How good of a finish do you get on the TM series mills..

[l u k e]

on aluminum?

99.9% of what I machine is 6061. I can't really spend much more than what the TMs are going for and was curious what kind of finishes these machines get.

I'm interested in feedback on any of the TM's, thanks.

[big_mak]

On any machine, you need good cutting tools preferably solid carbide running as fast as possible speed wise, and feed will depend on the finish requirement.

[l u k e]

I make after market paintball products. All stuff will be anodized, I would like to know how good of a finish you get with the lower RPM equipment like the TM's?

Am I going to need to invest in finish equipment too?

[big_mak]

No, It just takes longer brecause your feed rates will be lower.

[sundy58]

The Physics Machine Shop here on campus just turned out a box that is incredibly smooth. I don't have the tools or knowledge to give you a hard number but is very impressive to my eye.

[big_mak]

I worked at a place that did high end scientific digital camera bodies. We used Garr 242M series pretty much exclusively, and they worked well on 8,000 rpm machines and 15,000 rpm machines.

[toastydeath]

Tooling doesn't come into play in this question. The maximum obtainable surface finish is determined by the machine itself - especially in 6061, where you can use PCD and SPDT inserts. Obviously, a person needs to select the right tool for the job, but they are no longer the limiting factor in finishes.

Again - surface finish is machine dependent and that's what the OP wants, not tooling suggestions.

[big_mak]

The question was can he get good finishes with this machine with a lower spindle speed.

Besides if you say surface finish is entirely dependant on your machine you are WAY out to lunch. Compare surfaces from an HSS endmill and a SC Endmill compare finishes with the same tools @ different speeds and feeds. There are a lot of dynamics in the WHOLE system that will effect the surface finish that you can achieve. An endmill may want to shake rattle and role @ one speed, then settle down @ another. I've been around long enough to know that you can get a good finish on an old clunker, you just have to know how to caress it and sweet talk it.

YES - with proper cutting tools and speeds and feeds. Granted with a ؽ" endmill the spindle will be running full bore, but he won't be able to feed the same as say a 15K spindle machine. If you were say gonna run the same parts on a machine with an R8 Spindle then I may say no.

[axis]

how do you figure that tooling dosnt play a part. it plays a big part in time and money.
with only 7.5hp and 4000-6000rpm coolant or no coolant. tooling could be the make or brake of a small shop in finish quality and time per part. the finish on a high helux tool will look a lot different than a insertable tool. and then you can go single or mutiple flute cutter. the limiting factors are hp and rpm, but they are only limits if you use the wrong tooling. the tm will be fine to do what you are looking at but you will want to look at the tm-1p with aluminum you will want coolant the open machine is fine but you will get very wet.

[toastydeath]

Originally Posted by big_mak The question was can he get good finishes with this machine with a lower spindle speed.

Read the original post again. The title is "How good of a finish do you get on the TM series mills..", and goes on the specify aluminum in the body. He does not once mention spindle speed or tooling. He asked about a very specific series of machines, and what kind of surface finish are they capable of producing. A valid question for any precision engineer who has worked with surface finishing.

It's such a common question in industries that require good surface finishes that virtually all high precision machine manufacturers will guarantee maximum surface finish right along with the accuracy, spindle speed, travels, and other machine parameters.

Originally Posted by big_mak Besides if you say surface finish is entirely dependant on your machine you are WAY out to lunch. Compare surfaces from an HSS endmill and a SC Endmill compare finishes with the same tools @ different speeds and feeds. There are a lot of dynamics in the WHOLE system that will effect the surface finish that you can achieve. An endmill may want to shake rattle and role @ one speed, then settle down @ another. I've been around long enough to know that you can get a good finish on an old clunker, you just have to know how to caress it and sweet talk it.

I never said it's wholly dependent on the machine, there are other factors. But it's very easy to eliminate those factors, or make them an order of magnitude less important than the machine itself.


Things like cutter material, edge sharpness, RPM, et cetera all affect the apparent asynchronous error motion of the machine. That's the fundamental mechanical property that determines surface finish, and nothing else. We could get into a whole discussion about what tooling to use, why, and what is going on at the molecular level that makes such tooling desirable. But that's not what the guy asked - he asked a very valid question about the machine he is considering purchasing. Fortunately for him, he's working in aluminum, and can use PCD inserts. PCD doesn't care how fast you spin it. You can run it at 2 SFM or 20k SFM, and you will get the same surface. So that he has an 8 rpm spindle on some machine won't matter, it will just be slow as piss. He will still get the best surface his machine is capable of producing.

Machinists who have worked 30-40+ years in the industry usually have no clue why, again on a microscopic level, things like RPM affect the surface finish and how to eliminate RPM as a variable. They just know that RPM and tool material do affect the finish, and that faster is shinier.

[Geof]

I think until you have a definition of 'good' in the question; How good of a finish do you get on the TM series mills.. you cannot answer the question. No matter what machine is used or what cutter is used at what speed and feed, the surface finish will vary depending on whether it is a surface that has been faced with the end of the cutter or a profile that has been finished withe side of the cutter. If it is desirable that the product have a uniform surface finish over all surfaces no matter what their orientation to the tool during machining, secondary finishing is probably going to be essential.

[big_mak]

To quote Toasty "Tooling doesn't come into play in this question." says to me that tooling don't factor into the equation. If you didn't mean that, then you should think a little harder before you answer.

Aluminum is fickle, and one person's good finish is not acceptable to some one else. MAYbe LUKE can clarify for us what a good finish is. say 125 microinch or is he looking for 16 micro inch. I've done camera's where no machining marks were acceptable period. We have 16 finishes on them, then they got tumbled in walnut shells.

As for PCD inserts in 6061, it may work for you, but it won't work for everyone. Why spend $40 an insert when I can get the same results with Carbide for less than half the price.

Oh look we have a problem! let's throw some $$$$$$ and it will all be better!!!!!

when you talk of maximum finishes, these machines have been tested bolted to the optimum foudation isolated from any extraneous vibrations, with a solid hunk of material clamped to the machine table that ain't going now where's!!!! In the real world I'd say that most machines aren't mounted to the ideal foundation, and are not isolated from vibration from outside sources, so the manufactureres spec is almost never really achieveable aspiclaly when the dude in the test lab has the time to dial in the tips of his trusty PCD sutter with wipers to the nearest micron. Who in the REAL world has this time, let alone patience.

Paintball parts + TM mill = acceptable results