Lathe, how much material can these inserts take off at a time?

A

awaqa909

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I get to be a parts puller for the cnc lathe every once in a while, the problem is, just about every time I'm over there, inserts are wearing down fast. One job I think I changed about 10 threading inserts, with 3 points on them. They only lasted about 3~ parts per point and I tried to get the max out of them. On a more recent job I was told that there used to be a guy who could run both sides of this particular part in a day. It's been 2 days and the 1st side still isn't done. This job has a lot of material to bulk off. (Far more then 1 part)

What I know about the inserts, one is a 35 deg finishing insert and the other is a 50deg? roughing insert. (I know it's not the 55) The finishing insert can only take off a few thousandths and once there is even a tiny nick in the insert, the finish goes bad. The roughing, sometimes it's worn to hell but still makes a part like its fine, other times a decent sized nick will need to flip/change the insert.

These are as close to that actual inserts we use. I'm not sure if they're the right size, but the look very similar, same brand in fact... not sure if they're good or not.
35 deg I don't know how to "decypher" tool numbers to get a angle or anything.
https://www.alibaba.com/product-det...l?spm=a2700.7724857.main07.335.6dab7e0faXbWHd
45-50deg which may be the exact insert, or a 906, as it says 907 on it.
https://www.alibaba.com/product-det...?spm=a2700.7724838.2017115.112.52920af5lt4sJM

The 45 has a .5"~ edge on it? But from what I understand we only take off .045" per pass. The 35 is longer, but it looks like there is a area for cutting that is only .300"~ long, but we only take a few grand off with that tool. I wonder if these inserts are being used to their full potential and causing premature wear. I know the bite size was increased at some point and the spindle load was lower, but not sure about the Z load. But I also don't know if it was slowed in any way. Speaking of speed, the lathe plaque says it can go 4k rpm, but only recently have I seen it top out at 1600rpm.

I once watched a video on how train axles were made. They had that lathe insert in what looked like full depth.

Thanks,
Awaqa909
 
That REALLY depends on the component and the set up. The actual insert can handle one heck of a cut. Most machines, especially CNCs have lots of power. However, in order to take advantage of all that power you need a VERY strong set up (which includes the piece you are machining). I find most jobs, it is the set up or configuration of the part that is the limiting factor - the machine and the tooling can handle lots more load.

A train axle is a very robust component and it is pretty easy to hang onto - of course you can take a big cut.

You have not provided enough information to get a reasonable answer.
 
Chipper5783 said:
That REALLY depends on the component and the set up. The actual insert can handle one heck of a cut. Most machines, especially CNCs have lots of power. However, in order to take advantage of all that power you need a VERY strong set up (which includes the piece you are machining). I find most jobs, it is the set up or configuration of the part that is the limiting factor - the machine and the tooling can handle lots more load.

A train axle is a very robust component and it is pretty easy to hang onto - of course you can take a big cut.

You have not provided enough information to get a reasonable answer.
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I'm not sure what kind of info to provide. It's a 3 jaw chuck, that holds onto roughly 1/4" of material. The material is 6" diameter and maybe 1.25" thick. About a inch of material is to be bulked off, on the outer edge, as well as some bulk facing... Sorry about my terminology. Also trying not to tell too much about the part, don't want to get into any kind of trouble. I don't have the best memory of the part, so things are a bit vague. Believe it was mild steel. I'm not the programmer either, nor understand any of it.
 
What he said.

I roll the dice at first on a new part, high speed and DOC right off (this also greatly effects chip control as well) then dial it down if it eats tooling. The material plays a key role in this dance. If the chips get out of hand dial the feed rate up a bit in order to make the chip thick so it will break.

If you do not spend a large portion of your life herding chips you will never understand this.
 
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My questions to you are, what kind of material are you guys trying to cut on? And the hardness? What is the brand name of the machine along with the model number of the machine. With that I/we can give you an better idea of what you need to be doing. Get the insert numbers off the packages of the inserts being used, this will tell you the information needed for proper feeds and speeds and if it is the correct insert for the material being cut.
Ken
 
Feeds and Speeds...............Feeds and Speeds..................That's what my shop teacher preached
 
Ask your employers if this is acceptable tool wear, if there is enough money in the part one insert edge per part may still ring with the sweet sound of profit. Whomever set it up chose the tools and cutting conditions, ask that person instead of random people on the Web.

Good Luck
 
4gsr said:
My questions to you are, what kind of material are you guys trying to cut on? And the hardness?
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I agree!

  1. What material is being turned?
  2. What inserts are they exactly?
  3. what's the depth of cut, sfpm, and feed being used?

If your're changing out inserts take a photo at the back of the pack and post it.


Wreck™Wreck said:
Whomever set it up chose the tools and cutting conditions, ask that person instead of random people on the Web.
Click to expand...

You're assuming the person who set it up knows what they are doing. I have some friends in the industry who would tell you to assume everyone else is an idiot until they prove otherwise.
 
Okay guys, lets be nice here. We are suppose to help, not criticize what the OP is asking about. He's trying to learn something positive here.
 
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