Homing, Hard Stops, Proximity Sensors, and Soft Limits on an AVID CNC

[@cliffneal3118]

Thanks for taking the time on this one. Going to check my machine now…. I still have not taken the leap to add a laser but intend to rewatch all your laser videos prior to doing so!

[@andrewluger7133]

Excellent, I hope to be able to set my switches thanks...

[@davealbers1468]

Thanks so much for this. It helped me understand how to set my soft limits where they not set by the homing procedure.

[@JNWoodworks]

Hi Dave, You are welcome and I'm glad it was useful.

[@alanferrell9406]

Appreciate this video Jim. Just starting out and you helped me figure out why my Z soft limit kept tripping. Discovered there's a setting in Mach for how many lines ahead you want it to look. The default is 20.

[@JNWoodworks]

Ya, thats why it can be a little confusing sometimes because it doesn't stop on the exact line that has the problem. As you said, it is up ahead in the look ahead zone where it discovers the soft limit violation and stops.

[@Silverturky]

Hey man great video! It's really love to see your procedure for cutting aluminum on your machine. I just got a pro 4x8 and i really want to be able to make some aluminum parts but i know gantry stiffness can be an issue

[@JNWoodworks]

I actually haven't cut much aluminum yet. Most of the parts I made for my AVID machine I cut on the bandsaw. However, you can make really good cuts on average machine if you have the right bit and speeds and a mist cooling system really helps. Robert Cohen has a video on a mist cooler and so do I.

[@Sehast]

Very good video. Off topic but I couldn't miss the unusual placement of your E-Stop switch. You must always stand next to the gantry while a program is running or depend on a stop key you have set up on your wireless keyboard.

[@JNWoodworks]

Very observant :-) Well, I have a long history of leaning over equipment and accidentally hitting the EMO, so I don't want it on the perimeter of the machine. Also, if you have it on the perimeter, you still have to stand in the same place or have multiple buttons if you want to reach it on a big machine in time. Just using it as a floating switch doesn't work well for me because in my experience I usually leave it on the wrong side of the machine and I would like it to be in a consistent place. All that said, I am loathe to hit the EMO switch anymore since it requires re-homing and starting over, and I almost never need it, and when I do, a feed hold and software stop would have been just fine. So I am considering changing my screenset to run the screen's STOP button functions (which I already have doing a feedhold first), or at a minimum I will make a hotkey for they keyboard that toggles STOP (and just paint it red on my remote keyboard).

[@Sehast]

@@JNWoodworks I have a remote keyboard similar to yours and want to make a hot key for Feed Hold, the ESC key is already there for a full E-Stop. I agree most of the time that a Feed Hold is what is needed and I am hoping that since the keyboard is small that I will have it with me most of the time. If you have implemented a Feed Hold hot key on your remote keyboard I would be interested in the details. With Mach3 it was easy, all you had to do is hit the space bar but Mach4 did away with that.

[@JNWoodworks]

@@Sehast So far I have just incorporated feed hold into my STOP botton on Mach4, so now hitting stop first does feed hold, and then stop. I just need to hook up a keyboard key that I never use to that button. Maybe I will do that today :-)

[@JNWoodworks]

Ok, I updated my screenset (version 4 now), and instructions (version 8). An F10 on the keyboard will now initiate a feedhold and then a STOP. Just make sure you have keyboard inputs enabled or obviously it won't work (I would love to find a workaround for that catch22 where I could turn on keyboard inputs from the keyboard :-)). The updated files are here: drive.google.com/drive/folders/1xB6J0RZIU1j8g951NkP-8HXC1swC2C-B?usp=sharing I painted by F10 key bright red :-)

[@Sehast]

@@JNWoodworks Thanks Jim. I will take a look but I am still not very proficient with the Mach4 screen editor. I will look at the video you did on it again and go from there.

[@Swactionworks]

Man you have no idea how much I really appreciate this video!!! I’m in a bit of a jam my machine is doing what yours was with my zero on my z being at the top of its travel. Do you have a video of you fixing that?

[@JNWoodworks]

I don't have a video, but if you send me an email at [e-mail], I would be happy to walk through fixing it with you.

[@bstanga]

Great video Jim. I love that spoil board, especially the way it wraps around the 4th and it appears it locks in like a jigsaw. Am I seeing that correctly? I'll send you a pic of my pock marked screw hole filled spoil.. lol

[@JNWoodworks]

Thanks Brian. Ya, the back 3 feet or so of my spoilboard is fixed. Then the front up to the first brace is a part I can remove. I have one that is shaped to conform around my 4th axis (which is usually left in place), and one that is a solid rectangle for when I want to remove the whole 4th axis unit and use the full 4x4 ft area of my table. I also have a vertical board hidden down under there for doing vertical work (like dovetails and mortice/tenons). I just remove that front section and raise up the vertical part and lock it in place. One of these days I'll do an overview of my setup when I get time :-)

[@bstanga]

@@JNWoodworks That would make a good video. I have a need for a vertical table I've made a few table legs with a treadle that I needed to put a square hole in for the wedge as well as dovetails and the like. I'd like to see the design for sure.

[@JNWoodworks]

@@bstanga In the meantime, if you want a look at my vertical spoilboard, you can see the setup and how I use it pretty well in the rotary unit video I did. kzbin.info/www/bejne/kHiynHqmp9OibdE

[@habibaelmi1521]

Hello, thanks for the video. Nothing changes when I change the values of my custom soft limits. The router goes right past them anyway. Do you have any idea why this might be?

[@JNWoodworks]

Hi Habiba, Are you changing them in the AVID configuration area, or directly in the Mach4 soft limits area? Theoretically they should both work, but I have only done it in the Mach 4 menu, not in in the AVID one.

[@habibaelmi1521]

@@JNWoodworks I'm changing them in Mach4. The machine I'm using was custom-built by someone else and I'm very much a beginner in CNC. It also only has Y-proximity sensors, none for the X and Z axes. But, the soft limits should work independently of sensors, right?

[@JNWoodworks]

@@habibaelmi1521 Ok, here are a couple things. to check. First, make sure that there is a green checkmark in the "soft enable" column for the axis you want to use soft limits on in the mach4 homing/soft limits tab. You might also want to close and restart Mach4 as some setting only take effect when Mach4 is started. Next, hit the "switch to Machine coordinates" button in the mack\h4 screen, and jog to 0, 0, 0 for the 3 axis. That is where your soft limits are relative to. So if you set you soft limit to 24" on the X axis, it should stop the travel 24" to the right of where X=0 is. Since you only have Y proximity sensors, how to you set X and Z to zero? I assume you run some kind of manual homing process for those two axis?

[@CustomCraftedDesigns]

Hi, where did you get the nameplate with your logo? Thanks

[@JNWoodworks]

I made the aluminum plate, and my wife made the logo with her Cricut machine. Its multiple layers of adhesive backed vinyl. She did a nice job I think :-)

[@CustomCraftedDesigns]

@@JNWoodworks yea it came out great nice job. thanks for the reply

[@paulbergman8228]

Why would you ever turn off the soft limits after you tested the sensor limits? There is no need to turn them off! The other aspect is to move the sensor limit stop further away from the hard stop to give a larger ‘safety’ space, like 1/8”. Then you can set the soft limit even further away from the sensor limit. Having the soft limit just a ‘few thousands’ away from the sensor limit is a way to damage the machine if a little glitch occurs or the sensor limit fails to actuate for some unknown reason. The set-up instructions give practical limits to use, so why change those? You can even set the soft limits greater than ‘a few thousands’ all the time and never change them, or set them with a greater space if running the machine at a high x/y feed speed for that project. In squaring the Y axis, there is set sensor stop measurements to go by, and then see if both sensors light up at the same time. There is a very small ‘variation’ in the alignment of the Y axis and that is why those sensor stop bolts measurements are to be set very accurately. I found during set-up that the bolts in the rubber hard stops were too long and there was no ‘cushion’ in the rubber stop, so got a shorter bolt allow some real cushion effect. 😎

[@omongotdaniel]

thanks but my machine is jogging beyond the limits and its tripping

[@JNWoodworks]

Then your soft limits are either set wrong or turned off.