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Post by jreimers on Sept 4, 2017 17:46:32 GMT
Is it just trial and error to determine Feed and Speed and Step Over? Or is there some reference out there in layman's terms that can guide me?
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Post by Derek the Admin on Sept 4, 2017 19:41:14 GMT
Experience helps a lot, but give me an idea of what materials you want to cut and we can talk about it.
You are after a certain chip load. Too much and you break the cutter (and overload the machine in the process), too little and you overheat the end mill, dull it prematurely, and cause it to stop cutting.
Chip load = Feed Rate / (RPM x # of cutting flutes).
You'll see a lot of chip load charts say different things on the internet. These charts are usually written by a cutting tool manufacturer with the intent of their specific, purpose built cutting tools being used on industrial machines that can handle extreme forces and also make cutting feeds at 500+ inches per minute. As such, you often need to derate them a good amount. I like to hit around a .0008" to .00175" chip load in things like aluminum with a 1/8" end mill. With a 1/4" end mill I like to hit between .0015" and .0025" in aluminum. In something like MDF I might go .002 to .003 with a 1/8" end mill and a .0025 to .004" chip load with a 1/4" cutter. Now, it's not as though the end mill is going to just burn up if you go below these figures. I've gone below them many times. It's important not to go too low, however, because you'll end up rubbing instead of actually shearing a chip away and dulling the edge. Eventually, you might as well be spinning a spoon against the material.
Step over and depth of cut will also be determinants of the cutting forces experienced. A deep full slot cut at a high chip load might not go so well. Alternatively, a shallower full slot cut load at a moderate chip load might be appropriate. Step-over is also important for surface finish on the bottom of pockets. Smaller step-overs will result in a better finish on your pocket and higher resolution on 3D carvings.
Hope that helps.
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Post by aforww on Sept 5, 2017 1:12:55 GMT
I finally went ahead and bought G-wizard. I got tired of playing the guessing game. Although using GRBL 1.1 and UGSp with the on the fly feed adjustment makes guessing easier, I still like G-wizard.
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Post by andrew on Sept 5, 2017 18:38:13 GMT
The whole grbl 1.1 thing... Is that something you can just flash to an M3 and it will just work? Or is there more to it so it works with the M3? With the earlier versions and the stuff on the resource page there's multiple things to take into account to get the right one.. homing switches, no homing switches, laser, spindle, etc.. Is this the same with 1.1?
I'd like to give it a shot because adjusting the feed on the fly sounds interesting (struggling with that right now on a project I'm trying to cut). Have been using UGS platform lately but with the older version of grbl that came with the machine.
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Post by aforww on Sept 5, 2017 23:25:12 GMT
The whole grbl 1.1 thing... Is that something you can just flash to an M3 and it will just work? Or is there more to it so it works with the M3? With the earlier versions and the stuff on the resource page there's multiple things to take into account to get the right one.. homing switches, no homing switches, laser, spindle, etc.. Is this the same with 1.1? I'd like to give it a shot because adjusting the feed on the fly sounds interesting (struggling with that right now on a project I'm trying to cut). Have been using UGS platform lately but with the older version of grbl that came with the machine. You will just have to change the GRBL configuration to what you flashed from MillRight. Just type $$ and copy all those values. Save them to a notepad file. Flash latest GRBL and UGS-Platform. Once you open up UGS type $$ again and start changing parameters to match what you copied from stock. Easy peasy. It's handy to know what all these settings are as once you are comfortable with them, you can change things as you see fit. You can change your limit switch bounce off, mines 3mm now, maximum machine travel distances if you move you limit switches, adding soft or hard limits, etc. Don't change things until you have a good understanding of how things interact with each other though. Plus side, it's anything you can't easily fix as long as you change one variable at a time. |
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Post by andrew on Sept 6, 2017 15:32:04 GMT
Right on, thanks for the info. Will give it a shot! Did discover that I really need to tighten my X axis belt which I now think is causing most of my trouble with what I thought might just be a speed feed thing.. Thanks again for the info on 1.1, much appreciated.
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