Help calculating feeds/speeds
Hello,
I have started using GWizard to calculate my feeds/speeds as well as DOC and WOC. I tried to run a job today which immediately resulted in a broken end mill. I am hoping to receive some advice as to why this happened.
I am using a Tormach 770 and a 1/4" TIALN 5 flute end mill (part number JHH2500V from here). I am cutting a 1.25" deep by 1" wide slot out of the corner of a piece of 2.25" square mild steel bar.
I have attached a screenshot from GWizard that has all of the settings that I used.
Thanks
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Last edited by icecats; 08-12-2018 at 04:47 PM.
Re: Help calculating feeds/speeds
Maybe it's just because I'm unfamiliar with Tormach's software but it looks like you're trying to do that entire cut in one pass which is definitely way too deep for that little end mill. Is the end mill serrated? The coating will definitely help. Are you using coolant?
Re: Help calculating feeds/speeds
0.625 DOC is way too much with that endmill unless you are using a trochoidal cut pattern and a spiral lead in. If you are using a conventional pocketing routine, then a DOC of about 0.065 is about all that end mill will take. You may have to reduce the feed a bit also.
Jim Dawson
Sandy, Oregon, USA
Re: Help calculating feeds/speeds
Axial depth of .650 is wayyyyy to aggressive with a quarter inch endmill. I would start by doing around .125 (axial @ half of diam), and move towards .250 axial. I don't usually do anything over full axial & full diam unless it's plastics.
Base your feeds and speeds off of the charts by the tool manufacturer, and go on the conservative side.
I would def make sure to do a spiral pocket. I try to put pilot holes in there when applicable, it will help preserve tool life.
Axial is DOC, Radial is WOC.
This is where I would start, but it's up to you. I always start on the conservative side until I know where the tools I order like to cut, then I start pushing limits and thresholds.
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