Need Help!- Possible Mach 3 problem on Legacy Mill

[RADCO]

Hi,

Please go easy on me here guys! I am completely new to CNC controlled machines and I am trying my best to learn what I can but I am basically just a carpenter here.

I bought a CNC controlled wood mill from Legacy. It has three motors which drive feed screws for the X,Y,Z axis'. While running a long G code from Vector art 3D I noticed that the mill was not keeping in alignment with the project. This was noticable within the first 5 min of run time.

Listening to the mill run I noticed that the motors (especially the X,Y drives) were not running smooth at times. They almost sounded like they were stuttering or that they were trying to go CW and CCW at the same time. It is hard to explain but I knew it was not right. I disconnected all the drive screws and carriage plates from the motors to see if I had a mechanical problem, but this was not the case.

I do not know if MACH 3 is the same for all machines but there is a way to tab up a controller on screen to drive any axis you want. The motors run fairly smooth during this only glitching randomly every 20 seconds or so of straight run time. When I go to a program though the glitches are more frequent and severe.

The worst situation (again assuming that most MACH 3 programs are alike) is when I go to the "settings alt-6" tab and choose the "set steps per unit" feature on the screen that comes up. This is a command that allows the user to check for accurate travel by telling the machine how far to drive a feed screw and then measure the result. Well when I program any kind of number in for my X,Y or Z axis into the command box the motor that gets driven jumps, stutters, freezes and kicks like there is a war going on inside. I actually hit the reset button just to shut it down.

Is there anything that anyone can think of that a layman like myself can check? Why would the same drive motor act differently when being driven by different methods from the same program (tab=smooth, program=mild, set steps=severe)? I am not getting much info from Legacy and they don't know what to tell me.

I bought this 15k machine for my business in a bad economy and I have work to do but can't get this thing to run. Any information would be appreciated since I do not know where to turn. If I am in the wrong forum please forward this to anyone you can think of that may be able to help. Thanks again
-John

[ger21]

Did you supply the PC, or did it come already set up with the Legacy? It sounds like the velocity or acceleration are possibly set too high. You set the velocity and accel under Config>Motor tuning. What are your current settings? I'm not familiar with your machine, so really can't help you too much. Legacy should be able to tell you what the settings should be.

Or, perhaps the feedrate in the g-code is too high. What feedrate are you trying to run at? Try lowering the settings by 20%. Write down everything you change, so you can change it back if you need to. Once set, you really shouldn't be playing with the steps per unit. That's really for initial set up only. And btw, when you hit the tab key, you bring up the jogging controls. When you move that way, you're jogging the machine.

[RADCO]

Hi Gerry,

I bought the PC myself based on what Legacy required. I did have to get some kind of "patch" to make Mach 3 run with Vista because Dell refused to put XP on this unit.

I am having problems getting answers from Legacy. I was expecting this to be much more user friendly and I have even offered to pay for training from them. This is a big investment for a small guy like me and right now this is a giant paperweight. I truly believe that I will have to solve this problem with outside help from people like yourself and this CNC forum. I am just concerned that I am going to get in over my head with all these new terms. Anyway back to your post.

I did find the velocity settings and generally set everything at the halfway point. This did not make any change in my problem velocities were lowered but the jamming of the motors still occured. The G code for the program I was trying to run comes from a company that Legacy recommended and it was supposed to be set for this machine. I do not believe that the program was running too fast for the unit. Besides this would not explain the absolute horror that happens when I try to use the set step feature.

I agree with you that it is a set up only feature, but it was recommended by legacy on a set of "youtube" videos that they have online. They wanted me to check for proper step control but when the machine is told to drive the motors that is when I get the worst motor control/feedback ever. It is nothing like what is shown on the video and I am unable to do this initial setup to calibrate the machine.

I still do not get why I can Jog (tab) the machines motors and they run so smoothly but any program or set step commands make them freak out. Can you explain what Kernal speed is? At one time I got an error message saying that my speed was going to exceed my kernal speed settings. I can change that value but I do not want to until I know what I am doing. I have a pretty powerful computer which is dedicated to my CNC machine.

Thank you for brainstorming this. I am currently watching some Artsoft videos that are showing some Mach 3 features. I am also going to try and find a local G-code and Mach 3 class to go to. Please write with any other ideas.
-John

[ger21]

Ask on the Mach3 forum. You'll find more people that can help you. My guess is it's possibly a PC issue. Have you run drivertest.exe in the Mach3 folder? Try it, and see what the results are. You should see a flat line with little or no spikes.

[Kipper]

Within Mach click Operator/check config....it'll tell you if the core frequency etc is off.

Never used Vista ;puke;

[RADCO]

Hi,

I will try both suggestions and I will also move this post to Mach 3 forum.

I did run the driver exe as requested by legacy but they did not tell me what to look for. I remember that during it there was this thin black line which occasionally spiked to the point that there was a solid 1" strip across the screen then it went back down to the thin line with smaller less frequent spikes. I do not know what to make of this and when the test was over there was a message that said test complete but it did not display any kind of report.

-John

[ger21]

The 1" wide line is bad. A good result is a thin line with little to no spikes. As I said, I think your PC is causing the problem.