The Micro Lathe: New Tool Changer Electronics
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- Опубліковано 25 сер 2024
- Tired of unpredictable and unwanted tool changes? Me too. I allowed myself a bit more space and made a nicer circuit using a real Arduino. Everybody knows electronics don't work well unless they're in a pretty box, so I made one of those too. The code and schematic can be found on my Patreon for free!
Instagram: hlaps1990
Patreon: www.patreon.com/hlaps1990
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Love seeing more about this project. Thanks for the update.
this is so cool, cant wait to see the machine going with full tool changes, great job!
Thanks!
I have had problems with floating inputs causing my tool changer to pizza when it was supposed to french fry. I had a bad time.
Stan Marsh? More like Stan Darsh.
hlaps1990 I'm glad you got the reference. I was worried I might come off as a right weirdo.
Pete, we really do hang out in the same places! This guy is ace. I'm going to emulating some of hlaps1990's stuff HARD soon! Especially now I've lost access to that awesome FANUC lathe...
You are definitely a good engineer
thanks!
Great looking case. It's easy to line it with Kapton sheets. You can get them from McMaster Carr and some have a silicone adhesive backing. If you have your controller track what tool position is currently active, and if your controller knows how many steps between tools, when a change tool command comes, it's not hard to figure out how many steps to get to the target too, plus a wee bit more so you can back up and hit the ratchet pawl. But your motion control scheme should be a reiterative loop that minds the speed ramp starting out and lets you accelerate to max speed and automatically know when the number of remaining steps to go is below a certain value to start ramping the speed down. The trick with steppers is to minimize rotating mass and friction.
So the funny thing is, the controller never actually tells the turret what tool number to go to--it just tells it to go forward until it it sees the tool number it wants and then tells the turret to stop. Eric actually wrote a serial communication protocol for debugging that lets you command an actually tool number and that works quite well, but no controller uses anything similar. I've been quite surprised at how basic a lot of the turret command strategies are, but I guess they're simple and inherently safe.
The machined enclosure is very beautiful, forget extruded profiles with caps or 3D-printed plastic. If something shorts out one day, it will be worth it, haveing had the pleasure of looking at the machined case.
Thanks! I have so little faith in the electronics I feel like the risk is about the same if they were in a plastic enclosure:P
Awesome looking enclosure. Would look fantastic to see anodized. I did have to look up definition of "diminutive machinists." :)
Would you consider it too punny if I said maybe it went over some people's heads?
A bar feeder is a must have. No, just kidding. For home use i would be pretty happy with a small lathe with such a tool changer ;-)
to heat sink to the case maybe try adding some of the rubber thermal pad to the top of the heat sinks you already have? nice a squishy so tolerances can be quite rough
Hmm i had never heard of squishy rubber thermal pads. I would have used a paste which would not have filled the gap very well. Interesting..
hlaps1990 the paste is much better. But this is exactly the kind of thing the pads are destined for... They use them to cool the regulators on video cards, you can get it quite thick too
If you've not found them, try searching "Thermal - Pads, Sheets" on digikey. They have pads up to an amazing 1/2". You're doing amazing work!
Well I haven't machined the top yet, so maybe I'll look into them!
Thanks Kent!
I've heard that there are little things called ferrules that you can crimp onto the end of stranded wires which get you a long way away from stranded-wire-screw-connector hell. Saw it in one of the most recent AvE videos about VFDs, if you check those out (which you probably already have) you could see more on that. Looking great though!
What version of Tormach mill is that?
I second the ferrules. I use them at work for wiring our plasma tables. They work great and look professional as well.
Search eBay and you can find all the stuff for ~$30 bucks to get few sizes of ferrules and the crimping tool. Worth the investment if you make a lot of wire ends that need to go in screw blocks.
I don't recall seeing ferrules! I'll have to check them out. The tormach is a PCNC1100, but I think its pretty old.
Here's an Amazon link: www.amazon.com/Ferrules-Assorted-Connectors-Insulated-Assortment/dp/B01MTA7J1G
The last place I worked at, ferrules were strongly encouraged on ALL wires going into screw terminals. It makes things much more... magical I guess. No more fuzzy wire ends or dealing with stray strands trying to short on you.
Ferrules is a good option. To get the proper performance from them. Ther is some sience to it. But generally, smack on a few solves moste of the problems. Keeping wiring away from magnetic sorces. Or high current AC. Is a good practis in wire routing. Adittionally you can twist the wires and put a crimp shield over it , connected to signal ground.
Another idea, you could electrically insulate the inside of your case with the conformal coating that electronics manufacturers spray on circuit boards.
Hmm maybe a lacquer or something would work...
Yep, some of these types of coatings are sold as Acrylic Lacquer. If you search Amazon for conformal coating, you get plenty of options. MG Chemicals usually makes pretty good stuff.
I would totally buy the turret from you. :)
Well then if i ever do a production run I’ll let you know!
@08:49 Multi-core wires have to terminated with a ferrule to prevent them from fraying / reducing their cross-section / coming loose when used in a screw terminal.
Here's what you're looking for: www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Dtools&field-keywords=ferrule+crimp
I have since discovered this and am absolutely hooked on these things! They make everything so much easier!
Great video- I'm a bit confused about your stepper scheme- are you using the hall sensor to index position instead of just programming the stepper driver to move (Y) steps to the relevant tool position? Or are you using it as a home switch just to find tool position #1? My first few CNC projects used connectors like those DB-9's because I figured the wire was shielded and the connectors would not get full of chips- however, I have since quit those and am using either amphenol connectors or Chinese aviation-style connectors, which IMO are WAY better, and still pretty inexpensive. The DB-9's tend to get coolant and grime into the housings and the pins are really not up to passing motor currents over 2A or so.
Im using the hall sensor as a home switch. There are actually 2 magnets and some functions in the firmware that let it identify different turret heads by the placement of those magnets, but controllers dont really support that for now. I like chinese aviation style connectors as well, i was just pressed for space :p
I can't help think that you should have used D connectors with threaded fixing bolts to prevent the connectors working loose. I think the aluminium case, whilst it looks great, is a risk when it comes to potential shorts. Be aware that the more voltage you drop with your voltage dropping Arduino power board the more heat it will produce and heat sinking may be required at 24 volts. Your tool turrets look great!
Thanks Pete! Yeah the threaded studs were a weird size (a bit too long) so I omitted them for the video, but I think I'm going to extend the studs out of the housing and fasten everything with M3 nuts. Good point for the voltage regulator, maybe I'll look into heat sinking it somehow, though the datasheet seemed to indicate it was fairly efficient.
I am rebuilding my CNC turret
And I also use stepper motors
The original small motor
Probably not a suitable choice
I put the position sensor installed in the back of the stepper motor, the use of Hall sensors
In fact, I have conceived the stepper motor placed inside, but there is no way to change the motor shaft, if there is a way to replace the motor shaft, perhaps smaller size
My work is relatively busy, not too much free time to diy, so
It will take a long time for my small CNC turret to finish
Sounds like you're encountering one of the same problems I did -- the motor shaft just gets in the way. I ended up drilling out the back of the turret shaft to the size of the stepper shaft and making a weird built-in coupling thing, but there a all kinds of reasons that's not a good idea. Let me know if you want any advice!
I think you need a atc mill project!
Perhaps some day! I am playing with a few ideas that a mill ATC might come in handy for... *hint hint*
don't worry about a bar feeder, make a bar puller! we use them in industry
Fair point. I feel like the hard part for either design is a small automatically closing collet or chuck... ill take a swing at it one day im sure!
lol was the billet case really necessary? awesome project though!
Necessary? No. Worth it? Definitely :p
9:00 put ferrules on your wires
edit: to combat the pulling I mean
I've just heard about ferrules from comments in this video -- I'm going to check them out!
Do you sell these?
I may at some point, I just finished designing what I hope is the last version for my new lathe project.
11:15 jaws anyone?
Or you can buy a cast alu Hammond enclosure.
Yep for a fraction of the price:P
great video.. congratulations.. nice job.. we are working on a similar project, you can check our machine in our channel man..
Yeah I've seen your machines, they look awesome!