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Ideal BT30 Aluminum Finisher?

47_Waffles

Aluminum
Joined
Nov 10, 2013
Location
East Coast, US.
I have a few Brother Speedios, a few years old, and have been experiencing more finishing issues lately. One part in particular never used to be an issue, but the last year or so the surface finish on the outside face pass has declined considerably. This is a medium volume part, and it works perfectly fine for the current needs, but there's expectations of changing the coating on that part that will require a better finish.

Currently, I have been using standard length 3/8" Lakeshore Carbide square corner 2F tools, and years back they used to be the right combination of good price and availability with acceptable performance. I tried a few other tools, and have never had great success, just kept going back to the same tool with acceptable results. Oddly, the finishing is only an issue on the one part, on one surface, most of the time I can get great finishes in these machines with this exact tool.

That said, anyone have suggestions for a ~3/8" tool that's going to make my Speedios happy? They don't have much drawbar force, I think I heard of someone making tools optimized for BT30's, but I cant find anything.
 
Is the finish poor for peripheral milling, or for face milling with the 3/8" endmill? Please be more specific about what you don't like about the finish. A photo is worth a thousand words.
 
Do all your leveling feet have even contact with the floor? Have you checked your drawbar pressure lately?

I use Imco Streakers for aluminum. Up to 5/8" in my R650's with great success.
 
The best finisher, and all around end mill, for aluminum I have found is Destiny 3 flute Vipers. They may cost more but over the long haul they are cheaper than less expensive end mills, unless your end mills die before they wear out. I don't think any 1/2" or less end mills need to be made "special" for 30 tapers, it sounds like BS to me.

What tool holders are you using? I really like hydraulics now that I have finally tried them.
 
Yeah it's kinda standard YG1 Alupower, polished uncoated 3 flute.
If it looks bad it's your feeds and speeds or machine.
 
YG-1 Alu-Power
Garr Alumastar
Sandvik Duramill WhisperKut

Never tried Destiny Viper but I've used their Diamondback end mills in our Speedio with great success.

You can't go wrong with either of these.
 
Facemilling with the 3/8" tool has always been poor, but that's something I've avoided doing as a result. This is only an issue when the axial engagement is either too low, like facemilling, or too high, maybe above 2.5xD or so. This specific issue is very consistent, across several same spec machines, several holders, many thousands of parts, different lots and suppliers of aluminum. Only really noticeable on THIS tool, when its lightly loaded. Works great for roughing, and heavy finish passes. This one finish pass is running 0.001"/flute, 0.002 stepover, 16K RPM. Theres a pre-finish before it that's a decent finish at 0.002"/flute .010 stepover.

The holders are typically Nikken milling chucks, but we have tried Maritool hydraulic and Maritool SK16. No noticeable change, always the shortest gauge length tools possible, minimal sickout. I tried one of those fancy holders that the collet and tool fit into the taper of the spindle to get ultra short gauge length, negligible impact. The machines are within spec for drawbar force, we have a gauge and check it occasionally. These machines were purchased new, and have been fantastic. I don't really see why it's primarily an issue for this specific toolpath, but the program is the same, and it suddenly got worse a while back. We spent maybe two days trying to fix it, and it improved, but was still not ideal.

I'm not able to share a photo of the part, but it appears to be mild chatter. I appreciate the suggestions guys. I'll measure runout in the holder as is, and probably snag a tool or two.
 
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I don't really see why it's primarily an issue for this specific toolpath

Any chance this involves trying to finish both a wall and the floor at the same time? In other words, a combination of peripheral and face milling?
 
I use mainly Destiny Vipers with the stealth coating for finishing. Excellent finishes. I use some YG1 Alumpowers also which leave great finishes also just don't rough with them. The snap off if you look at them funny.
 
I had a similar issue recently with some parts I had made once with no issues. Then the second time the finish (side milling) was not so good. I tried various cutters including the YG-1 polished cutters. This didn't go over well and I wound up doing some rework. The third time I spent some time researching up front.

A local guy here makes fancy car parts and is nuts about finishing. He does very nice work. He's very big on SwiftCarb and recommended one of their AF finishers. The one I bought is 4 flute uncoated. These things made an excellent finish far better than anything else I've tried. They were not cheap. Like $120 each for a 1/2" one with I think 1-3/4" or 1-5/8" cut (can't remember). The odd thing is that out of the tube they don't feel as sharp as most other cutters. Seems like they have almost an edge radius. Also, the finish was best with it taking off about .01" or so. And a spring pass makes it worse. Supposedly these things hold up for many thousands of parts.
 
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I'm intrigued... a pic of the wall without showing the whole part would help. I finish 2" deep with a 1/2" YG-1 regularly with great results (I think). Would be good to have a reference to compare.
 
probably already mentioned, make sure you check level, on those fast machines you should check once a year min.
I have to re-lelvel mine because they aren't bolted down.
 
I mean... how exotic do you want to get?

Semi-exotic; Frasia has their NX line that is producing bonkers good floor finishes. I've seen folks have success with them in aluminum, despite not being ground or coated for it.

Super-exotic; a couple of companies are now making helical fluted PCD end mills, in standard sizes, that can have wiper flats and corner geometry tuned for the exact DOC you'll be running. These are all custom, and like $800+ each.
 
Currently, I have been using standard length 3/8" Lakeshore Carbide square corner 2F tools
Facemilling with the 3/8" tool has always been poor, but that's something I've avoided doing as a result.

Did you try an endmill with a corner radius for facemilling? The YG-1 Alu-Powers (and others) are available with a variety of corner radii and seems like even a small radius improves the facemilled finish.
 
I use some YG1 Alumpowers also which leave great finishes also just don't rough with them. The snap off if you look at them funny.
Not in my experience. I have a 3/4 necked 3 flue Alu-Power that has roughed a ton of 7075 aluminum at full flute length and about a 30% stepover, just ripping that material off. Still looks brand new after 3 months of cutting.
 








 
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