In response to many of the comments, yes, my R2 is printed using PLA/PLA+. For the particular part in question, the portion that broke was effectively solid - nothing but perimeters. For this particular instance, the nature of the part requires a degree of flexibility as the surround is cinched around the motor to hold it in place. PETG generally has a bit more flex to it and could be a better material to use for this part. I've noticed some things printed in TPU have lost some of the flex over time, and wonder if anyone has any insight into the stability of PETG over extended periods of time. FWIW, I think that regardless of the material used for your build, you want to be vigilant and inspect/check your build periodically. I strongly believe this could happen to any build.
It took some digging but you want to look at a chart that talks about Elastic Modulus(AKA Young's Modulus). This is stress vs strain, the higher the number the more stiff it is. As you describe standard PLA(not +) is 40% higher here based on the chart. There is also the heat factor since it is close to a motor, PLA is known for less temperature resistance which will reduce many mechanical properties. Elongation at break is notable in the chart, 7% for PLA vs 130% in PETG, this shows that PETG is MUCH more flexible compared to PETG. PLA does show a higher yield and tensile strength which means it shows deformation at higher stresses, but I think the more flexible nature of PETG in your application would show an improvement. The real question I have is, if that is enough to cause an improvement in the application. ABS would be a much more noticeable improvement but comes with its challenges for printing. matmatch.com/learn/material/petg-vs-pla
Neat link, thanks for sharing! CNC kitchen has also done some excellent videos comparing various filaments and other build techniques. He gets pretty technical with his setups and his data is often surprising.
I am not even finished with my R2 Body yet in my build and now see a lot maintenance effort... oh boy, more fun ahead... You did well to open up all drive parts... thumbs up!
It's fortuitous you posted this. I was laying in bed last night thinking I should really restart my R2. I started him and stopped due to the poor quality of prints I was getting and it kind of took the beep out of my boop. 6:15 I started my R2 on a Creality XR10 2 years ago and now I have a Bambu Lab X1Carbon with AMS and man the difference is amazing. So glad I upgraded, with the new Prusa and the Bambu labs printers, the days of screwing around with adjustments, fixing issues etc are gone. I just printed a 8foot x 5 foot gaming table surround and went through 22 rolls of filament without a single fail (other than some mistakes I made). This new generation of 3D printers are more like appliances than they are printers we started with years ago. I am probably going to restart him again with my new printer and save myself a ton of sanding/finishing work. Thanks again
The past 12-18 months has been huge for 3D printing. It would seem the FDM technology has finally turned the corner. By all means, kick-start your build again. It's challenging but fun and a very rewarding journey.
Ouch, glad you caught that before it got any worse. An excellent reminder for everybody to remember to do regular droid maintenance! What a difference in print quality on the XL.
Areas vulnerable to splitting, you could laminate with epoxy resin some carbon/glass fibre tape over those areas to help stop them splitting in future. Epoxy wont attack the PLA and the carbon tape will help add a fair bit of strength. Composite laminates can still flex so you could vary the number of layers to ensure you still maintain enough flex to clamp up the bracket.
It's the one area in consider fabricating out of metal instead of printing. I'm far away from this still but have been reviewing drive stall currents when designing my electronics. The vexx wheel upgrade always made sense to me but I think I need to consider a non printed drive for the critical structural components. I just started reading on scavenger drives on the forum.
Absolutely! There are shells designed to fit around the scavenger drives already available in the Baddeley file share. As I mentioned, I don't drive R2 aggressively, but that doesn't mean I won't ever hit a bump or some other hard-to-see obstacle and risk catastrophic damage. I will keep an eye on R2 as we (hopefully) attend a lot more events this year. I hope not to have to update/replace the drives, but you gotta be prepared for the unexpected.
I will be following this closely as I am hoping to dive into the body and drives of R2 next year, hopefully getting the dome wrapped up or at least close to it in 2023.
Thank you for the update! Did you print the parts in PETG? I've been concerned about mine too but I haven't even gotten it assembled yet. They are printed in PETG which was a nightmare to get the supports out. The Allen key trick: Yeah, I had that problem too and yeah, I figured out the allen key after a lot of swearing and attempts to use other tools to hold the nut in. :)
Mine were/are printed in PLA/PLA+. There were enough perimeters, though, where the part that wraps around the motor was effectively solid. My understanding of PETG is that it tends to have slightly more flex than PLA, so for this application (where the surround is cinched around the motor), PETG might be more forgiving, but I think all 3D printed materials gradually change/degrade over time. I'll pin a comment for additional discussion.
Im actually in the middle of redoing my drives because of the same reason. I came across a split drive file on printables that the clamp piece is its own piece and it just bolts in i plan on printing the clamp itself out of petg then the rest of the drive out of pla+ check it out might be helpful
I pinned a comment above. My build is PLA/PLA+. This is the first time I've seen any sort of significant break in any parts - until now, R2 has been very reliable.
What is the black ring at the 3:35 timestamp? Is that a neoprene washer and are you using it between the wheel and the housing? If so, doesn't that just rub and make friction?
It is a neoprene washer - I opted to use that instead of a printed spacer as called for in the original design. It's not really tightly compressed into place - it really just takes up the space. Although a metal washer would probably be more durable my thinking was the neoprene would provide a little cushion to vibration or bumps. Hard to say how much of a difference it really makes, though.
Do you have software to ramp your drive speeds up and down or are they bang-bang start and stop? This can make a large different to the force applied to the motor mounts?
For the stock arduino Shadow code, I don't think there's any hard-coded, overriding ramp-up acceleration included. As was mentioned, the speed is variable according to the input stick, so I can drive R2 very slowly by simply being careful on the stick, but I think I get what you're saying that there could be a ramp up in the code to ease in regardless of the stick input.
@@jasonsR2D2 Yes. Even requesting to go from 0% speed to 25% speed will impart a high jolt of torque to the mounts. Whereas if your joystick requested 25% but the software ramped 0-5%-10%-15%-20%-25% even over a fairly short period of time (say 50 or 100ms per 5% step) will greatly reduce the torque and therefore strain on the motor mount while have a barely perceptible change in performance.
That would probably be the strongest way to repair it - and the best approach if you really had little time, but you would want to make sure it is smooth on the inside so that it makes uniform contact with the motor to hold it in place. I set up the print before bed and it was done when I got up in the morning, so that turned out to be pretty painless!
In response to many of the comments, yes, my R2 is printed using PLA/PLA+. For the particular part in question, the portion that broke was effectively solid - nothing but perimeters. For this particular instance, the nature of the part requires a degree of flexibility as the surround is cinched around the motor to hold it in place. PETG generally has a bit more flex to it and could be a better material to use for this part. I've noticed some things printed in TPU have lost some of the flex over time, and wonder if anyone has any insight into the stability of PETG over extended periods of time. FWIW, I think that regardless of the material used for your build, you want to be vigilant and inspect/check your build periodically. I strongly believe this could happen to any build.
It took some digging but you want to look at a chart that talks about Elastic Modulus(AKA Young's Modulus). This is stress vs strain, the higher the number the more stiff it is. As you describe standard PLA(not +) is 40% higher here based on the chart. There is also the heat factor since it is close to a motor, PLA is known for less temperature resistance which will reduce many mechanical properties. Elongation at break is notable in the chart, 7% for PLA vs 130% in PETG, this shows that PETG is MUCH more flexible compared to PETG.
PLA does show a higher yield and tensile strength which means it shows deformation at higher stresses, but I think the more flexible nature of PETG in your application would show an improvement. The real question I have is, if that is enough to cause an improvement in the application. ABS would be a much more noticeable improvement but comes with its challenges for printing.
matmatch.com/learn/material/petg-vs-pla
Neat link, thanks for sharing! CNC kitchen has also done some excellent videos comparing various filaments and other build techniques. He gets pretty technical with his setups and his data is often surprising.
I am not even finished with my R2 Body yet in my build and now see a lot maintenance effort... oh boy, more fun ahead... You did well to open up all drive parts... thumbs up!
Thanks! Chalk droids up as another "thing that's never really complete."
It's fortuitous you posted this. I was laying in bed last night thinking I should really restart my R2. I started him and stopped due to the poor quality of prints I was getting and it kind of took the beep out of my boop. 6:15 I started my R2 on a Creality XR10 2 years ago and now I have a Bambu Lab X1Carbon with AMS and man the difference is amazing. So glad I upgraded, with the new Prusa and the Bambu labs printers, the days of screwing around with adjustments, fixing issues etc are gone. I just printed a 8foot x 5 foot gaming table surround and went through 22 rolls of filament without a single fail (other than some mistakes I made). This new generation of 3D printers are more like appliances than they are printers we started with years ago. I am probably going to restart him again with my new printer and save myself a ton of sanding/finishing work.
Thanks again
The past 12-18 months has been huge for 3D printing. It would seem the FDM technology has finally turned the corner. By all means, kick-start your build again. It's challenging but fun and a very rewarding journey.
What Prusa did you go for?
Ouch, glad you caught that before it got any worse. An excellent reminder for everybody to remember to do regular droid maintenance! What a difference in print quality on the XL.
Great catch. I had similar banding in my foot shells ....recently made some changes including running clipper. I may go back myself and reprint them.
Great video. One to keep in mind
Nice catch! Glad you were inspecting it!
Areas vulnerable to splitting, you could laminate with epoxy resin some carbon/glass fibre tape over those areas to help stop them splitting in future. Epoxy wont attack the PLA and the carbon tape will help add a fair bit of strength. Composite laminates can still flex so you could vary the number of layers to ensure you still maintain enough flex to clamp up the bracket.
It's the one area in consider fabricating out of metal instead of printing. I'm far away from this still but have been reviewing drive stall currents when designing my electronics. The vexx wheel upgrade always made sense to me but I think I need to consider a non printed drive for the critical structural components. I just started reading on scavenger drives on the forum.
Absolutely! There are shells designed to fit around the scavenger drives already available in the Baddeley file share. As I mentioned, I don't drive R2 aggressively, but that doesn't mean I won't ever hit a bump or some other hard-to-see obstacle and risk catastrophic damage. I will keep an eye on R2 as we (hopefully) attend a lot more events this year. I hope not to have to update/replace the drives, but you gotta be prepared for the unexpected.
I will be following this closely as I am hoping to dive into the body and drives of R2 next year, hopefully getting the dome wrapped up or at least close to it in 2023.
Thank you for the update! Did you print the parts in PETG? I've been concerned about mine too but I haven't even gotten it assembled yet. They are printed in PETG which was a nightmare to get the supports out.
The Allen key trick: Yeah, I had that problem too and yeah, I figured out the allen key after a lot of swearing and attempts to use other tools to hold the nut in. :)
Mine were/are printed in PLA/PLA+. There were enough perimeters, though, where the part that wraps around the motor was effectively solid. My understanding of PETG is that it tends to have slightly more flex than PLA, so for this application (where the surround is cinched around the motor), PETG might be more forgiving, but I think all 3D printed materials gradually change/degrade over time. I'll pin a comment for additional discussion.
I would have to imagine the motors get warm as well which would reduce the mechanical properties
Im actually in the middle of redoing my drives because of the same reason. I came across a split drive file on printables that the clamp piece is its own piece and it just bolts in i plan on printing the clamp itself out of petg then the rest of the drive out of pla+ check it out might be helpful
Jason are you printing in ABS or PETG?
I pinned a comment above. My build is PLA/PLA+. This is the first time I've seen any sort of significant break in any parts - until now, R2 has been very reliable.
What is the black ring at the 3:35 timestamp? Is that a neoprene washer and are you using it between the wheel and the housing? If so, doesn't that just rub and make friction?
It is a neoprene washer - I opted to use that instead of a printed spacer as called for in the original design. It's not really tightly compressed into place - it really just takes up the space. Although a metal washer would probably be more durable my thinking was the neoprene would provide a little cushion to vibration or bumps. Hard to say how much of a difference it really makes, though.
Do you have software to ramp your drive speeds up and down or are they bang-bang start and stop? This can make a large different to the force applied to the motor mounts?
The speed is variable and top speed can be adjusted in the sketch for the arduino
@@chasenorman2862 Thank you for the response but I was asking more about the rate of change of desired speed rather than the top speed.
It's variable very sensitive you can go very slow or full speed and anything in-between
For the stock arduino Shadow code, I don't think there's any hard-coded, overriding ramp-up acceleration included. As was mentioned, the speed is variable according to the input stick, so I can drive R2 very slowly by simply being careful on the stick, but I think I get what you're saying that there could be a ramp up in the code to ease in regardless of the stick input.
@@jasonsR2D2 Yes. Even requesting to go from 0% speed to 25% speed will impart a high jolt of torque to the mounts. Whereas if your joystick requested 25% but the software ramped 0-5%-10%-15%-20%-25% even over a fairly short period of time (say 50 or 100ms per 5% step) will greatly reduce the torque and therefore strain on the motor mount while have a barely perceptible change in performance.
3d pen weld it?
That would probably be the strongest way to repair it - and the best approach if you really had little time, but you would want to make sure it is smooth on the inside so that it makes uniform contact with the motor to hold it in place. I set up the print before bed and it was done when I got up in the morning, so that turned out to be pretty painless!
is the original (broken) done with PLA/PETG or other?
just noticed all of the other comments asking about filament type. :)
we're probably, as a group, at this build process.
I pinned a comment above with more details about my build. Good luck with yours!
Thank you! I've printed quite a few of your printables files and they've been incredibly helpful!
@@jasonsR2D2