3D Milling in Bubblegum(1045)

[g huns]

We build big ole nasty injection molds. The softest material we typically deal with is high hard P-20, lower 40s Rc. A customer has decided that henceforth and hereafter, all their molds will be constructed of 1045. They claim a measurable benefit in thermal conductivity, whatever.

 

These molds are mostly for automotive cooling fans, so there's not many flat surfaces, but nothing terribly deep or steep either. Our traditional TiALN cutters are performing real bad. Wearing, bad surface finish, etc. 

 

I can tell you how to mill 62Rc D2, but I have no clue how to improve this.

 

Any other coatings, cutter geometry, etc I should be looking for? Or are el-cheapo, uncoated Niagaras my best bet? 

[crazy^millman]

Might check your SFM for it. Keep your chip load per tooth high and use inserted tools where you can for roughing. Keep trying to break a chip and might try running it dry verses wet and see if your tool life increases. I would assume you guys have been running a lot of stuff dry for years on the that hard material. Might even try aluminum 3 flute tools unoated for finishing and see if that helps, but would run with coolant with the percentage of coolant to the high side.

[betts]

That's what happens when the wrong people are making decisions.  Assuming they can measure this thermal conductivity, it alone is not the only variable to consider in mold design.  If temperature control is king there are many other ways to get it, in spades.

 

That being said, in my experience you may be beating your head against the wall trying to get a really good milled finish in 3D work.  Ron's suggestions are good but IMHO you get a little increase in old TIN coating over uncoated but I wouldn't be going out of my way to use it exclusively.  Again as Ron said inserted tools for roughing if you can and again the coating on those inserts could be TIN and not anything real expensive.

[g huns]

Yeah, we run most everything dry with airblast. Filled it up with coolant for this job. Doesn't seem to help much.

 

Roughing is not really a problem so far. The biggest problem we are having is with the 1/4 ball that finishes all the part areas, the blades of the fan. They laser the tool, run program, re-laser, and the tool has .003-.004 worn off the tip.

 

It's really more area than I like to see done with a 1/4 ball in one program. When I mentioned that, the guy who programmed it just threw up his hands and said, well it's always worked before. Yes, it has. For several dozen tools that were all made of P-20 high hard.   

[Rstewart]

Not to Hijack your thread buuuuut...

 

I feel ya!!  I'm getting terrible tool life on a 4140 43Rc production part at the moment.

 

I bought the best 1/16" endmills Harvey tool offers and even called them a few times.  I'm just not getting the tool life I Think I should be getting.

 

Been everywhere between 83 to 110 SFPM and .00025 to .00045 chip load per tooth- Shallow slotting (.018" deep)

[g huns]

Not to Hijack your thread buuuuut...

 

I feel ya!!  I'm getting terrible tool life on a 4140 43Rc production part at the moment.

 

I bought the best 1/16" endmills Harvey tool offers and even called them a few times.  I'm just not getting the tool life I Think I should be getting.

 

Been everywhere between 83 to 110 SFPM and .00025 to .00045 chip load per tooth- Shallow slotting (.018" deep)

 

SECOs line of solid tooling, Jabro, will eat it up. Kinda spendy, actually VERY spendy, but they cut sooooooooo nice. And there support guys are excellent.

 

Their options in inch cutters are also very limited, but if you can divide by 25.4, it should be OK.

[Matthew Hajicek - Singularity]

 

 

They claim a measurable benefit in thermal conductivity, whatever.

 

Huh.  I looked it up.  1045's thermal conductivity is almost double that of H-13:

 

H-13:

http://www.azom.com/article.aspx?ArticleID=9107#5

 

1045:

http://www.azom.com/article.aspx?ArticleID=9153#4

[g huns]

I bought the best 1/16" endmills Harvey tool offers and even called them a few times.  I'm just not getting the tool life I Think I should be getting.

 

Been everywhere between 83 to 110 SFPM and .00025 to .00045 chip load per tooth- Shallow slotting (.018" deep)

 

If I read my SECO book right, which isn't very likely : 

 

For slotting in that kind of material, a 1.5mm endmill with a .15 corner radius should be run with a .012'" DOC and a chip load of .0008". 33953RPM and 54IPM. That's 555SFPM .

 

I think...

 

I sometimes have trouble with math.

[balnh]

We had tool life issues with gummy stuff like kovar, 304, and my personal favorite niobium. We switched out our usual hocut for some new cimtech coolant. We saw immediate tool life and finish improvements. Off the top of my head I can't remember which cimtech stuff I think it's called 610 or something it's fairly new but supposed to shine on gummy crap. It's pricey but worth it