Lesson For today

Dan Noren

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6,762
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falcon heights, minnesota
50 ft/min?! you trying to set some sort of speed record don? hopefully you're not trying to do it all in one pass. slow those feet down to inches, and several passes for a clean cut, depending on the thickness of material. you may have a tank for a cnc machine, but you cannot drive it like one...
 

Don Baer

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Staff member
50 ft/min?! you trying to set some sort of speed record don? hopefully you're not trying to do it all in one pass. slow those feet down to inches, and several passes for a clean cut, depending on the thickness of material. you may have a tank for a cnc machine, but you cannot drive it like one...
It all about units... the lesson is pay attention to the unit you are using when you set up the program and don't confuse inches with feet...lol. This machine is way way over sized both in axis drives and in spindle. It could be geared way down and use smaller motors and still have plenty of torque. It will plunge a 1/4 inch bit into material at 50 FPM with a spindle speed of 18000 RPM and not even hesitate. :oops: :oops: When I turned it on the first time and did some moves the default parameters had it doing rapid move at over 2000 inches per minute. I turned it down to 1000 ipm and now I think I'll just turn it down again to 500 IPM. 1000 IPM is over 83 Feet per minute.
 
Back when I had my shop I went to the wood show in Atlanta Ga and Andi had a machine there cutting at 3000ipm that thing screamed and I cant remember the name of the other company but they were demoing their machine cutting plywood with a 1/4" bit at 3000 ipm also. My Andi would cut all day long at 400 to 600 ipm I normal ran at around the 400 mark
 

Don Baer

Moderator
Staff member
Back when I had my shop I went to the wood show in Atlanta Ga and Andi had a machine there cutting at 3000ipm that thing screamed and I cant remember the name of the other company but they were demoing their machine cutting plywood with a 1/4" bit at 3000 ipm also. My Andi would cut all day long at 400 to 600 ipm I normal ran at around the 400 mark
If I had a production shop I would want my machines running at the fastest possible speed to but my little shop is just a hobby. the Machine is only got a max travel of 49 inches in x and 25 in Y so at 1000 ipm it would take it 3 second to go full travel. for my purposes slower is better, easier on the machine, easier on the tooling and easier on my nerves. If it takes my 60 minutes to run a program verses 20 minutes it really is no different, I got all the time in the world. I feel real comfortable at 50 ipm but 50 FPM is down right scary. I will crank the feed rate up to 150 ipm if I dry running a program to check it out but when it comes to making chips it's slow and steady.
 

Leo Voisine

Member
Messages
3,987
Location
East Freeetown, Massachusetts
50 FEET per minute is 600 IPM. I believe a RIGID machine should be able to do that, but that is pretty fast. By Rigid - I mean more rigid than my machine. Something commercial or industrial.

I cut some WALNUT at I think up to 500 IPM with a 1/2 end mill. I have a video on that. That was just flat facing.

Normally I don't cut much over 250 even though I can. It depends on what is being done. Acel and Decel and constant velocity and other settings can have some significant effects on curves and corners.

I can cut at 500 IPM all day long, but it may not be pretty. Then again I am still learning about the settings in Mach-3

I do stuff to get paid, but on such a low level that I really don't need to be really fast. I can do some gardening while the machine is running.
 
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