Messages

1

General Mach Discussion / Re: What is a good feed rate?

« 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.

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General Mach Discussion / Re: increased speed equals bad corners

« on: March 16, 2007, 03:01:10 PM »

Quantum sounds really cool.  Probably just what the doctor ordered for my applications.  And lots of others.  But I think I'll wait for a final release.  It would cost me too much time and $ if I use something that still has glitches.

I am pretty much using Mach3 with its default settings.  I got it up and running easy enough and my focus has been on learning the CAM software.  So are there any other suggested changes to setting in Mach3 that I should consider?  Do most people run in CV or Exact Stop mode?  Are there any other settings that could be tweaked to make performance or accuracy better?  I think I need to go back and watch the setup videos again now that I have a better understanding of the software and machine.

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General Mach Discussion / Re: increased speed equals bad corners

« on: March 15, 2007, 04:18:11 AM »

Well after increasing the acceleration from 8 to 25,  I am now getting accurate cuts at 100 IPM.  Though I may experiment with switching to exact stop mode by editing the G-code for some parts of the process.  But i have tons of files and don't really want to edit all of them.  I'll try that on one of my most popular guitar bodies and see how it works out.

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General Mach Discussion / Re: increased speed equals bad corners

« on: March 14, 2007, 04:39:28 PM »

Brett,  I just switched to Exact Stop mode and ran the perimeter of a guitar body.  The thing is that going around the wide curves of the body, it is moving in very tiny increments.  I can see how this may be more accurate for pockets but it seems to be very slow and jerky type of movement.  Would there be any way to program this type of movement into the G code for the pockets and constant velocity for other portions of the guitar like the perimeter?

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General Mach Discussion / Re: increased speed equals bad corners

« on: March 14, 2007, 04:28:18 PM »

Brett,  I  saw that option but have not tried it yet.  Does this mean that it will go to and stop at every location?  Sounds like this may be more accurate but time consuming.  I'll try this as well and see what happens.

6

General Mach Discussion / increased speed equals bad corners

« on: March 14, 2007, 03:13:51 PM »

I have been asking around about feed rates and the info I have seen pretty much says to cut at the highest feed rate possible before breaking the router bit. Well I have been increasing my feed rates little by little.  I am making guitar bodies.  Shaping like tummy cuts and carve tops can probably get away with a little inaccuracy but neck pockets and cavity covers need to fit exactly.  I have cut many guitar bodies now at feed rates around 50 to 75 IPM.  These have been cutting properly, no problems.  But as I have increased feed rates up to 100 and 150 IPM,  I am now getting sloppy corners. 

Example:  In a square neck pocket with a .5" bit.  The first corner where the bit plunges in looks exactly as it should with a .25" radius corner.  The other corners that the bit travels through look more like .3" to .35" radius corner.

What I am wondering about is under Motor tuning - Acceleration.  I had this set at 8.  If I bump it up to 20, it seems that I get less deceleration going into a corner.  I am thinking that with the lower acceleration one axis is starting its move before the other axis is reaching its full position. 

I am going to run some tests on this but any thoughts on acceleration or anything else that may be affecting this? And are there any drawbacks to using too high of an acceleration?  I will say that the movement seems a lot more jerky and maybe could be harder on the motors and parts?...

7

General Mach Discussion / Re: What is a good feed rate?

« 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....

8

General Mach Discussion / Re: What is a good feed rate?

« 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. 

9

General Mach Discussion / Re: What is a good feed rate?

« 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.

10

General Mach Discussion / Re: What is a good feed rate?

« on: October 24, 2006, 01:17:53 PM »

I'll pass on another link for router bits.  -  http://drillcity.stores.yahoo.net/  -  drill bit city seems to specialize in small sizes.  I get my 1/32" there for my inlay work and these sizes are hard to find. 

By the way,  I kicked my "velocity" up to the max which was 150 in Mach 3.  The machine seems to run fine at that speed for jogs.  Although 50 IPM seems like a good cut rate and I probably won't go any higher.  But its nice to be able to jog the router out of the way quicker...  But I am surprized that 150 is the max.  Don't know if I am missing something, and I don't think that I need anymore speed then that, but I assumed that faster speeds would be possible.