TM-1 and milling stainless

[CJH]

Hey everyone...

I have a question and also need a little guidance. I was handed a sheet of stainless and a drawing of a project by one of our managers today to look at and see if it is possible to cut on our TM. I'm not sure if the TM has the rpm's and feeds adequate enough for doing the job in stainless. Aslo I've never machined stainless before. We've done lots of mild steel on the machine with little dificulty. So before I say yes or no to the job I want to get some advise.

Here is the criteria of the job...

material thickness- .030" stainless sheet.

part size is approx. - 8" X 24"

The part will resemble an automotive type grill. With a series of what will probably end up being multiple length slots ranging from 3" to 12" long and about .5" wide, the area between them will be (I'm guessing) about .625" at the most.

I don't have a CAD drawing I can post, for people to see. I'm mainly working in generalities going from the non dimenioned drawing I got. Not my favorite way to work but hey I figure I can be adaptable. I'll have to work one up later on.

Some of the concerns I have are being able to hold the part down. The edges require a clean contour and placing tabs on them to remove later may not be an option. My fist instinct was to send it out for water jet, but the cash isn't there for doing this. They want to keep it in house to avoid costs if at all possble. Plus I'm not sure how much WJ cutting even costs.

[Ken_Shea]

CJH,
Your TM1 will be more then adequate, you will not be using near the max rpm or feed and it has plenty of umph for this.

As I see it, your problem will be holding the sheet down flat and secure, this can be troublesome for sure.

I have used some form of sacrificial sub plate with clamping bars that kept the sheet from vibrating and ruining the part or leaving a bad finish. These bars then needed to be moved as necessary to machine the next area.
Time consuming, yes, but when only one is needed the time and expense of a dedicated fixture cannot always be justified.


Ken

[DEAN]

Yeah like Ken says.
My $0.02 for thin stuff like that is to sandwich it between a couple pieces of thicker material, maybe some aluminum plate, 1/4", 5/16" maybe. If there will be any chance of multiple pieces spend a little time on dowel positioning and you can reuse your fixture without doing too much re-cutting of the fixture.

[Geof]

Try and convince them to get it laser cut. If the laser is using nitrogen or an inert gas it will give an edge finish very close to what you can get with milling. Abrasive water jet would also work but probably be more expensive than laser.

If you are forced into machining you have no choice but to sandwich it between mild steel or aluminum with multiple clamps that you move around during machining.

[handlewanker]

Hi you could epoxy glue it to a piece of alluminium plate, to keep the .5" ribs from moving away from the cutter.
To remove it just heat the resin and it will melt and release.
I glued some alluminium to a piece of steel to grind it thinner on a surface grinder mag chuck.
If you are going to do this as a production job, it is cheaper to make a press tool and punch it out in one go, or even one slot at a time if you can line up the slots from the previous punching.
A press tool to punch one slot at a time is prettry cheap and there is less tonnage to use, just takes a bit longer.
You could probably punch the slots out with the tool mounted in a hand worked 3 ton arbor press on the bench.
Ian.

[GITRDUN]

Originally Posted by Geof Try and convince them to get it laser cut. If the laser is using nitrogen or an inert gas it will give an edge finish very close to what you can get with milling. Abrasive water jet would also work but probably be more expensive than laser. If you are forced into machining you have no choice but to sandwich it between mild steel or aluminum with multiple clamps that you move around during machining.

I agree with Geof. I have lots of our production parts laser cut. its cheaper in the long run than trying to machine it ourselves. If its more than 1 or 2 parts just sub it out to somebody with the right equipment.

[big_mak]

http://www.industriallaser.com/

Geof is on the right track. check out these guys. They are reasonable. MAybe there is someone in your area.

I've had stuff done by them and it's not worth it to set up a mill for this type of thing.

Really more headache than what it is worth

[Edster]

Do you really save anything by taking 10 times longer to do a job than the guy with the right equipment.

[Geof]

Originally Posted by Edster Do you really save anything by taking 10 times longer to do a job than the guy with the right equipment.

Sometimes yes; when the guy with the right equipment has a minimum order in the many hundreds of dollars and you are not sure your design will work.

I have done stainless parts that had to be bent to a precise shape with pre-existing holes finishing up correctly spaced to within around 0.01". It is difficult to predict exactly how the material will stretch and I did not want to get a hundred pieces laser cut and then find sizes and hole positions needed tweaking. I milled the first samples sandwiched between aluminum plate, proved everything out and then had them laser cut.

A hard and fast approach that only one way is the correct way or least expensive way is not always correct.

[M30]

I may not know what I am talking about, but I've read this about straight flute endmills:

Straight Flute
Used for light cuts on very hard and abrasive ferrous materials, and also for use on thin sheeting where spiral flutes would lift up the material.


May be something to check in to if you have not already.

[CNCPrototype]

There are better ways to do it like mentioned above, but if I was going to do a one off or two, I would use a sacrificial piece of aluminum. Clamp it down, super glue the stainless to the aluminum, machine, then poor acetone on it to break the bond.

[CNCPrototype]

There are better ways to do it like mentioned above, but if I was going to do a one off or two, I would use a sacrificial piece of aluminum. Clamp it down, super glue the stainless to the aluminum, machine, then poor acetone on it to break the bond.