Help me understand, wheter this is chatter or normal operation?

[usolutions]

A VF-2 doesn't need it, I did a foundation for a VF-3 and spoke at length with the factory.

I mean I would move it on my own with VF2, may be VF3, not 8 ton machine. Dropping/collapsing it for some spherical advantage is not a gamble I am willing to make. Esp. taking into account that there are no readily available parts for these machine unlike said HAAS.
Current foundation is over spec, except m16 bars to lock down the feet.
If I had rigidity related problems, and those would be paramount for current project I would go through the hustle.
For most of folk on PM 10-12 grand is something they can afford and get back in less than a month just on a credit card, this for me is year work investment. We dont have medical and aerospace at all, so no high prescision high buck jobs here that would justify calling in riggers from other country to do the job.
If I have good surface finish, I am not concerned about rigidity. 8 tons of cast iron can handle just fine on their own for this year while I get my money worth back from the machine.
One more time, this is 25y surplus machine for 10k usd. Work olerances are about 0.02mm(1 thou) max. I can not afford riggers, 2 week standstill, paralysis of whole workshop operations to get 5% improvement, which i really doubt is the case.
No more discussion on redoing foundation.

 

[farmersamm]

By the sound of the cutter............that isn't chatter. I'm the King of chatter, what with my not-so-great machines. Chatter is generally when the tool screams at you, or you get a lousy surface finish. Both of which are remedied by slowing the rpm down, or decreasing feed and DOC.

This old Iscar is somewhat similar, and it takes a bit of patience to run. Gotta slow it down, and keep DOC to a minimum. Unless fully loaded across the entire diameter, it's very noisy, but the surface finish is very good. It will deliver the same quality at about 1/3 tool engagement, just louder. So I don't worry. Besides.........milling inserts are designed for repeated heavy impact. You can get chatter with a 1" mill if you don't run it right. Leastways on my lil' machines.

THIS IS CHATTER!!!!!!!!!!!!!!!!!!! (big grin) Side milling N95 weld buildup with a 3/4 x 3" mill. LOL. Rigidity issues out the wazoo. No way to fixture it to be face milled, so you gets what you gets. Some nasty stuff.

Then there's the chatter you don't hear..............................

Didn't have a thick enough boring bar for the required depth of the bore(6 1/2 inches). And.....it was carbide tooling to boot(HSS would have been better) Started out screaming at me. Was able to eliminate the howling banshees by dropping DOC, and reducing feed......but the chatter was still there. The bore is 10xx steel, real gummy..............the face is 7018 buildup.

There was a discussion here about what type of lathes to buy for a school machine shop. I felt that the cheapest machines available, in a relatively small size, would be the ideal teaching tool. You learn what materials machine best, what type of cutting tools work best, given limitations imposed by the machine. Start someone out on the "best", and they don't really learn how to compensate for different conditions. Although, realistically I guess........the days of manual machining are long gone mostly. I see tons of it around here,, but this is oil country. Lot of repair work, virtually no extended single part runs.

Another way to put the same idea. I can teach you to be a very good welder. Start you out on a little buzzbox,, where it takes a high degree of skill to make acceptable welds. Then move you to an SA200, or other machine with very nice arc characteristics, where the talent you developed can really shine. After that.........it'll take you about 5 minutes to learn to run a wire welder.

Probably not terribly relevant, but just a few thoughts.

 

[usolutions]

Another way to put the same idea. I can teach you to be a very good welder. Start you out on a little buzzbox,, where it takes a high degree of skill to make acceptable welds. Then move you to an SA200, or other machine with very nice arc characteristics, where the talent you developed can really shine. After that.........it'll take you about 5 minutes to learn to run a wire welder.

Probably not terribly relevant, but just a few thoughts.

There is a difference between learning with a tutor and learning on your own.
When you learn on your own, you have no idea whether you do something actually wrong or this is machine jinxing out. Especially on welding.

However all input is appreciated.

Not yet tried 65%woc, waiting for some tools to arrive, to finish last op from friday.

 

[eKretz]

There is a difference between learning with a tutor and learning on your own.
When you learn on your own, you have no idea whether you do something actually wrong or this is machine jinxing out. Especially on welding.

That's true in the beginning, but as long as one is at least fairly smart and especially curious, experience teaches you what to expect from the machines and how to use them. I served an apprenticeship as a machinist, but after the basics I learned far more by doing research and using trial and error on my own. It is helpful to work in at least a few larger shops to get exposure to new machines, methods and ways of thinking though.

 

[usolutions]

I gace tried 65% woc with 11mm DOC same basic speeds and feeds, it is screechfest, tried adjusting s/f with handles on the machine, no luck there. As it somehow got more load per tooth, as i had witness marks of material on tool body itself beyond insert. I am also getting vibes that my shell mill/mill holder combo does lack rigidity on itslef.
Might want to go lower doc and increase feedrate instead.

 

[Milland]

I gace tried 65% woc with 11mm DOC same basic speeds and feeds, it is screechfest, tried adjusting s/f with handles on the machine, no luck there. As it somehow got more load per tooth, as i had witness marks of material on tool body itself beyond insert. I am also getting vibes that my shell mill/mill holder combo does lack rigidity on itslef.
Might want to go lower doc and increase feedrate instead.

Same cutter body and inserts as before, or different? Video of the bad cuts (if you are ok with repeating it) will be of interest.

Also, a bit of relevant G-code from the old (acceptable) program and the new noisy one might be useful to check here.

 

[usolutions]

Same cutter body and inserts as before, or different? Video of the bad cuts (if you are ok with repeating it) will be of interest.

Also, a bit of relevant G-code from the old (acceptable) program and the new noisy one might be useful to check here.

Not really willing to replicate. I am short on tools and material RN. Dont have Gcode, as I only keep stuff that works. However I am willing to find recepie that works better, Im just not keen on replicating failure. May be 65% with reduced DOC will work fine

 

[Joe Gwinn]

Is there any way to use wood to clamp the workpiece? Machine a close-fitting recess in the wood and then clamp?

 

[eKretz]

You might also still want to try that smaller cutter. The middle sized solid carbides rip pretty good these days. Especially useful in smaller, less stiff machines.

 

[usolutions]

You might also still want to try that smaller cutter. The middle sized solid carbides rip pretty good these days. Especially useful in smaller, less stiff machines.

16mm SC 4 flute is something i am currently experimenting with, and getting good results. My understanding is on non-hobby machines spindle/axis power+-matches overall machine stiffness. And if it only goes like 40 percent max then it must be tool rigidity and not machine rigidity.

 

[usolutions]

Is there any way to use wood to clamp the workpiece? Machine a close-fitting recess in the wood and then clamp?

Definetly adding wood is not something I'm trying
Also inspected and checked inserts, they are shot. Overall on both sides of Gesac APKT1604 managed 160 minutes in cut before failure. IDK if it is bad or not. That is about hour and change on a cutting edge.

 

[Milland]

Also inspected and checked inserts, they are shot. Overall on both sides of Gesac APKT1604 managed 160 minutes in cut before failure. IDK if it is bad or not. That is about hour and change on a cutting edge.

~160 minutes isn't unreasonable, although some life was lost if these are the same inserts from the bad program run. Carbidebob would have more insight into insert use tradeoffs (metal removal rate vs lifetime).

 

[usolutions]

~160 minutes isn't unreasonable, although some life was lost if these are the same inserts from the bad program run. Carbidebob would have more insight into insert use tradeoffs (metal removal rate vs lifetime).

One side was shot by collision with vise jaws, other side was shot after bad run. So I might get more out of them, but as a bottom line not bad for 3$ per cutting edge from my understanding

 

[Joe Gwinn]

Definitely adding wood is not something I'm trying

The reason to consider wood (perhaps saturated with oil) is that it is cheap and available, and provides very good vibration damping, which could reduce the effect of the hammering.

 

[usolutions]

The reason to consider wood (perhaps saturated with oil) is that it is cheap and available, and provides very good vibration damping, which could reduce the effect of the hammering.

I understand that, however I want to try to adjust my machining strategies before redoing setup, because in same'ish setup other guy can avoid it.