stainless steel

[cboys22]

I have a serious question I work for a small machine shop and our program writer is self taught and we are all taught through him here but my question is everytime he writes a new program for stainless he slows the feeds and speeds way down and our inserts and drills seem to wear faster and sizes are hard to keep consistant is there a reason why they have to be slow or could we run them at a higher rate just wondering thanks.

[Geof]

Generally stainless does have to be machined at a lower speed than plain carbon steel but often the feed should be higher. (Most) stainless tends to be very tough and abrasive and work hardens readily. Coated inserts, or milling cutters, specifically recommended for stainless should be used and run no faster than the manufacturer recommends, I tend to go much slower even down to half the suggested speeds. But always keep a good feed of at least 0.002" per tooth so you are cutting below the work hardened surface from the previous pass. With coated carbides using coolant is not always a good idea and a strong air blast should be used to clear chips and provide some cooling.

[Shane123]

maybe you should ask him why he programs slow? maybe he has been down that path and seen excessive tool wear due to lack of rigidity in the machine/clamping?

[cboys22]

We have Emco 340 and was wondering what are the normal feeds ans speed for 303 stainless steel and 316 stainless thank you.

[roninB4]

Originally Posted by cboys22 We have Emco 340 and was wondering what are the normal feeds ans speed for 303 stainless steel and 316 stainless thank you.

I can fully understand getting on here in search of information, I don't know everything either. What I don't understand is not being willing to look this info up on your own, preferring to let others spoon feed you the answers. This is such a basic question of speeds/feeds per material condition that I can't believe you're a machinist and wonder why you're in a machine shop (unless you're the investor).

This is not a question of tooling geometry, trouble holding tolerance, or which insert works well. This is the sort of question an office type asks, not a shop type. I really don't mean to be rude but if you're not willilng to do your own homework on something this simple then your question isn't really about proper speeds/feeds is it? It's personal isn't it? Get your own ammo.

[Shane123]

Originally Posted by roninB4 This is the sort of question an office type asks, not a shop type.

I had the same impression, hence why i asked why he didnt ask the guy who does this.......

As to the original poster, each tool you stock should have data sheets on them about the general cutting conditions. If your lead guy is slowing it down, he is most likely experiencing issues at higher rates and trying to save tool life. If you are comparing the speeds/feeds to what he programs other materials (such as mild steel), then you really should educate yourself on machining.

[christinandavid]

The programmer should only provide the initial speeds and feeds based on a combination of experience and technical data corresponding to the method and tooling being used.

These should then be refined by shop floor operators to suit actual conditions and priorities; what is the point of speeding up the program to save time/labour costs and spending more money on replacement tooling/reworking poor quality? It can take a few batch runs to achieve the correct balance.

It's good to know there are some pessimistic programmers out there and they don't all go straight in hell-for-leather at the manufacturers top-end in-a-perfect-world rate.

I would actually run everything slower speed-wise (and leave the feeds alone probly) if your tools are wearing out prematurely - recognise the difference between burn-out and chipping. You've got to bully the stuff off ideally - but that relies on having proper grade tools for the material - and a good set-up...

DP

[roninB4]

[QUOTE=Shane123;844303]I had the same impression, hence why i asked why he didnt ask the guy who does this.......

QUOTE]

-One of the things that got me was he didn't post the f/s, asks what "normal" is, but is able to decide that things have been slowed down and tools are wearing out prematurely. There are dozens of trolls that come on boards like this trying get others to spoon feed them the answers, rather than taking the time to learn like most of us have. So they solicit knowledge from others, profit from said advice, and then laugh at how stupid we are for giving hard won knowledge away for nothing. I like sharing my knowledge with others in the trade, the old men that broke me in insisted that I pass the knowledge on to the next generation. But trolls like this are the very guys that ruined the machine tool trade for the rest of us back in the 80's. Guard your knowledge wisely.


Christinandavid- that was a good reply, I fully agree with your asessment.

[roninB4]

There's another thread in this forum "First post" that sure sounds like this guy. He's just changed names (Ray D in the other thread) and thinks he's outsmarted us cuz we're just shop donks. Check him out.

[MikeZee]

Way to go!!!!!