Looking to double my current 11-tool magazine on the rear of my PRO4896.
Current setup is using rearward facing CNC Depot forks on individual posts to allow for changes without removing the dust shoe.
Two rows of closely spaced vertical “drop-in” style stations would allow this without having to remove the dust shoe as well. I could double my current magazine capacity, slightly reduce each tool change time and even eliminate any tool release “sticking” challenges often faced with fork-style stations.
Here are some station designs protos as shared by a since retired user I’ve tracked down. He claims he used coiled automotive fuel line in the bottom of the bores to add the needed play.
Anyone here have any experience with this station style or insight into pitfalls as I move forward here?
For starters I’m OK with the limitations on cutter width as surfacing projects are seldom. With the ISO30 tool holders I’d still be able to get away with 1-1/4" width cutters.
I have a design like this in development. The biggest challenge to solve is the fact that the face of the collet nut is not a reliable height to work from. It can change depending on how much it is tightened on the collet. Your design needs to take that into account. They are also prone to catching dust and chips which makes the first challenge worse. The can work great.
I’d think taking measurements and applying those variations per tool would be easy enough, yeah? Another option would be to find a spring material that could incorporate the additional tolerance range needed, no?
Have you planned on a “spring” buffering material?
My ATC occasionally doesn’t want to “drop” the tool, and the tool holder ends up pulling it out of the spindle. If you rely on it “dropping” out, I’d add some way to check that it actually did.
I would not suggest changing the tool change height for each tool. Your design should have another way of solving that issue.
This is really important in this design.
Yeah, that’s a conundrum, eh?
Proximity sensors on each station seems a bit rich…
12v continuity to each station…
I have a bunch of cheap microswitches…
Or one measuring station that can both measure tool length and check for the tool holder itself…
I have a whole bunch of this stuff as STL files somewhere. I forget why I abandoned it. I think it had something to do with alignment issues with loading.
You could use an IR/laser break sensor (think garage door sensor that stops the door if the beam is broken). Raise the spindle to a height high enough above the tops of holders in the rack, and if the beam is still blocked, you know the tool is still in the spindle.
This is the since -retired guy who’d inspired the project.
One of the proto-type stations is made from his .stl files, though his is made of starboard HDPE.
Seems he’s using the tooth measuring setup though…
He said he used the automotive fuel line in a coil as a take-up spring and routed a 0.05" pocket in the bottom to assist with alignment.
Yeah Scott, that had crossed my mind as well… no experience with them but can’t be too hard to install I’d think…
I’ve been looking into it as part of my current efforts to update the rack for my S30C. I just picked up a “RapidChange ATC” for my smaller CNC. Don, the guy that created the RapidChange is pretty brilliant in what he’s accomplished. It uses standard spindles and the changer rack provides a way to spin the collets on and off. Anyway, he uses an IR break sensor to verify tool pickup/dropoff. You might reach out to him on how he grabs the sensor data.
And once I make some progress and have something to share, I’ll add to this thread
I’ll do that.
Super helpful Scott!
This collet nut discrepancy is confirmed on my collection of tool holders - with my mix of collet brands it varies by 0.08" across the lot.
The guy in the above vid claims to have use coiled automotive vacuum line in the bottom of the tool posts as an absorber.
I was thinking a cleaner solution might be to use a coil spring in the bottom of each tool post. Found this at DigiKey:
OD: 1.875" - tool post bore diameter would be approx 1.98"-2.00"
Tool holders are about 1.5lb, so 25% of compression travel just in tool weight with the remainder to take up the collet nut height discrepancy and spindle push-out…
The coil ends are squared off and the wire is not flat-ground so it’d better interact with the outer chamfer on the face of the collet nut.
Yep, been there, done that.
Just so you know, the tool holders will change even even from the same manufacturer and same model number.
Springs will deform over time. Especially with higher use.
Just go buy the spec tool holders. If what you and I tried was workable you would see it on machines being shipped from the big 3.
AND! Your solution should be to use the standard tool holder clamp and not the little starters that CNCDepot gives you.
They wear out (they are a consumable on your expenses worksheet) and you should just have a big bag of them to swap them as they do. They are cheap and you can get them on Amazon and eBay for about $5 a piece.
Out of curiosity how do you find the CNCDepot tool holder clamps deficient relative to the other design?
Depends on how closely your docking is to being in line with the clamp and how rigid the clamp is.
I had them dialed in as far as positioning but they were rigid. They lost the ability to hold the tool pretty fast. I would say about 6 months I had to replaced all of them with 3D printed and then eventually I gave up and started buying them.
With the carousel it has play in it both horizontal and vertical so it doesn’t wear anywhere as bad now. It also has stopped scaring the taper sleeve in the spindle.
I’m looking at them both in hand here the standard tool clamps have a heartier guide tang - which is what seems to take the brunt of the wear.
There are limitations to the vertical docking style of tool holder but that does not make them useless. They work great for x/y travel constrained areas or with dust boots that can’t be opened or removed automatically. They don’t work great with different tool holders. The don’t work at all with wide diameter tools.
If designed properly, this is a non-issue. I have a set of vertical docking tool holders that have done over 10k changes each with no appreciable wear. I would still call them a consumable but they don’t wear fast.
If wishes were fishes…
I’d spent my time fixing the real problem, the dust manifold. The lousy few centimeters you hope to reclaim in your workspace aren’t going to pay for the effort.
Best of luck though.