QuoteMKSA @boggen79 This thread has been dead for more than a year ! Let bad ideas, unsubstantiated claims rest in peace for fear that like vampires they pop up again You should consider talking to someone about your feelings. Carrying a weird unsubstantiated grudge for over a year isn't healthy. Best of luck in your healing!by Apsu - Look what I made!
QuotePougnagna Hi Apsu (and everybody else), I've registered an account only to make you sure your work is still closely looked at. It was exciting to read every post in one go, and I'm now like a kid in a candy shop. Thank you for all you have done and for what is coming! Hey there, sorry for the delayed response. I appreciate the feedback and sentiment! The project has been a lot of fun, buby Apsu - Look what I made!
QuoteJoergS5 I offered the ideas only because in your second video at second 18, when you change from X motion to Y motion, there is a jerk in the gears which may produce X direction errors. I thought this is due to backlash, but this may have another reason. I agree that using flexible material will create other problems. Yeah, I saw it as well. Some of it was definitely backlash between theby Apsu - Look what I made!
QuoteJoergS5 This a very interesing idea. If you suffer from backlash in the gears, you can try a friction drive (with 90 degree pivoted), or the idea of Looking forward your further development! Thanks! I'm really trying to stay away from flexible materials entirely, that's one of the goals here (as well as simplicity and low part count/high temp materials), so I'm not looking at 90deg beltby Apsu - Look what I made!
Quotethe_digital_dentist Cool! Sound? It's coming, the TV was on when I took those videos so I muted it. I will make a better video with explanations/commentary of the parts and design and operation very soon, and get the X carriage mount in place so it's easier to see both axes.by Apsu - Look what I made!
Update time! It works!! First moves X only then Y only The left gearbox has some spacing issues and extra tooth-tooth backlash as a result, but that's fixable. I'm just super excited that it works on stock CoreXY kinematics and demonstrates all three differential behavior modes correctly. I'm going to get the X carriage connected to the X screw with a nut and work on the gear mesh, then I'llby Apsu - Look what I made!
QuoteTrakyan I get you on not wanting flexibility from cables, but what I'm talking about the cables are very short, they are only enough to wrap around the two drums that are almost touching in a figure 8 type arrangement, they serve to take out backlash/slop more than transmit force. It was just a suggestion for some ghetto low backlash gears. Why would the worm need to back drive the pinion?by Apsu - Look what I made!
QuoteTrakyan Well someone came out from under the bridge. Anyways, the "parasitic" effect I was meaning mostly is if friction between the nut and screw causing the nut to spin with the screw (thus not moving axially as it should) rather than stay stationary when you want it, or vice versa friction in the bevel gears stopping the nut from rotating freely with the lead screw (and thus causing it tby Apsu - Look what I made!
QuoteVDX ... an interesting "slip-free" alternative to gears are two strong ring-magnets with beveled perimeters Interesting idea! Not sure how well that'd actually work or how easy to obtain for testing, but interesting.by Apsu - Look what I made!
Quoteleadinglights QuoteMKSA ............................................................................. So no need for "conversation", just build the prototypes and prove your points. ....................................... Hmmm, and I always thought that a forum was a place you come to discuss ideas, to have a conversation. I never realised that it is just a place to present a glorious andby Apsu - Look what I made!
Quotecozmicray Perhaps a sprial bevel gear they are very smooth and used in Hi torque applications (differentials) ?What is the best (smoothest) right angle gear configuration? Have to also consider the locking of the gear? Yes indeed, I am actually using spiral bevel gears right now. They are excellent for this application. I'm not sure what you mean by "locking" though. Do you mean fastby Apsu - Look what I made!
QuoteMKSA QuoteApsu QuoteMKSA What kind of test did you carry to back your claims ? I'm not sure you're following what I'm presenting here. The items I listed as potential benefits over a belted system are observations of facts based on assuming a well-executed build in terms of materials and mechanical construction. There's no testing required to note the advantage of a screw over a belt in thby Apsu - Look what I made!
QuoteMKSA What kind of test did you carry to back your claims ? I'm not sure you're following what I'm presenting here. The items I listed as potential benefits over a belted system are observations of facts based on assuming a well-executed build in terms of materials and mechanical construction. There's no testing required to note the advantage of a screw over a belt in the aspects I mentioneby Apsu - Look what I made!
QuoteMKSA . A CoreXY is also a "differential" based system. I fail to see the advantages, as for issues, you noticed a few already. There's quite a few potential advantages if executed well. I mention a bunch at the bottom of the github document, but to recap: No long complex belt paths means less issues with tensioning/alignment/pulleys/tiny bearings/hysteresis/stretch/temperature. Easier matby Apsu - Look what I made!
Quotethe_digital_dentist Interesting, but I suspect the hardware to make it work is going to be pretty expensive. My experience with using cheap gears to make a belt lifted Z axis tells me that any flaws in the gears are going to show up as repeating defects in the prints each time each of the gears makes one rev. You're going to need very high quality (read expensive) gears to make it work weby Apsu - Look what I made!
Thanks for the kind words on the *pteron work! You are indeed correct that backlash and friction are the enemy here, but I think they can be mitigated fairly well. My current design is using spiral bevel/helical gear profiles, which mate extremely well and have almost no detectable backlash (more on this in a sec). I am also using carefully fixed spacing and sizing of parts to maintain a solid gby Apsu - Look what I made!
Hey folks, After spending many years on my Tripteron and Delteron projects, I recently came up with a new and, I believe completely unique, parallel XY gantry design. I've been developing it for about a month now, and figured I'd post about it here. I call it DiffBot, and there's an in-depth writeup with pictures and animations here. The general idea is to use screws (leadscrews in the prototyby Apsu - Look what I made!
Thanks Nicholas, I appreciate your input. I did pursue the non-commercial aspect and even talked about acquiring the patent, and they informed me that they value it for its commercial and research potential, and are only willing to license for commercial use. I also met someone who worked on a *pteron industrial machine, so they have had some large commercial licensees in the past, which makes itby Apsu - Look what I made!
I've decided to put this thread on hold. It's too large and I'm really the only one posting now. I have run into some patent licensing roadblocks (they want a company to license to with a business plan and sales forecasts to determine royalties, etc), as well. If I develop this idea or specific design further, I will post something new, but for right now I don't have a lot of new things to say.by Apsu - Look what I made!
Welp, I decided to go ahead and model it up. I was able to connect everything with literally just the parts from 80/20, which is kind of amazing. I got a clever idea about using a 2"x2"x2" extrusion for the effector and with a little more mounting cleverness, it works shockingly well. I also reduced the outer frame lengths to 16" instead of 18", to avoid Z arm jackknifing. Here is a video link aby Apsu - Look what I made!
Welp, turns out, even for shops that specialize in small runs of custom parts, these pieces are going to be extremely expensive to do in milled aluminum. I'm investigating an alternative approach right now, using a US vendor called 80/20. They have a variety of awesome products centered around aluminum extrusion, and although they do have some common metric sizes like 2020, they mostly deal withby Apsu - Look what I made!
Hey folks, sorry for the delays, got hit with a bunch of work stuff and took longer to make some progress in redesign work. I also have an update on the patent situation. I'm in talks with the University that holds the patent on obtaining a license, and I likely will be able to obtain one for the purpose of a small startup with an eye towards being legally able to sell kits or completed printersby Apsu - Look what I made!
QuoteOhmarinusWhat if you were to use long polymer bushings or some long version of this: I think that could take care of both having linear movement as well as rotational movement and have a tight diameter without much play? Am I missing important details why this is or isn't a good idea? I definitely think polymer bushings are a great way to go, and in fact that's where I'm focusing right noby Apsu - Look what I made!
So I've been thinking about this a lot lately, and I think that one of the difficulties I was facing even with the machined joints is that the bearings are the weakest point now. It occurred to me that I only went down the bearing route in the first place because I was trying to solve for printed joints. But if I get the machining route, there's some extremely simple and cheap to make part geometby Apsu - Look what I made!
Hello anyone still following this thread! Man, it's been a while. I've had a lot of major life events happen that have kept me away but I haven't given up on the Tripteron development process, and I believe I'm in a place now where I can continue. I also got a new job (one of those life events), and now work for a subsidiary of Autodesk(!), which means I have full access to fun tools like Fusioby Apsu - Look what I made!
Hey Scotty, That was referring to the second design I began working on, where there's an angle the actuators are rotated with respect to the arm joints. The actuator arms have 3 joints -- actuator-arm, arm-arm, arm-effector. So really when I say "joint plane" I mean that those three joints are all aligned the same. However, how the two end joints attach to the actuator and the effector has a fixby Apsu - Look what I made!
Quotebrazenrain In the meantime I'm looking into these. How do you think delteron will hold up with 10mm arms? Oo interesting. I mean, it really depends on frame scale. In the 300ish XY frame member scale, and thus 300+ arm length scale, it seems like 15mm links is just big enough. However, if those hinges can be low enough friction without a lot of slop (getting the nut tightness just right frby Apsu - Look what I made!
QuoteMechaBits Nice joints, musta cost a packet, looking forward to seeing them in action. Yeah, me too! They were reasonably priced considering. About $65 for the pair, he was asking, but I did pay the guy extra because he did great work and treated me great. Forging that relationship is worth it. And really, cost of prototyping... I knew what I was getting into Not going to be cheap, but I hoby Apsu - Look what I made!
Prototype machined joints came in! Bolt holes are nice tight clearance fits, bearings fit great, tolerances and clearance are great, and the joint is, as expected, rock solid I paid for these and asked the guy to make the other 10 for me, because for the rapid turnaround time and one-off nature this is perfect. Should have a machined assembly put together in a week or two looks likeby Apsu - Look what I made!
Quotebrazenrain It sure would be nice if there was a 15mm version of this. You could just throw in some slippery washers or thrust bearings and be done with it. Yes indeed! I've looked a lot at the die-cast and similar extrusion pivots, but they're really expensive. Well... they were really expensive, before I got to the point of getting joints machined which definitely costs more I'm not sureby Apsu - Look what I made!