Planet CNC controller and software

[sairfan1]

Sairfan 1 - I have converted an Isel router to Planet CNC and found the process quite easy. I am no machine builder and if I can do it, must be easy. I moved from Mach 3 and find Planet CNC far better. The new TNG software still has a few minor peripheral bits to resolve. But which controller system on the market does not? I particularly like the Warp feature and use it frequently to engrave on irregular or 3D surfaces. I believe it was originally developed for PCB work.

Thanks for help, i bought new module and software license, I'm new to CNC machines, I found that controller card supports limit switches but my machine does not have, I believe it can work without limit switches but i want to know how important it is to install limit switches, are they really helpful or something we can avoid.

thanks.

[Leadhead]

Limit switches are a personal thing. I have them on one machine but never use them as I do not trust their accuracy and thus the repeatability. So on my main machine I just use the "soft limits" as an idiot border, so to speak. I zero XY&Z independently each time. Or put a hard stop(s) on the bed if making multiples. If I need to home all, or home XY, or just Z the TNG buttons on the l/h side bar are efficient and effective.
So for my part, limit switches are not needed. I work perfectly well without them.

[Clive S]

To stop confusion. Limit switches and home switches are different things, homing switches need to be accurate and reliable. Limit switches do not need to be accurate.

But it is possible to use a home switch as a limit switch combined. In this case you can make the machine set the SOFT limits so when homed the machine knows where it is and thus should not crash at the other end.

[A_Camera]

To stop confusion. Limit switches and home switches are different things, homing switches need to be accurate and reliable. Limit switches do not need to be accurate.

But it is possible to use a home switch as a limit switch combined. In this case you can make the machine set the SOFT limits so when homed the machine knows where it is and thus should not crash at the other end.

Yes. And to make things even clearer, the difference between hitting the home switch and hitting the limit switch is that when the machine hits the home switch (soft or hard, makes no difference here), it decelerates in a controlled manner and not losing position. Limit switches are for safety reason, so when the limit switch is hit you want the machine to stop as fast as possible and don't care about losing position. After hitting the limit switch the machine must be homed again, or zeroed at the right position, whichever you prefer, otherwise you will not be able to continue the job.

Yes, soft limits CAN prevent you hitting the wrong end, but that assumes that the machine was homed initially when the machine is powered on and that the positions are still safe to use. This is not always the case, for example after stalling or some other error which can cause offset or lost or extra steps. Especially with my 3D printer, when I power it on all axis values are zero, regardless of where the extruder head is positioned, so hitting the wrong end is easy. Of course, this can be prevented through prohibiting any move except homing after power on, but since it is just a 3D printer, I don't care about that.

[A_Camera]

Thanks for help, i bought new module and software license, I'm new to CNC machines, I found that controller card supports limit switches but my machine does not have, I believe it can work without limit switches but i want to know how important it is to install limit switches, are they really helpful or something we can avoid.

thanks.

There are different schools... some prefer limit switches, some don't. Personally I would not run a CNC without limit switches to prevent unintentional runaway. On my 3D printer I only have home switches, and those work as limit switches for one end of the axis, but have no limit switches at the other. Now and then I make a mistake resulting in hitting the wrong end, and even with the weak NEMA17 motors it sounds pretty violent. I want my CNC to stop in a more controlled and less violent way so I have limit switches at both ends to prevent that. On the other hand, I don't use home switch on my CNC at all, since I always start from zero on the material I work with and I set the zero each time I need to.