don't mean to make anything, just want to get a feel for 'this is how it should be operating' as I mill/destroy some aluminium.

I have been trying to level out a piece using 10mm 2 flute slot drill without much success. Chips seem to be sticking. It also doesn't want to plunge beyond about 0.5mm depth.

Hello J,

Until very recently I had milled and turned very little aluminium and adhesion of the aluminium to the cutter had invariably marred the finish. For me lubrication was the answer and this thread contains a number of alternatives - //metalworkforums.com/f65/t1993...20#post1907920 Some might be worth a try. I use ATF.

Bob

Try making a cube. And Sed how square you get it


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I've been using this as a cutting fluid, I thought it might help chip evacuation, it doesn't seem to a whole lot - https://www.machineryhouse.com.au/S090A Maybe it's meant for steel? I'll try kero, probably cant get my hands on ATF over easter

My first thing I wanted to do was make a cube Azz, but after the first few cuts left a bad surface finish with a lot of vibration I have just been trying to make 'nicer cuts'.

I followed the usual formulas, but the recommended SFM for aluminium leads to a much higher RPM than my mill is capable. No problem, I just plug in what it is capable of (~1560rpm) and go from there. Depending on the chip load I get a recommended feed speed of anything from 150mm/min (60 turns of wheel/min) to 450mm/min (180 turns of feed wheel/min, or 3 turns per second!). I start of slow and increase until I feel vibration, then back off. Not sure if this is correct. I try not to go too slow as you want a decent chip load to avoid 'recutting chips' and rubbing, or so I read.

I will try some more tomorrow and attempt to get up a few videos.

What end mill are you using ? HSS or Carbide ? does it have a coating or is it a polished finish ?
Guessing maybe one of these M3210 | Metric Slot Drill Plain Shank - HSS | For Sale Sydney Brisbane Melbourne Perth | Buy Workshop Equipment & Machinery online at machineryhouse.com.au
What grade of aluminium are you cutting ? (some cuts real nice, others tend to want to get gummy)
What type of cuts are you doing ?
Lock the Z, lock the quill, lock the Y, depth of cut 1-2mm, 50% step over, bit of lube, max RPM, see what it will do
Plunging is always rough on the cutters, are you possibly hitting issues where you are getting build up on the cutting edges when plunging then you are trying to cut with the build up ? Ideally you want to set depth with the cutter not on the material, bring it into the material.

Remember that depending on the grade of Al you may not get a good finish. Those pictures of mirror finish bits of Al you may be comparing to could have been polished as well. Finally, a smooth shiny finish is influenced by the rigidity of the machine that the work is being done on. If you feed too fast or things are not tight on your mill, it may be causing problems.

Michael

A cheap lubricant I used for Aluminium is Kerosene. It gives a great finish, but all depends on you feed, speed and your cutter (mainly) like MasterSpoon said what cutter are you using? I wouldnt use and recommend anything over 3 flutes to cut aluminium. Anything more will gum up. I only use carbide cutters at work and home.

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Originally Posted by Woodyo

A cheap lubricant I used for Aluminium is Kerosene. It gives a great finish, but all depends on you feed, speed and your cutter (mainly) like MasterSpoon said what cutter are you using? I wouldnt use and recommend anything over 3 flutes to cut aluminium. Anything more will gum up. I only use carbide cutters at work and home.

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yeah I always found Kero the best, but makes me sneeze �� so wd it's always been. Keep your speed up.

Originally Posted by MasterSpoon

What end mill are you using ? HSS or Carbide ? does it have a coating or is it a polished finish ?
Guessing maybe one of these M3210 | Metric Slot Drill Plain Shank - HSS | For Sale Sydney Brisbane Melbourne Perth | Buy Workshop Equipment & Machinery online at machineryhouse.com.au
What grade of aluminium are you cutting ? (some cuts real nice, others tend to want to get gummy)
What type of cuts are you doing ?
Lock the Z, lock the quill, lock the Y, depth of cut 1-2mm, 50% step over, bit of lube, max RPM, see what it will do
Plunging is always rough on the cutters, are you possibly hitting issues where you are getting build up on the cutting edges when plunging then you are trying to cut with the build up ? Ideally you want to set depth with the cutter not on the material, bring it into the material.

Using the exact tool you linked there.

Not sure on the aluminium grade, I just asked for sizes (doh). I'll go back and try and find out what he gave me next week.

I tried a 0.5mm and 1mm slot cut today - lots of shaking, very noisy. At 1.5mm depth the mill wouldn't move into the piece, I had a closer look and pieces of aluminium were stuck hard to the cutter edge.

I also noticed that the parallels were coming out of the vice. I guess the piece is bowing under vice pressure and lifting up, or the back jaw is tilting up. Either way I'm not sure how to fix it, I did give it a tap down with the hammer before doing the vice up tight, but every time the parallels slide out.

I might try something else tomorrow, and perhaps do more reading on securing work - use clamps instead of a vice, and see if the material still behaves the same way. If anyone has any good links on securing work that would be great..... Most of my net searches on setting up vices are just how to tram one, and I can do that.

I just tried out milling with WD40 to see if it made a diff, nope it didn't. In fact the tool blunted, so I tried a 12mm tool and this effect occurred:

The aluminium was sort of 'peeling up'! I didnt see any chips. I tried this at 1000rpm. 1600rpm was vibrating too much with the 12mm tool.
https://ibb.co/caXNqk

Can the jaws be replaced from the vice? To stop the parallels from coming out you. You can shim between the work piece and the top of vice to stop work piece from bowing up.

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With my basic DM 45 mill/drill , I can perform 5mm deep cuts in Aluminium no problem, but I use a nice sharp new cutter , I do this type of job dry . The cutter I use is a good brand , a Dormer or similar with very sharp edges. I will try to take a pic of it . Memory is getting bad but I think this is the cutter I used , its a roughing ? cutter .

sounds to me like you are feeding way to fast . ( i have the same mill ) either that or your running in reverse .also some cutters will not plunge cut no matter what you do some are not meant to plunge cut if they are not centre cutting tools .

My first thought also was that it may be running in reverse, the finish in the photo tends to support this.

Originally Posted by Techo1

My first thought also was that it may be running in reverse, the finish in the photo tends to support this.

yep thats what i rekon but was in two minds to say it or not .

Originally Posted by Techo1

My first thought also was that it may be running in reverse, the finish in the photo tends to support this.

Godamnit I had it running in reverse. *facepalm*. Thanks guys. Switched it around and its cutting beautifully.

At least I didn't try to return the aluminium? Or the mill? :P