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Hardcutting 3D surfaces in h13 at 55RC

KevintheCrawdad

Plastic
Joined
Feb 20, 2021
Sup ya'll,

Im currently tackling some hard cut surfacing on some hot stamp die details I made last week, and quite honestly haven't had much experience in this area. The majority of the harcutting I've seen done was programmed by a colleague of mine. Here's what I have to work with: A reasonably large selection of solid carbide ballnose cutters in addition to a .750 inserted ballnose cutter from dapra cutting tools. My question is this, is there a general rule of thumb in regards to establishing proper speed and feed? We are all aware that tool wear is a concern over large surface areas, and I'd like to mitigate this as much as possible so that the surfacing can run overnight with the supervision of one of my operators. Any and all suggestions, experiences, tips, and tricks would be greatly appreciated in an attempt to better understand the process. I'm happy to answer any questions that would warrant better responses via commentary!

Cheers!

Clawdaddy
 
Yeah, more info would help. But I have cut tons of H-13 in the hard state. Cuts beautifully, actually. surface finish is the bomb. I would start with 200SFPM and about .003 chip load. Speak with your tool supplier though, especially for that inserted cutter. I used an Iscar .750" 2 flute insert cutter with a .06" corner radius. They were Cham-mills back in the day. These worked great for roughing mold cores and cavities. We would put all the screw holes and water lines in, then harden them. Rough and finish hard. Detailing then commenced with .500, .250, .125 all they way down to .015" cutters.

Paul
 
How much stock removal?
Aer you finish profiling? Need more info!

So the skinny is this. I have a couple of areas that require hardmilling. The largest of the sections is the top form of the die detail itself in all of its sweeping, curved splendor. This is where the ballnose is doing a majority of the work by means of a parallel plane machining strategy (I program with esprit though I'd imagine parallel plane toolpaths are about verbatim regardles of CAM platform). Ended up running that inserted ball at about 6k rpm with a .008 stepover, followed with subsequent remachining.

I also have a couple of profiles that I will cut with the flank of a .750 Helical Bullnose Endmill, these cutters i'd usually run at about 150 sfpm with a chipload of anwhere between .0015 and .003

I guess my largest curiosity lies in general rules of thumb for finishing strategies with ballnose cutters in materials of similar hardness. Hope this helps
 
So the skinny is this. I have a couple of areas that require hardmilling. The largest of the sections is the top form of the die detail itself in all of its sweeping, curved splendor. This is where the ballnose is doing a majority of the work by means of a parallel plane machining strategy (I program with esprit though I'd imagine parallel plane toolpaths are about verbatim regardles of CAM platform). Ended up running that inserted ball at about 6k rpm with a .008 stepover, followed with subsequent remachining.

I also have a couple of profiles that I will cut with the flank of a .750 Helical Bullnose Endmill, these cutters i'd usually run at about 150 sfpm with a chipload of anwhere between .0015 and .003

I guess my largest curiosity lies in general rules of thumb for finishing strategies with ballnose cutters in materials of similar hardness. Hope this helps

In addition: I'm scraping off a little over .010 due to thermal expansion I presume
 
Those Dapra inserted guys like to eat. Used to rough (soft) A2 D2 S7, etc with somewhere around 250ipm, 10k rpm, with 1/8" doc.
 








 
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