Ways to speed up milling of 80% lower

[Intimid8tor]

So I am finishing up my second one and it is going much quicker than the first, but I would like to speed up the process. Perhaps I am being too conservative on my depth of cut.

What tips are out there to speed up the process of getting material out of the lower prior to finishing passes?

[Alex$]

Bigger drillbit?

I have not done an 80, so take it with a grain of salt.

[chillincody]

take your time dont rush it and your work will show it easy to remove metal not so easy to add metal

[kcstott]

A good machinist pushes the speed and feed as hard as he can. But things that will determine how hard you can push it are:
How rigid is your machine?
How rigid is your set up?
How sharp are your tools?
Flood coolant?
How accurate does the part need to be when finished?
and how nice of a surface finish?

Those things right there will be the determining factors in how fast you can machine a part.

The old rule of thumb is take as much as you can as fast as you can and RPM's will not help you. Feed rate and depth of cut are the speed increasers.

[Intimid8tor]

I think I might be being too conservative on what I am doing. I just watched hoss take a 1/2 endmill 1/2" DOC at like 11 ipm with the same machine I have. Mill took it fine. I think I am just trying to figure out the feel of the machine without breaking something.

I guess it will just take time.

Of course, the finishing passes to get to final dimension are much smaller and taking big cuts means clearing ships out better. For that I am working on an adapter for my shopvac that will help me to do it quicker.

[milotrain]

I push a 3/4 (non roughing end mill) through a 3/8" deep cut in aluminum with a SEIG X3. Obviously I wouldn't do that on a finishing pass but for just getting the material out of the way go until she chatters.

A good machinist friend said to me when I was being to conservative: "Chatter isn't bad, it's just chatter. It wears your tool faster, wears your mill faster, but oftentimes the speed outweighs the cost. Just do a finishing pass."

Fake a flood coolant system with a pressure weed sprayer and water based coolant. Then you can really move.

[kcstott]

Well chatter is bad And that was said by someone not paying for the machine. If he bought the machine he'd think a little differently about beating it up for no reason.

You can cut plenty fast enough without chatter. Endmills costs money, sharpening costs money or time. (in my case time as I have the fixture) Rebuilding your machine costs a lot of money.

I can't agree with that guy.

But I will say a spray bottle, weed sprayer, or just and air hose helps.

[milotrain]

His point was that in the work he did time was more important than tool life. He also had the luxury of buying a box way machine and mostly running aluminum on it. I don't run a mill enough to worry about chatter ruining the tolerances of my machine (and it's a chinese machine so the tolerance was never that good to begin with).

I totally agree that in an environment where you are manufacturing the same part, or new parts, but on only semi critical schedules and you have to make the machine pay for itself with every part then you should reduce chatter as much as possible, but when you need it built yesterday sometimes hours cost more than Carbide and iron.

[bohoki]

whats the hurry

you know the manufacturers triangle fast,cheap,good
pick 2

[kcstott]

I know where you are coming from but I just can't bring myself to abuse my machines. And in the shops I worked they'd fire you for such practices.
There was no job so important that the proper time could not be spent on it to do it right. But there again I've seen the shops you are referring too quick fast and dirty with cut throat rates and machine that look like they've had the crap beat out of them. But they made money.

[2nd Shot]

It takes some trial and error and some careful tweaking your feedrate override knob to learn what every tool in a particular machine will tolerate in various situations... Too far and you'll move a part, break the tool, or even stall the spindle on a smaller machine (bad), but you might be surprised how hard you can push it with a little caution and understanding of feeds and speeds.

- End mills hate plunging. You may find that drilling a hole where you're going to plunge may prevent the tool from having to end cut at the center where it's susceptible to packing up. Reground tools are typically even worse, depending.

- Speed is your friend when it comes to material removal - if an end mill comfortably takes so many thousandths of material per cutting edge per rev, the more RPM, the faster you can advance it into the material, provided other factors don't stop you.

- Chatter can usually be overcome by several methods: 1.) Increase tool rigidity - don't stick the tool out of the holder any further than needed for the job, use the largest dia, shortest tool that will work if you can. 2.) Increase setup rigidity - don't leave anything cantilevered out the side of the vise, or whatnot. 3.) Reducing spindle RPM can stop chatter - if nothing else works, and you're doing a critical pass, slow it way down if nothing else will do. Sometimes increasing spindle speed can pull it out of a resonant place - try fiddling with the spindle speed override. 4.) Don't overlook tool load - sometimes loading the tool a little MORE will quiet chatter... A lot of chatter happens when the tool isn't pushed hard enough. Worst case scenario, on a roughing operation, a little chatter won't hurt much - just be sure you're not digging into the finished surface if it does chatter.

- Heat and friction are not your friend - with aluminum (and doubly true with plunging), you may get to a limit where the aluminum packs up or galls and jams up the tool without coolant to cool and to lubricate the tool and help flush away chips. You'll know pretty quickly since it'll rumble loudly as the tool with no cutting edges tries to smear through the metal. Rig up some coolant as best you can. Keep it out of the servos/encoders.

Funny story - I was pushing a .750 ball end mill as fast as I dared (~100+ ipm, .025 depth of cut) on a 3d surface when I turned off the coolant to get a better look ...It took all of 3 seconds for the tool to jam, stall the spindle, bringing the machine to a crashing halt! Oops! Living on the edge!

And, last but not least, if you have the option of time, use it to your advantage - take your time and enjoy! That said, I do machining of components for internal company projects that aren't on a tight schedule, but still try to push it just for the sport of it, so if that's the case, give it hell!

[2nd Shot]

It takes some trial and error and some careful tweaking your feedrate override knob to learn what every tool in a particular machine will tolerate in various situations... Too far and you'll move a part, break the tool, or even stall the spindle on a smaller machine (bad), but you might be surprised how hard you can push it with a little caution and understanding of feeds and speeds.

- End mills hate plunging. You may find that drilling a hole where you're going to plunge may prevent the tool from having to end cut at the center where it's susceptible to packing up. Reground tools are typically even worse, depending.

- Speed is your friend when it comes to material removal - if an end mill comfortably takes so many thousandths of material per cutting edge per rev, the more RPM, the faster you can advance it into the material, provided other factors don't stop you.

- Chatter can usually be overcome by several methods: 1.) Increase tool rigidity - don't stick the tool out of the holder any further than needed for the job, use the largest dia, shortest tool that will work if you can. 2.) Increase setup rigidity - don't leave anything cantilevered out the side of the vise, or whatnot. 3.) Reducing spindle RPM can stop chatter - if nothing else works, and you're doing a critical pass, slow it way down if nothing else will do. Sometimes increasing spindle speed can pull it out of a resonant place - try fiddling with the spindle speed override. 4.) Don't overlook tool load - sometimes loading the tool a little MORE will quiet chatter... A lot of chatter happens when the tool isn't pushed hard enough. Worst case scenario, on a roughing operation, a little chatter won't hurt much - just be sure you're not digging into the finished surface if it does chatter.

- Heat and friction are not your friend - with aluminum (and doubly true with plunging), you may get to a limit where the aluminum packs up or galls and jams up the tool without coolant to cool and to lubricate the tool and help flush away chips. You'll know pretty quickly since it'll rumble loudly as the tool with no cutting edges tries to smear through the metal. Rig up some coolant as best you can. Keep it out of the servos/encoders.

Funny story - I was pushing a .750 ball end mill as fast as I dared (~100+ ipm, .025 depth of cut) on a 3d surface when I turned off the coolant to get a better look ...It took all of 3 seconds for the tool to jam, stall the spindle, bringing the machine to a crashing halt! Oops! Living on the edge!

And, last but not least, if you have the option of time, use it to your advantage - take your time and enjoy! That said, I do machining of components for internal company projects that aren't on a tight schedule, but still try to push it just for the sport of it, so if that's the case, give it hell!

[Intimid8tor]

I guess I should be clear. I'm not trying to rush the process, just trying to be efficient. I enjoy machining, but have a nice line of things to get done. I don't run dry. I have a gallon of WD-40 with a sprayer on the end and keep everything moist. The best cutting tool so far has been an accupro 2 flute center cutting end mill. I've tried a few others and haven't been all that impressed with them.

Lots of trial and error. I was surprised to see some videos that if you get chatter to increase the feed rate. That was on a lathe, but having the right feed rate makes a difference. Too fast and too slow both can create issues.

What I am trying to do is to find the balance of it all. I don't want to hurt my machine or my tools, but I don't want to take .005" cuts when I could be taking .025 or .25" cuts without undue wear or damage. I am mostly focused on ways to get the material out of the main cavity quicker so I can work on my final dimensions.

I think on the 3rd one I do I am going to try drilling a few holes in the main cavity so I don't have to plunge in so much.

It is just an experience thing I guess.

[kcstott]

In my Bridgeport when I was pocketing out the FCG I was taking .100" depth of cut. I also left a little more around the edges for clean up except the .437 slot. I was using a 7/16" endmill so I had no choice.

First thing I would do is increase your depth of cut. I'd start at .030" on a small machine and increase from there. Feed rat is easy turn it up or down till it feels right.

And poor on the coolant.

Oh and don't us anything other then a two flute cutter on aluminum. you are asking for a broken endmill.

[Targets From Us]

First off what type of machine? if you arent using cnc then your speeds dont really matter that much. Also if you are using a knee type mill or worse...a china benchtop mill.. then you absolutely will not be taking that kind of DOC like you saw on the haas video. VMC's are alot more rigid.

knee mills like a bridgeport type, you would be lucky to get an accurate cut at .250 DOC, there is just too much flex in the neck of the mill.

All that being said, i run a half inch finishing endmill at 12krpm at 180ipm with a DOC of .625. I personally dont like 3/4" endmills finishing or roughing..they chatter too much for my liking!

like kcstott said, .100" DOC for a bridgeport type is about the max you want to run since the machine isnt very rigid.