[karandex]

what is max your cnc's max feed rate
i need to know what feed rate can be achived from acme threds
my current machine runs at 300 mm/min, the motors are about 5kg torque as they are running on 12v.
how many times feedrate should i get if i go for acme rods?

[mlabruyere]

I have 1/2-10 5 start lead screws. I am running 620 oz/in steppers on the X(dual lead) and Y. I am running a 282 oz/in on the Z.

My rapids are set at 400 IPM (X and Y) but I can run at 800 IPM but I don't need that much speed so I limit it.

[louieatienza]

I have 1/2"-8, 8 start ACME screws, direct driven from 425 in oz steppers. I use a timing belt to drivev 2 screws on the x axis. I get 275ipm (about 7000mm/min) on the x and 375ipm (9500mm/min) on the y, rapids. The fastest I ever used for wood was 160ipm at 1/8" doc, and 1/8" bit. The fastest for aluminum 75ipm at 1/4" doc (pocketing.) I've cut plastic at over 60ipm if edge finish is not a concern, though it still cuts pretty cleanly.

[JC1]

I'm not arguing at all, but I was under the impression that high feed rates were damaging to the Acme nuts? I read a post while browsing around here on 1/2-10 5 starts saying max was around 150ipm?

If I'm wrong, that's great I'll crank it up, but I hate destroying things.

[mlabruyere]

I'm not arguing at all, but I was under the impression that high feed rates were damaging to the Acme nuts? I read a post while browsing around here on 1/2-10 5 starts saying max was around 150ipm?

If I'm wrong, that's great I'll crank it up, but I hate destroying things.

You might have seen someone write that....who's to say. I know what I am running at and I've been running at those rapids for more than a year. I can actually go much faster but I keep it lower as the lead screws will whip.

[JC1]

I bet this might come down to the nuts you're running? What nuts are you running on your setup? I'm running dumpstercnc nuts which seem undersized, but I'm pretty new at this, who's to say aside from more experienced folks?

You might have seen someone write that....who's to say. I know what I am running at and I've been running at those rapids for more than a year. I can actually go much faster but I keep it lower as the lead screws will whip.

[mlabruyere]

These are the ones I am using on my large machine:
CNCRouterParts

I am going to use these on my smaller CNC since I want better resolution and I don't need to speeds:

CNCRouterParts

[CarveOne]

I'm not arguing at all, but I was under the impression that high feed rates were damaging to the Acme nuts? I read a post while browsing around here on 1/2-10 5 starts saying max was around 150ipm?

If I'm wrong, that's great I'll crank it up, but I hate destroying things.

Max for THEM may be 150 ipm, depending on the quality of their lead screws and drive system, but I'm sure that others here run them faster. Using a little dry teflon spray lubricant on the lead screws reduces friction and helps reduce rust formation. Using low quality lead screws may be wearing out the nuts due to rough edges on the screw threads. $10 single start ACME screws I have used were not polished, just utility grade stuff not well suited for CNC work.

CarveOne

[ger21]

I run my 1/2-8 2 start with Dumpster nuts at 190 ipm, which is 760 rpm. Been running it almost 2 years with no problems. I do oil the screws with a light oil, though. As long as you don't let them get hot, there should be no problems with them.
I've found that oil is much better than dry lubricants.

[mlabruyere]

I run my 1/2-8 2 start with Dumpster nuts at 190 ipm, which is 760 rpm. Been running it almost 2 years with no problems. I do oil the screws with a light oil, though. As long as you don't let them get hot, there should be no problems with them.
I've found that oil is much better than dry lubricants.

I tried oil but the dust turns to goobers all over and in my lead nuts....hasn't affected anything but it does make me worry....

Now I clean everything down everytime I run it....takes a long time. I need to get some kind of wipers built.

[mouch]

I run my machine (1/2-10 5 starts) at 250ipm, no problems.
Could run it higher but thats more than fast enough for me.
Ive ran it at 500ipm but the screws do start to whip alittle.

[ger21]

I tried oil but the dust turns to goobers all over and in my lead nuts.......

Mine don't get any dust on them, the dust shoe gets it all. I use pneumatic tool oil, which is very thin, and only use about 5-10 drops, so it's not like they're dripping in oil.

[CarveOne]

The dry, wax, Teflon type spray lubricants go on wet and then dry off in a few minutes. The Teflon and wax remains as the lubricant. With use, you may see little curls of a tan waxy substance coming out of a DumpsterCNC anti-backlash nut but it isn't the black Delrin plastic wearing. That will stop after a while. Just clean it off with a small brush. Once the screws and nuts have this stuff embedded in them you will not need another application more than two or three times a year.

MDF dust that settles on bone dry screws will turn to goobers too, if the humidity is high.

CarveOne

[PaulRowntree]

The attached document from NookIndustries describes the speed limitations on ACME screws, and shows the max speeds (ie limited by whipping) according the shaft diameter and supporting geometries, as well as a lot of good design points. Check out Pages 10,11.
I am not affiliated with NookIndustries and take no responsibility for this information provided.
Cheers!

[karandex]

i think i am going to get single start ones, what is the good tpi for single start for moderate speed ( 12inch by 12 inch bed) and accuracy for pcb at 16 microstep. what speed i will get

[JC1]

The dry, wax, Teflon type spray lubricants go on wet and then dry off in a few minutes.
CarveOne

Would you recommend a particular spray that you like or should I just go shopping for anything claiming Teflon dry lubricant and be ok? I ran a little bit of white lithium on my acme screws and the wiped them down fairly well. This helped things run quite a bit smoother and I've got them up to 300 with no heating in the nuts under normal use (if I run them back and forth constantly for a few minutes the lead nuts do get a little warm)

[CarveOne]

Would you recommend a particular spray that you like or should I just go shopping for anything claiming Teflon dry lubricant and be ok? I ran a little bit of white lithium on my acme screws and the wiped them down fairly well. This helped things run quite a bit smoother and I've got them up to 300 with no heating in the nuts under normal use (if I run them back and forth constantly for a few minutes the lead nuts do get a little warm)

Anything claiming to give similar results should be ok. Garage door spray lube is similar.

The one I use that was recommended by a forum member a couple of years ago is labeled "Dupont Teflon Multi-Use Dry, Wax Lubricant" in an 11 ounce spray can purchased at Lowe's. One can lasts a long time.

I used white lithium grease on my first machine until I saw the above recommendation. The white grease turns black after a while and will transfer to anything that touches it. I would get it on my shirt while working on it (but not running of course). White or black it is hard to get it out of clothes. The Dupont lube doesn't do that.

CarveOne