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Author Topic: What is a good feed rate?  (Read 10148 times)

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Re: What is a good feed rate?
« Reply #10 on: October 27, 2006, 11:26:17 PM »
Hi,
I have a K2 cnc router too, it's a K2-2514 and I have been having problems with the stepper motors loosing there place, it seems like the get stuck and then get freed and start cutting again but out of place. I played with the acceleration and velocity and almost had them down to nothing.  With a tip from K2 I started using WD-40 on the leadscrews and it helped a lot but I was still limited, it still screwed up once and a while. I changed from Mach2 to Mach3 and that made a big difference as well, but I'm still not too sure about finding the sweet spot. What I've been told is to crank it up till it screws up then back it off until it stops screwing up, but I can't afford to do that it always does it at times when I don't want it to. Does anyone have any better way to find the limit for the machine?
I was thinking about building a router like the K2 models, 4x8 with 6in Z travel any tips?

Thanks,
Greg
P.S. try www.harveytool.com for small endmills for example .001 dia x .003 long or TiAIN coated 4 flute 1/32 ball for$22.20.
"Ideas have consequence" Ravi Zaccharias
Re: What is a good feed rate?
« Reply #11 on: October 28, 2006, 02:24:42 AM »
Greg,  Hello.  I had a lot of problems with my machine at first as well.  First question for you is,  you said that you had better results using Mach3 over Mach2.  Have you had any problems using Mach3?  Meaning, is it your CNC that is messing up or the computer/ software side of things?

- make sure that your electricity is adequate.  I had big problems due to the fact that I was using a long under rated extension cord for power.  Changing to a heavy duty and short cord made a huge difference for me.

- In Mach3 under motor tuning, what do you have for: Step Pulse & Dir Pulse?  By default, mine was originally set at 0.  And I was loosing steps which would get really bad over a period of 15 minutes or so of running a program to the point where the machine would be way off when I set it back to zero.  I inquired about it on this forum and was told to try setting these to 5 for each one.  Since then I have been running smoothly.  There was another guy who was having the same problem who eventually had to get some kind of an output signal booster because his computer port pins were not giving out a strong enough signal. 

Hope this info helps you out.
Re: What is a good feed rate?
« Reply #12 on: October 28, 2006, 08:25:39 AM »
Also run a driver test and see if you have a nice flat line :)
Fixing problems one post at a time ;)

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Re: What is a good feed rate?
« Reply #13 on: October 28, 2006, 12:30:12 PM »
I think its the machine side because if I run the machine at slow feeds in doesn't screwup but if I turn my feeds up it at random will screw up. I can run one program at high feeds and no mistakes then the next program will screw up at some time, sometimes it will not happen at all that day but on the next day it happens all day, it seems totally random.

I have everything running to one power bar, then into the wall, I have my computer, monitor,speakers, stepper box, router, light and fans running off the one power bar.  Do you think thats the problem? The only time I had a problem is when it lost it's location and then it slammed into the top of my aluminum work piece and it blew the breaker.

Step pulse is set to 6 and the Dir pulse is set to 0.

The Driver test this is what the screen said,
Pulse per Sec. in 25Khz Mode=23853
CPU Speed=1999
Apic timing constant=4192
and the line had some fuzz in it and it would go flat then come back and so on....the fuzz never went more than the line above or below.

Did your K2 Stepper box get very hot?

Thanks for the input!

Greg
"Ideas have consequence" Ravi Zaccharias
Re: What is a good feed rate?
« Reply #14 on: October 28, 2006, 03:30:59 PM »
Greg,   well I dunno.  I am not expert in these areas.  I was just relaying my experiences.  With my situation, the problems would occur more consistently so I was able to do things to make the problem happen, change something and then I'd know pretty quickly if it worked or not. 

How about when you shut your mechaine down, are you able to turn the axis easily by hand?  Does the problem always happen to 1 axis or does the whole thing freeze up?

I think that my stepper box gets a bit warm but not hot. 

Re: What is a good feed rate?
« Reply #15 on: October 28, 2006, 03:41:33 PM »
By the way,  anyone know if there is a particular file that I can back up to save all of my Mach3 settings?  I'm thinking of re-installing my OS to get a bunch of junk off the computer.  And would like to back it up just incase....
Re: What is a good feed rate?
« Reply #16 on: October 28, 2006, 04:24:19 PM »
Thanks for the reply, I just want let you know all the details just so I don't miss telling somthing that might be the problem. I think is screws up at random, I attached a few pics to show you want I mean. 

I can move the machine when the power is off with out a problem. 

I had to add fans to my stepper box because it was getting too hot to touch especially after long period of time, even if it wasn't running. 

What do you think of the Dir pulse being set to 0?

I wonder what Barker thinks of the Driver Test results?

Thanks,
Greg
« Last Edit: October 28, 2006, 04:26:31 PM by method13 »
"Ideas have consequence" Ravi Zaccharias

Offline Chaoticone

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Re: What is a good feed rate?
« Reply #17 on: October 28, 2006, 04:27:47 PM »
Hi Chris,
    I think if you back up your xml files. screen sets, and keygrabber profile you will have everything you need. Let someone else confirm though.

Also, I saw my machine acting weird one day that is was in a long run. The drives were hot. I cooled the drives off and it smoothed right out. I'm not sure this was the problem. Since then I have kept air going across the drives and have not seen that again. :) I'm building a cabinet this week with fans. The first box is very small, it was one I had laying around.

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

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Offline olf20

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Re: What is a good feed rate?
« Reply #18 on: June 10, 2007, 08:42:07 AM »
Hi all, just getting started in the wood engraving / routing end of CNC. Ger21 I was interested in your comments on feed rates etc.
What router motor do you recommend? I want to be able to take a log (12 dia x 30" length ) cut a large flat on it, then engrave lettering on it. My machine is a converted Atlas knee mill. I want to use a router instead of the 3hp motor.
Thanks for any suggestions!!!
olf20
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998
Re: What is a good feed rate?
« Reply #19 on: June 10, 2007, 01:30:00 PM »
Here is what I have found using my machine.  First, here is the machine: 

http://homepage.mac.com/bigvelvetdog/workshop-cnc.html

It is an older K2 and has the Hatachi 3Hp varible speed router.  I almost always run the router at full speed.  My most common setup is cutting alder or mahohany, sometimes with a hardwwod top like maple with a .5" 2-flute straight bit.  I typically do rough cuts a 75 IPM.  Precision cuts at 50 IPM or less.  If I am just skimming the surface I may run at 100 IPM.  And If I am using tiny inlay bits I run at about 15 IPM. 

In a nutshell,  this is what works for me on my machine.