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Re: Motion unit development - 4 years ago
It has been quiet for some time now around the motion system. I've been waiting for the 1 mm braided Dyneema line with a reflective pattern. I should have paid a little bit for shipping with a faster parcel... Hopefully I get the line before Christmasby atmark - Hangprinter
Re: Motion unit development - 5 years ago
That's a great idea! I was already thinking if the fishing line guides would be able to handle the stress at all. The ceramic eyelets are way more compact and you can insert them in a solid block for more resistance to the expected stress. The current 6 mm wide GT2-belt allows two grooves at maximum. There are also 20 mm wide belts. Or maybe it could work also if the line winds only few times unby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Few thoughts on helical drum winches: The Fraunhofer Institute uses them in their IPAnema cable driven parallel robot. The pictures and concept images show a pretty solid approach and I think it is currently the best way to implement the motion system. But, there's a major misconception when it comes to scalability. The area of end-effector movement is limited by the size of the drum and at someby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Quotetobben Interesting! Is the length of each color segment ca 4 mm long? If each impulse measures a color change, then the readout will be 4 mm * 150 impulses/sec = 600 mm/sec Do I understand correctly how the sensor works? Yes, the distance from one color to the next segment of the same color is approx. 4 mm. The sensor sensibility is tunable by a potentiometer, so you can set the thresholdby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Thanks Tobben for the info! I will reflash my Odrive soon. In the mean time I did some experiments with the black/yellow-striped PE-line I bought. It is twisted, so it won't work in the printer, but for testing the concept its perfectly suitable. So, I printed a small casing for the Seeedstudio IR-proximity sensor with a small channel to guide the line in front of the sensor. Then, I compiled thby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Update: The rig is now ready. I made a secondary spool with a build in spiral spring. One end of the spring is fixed to the spool and the other end on the axle. The spring is pretensioned before the line is attached to the spool. That way it automatically winds in the line the first spool is feeding and vice versa. It works very nice, basically its the same wind in mechanism as in your vacuum cleby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Got it. I had a old firmware on my ODrive, after an update it worked and I also worked my way to the point that I can spin the motor!! Video: testing the motor Next, I'm going to combine the motor bracket and the spool bracket into one single piece. I think it's bit easier to get the belt and the line deflectors aligned properly that way. Btw, I've been thinking lately about a round timing beltby atmark - Hangprinter
Re: Motion unit development - 5 years ago
@tobben Ok, so far I was able to setup the rig, setup Duet and now I'm configuring ODrive. I ran at this point into an issue while setting up the step_gpio_pin and dir_gpio_pin Both will give me this error: "Attribute step/dir_gpio_pin not found" Did you encounter something similar? Any advise before I dive into ODrive docs?by atmark - Hangprinter
Re: Motion unit development - 5 years ago
QuoteJoergS5 @atmark I bought the Zylon yarn now. If you have a test setup for me, I can measure the properties after receiving it. Hey, that's cool! I just need to build my test rig first. Also, I would need to know the yarn diameter once you can measure it. For now, I can confirm that the GT2 spool made of PLA can't hold the line, it slips under the belt no matter how tense it is. So, the suby atmark - Hangprinter
Re: Motion unit development - 5 years ago
QuoteJoergS5 Another interesting material is yarn from PBO Zylon Yes, this is also interesting. Quick googling brought up a japanese fishing line manufacturer called Yotsumi. They have a Zylon base product line called YGK. Its a 5 m long line so it would about a suitable length. But its really expensive. 20-25€/5m :Oby atmark - Hangprinter
Re: Motion unit development - 5 years ago
QuoteVDX ... you can try with "high elastic" steel wires -- have some with outer diameters from 0,3mm upwards ... That's interesting. Seems to be a kind of spring steel? Do you have a supplier and/or some material specs for me?by atmark - Hangprinter
Re: Motion unit development - 5 years ago
What would be the ideal line in your opinion? I was thinking of carbon fiber yarn. I actually bought some a while ago. Plain yarn with 2 or 3k fibers. It truly is extremely strong, but it wears fast in its natural form. One option would be to soak it in polyurethane and let it cure. This way the fibers would stay neatly bundled, but it would also have a strong and flexible shell. Its not impossiby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Ok, here are some pics and vids of todays testing. I found two identical steel pieces, each way over 4 kg (the gauge maxed out). They might weight around 5 kg. So, I put first one to each end of the line to have a counter balance. Then I attached a power drill to the motor axle and spun it a little. That went well. After that, I replaced one of the weights with a set of allen keys, just enoughby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Quotetobben The line will always be twisted though. How would the system cope with that? And how would it behave if the line got very slack? Could we route the line through a very thin transparent tube, to keep it from kinking under the sensor? For such a sensor to be useful, it would need to be very fool proof since so many weird things can happen during a print. That are very good questions! Iby atmark - Hangprinter
Re: Motion unit development - 5 years ago
Quotetobben If the fishing line has any flex at all, this will affect the readings. So if the line (and hence the pattern) is stretched out, you might wind in 10.1 mm when you thought you did only 10.0. On the other hand, since you're detecting the pattern, you'll know when you have unwound the same segment of fishing line, regardless of how stretched it was when wound and unwound. This makes theby atmark - Hangprinter
Motion unit development - 5 years ago
This thread is split up from the main thread. Down below you'll find previous discussions about the concept. Quoteatmark I'm currently designing a bracket for the HP4 bldc servo motor and the spool, and I wanted to share my tests so far. The bracket is meant for the ODrive D5065 motor. My goal is to design a single motion unit, that includes the motor, a belt tensioner and the spool system in onby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Let me do a dedicated thread to this topic, and we continue the discussion thereby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Yeah, I was quite amazed too to be honest. The line snapped 5 mm before the knot I made to hold the weight. So the CF spool didn't have any effect on the snapping. I'm aware of the abrasive nature of CF, so it's not said that it could not happen, but in this case it didn't. I can print a new spool out of PLA, no problem. It will be interesting to test it. Let's see how I can setup a test rig. Tby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Thanks! I just put a heavy weight on the line and looked first if the line holds, and after I couldn't see any slipping, I bounced the whole system until the line snapped Video: testing slipping No slipping what so ever I believe the line should be able to handle 40 kg of drag, so friction-wise I can't see any issues. Obviously the long term failure rate is a question mark, but I think it migby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
I'm currently designing a bracket for the HP4 bldc servo motor and the spool, and I wanted to share my tests so far. The bracket is meant for the ODrive D5065 motor. My goal is to design a single motion unit, that includes the motor, a belt tensioner and the spool system in one rigid frame, which I probably am going to lasercut out of sheet metal. For now, I'm still thinking about the spool systeby atmark - Hangprinter
Re: The "three wires suspended" hangprinter - 5 years ago
@tobben Yes, you're right about the replacement of one structure with another. And also its not optimal in regard to the achievable height. But, I believe we would be able to get more usable print volume that way. Also, for the Hangprinter's concept core essence of scalablity, it is nessecary to be independent of the high point structure directly above the print surface. If one wants to scale upby atmark - Hangprinter
Re: The "three wires suspended" hangprinter - 5 years ago
Recently, I've been thinking about the same approach to the frame design. Basically I want overcome the necessity of having a structure at a high point above the print surface. My current frame design has almost all the mechanics and electronics attached to the base plate that is installed at the tip of three legs. It has proved to be difficult to calibrate and to maintain, since its in 2,5 m heiby atmark - Hangprinter
Filament hot swap - 5 years ago
Now that we have done some big prints I started to wonder if we could use the Prusa MMU2S for hot swapping the filaments during long prints (and why not multi color printing for that matter too). The SuperVulcano consumes a one kilo spool fairy quickly, so it's not possible to span the print over the whole length of the night. We are doing a lot of prints that are tight on schedule, so we would lby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Quotetobben Could it be that the plastic trace will look different when going clock-wise versus counter-clock-wise? Yes, this seems to be the case. Could this be an issue with flexing of the line spools since their axle is supported on one side?by atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
The last project was sliced with cura 3.6 and the gcode wasn't as smooth as the code produced by simplify3d. The printhead jittered quite alot when printing the cura code. Also the print speed might have been a bit too high. But the biggest improvement so far has been the huge 1000 mm dia silicone heater mat, which I got installed a week ago. No more issues with first layer adhesion.by atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Hey Do you have had similar issues with print quality than I had with the last project (still going on)? The skin was partly separated from the printed object and that caused issues during post-processing (sanding, etc.) It affected only the outermost wall, the inner walls were connected as they should have been. Here's a picture of the crime scene. Any suggestions are warmly welcome, since I'mby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Hi pvsfa Those extruder clones might come as a cheap ootion, but from my experience the extruder/hotend combo is a critical component where you really should invest in quality hardware. For example e3d or Bondtech. I once ordered e3d Titan clones from China and they were so badly manufactured that they were practically not usable. Since then I'm sticking with e3d. It saves you the hassle, trustby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Ok, major disaster... One line snapped while printing overnight And the culprit seems to be here in picture The line sheared at the point where it enters the anchor at the top. Also for some reason the line at the bottom has been almost torn apart. It's the only line looking like this. Maybe the bearings are faulty or something. Anyway, I think there should be a safety measurement to kilby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Hey, does anyone have experience in attaching a z probe to the hangprinter. I'm working currently with the precision piezo orion module which measures the z height by the nozzle tip. It's already attached to the extruder, but I'm having issues configuring the firmware. There's a tutorial on thingiverse how to tweak Marlin, but after doing the changes it won't compile. I'll put the compiler outpurby atmark - Hangprinter
Re: Hangprinter version 3 - 5 years ago
Actually, this my own design, but it is based on your older design. I added a third slot for the center beams that connect the extruder carriage to the mover. I'll add some new pics on wednesday. If you like, I can share the design. Althpugj, it will undergo few redesigns when I get the time for it. It's still missing stress relief for the cables, a signle, magnetic, connector for all cables. Andby atmark - Hangprinter