Newbie - Looking for advice on ATC compressor

Hi all, new to the forum, new to operating a cnc, not new to CAD.

I'm putting together a build for an AvidCNC Pro that I'm going to use for hobby woodworking. One of the things I want to make sure I add to the machine in relatively short order (once I've got it up and running, dialed in, etc) is an ATC. I plan to use the S30C ATC spindle (https://www.cncdepot.net/product-pag...d-cnc-machines). Naturally, it requires a compressor to operate the drawbar and the product page indicates it needs a compressor capable of 100psi output at 5-6cfm.

I'm curious if anyone else is using this ATC and if so, what compressor are you using. Most compressors have their SCFM rated at 90psi and pressure typically has an inverse relationship with volume. So if I get a compressor that just meets the requirements at 90psi, at 100psi the same compressor likely will not meet the requirements.

Since this is just for hobby woodworking, I'm not trying to spend a lot until I've proven the usefulness of it all but I doubt I would want a CNC without an ATC as I don't want to babysit the thing for tool changes all day.

Also, I don't know what is meant by "case pressure" so that would probably help.

TIA.

I am not sure if you have seen Clough42's YT channel, but he has that spindle, and more recently added your CNC to his shop. I really like his work and teaching style - his ATC build series of videos helped me in my own recent ATC build (different spindle but same Hitachi VFD). If you have not seen his work I highly recommend it as I am sure it will inform your ATC upgrade as well.

I specifically mention this also because he uses one compressor in his shop that also handles the tool changes with this spindle, and as far as I know it is performing well. It is a California Air Tools 10 Gal 5-6 CFM @ 90 PSI.

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Originally Posted by jmdye

Hi all, new to the forum, new to operating a cnc, not new to CAD.

I'm putting together a build for an AvidCNC Pro that I'm going to use for hobby woodworking. One of the things I want to make sure I add to the machine in relatively short order (once I've got it up and running, dialed in, etc) is an ATC. I plan to use the S30C ATC spindle (https://www.cncdepot.net/product-pag...d-cnc-machines). Naturally, it requires a compressor to operate the drawbar and the product page indicates it needs a compressor capable of 100psi output at 5-6cfm.

I'm curious if anyone else is using this ATC and if so, what compressor are you using. Most compressors have their SCFM rated at 90psi and pressure typically has an inverse relationship with volume. So if I get a compressor that just meets the requirements at 90psi, at 100psi the same compressor likely will not meet the requirements.

Since this is just for hobby woodworking, I'm not trying to spend a lot until I've proven the usefulness of it all but I doubt I would want a CNC without an ATC as I don't want to babysit the thing for tool changes all day.

Also, I don't know what is meant by "case pressure" so that would probably help.

TIA.

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I have been running the S30C since later 2019 on my PRO60120. I have a 60 gallon Quincy (QT-54 Vertical). 15.2 CFM @ 170 PSI 100% duty cycle. It runs about ever 10 minutes or so with just the spindle plugged in and idle (not cutting drawbar engaged).

If there was one thing I would change, I would go for the 80 gal version. You can run the pneumatics for the S30C off a little oil-less pancake compressor just fine but it will run continuously. The 60 gallon is great and has nice long periods between runs. The 80 gallon would be ideal.

As to case pressure, the spindle is cooled and purged of contaminants by positive case pressure. So the spindle is constantly hissing. You can feel the most air coming out from around the bottom bearings and ISO30 taper.

As such, I would buy a very effective and complete dehumidifier and oil trap for your air system. Otherwise your S30C won't last the week.

I use a Quincy QPNC-25 refrigerated system as I live in Georgia. High humidity and it rarely gets below 50° F in my shop. 68° F is really the lowest I would allow it to go.

I would not skimp on that aspect of the air system. Squirting nasty tank water and waste oil through that spindle will make short work of that expensive toy.

But, if you think you are going to be happy with static post for your tool holders, you are wrong. The retracting carousel will be partially pneumatic. And you will realize that you need a better dust control to stop the dust from choking your shop and then you are using pneumatic rotaries on fancy dust shoes. Then you will wake up in the middle of the night in a cold sweat and shout, "I need a retracting tool setter!"

Once you get that ATC, the less you will want your body parts inside of that work envelope and thus more automation is better. And most of that automation will be pneumatic and thus you will need a bigger and bigger compressor.

Piece of advice; it's not necessary but it can save you a boat load of trouble, two pressure sensors. One to read the system pressure supply and write some code to stop the machine if it falls below 100 PSI. The second to read the pressure to the drawbar. Then write your tool change code to check that pressure is 100+ PSI before you retract fully.

Alex over at CNCDepot will tell you I am exaggerating (and I could be but why chance it?) but if you forget to turn on your compressor or plug in the solenoid for the drawbar your CNC machine isn't going to stop tearing itself apart and wait for you to hit the panic button.

It won't be long before you are nervous every time an M6 is executed. You will be white knuckling that e-stop like a 10 hour pilot in a 20kt crosswind.

But, congrats on a great spindle! It has run flawless for me. I have wrecked it pretty bad and it has survived. I have torn up tool carousels, driven it straight down through my tool setter and the truck and it survived.

In the end both the S30C and the AvidCNC machines are fault tolerant and robust devices.

An ATC adds a level of complexity and more avenues for faults so it does require 100% of your attention!

PS never run your S30C without air! You will melt the core. At the end of a long cut, let the compressor run until the spindle is cool enough to touch and keep your hand on it.

Thank you TMToronto! I will definitely check out Clough42's channel.

WOW! What an informative post. Thanks so much for taking the time to share all of that super useful info SubNoize. I am definitely planning on using an air dryer - specifically this one, https://www.harborfreight.com/compre...yer-40211.html (I know, but I've had decent luck with most of their rudimentary tools though I never use anything from there that would put life or limb at risk if it failed). I also planned to back it up with an inline desiccant dryer as well.

Thank you for explaining case pressure to me. That makes total sense.

I'd not considered a retracting tool holder, but I can see how that would be very useful. For dust control, my shop already as 3" lines running to every tool and I have a central dust collector, two shop fox central air filters hanging from the ceiling and I will use a dedicated wall mounted dust collector for the CNC. I will also install this dust shoe from digitallyfabbed (http://www.digitallyfabbed.com/#/dustshoe/). The CNC will also be in a walled off section of my shop that is just big enough to hold it (5 x 8) plus walking space around three sides. Hopefully all of that should keep the mess to a minimum and what mess is created should be localized to just the CNC room. I'll have the computer outside the room.

Two pressure sensors makes a lot of sense. I agree that having the machine stop automagically whenever the PSI drops below 100 is an good investment when you dumping this much cash on a toy.

I've worked with CAD software for the better part of 15 years but never actually run a machine myself. I've always passed off my designs to someone else, so it will be interesting learning how to actually run a machine. Still, it will be fun. I have a whole list of projects and things I want to build and my 11 year old son is super interested too, so it should make for some good memories and I'd pay any price for that.

Any other advice, tips, tricks would be super appreciated from anyone and everyone. I 'll probably make another post with my build-list sometime today for others to review, critique and provide thoughts on. I really appreciate everyone's insight.

An ATC is very cool and could be a real-time saver/money maker in a production shop. For a beginner, hobbyist KISS will be your best friend. Manually changing a cutter is really not that big of a deal and takes a large amount of complexity out of the machine setup and build. Add learning software, programming, setups....etc It will be like drinking from a fire hose unless you already have all the skills. KISS at first

Thanks LorenBMS. I am a big believer in the KISS principal. ATC is a probably the first "complication" I will introduce to the setup, but I plan to make sure I am comfortable with operating the machine manually and build a few projects manually before making anything any more complicated than it needs to be.

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Originally Posted by jmdye

For dust control, my shop already as 3" lines running to every tool and I have a central dust collector, two shop fox central air filters hanging from the ceiling and I will use a dedicated wall mounted dust collector for the CNC....

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My bad, I didn't explain well enough!

Your dust shoe will get in the way of you docking your tool to the tool holder. Especially if you have static posts.

The reason is the tool holder sticks out and you have to level the spindle and tool's groove to the same height as the tool holder and then ease into the tool holder. That is about 6 inches?

That means the opening for your dust shoe has to be big enough to fit the entire tool holder PLUS the distance to travel.

So the ISO30 is about 50mm is diameter and the docked tool position will be another 50mm and then the screws that hold the tool holder to the post is another 30mm to 50mm depending on the holder?

If your dust shoe orifice is that wide, trust me, you aren't sucking up anything in your dust system when you are machining.

My shop has to be super clean. Virtually zero dust can escape the cutter and so my dust shoe orifice is ~4 inches and encloses the cutter with 1 to 3 inch brush coming down around it depending on cutter length and job.

As such my dust shoe has to open to allow the tool holder to slide into the groove on the ISO30 tool.

I have included a CAD drawing on the problem seeing as trying to take an actual photo of it would be very dangerous or I would have to pause it and remove parts to get this picture.

So to restate the problem, a big enough shoe to fit all that under it will not be of much use in dust control. If you remove the dust shoe manually before and after each tool change, you don't really have an "ATC." If you automate the dust shoe then you have more cables and pressure lines, more code.

I find very few people ever get this far in thinking about ATC and dust collection. It really does matter. A clean shop is a healthy shop and wood dust can seriously harm your health.

Also, Fusion 360 and motion studies really help figure all this out. Nothing like spend time and energy only to assemble it and find that things collide. Put it into CAD and generate motion studies and airflow and you will save yourself a lot of time and heartache.

Also, get really proficient in Lua if you are using Mach4. I am a Java, C/C++ guy and spent years in embedded and enterprise system design but Lua was a "challenge."

Ah. Yeah I considered that in my research. The dust shoe I am planning on has a sensor so you can program your tool changes to drop the show prior to making a tool change, then pick it back up post tool change. Check it out at: https://youtu.be/KseKEv1NmLI

Someone in another forum that I am a member of, and who did a similar ATC build to mine, is using this dust shoe. He also programmed it to be part of the ATC process and it works quite well. If I remember correctly, the person who makes them will customize the diameter to meet the sizing of your spindle.

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Originally Posted by jmdye

Ah. Yeah I considered that in my research. The dust shoe I am planning on has a sensor so you can program your tool changes to drop the show prior to making a tool change, then pick it back up post tool change.

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Tried that approach already;
https://youtu.be/zqcIa6W_yMk

Problem is the AvidCNC doesn't have a structure to hang that fixture for the dust shoe so you have to bolt one to an end of your gantry. If you did not buy the extended gantry you will slice a huge chunk off the side of your work envelope unless you are really careful.

I have the extended gantry but I ran into the next problem, the spindle will melt the plastic touching it. Especially if you are doing a long run and the shop is warm.

I had a bad z axis and I ended up wrecking into the dust shoe rack you see in my video. About $700 in damage so I really lucked out. After that, I dumped that design.

Now, you might be ok with that giant arm sticking out from the ganty like that but the one thing that was the final straw for that design was the vibration. It would vibrate and cause wavy lines in my cuts. So 1/4" steel wasn't ideal for that. I added a second plate and sandwiched rubber pads between it which reduced the ringing but I had already decided to dump the design before it crashed.

Good information to know - thank you for detailing your user experience, it is appreciated.

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Originally Posted by TMToronto

Good information to know - thank you for detailing your user experience, it is appreciated.

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If I could save you money and heartache then I have done my job! But I also want to encourage everyone. I have conquered this task and so can you.

I watched that other video again and knowing just how hot the S30C can get, I doubt that shoe lasted much longer than that video. You could tell by the distinct lack of dust on his shoe he recorded that before he had actually used it.

Polycarbonate can withstand a fair amount of heat, yes, but over time it would start to sag. Especially holding the weight of the vacuum hose.

Given enough time those tabs that lock the brush in to the holder would warp out of alignment from the heat. EIther the brush would fall harmlessly off or worse catch the movement of the spindle in the X axis enough to make it lose steps. Then when the machine tried to dock the tool it would be off center from the tool holder because of the lost steps and the breaking would begin!

Yeeeow!

Been there, done that.

No more plastic shoes mounted to that spindle!

Well, all of the stock is "sold out" atm anyway. My guess is that he is probably looking at alternatively materials that can take the heat. I sent a message on the website to inquire. Your point about a retracting tool stand is still noted though. Maybe it will be one of the first projects after the I'm comfortable operating the machine manually. Have you done a post on the build? I would be super interested to see what you came up with.

Quote:

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Originally Posted by jmdye

Well, all of the stock is "sold out" atm anyway. My guess is that he is probably looking at alternatively materials that can take the heat. I sent a message on the website to inquire. Your point about a retracting tool stand is still noted though. Maybe it will be one of the first projects after the I'm comfortable operating the machine manually. Have you done a post on the build? I would be super interested to see what you came up with.

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I need to update that posting;

https://www.cnczone.com/forums/avid-...-cncdepot.html

I was going to do a video on the controller part but I have been distracted with a new project. My problem with publishing videos is I never intended to go this route so I never documented the stuff I was building. Now everyone wants me to make one for them and I am kind of behind on my other projects.

The good news is I am video recording everything. Now I can go back and publish the how too.

Just an "FYI" you do know the electronics package from AvidCNC is maximum 4 axis?

The reason I ask is that in commercial systems the tool carousels and tool magazines are actually axis of control in the CNC. So like you will see a machine advertised as "9 axis" but in fact its 5 axis with the 4 additional axis for the tool magazine. Just be aware of that before you start.

For me I have the dual process (spindle and plasma) as well as a 4th axis (actually 5 axis machine as the AvidCNC machines use two axis channels for the Y axis) which means my control board is maxed out. Then to add to the problem I have Torch Height Control (THC). So all of my spare ports for GPIO are used up as well. Essentially one axis is unplugged at any time. I either have the extra head (U axis) or I have the rotary A axis but not both at the same time.

I had to resort to building and writing my own controller for the tool carousel. My controller supports ModBus over TCP/IP so it is easy to configure and use within Mach4 or LinuxCNC.

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Originally Posted by subnoize

I need to update that posting;

https://www.cnczone.com/forums/avid-...-cncdepot.html
I had to resort to building and writing my own controller for the tool carousel.

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For the record, my AvidCNC PRO60120 now has 8 axis, 10 proximity sensors, 3 solenoids for compressed air, 2 analog pressure sensors and a tool length/setter sensor.

You will not fit that into an AvidCNC provided controller. At least not one based on the Warp9 Ltd Ethernet Smooth Stepper.

That breaks down to 4 axis for the X, Y (A/B) and Z. The U / A axis is the 5th so now you have maxed that out on the AvidCNC control board.

Add 3 more axis, one for the carousel carriage, one for the carousel table, one for the tool length / setter carriage.

An additional axis is the dust shoe (also referred to in the industry as the "dust hood") actuator, but thankfully that can be done with pneumatics. You can also replace the carriage axis' listed above with pneumatics and like the with the dust shoe, use air flow control on the exhaust cycle to make it not slam around.

10 proximity sensors are the 6 for the X, Y (A/B + limit, so three), Z and U/A. 4 more are for carousel carriage home or limit if pneumatic, carousel table home, tool length/setter home / limit and on the dust shoe (hood) open.

The 3 solenoids for air pressure will change if you use pneumatic carriages but on my machine they are drawbar release, dust hood, chip blower for the tool length / setter sensor.

If you know this already, I apologize for saying it again; Yes, the tool length / setter sensor is "required", sorry. You can run without it but you will eventually wreck, and it will be costly. There is just more to break in an ATC system.

#1 For ATC to work the tool table has to have the offsets from tool No 1 pre-calculated before the current cycle / run. This is because there is no pause to touch off to the work surface again so the machine needs to know where that tool's tip is very precisely. You could add that pause in code but then you don't have an ATC system. You have a manual system that makes a lot of noise.

#2 The tool length part of the tool length setter sensor is where the machine double checks to make sure the tool offset matches what is in the table before using the tool. If not, it will error out. This catches the humans putting tools in the wrong slots and tool breakage.


Best of luck!

Sorry, I shouldn't have called the two X axis by letters like this (A/B) but should have used (X / Slave) instead.