[Magnetboy]

Hello Everyone,

I have recently started to learn both BobCad and MACH 3 software. My questions involve the MACH 3 software. I understand the DRO and the coordinate systems, and I have a pretty good feel for all of the controls/buttons. My questions are the following:

1) Are the soft limits arbitrary values which are set based upon the work envelope of my milling machine? In other words, can I change my soft limits if need to do so in order to accomodate larger workpieces? Right now my soft limits are only 100mm x 100mm. My mill has a larger work envelope than that. I do realize that I have to restart the software if I change these values, but if I DO change the soft limit values, how do I correctly correlate them to the same position of my actual work envelope?

2) How do I turn on the spindle? This might sound like an odd question, but I have made a couple of simple drawings in BobCad and ran them through MACH 3 already. The tool path will run but the spindle will not turn on. I can turn the spindle on manually though. Is this normal? Do I have to manually set the spindle speed before I start the G code running? I am thinking that I do need to manually do this, but the BobCad software allows for setting the tool type and spindle RPM in the CAM tree, thus I am confused.... When I change the spindle speed in MACH 3, nothing happens.

This is a complete running CNC set up that I purchased from another party a while back. I know that everything worked when I bought the unit so I'm just thinking that my issues are due to my unfamiliarity with the CNC software or set up. Thanks in advance for your help with my questions. I appreciate any assistance and direction that anyone can provide.

[ger21]

1) Soft Limits are based on your home switch locations (Machine Coordinates), and are typically set to the extents of you machine, to keep you machine from crashing into the stops or limit switches. You should set them once, and never have to change them.

2) What kind of spindle, and how is it wired? Is there a relay to turn it on? Are the ports and pins in Mach3 setup properly? If you spindle is set up for Mach3 control, M3 in the g-code will start it.

[Magnetboy]

1) Soft Limits are based on your home switch locations (Machine Coordinates), and are typically set to the extents of you machine, to keep you machine from crashing into the stops or limit switches. You should set them once, and never have to change them.

I do not have limit switches on this unit so I am guessing that would make accurate soft limits that much more important. Can I just tailor the soft limits to a size slightly smaller than the travel limits of my X,Y, and Z axes and reset them?

2) What kind of spindle, and how is it wired? Is there a relay to turn it on? Are the ports and pins in Mach3 setup properly? If you spindle is set up for Mach3 control, M3 in the g-code will start it.

I am not sure of how the spindle is wired. I will have to do some investigating. The ports and pins are set correctly. I have loaded G code into MACH 3 and the software will run the tool path and the X, Y, and Z axes will move appropriately. Like I said in my first post, I purchased this machine as a complete running unit, PC and all. The only thing that I can think of that might be a stumbling point is that the owner reset most of the software configs back to factory settings. He had changed some settings to meet his personal requirements. I have watched the MACH 3 tutorial videos and some of this is becoming clearer. I just want to be sure I am doing the right things before I make any changes.

[ger21]

Without Home switches, your Softlimits won't be consistent over time. Every time you turn your machine off and on, it's position will likely change a small amount. Over time, this will shift your softlimit locations.
What you need to do is jog your machine to a repeatable position each time you turn it on, and press the Ref All button, which will set your machine zero location to the current machine position. This is where your softlimits will be referenced from.

[Magnetboy]

Without Home switches, your Softlimits won't be consistent over time. Every time you turn your machine off and on, it's position will likely change a small amount. Over time, this will shift your softlimit locations.
What you need to do is jog your machine to a repeatable position each time you turn it on, and press the Ref All button, which will set your machine zero location to the current machine position. This is where your softlimits will be referenced from.

Funny that you mentioned that because I had searched for earlier posts on this very subject and I was trying to do what you were suggesting at the very same time that you were replying. Unfortunately, it is not working for me. I jogged the X,Y, and Z axes where I would like my machine zero to be. In reference to the table, X0 to the extreme left, y0 to the extreme front, and Z0 to the extreme top. When I hit the "ref all home" button, the DRO did not reset. The values that were originally there remained there. Any other suggestions? I saw a comment on the "persistent DRO" option in another thread. Is that part of my issue as well?

EDIT:I figured out how to zero the DRO for the machine coordinates. However, when I tried to set a work offset, I didn't have as much luck. I loaded G code from a part that I put a basic pocket in. It will be my first real test and just an easy pocket to attempt as a first time trial. I did not place any stock on the mill. I just tried to run the g code. Mach 3 ran the G code but not where I set the work offset to. Maybe I am not setting my soft limits correctly? I've watched the Mach 3 tutorial video more than once. I'm just confused now.

[ger21]

To set your work offsets, just jog to where you want your X and Y zero positions to be, and press the Zero X and Zero Y buttons. This will set your offsets where you want them.

Softlimits have no effect on the coordinate systems.

[Magnetboy]

To set your work offsets, just jog to where you want your X and Y zero positions to be, and press the Zero X and Zero Y buttons. This will set your offsets where you want them.

Softlimits have no effect on the coordinate systems.

When I did that the machine started the tool path in a different spot. To be clear, I set the soft limits, zeroed the DRO at the left/front/top of my soft limits for my machine coordinates, jogged to a new position within the soft limits that I had set, zeroed my work offset DRO, and clicked on "regen toolpath". When the mill began running, it was not cutting where I would have expected it to. I have a vice on the mill table that I am using for a landmark with an imaginary piece of stock. My work offset DRO is zeroed to where I would expect the left/front/top of that stock to be. The tool path was not running where the stock would have been. It was clearly off the stock, but wtill within the working envelope of the mill.

I am going to have to ponder this while I am working today. Tonight I will try it again. Maybe I am missing something obvious. I have read posts from other users who have had similar issues in the past and I have done the same as they have, but I have not gotten the same results. Thank you for your assistance. I appreciate your willingness to help. I will get the mill PC set up in my wireless network so I can save a few screen shots of MACH 3 as I go through this process. It is likely that I am missing something that you or others might be able to pick up on when you see it.

[ger21]

Then it sounds like your g-code is not what you expect it to be.

[Magnetboy]

Then it sounds like your g-code is not what you expect it to be.

That was what I was thinking, but BobCad generated the tool path and the G code. I'm not sure why this would be causing my issue yet.

[ger21]

Did you tell Bobcad where 0,0 was supposed to be?

[LeeWay]

Think of the CAD software as an aerial view of your machine. The 0,0 point in the CAD software needs to match the same point in your machine. You lay out parts to be cut with this point in mind.

[zool]

Reading section 6.2 in this PDF might help.

http://vortechcnc.com/MACHInstructionManual2.pdf


Watch the video titled: Homing, Limits, and Offsets [3rd down on left]

at this site: ArtSoft USA - Video Tutorials

[ger21]

No, Z zero in machine coordinates (home) is at the top.

[Magnetboy]

Did you tell Bobcad where 0,0 was supposed to be?

Think of the CAD software as an aerial view of your machine. The 0,0 point in the CAD software needs to match the same point in your machine. You lay out parts to be cut with this point in mind.

I actually thought about this the other night. My x0/y0 is at the center of the part in BobCad. On the machine, I zeroed the work offset at the left front of where the stock would have been. I was thinking that this might be a potential issue as well, but I didn't yet attempt to retry the part as if it were zeroed at the center of the stock. This seems to fit my potential problem though. The tool path that the mill was cutting was about 2 inches off in 2 directions on what would have been a 4"x 4" square piece of stock. I now pretty sure that this the problem with the tool path not being where I expected it to be, especially if you think this might be a problem as well. I will see if I can change the file to accept the different X0, Y0 tomorrow morning and see what happens. I will post my findings.

All this being said, I still can not come up with the reason that my spindle won't start. I do have an M03 command within the first few lines of the G code but the spindle won't turn on. I tried running the G code from another file which the former owner left on the PC, but the spindle wouldn't turn on during that run either. I'm trying to double check all of my cables and connections, even within the mill column, just to avoid overlooking anything. Unfortunately, I have no paperwork to verify any wiring that was done during the CNC conversion or MACH 3 configuration.

Reading section 6.2 in this PDF might help.

http://vortechcnc.com/MACHInstructionManual2.pdf


Watch the video titled: Homing, Limits, and Offsets [3rd down on left]

at this site: ArtSoft USA - Video Tutorials

I feel comfortable with the MACH 3 controls, at least comfortable enough to get myself going. I know that I am going to learn plenty more as I gain experience using my machine and the software.

I've probably watched the homing and limits video 4 times already. I understand the machine coordinates vs. work offset coordinates and I have what I think is an understanding of the soft limits with the exception of how to determine what my soft limits should be set to with reference to my table. Right now, I'd be satisfied with getting the tool path in the right position with reference to the table and getting the spindle to turn on. Once I know those two issues are resolved, and I think the X0, Y0 issue is, I can move on to other concerns. I haven't cut a single part yet, but I have already learned enough to know that I am going to put home and limit switches on this machine once I get going.

No, Z zero in machine coordinates (home) is at the top.

Was this in response to something I posted or something another user posted? Did I miss something?

Thanks to everyone who has offered their assistance. I am sorry to be so difficult. I'm new to CNC and I'm learning as I go. I appreciate everyone's efforts to help me get started.