Is 1000 rpm too slow?

[HereinCS]

My screws have a 10mm pitch. Is 1000 rpm too slow? That translate to 10,000 mm/minute, right? or 10 meters/minute, or around 400ipm. Is that considered fast or slow? Should I go for a faster motor?

[LeeWay]

Not too slow. That is on a mill. I use 10mm screws with direct drive couplings on my mill and it will flat scream speed if I wanted. Way too fast. On a router, depending on material being cut, that should work great. Not sure on the math. Sounds about right at first glance though.
I think you will need to do some testing. Torque or strength is just as important as speed. Depending on the bearings and the weight of the axes and what you cut, speed may be the least of your issues.

[mactec54]

HereinCS

What type of rails are you going to use,The one I showed in the video has 400w motors geared down to almost 3/1 but he has 20mm pitch screws, Rod to can easily hit the 400IPM, but it is to much for his machine to go that fast, check to see what the max RPM your ballscrews can take for there length, without flexing/whipping, this will tell you how fast you can turn your screws,Then you have to make your machine ridgid/strong enough to go that speed

[HereinCS]

Originally Posted by mactec54 HereinCS What type of rails are you going to use,The one I showed in the video has 400w motors geared down to almost 3/1 but he has 20mm pitch screws, Rod to can easily hit the 400IPM, but it is to much for his machine to go that fast, check to see what the max RPM your ballscrews can take for there length, without flexing/whipping, this will tell you how fast you can turn your screws,Then you have to make your machine ridgid/strong enough to go that speed

My x axis screw has a max rpm of 2250. I assume similar max in the y axis.

BTW mactec54, I'm looking at the dmm servo package after reading all your posts! Are they still working well? I noticed that you went with the 400w motors. I'm trying to decided between the 400 and 900w motors. I don't mind too much power, as long as it doesn't screw things up some how. So you went with the 400 then geared down 3/1, which makes it essentially as torquey as a 900w right? Can I as why you didn't just buy the 900w and save the trouble? I also notice that I have not seen anyone direct mount their servo motor to a ballscrew. Is it harmful to the motor?

[mactec54]

HereinCS

It is not my machine, it is a business friend that I have helped him setup his system,I'm testing some on a knee mill as well,Rods machine was geared down because of the 20mm pitch screws,If the motors were direct drive it would of been just over 2,000IPM !!! so way to fast for his machine, With the larger motors I don't think you will have any problem going direct drive on your 10mm screws, (Alignment of the 2 shafts have to be very accurate), For working well, Rod runs his machine every day, we need more people on the Zone to be using this system, It is way better than any stepper system & there is more good stuff in the works for this DMM system as well

Another reason I like the 400w motor, on 10mm screws at 2/1 gearing you would get 590IPM as to the direct drive 900w motor you will get 393IPM, it just depends if you want & can use more speed, & your machine can take that extra speed

[HereinCS]

Thanks. I just bought the kit with 900w motors. I figure that 390ipm should be ok. I can always gear it 1:2 to get more speed right?

[Al_The_Man]

Originally Posted by HereinCS I can always gear it 1:2 to get more speed right?

Twice the rpm, half the torque, and 4 times the load to motor inertia ratio.
The latter of which will cut or reduce your maximum possible accel/decel rates x4.
Al.