TIN COATING BARREL/ comp problem

[belus]

On 11/26/2019 at 11:08 PM, yigal said:

Just did not mention that the efforts/forces  for these tools are different  from gun parts and the life of these tools is measured in minutes and not tens of thousands of cycles with impact like in guns.

 

8 minutes ago, yigal said:

different materials for mill cutters  and different hardness. and expected life for this cutters  measurements in minutes.

if u will make calculations for handgun impacts  u will discover that they much higher than u think.

 

I can buy that forces are greater in the gun, but material properties are measured with stresses which has a surface area quotient.  Your peak forces on a tool are spread across square microns and they get much hotter. I think the gun is a lower intensity system. It's also nice to have a high surface hardness from these coatings over a tougher interior metal.
https://imgur.com/gallery/mwmqEAo

An end mill has impact events every time a flute takes a bite. A 3/8" four end mill will typically have a spindle speed of 2000rpm when cutting austenitic steels, if I understood a bit of background reading correctly (https://www.the-carbide-end-mill-store.com/Feeds-and-Speeds.html). That's 500 impacts per minute per tooth, each taking a bite 0.002" deep. The coated TiN end-mills are advertised as lasting about twice as long as the non-coated examples, which is approximately what the table above says too. (lifetime in the paper attached above is measured in parts completed, not minutes and seconds)

[yigal]

gun is not work like mill cutter .and have different purpose than cutter.

Edited December 2, 2019 by yigal

[MikeBurgess]

1 hour ago, belus said:

 

 

I can buy that forces are greater in the gun, but material properties are measured with stresses which has a surface area quotient.  Your peak forces on a tool are spread across square microns and they get much hotter. I think the gun is a lower intensity system. It's also nice to have a high surface hardness from these coatings over a tougher interior metal.
https://imgur.com/gallery/mwmqEAo

An end mill has impact events every time a flute takes a bite. A 3/8" four end mill will typically have a spindle speed of 2000rpm when cutting austenitic steels, if I understood a bit of background reading correctly (https://www.the-carbide-end-mill-store.com/Feeds-and-Speeds.html). That's 500 impacts per minute per tooth, each taking a bite 0.002" deep. The coated TiN end-mills are advertised as lasting about twice as long as the non-coated examples, which is approximately what the table above says too. (lifetime in the paper attached above is measured in parts completed, not minutes and seconds)

Actually it will have 2000 impacts per minute (each flute cuts every revolution) you divide the feed by the flutes to get the chip load per flute. 

 

25 minutes ago, yigal said:

gun is not work like mill cutter .and have different purpose than cutter.

yes gun parts (ideally) should be floating on a film of oil and have very low surface loads, that's why blued guns last thousands and thousands of rounds, heck you can even get many 10"s of thousands of rounds on a aluminum framed gun.

 

 

 

[cecil]

my STI DVC's barrel has TIN coating on it... nary a scratch or evidence of any wear what so ever on the TIN coated barrel... seems pretty durable to me... who ever does STI's TIN coating knows what the heck they are doing....

[belus]

4 hours ago, MikeBurgess said:

Actually it will have 2000 impacts per minute (each flute cuts every revolution) you divide the feed by the flutes to get the chip load per flute.

Doh, thanks for catching that.