Newbie Question about CNC Software | Post Processor | Limit Switch Set Up | First Run

[arcadiax]

Hi all,

I have a couple of newbie questions and if anyone has a couple of minutes to spare and guide me in the right direction, that would be much appreciated.

I am a desktop hobbyist with the CNC and I had bought a ZEN CNC desktop machine a couple months back.

Although the company provides instructions, sometimes they are lacking in certain areas or not up-to-date despite marketing their products as for beginners. I am really a beginner.

This is the link to their website so whoever is looking to respond can know a little more about the machine I bought. It is their biggest version - 12" x 12".

Arduino Limit Switch Installation Instructions - Zen_Toolworks_Wiki

My questions are concerned mainly with the order of softwares, communication and also limit switch workings and perhaps initial test runs tips.

I have a 3D animation background with 3D Studio Max and now I would like to make some actual 3D stuff with my 3D files.

This has truly been an on and off adventure of sorts and I am still not too familiar with terminologies so forgive me if I describe things in layman terms at times. I am quite familiar with 3D printing but I realized CNC is quite on another level.

1. For modeling the actual 3D file, I use 3D studio max than export the raw 3d file into acceptable file format for Fusion 360.

2. I think they call Fusion 360 the post processor software? Is this correct? Or is the post processor something else? Someone told me post processor is built into the Fusion 360. What would we call the Fusion 360? Someone told me post processors turn 3D files into readable machine codes (Gcodes)?

3. I also have something else right now that I use to primitively control my machine's x, y and z axis. It is called an Universal Gcode Sender (GRBL). I haven't gotten to the milling stage yet at all. This part also confuses me a little. Is the GRBL universal gcode sender a post processor (I don't think it processes anything though?) or just a receptable for accepting processed gcodes from Fusion 360? Can't Fusion 360 directly communicate with the CNC machine?

So far, I have finished leveling the machine's beds / axis to an acceptable tolerance and if things are slightly off or sloped, it is ok because I am not milling machine parts - just soft plaster for molds or wax.

On top, I was just a little baffled by how limit switches are usually set up. The instructions say to turn on hard limits within the GRBL and than to do a reset on the Arduino board's button. This will release the lock on the spindle. All very confusing for a non-techie. The seller of the ZenCNC says usually people do not really even use limit switches for simple milling and I am starting to wonder if this is necessary? It came with my machine though and I am sort of leaning towards having it installed fully for safety reasons - just in case a bug of some sort decides to take one of my axis's beyond its hard limit.

1. Are limit switches detected and initialized in software such as GRBL?

2. How do I actually detect or know if my limit switches are working?

For the first run, I will probably make a simple square file to engrave to test out the x, y, z axis travel accuracy but any tip is appreciated in this area. I still have much to read up in terms of Fusion 360 but I wanted to get some of the very primary fundamental questions out of the way first.

I am probably off in alot of areas so any guidance will be deeply appreciated!!

Thank you for spending the time to read my post and feel free to request for any further information.

- Steven

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[ger21]

Fusion 360 is CAD/CAM software, but in your case, you're just using the CAM portion.

Someone told me post processors turn 3D files into readable machine codes (Gcodes)

Sort of.
In Fusion 360, you use the CAM environment to create toolpaths from your 3D model. The post processor converts those toolpaths into g-code.
A post processor is an instruction set to format the g-code in a particular way, to suit a particular machine control. Fusion 360 comes with a large variety of post processors.

Is the GRBL universal gcode sender a post processor (I don't think it processes anything though?) or just a receptable for accepting processed gcodes from Fusion 360?

Basically, yes.

Can't Fusion 360 directly communicate with the CNC machine?

No. CAM software does not communicate with machines.

Never used GRBL, so can't help with it's limit switch handling.

[109jb]

GRBL and Universal G-code sender are not the same thing, and they are not a post-processor. They work hand in hand and would be considered "Machine control Software" GRBL is the real machine controller, and universal G-code sender (UGS) is the user interface for GRBL. There are many other interfaces besides UGS.

Limit switches are wired to GRBL,and GRBL is what detects a limit switch trip and halts the run.

Using limit switches in GRBL >> Where the switches are connected depends on the version of GRBL, and how it is configured. If not configured for variable spindle control, the X axis is pin 9, the y axis is pin 10, and the Z axis is pin 11. If using Variable spindle PWM, then the Z-axis limit moves to pin 12. Simply wire the limit switch between the pin noted and the ground pin on the arduino. I would use normally closed switches in series, but you can also use normally open switches in parallel. Once the switches are physically installed and wired, you have to access the GRBL settings to turn them on. I think that UGS has a screen for changing GRBL settings, but I don't use UGS so can't remember. If it doesn't you can use any serial terminal program. There is one in the Arduino IDE. To activate the hard limits, you need to change $21 setting to 1. In the serial terminal, after connecting to GRBL, just type $21=1. That should get the limits working.

[arcadiax]

hi ger21,

thanks for getting to my threads so quickly.

sorry for the late replies, been a little busy with work and the holidays.

yes, i had it figured out cad - cam - post processor.

just going to attack the limit switches now.

[arcadiax]

hi 109jb, sorry for the late reply.

i will take some pictures and show you how the machine is wired up. to be honest, i am not an electronics expert so i will be taking this a little slow...

ok i'll upload some images asap so i can better visualize this with you.

thanks 109jb!