First off, thanks to all the members on here, I've read countless posts and learned so much. I have the relatively new PocketNC V2-50, so it is difficult finding information relating to such a small machine. Here are the machine basics:
*0.268HP
*Spindle speed of 1,000-50,000
*Feed rate limit of 60ipm
*Shank diameter limited to 1/8"
I eventually plan on milling carbon steel, but starting off with 6061 Aluminum. I'm only using Harvey Tools designed for aluminum, best coating available, and I've tried ball mills, square center-cutting mills, and corner radius end mills, all ranging in 0.093" to 0.125" cutting diameter. I've tried to use the shortest length tools possible for rigidity. I'm having issues breaking tools relatively quickly. I've immersed myself in cutting parameters, but I'm still struggling immensely, even while utilizing Bob's GWizard. The only luck I've had is with a relatively shallow cut (40%) with a light step over (20%) at the recommended RPM for the tool diameter (0.093" diameter = 40k RPM). In this particular instance, I was feeding at a full 60ipm, but the resulting chip load was nowhere near Harvey's recommended roughing settings for that tool (likely closer to 1/10th). At that RPM, the tool burned out in less than 2 hours of cutting, and it was only removing a modest 2.5 cubic inches per hour; in hindsight, I can see how the tool was likely rubbing and the heat from that killed the tool.
Using Bob's GWizard, a 1/8" 3F ball mill (with 0.187LOC, total length of 1.5" which I set for a stickout of 0.75"), with my machines specs, called for 26k RPM with a full 60ipm at a specified DOC of 90% and WOC of 10% (in an attempt for HEM). I backed off all ramping & lead in/out rates to 5ipm. After helix ramping, the tool snapped before even getting toolpath cutting going. Reloaded a new tool, backed off the settings to 10k RPM and 53ipm, snapped her right off in the same fashion. And yes, I carefully entered ALL information (even advanced specs) for the tools & my machine into Bob's software, but obviously something is off there (which is incredibly frustrating considering I paid for the software and it resulted in $75 of broken tools right off the bat). I've tried so many recommended settings otherwise, using the "standard" basic equations and Harvey's recommended SFM (1000), and WOC & DOC for roughing for whatever particular tool I was using, to no avail. Again, it's tough to find information for similar issues for machines this size/power/spindle capabilities, because there just aren't many out there. I just don't understand where I'm going wrong. Yes I could probably back off settings until the MRR is to the point where I'm throwing up aluminum dust, but I would like to achieve Bob's balanced "sweet spot" of good tool life and decent MRR. Tearing my hair out (whatever I have left anyways). I feel like I've studied, read, and have a great understanding of machining basics (relatively anyways), and I'm getting nothing but broken tools. Oh, I'm using Fusion 360 for CAM at the moment if that matters, heading to HSMWorks soon though.
*0.268HP
*Spindle speed of 1,000-50,000
*Feed rate limit of 60ipm
*Shank diameter limited to 1/8"
I eventually plan on milling carbon steel, but starting off with 6061 Aluminum. I'm only using Harvey Tools designed for aluminum, best coating available, and I've tried ball mills, square center-cutting mills, and corner radius end mills, all ranging in 0.093" to 0.125" cutting diameter. I've tried to use the shortest length tools possible for rigidity. I'm having issues breaking tools relatively quickly. I've immersed myself in cutting parameters, but I'm still struggling immensely, even while utilizing Bob's GWizard. The only luck I've had is with a relatively shallow cut (40%) with a light step over (20%) at the recommended RPM for the tool diameter (0.093" diameter = 40k RPM). In this particular instance, I was feeding at a full 60ipm, but the resulting chip load was nowhere near Harvey's recommended roughing settings for that tool (likely closer to 1/10th). At that RPM, the tool burned out in less than 2 hours of cutting, and it was only removing a modest 2.5 cubic inches per hour; in hindsight, I can see how the tool was likely rubbing and the heat from that killed the tool.
Using Bob's GWizard, a 1/8" 3F ball mill (with 0.187LOC, total length of 1.5" which I set for a stickout of 0.75"), with my machines specs, called for 26k RPM with a full 60ipm at a specified DOC of 90% and WOC of 10% (in an attempt for HEM). I backed off all ramping & lead in/out rates to 5ipm. After helix ramping, the tool snapped before even getting toolpath cutting going. Reloaded a new tool, backed off the settings to 10k RPM and 53ipm, snapped her right off in the same fashion. And yes, I carefully entered ALL information (even advanced specs) for the tools & my machine into Bob's software, but obviously something is off there (which is incredibly frustrating considering I paid for the software and it resulted in $75 of broken tools right off the bat). I've tried so many recommended settings otherwise, using the "standard" basic equations and Harvey's recommended SFM (1000), and WOC & DOC for roughing for whatever particular tool I was using, to no avail. Again, it's tough to find information for similar issues for machines this size/power/spindle capabilities, because there just aren't many out there. I just don't understand where I'm going wrong. Yes I could probably back off settings until the MRR is to the point where I'm throwing up aluminum dust, but I would like to achieve Bob's balanced "sweet spot" of good tool life and decent MRR. Tearing my hair out (whatever I have left anyways). I feel like I've studied, read, and have a great understanding of machining basics (relatively anyways), and I'm getting nothing but broken tools. Oh, I'm using Fusion 360 for CAM at the moment if that matters, heading to HSMWorks soon though.