Odd circle test results (Page 9 of 24)

No improvement. Nonetheless this was something that had to be done. Off to print spares of the lawsy  parts in case I break one.

If this upgrade doesn't fix it that'll be sometning to behold lol

Here are my results. I made a video for them

https://www.youtube.com/watch?v=eJJtBVD … e=youtu.be

I'm in the middle of (among other things) putting in stronger Y idler brackets. I didn't have any problems with the big bolt, but the little M3 button heads holding the bracket on are stuck on with locktite. A heat gun worked for one of them, but the other one apparently had a stripped head, so I had to cut off the plastic bracket so I could grab the M3 screw that was now sticking out by the bracket thickness with a vice grip and unscrew it that way. Loads of fun. (Next up - try fishing line instead of putting the belts back).

Fishing line is in my future but I'm stalking on it because my vision will make it a bit of a pain. I'm gonna get some zip ties and see if I can tie into one of the holes and give the pulley enough tension in the opposite direction so I can at least not let my printer sit cold while I wait for rods.

The trouble it seems is that the part holding the x pulley in place was designed at a straight up 90 degree angle ... No ribbing or fillet for strength so this was bound to happen. Hopefully my zip tie idea works well enough to give the x belt a little tension. Otherwise hosed until rods come on Monday (shipping from Atlanta and I'm in Raleigh. McMaster-Carr has a warehouse in Durham but I guess the rods aren't there this time).

Yeah I watched it again and you may have the same problem. Mind doing another video at 60mm/s? You were printing pretty slow

It doesn't matter anyway. I have NO interest in getting the stock carriage to work. Anyone who wants good circles should put in the effort to upgrade to the lawsy carriage. Any other route is a waste of time and probably won't get you anywhere. But you're welcome to try. Now that mine is busted I have even less interest.

Might as well not resist putting in effort to make it work well. Do you want a 3d printer that works or hurt feelings? The issue is so minor that your printers are usable so you will have to make the time/effort vs results trade-off yourselves. The upgrade is not difficult; I know what to do already and I don't have a single part except the printed carriages. I spent $70, you guys could do it for $20 if you put in the effort to salvage your existing rods. I'm just being anal and throwing out all stock components to be on the safe side. Since we're all novices, I'll walk you guys through the upgrade if you are at all interested, but you're going to need to show some willingness to put in effort toward your printer.

I'm done thinking about circles... I want to master the art of 3d printing.

But I will post a perfect circle in this thread once I have it.

pics from fb post show stock sd3 doing this print perfectly too lol

I said probably if you get another solution to work you will be a hero to everyone who has this problem. upgrading the carriage is a pain in the butt but i anticipate i'll have it all done in 2-3 hours once i get the rods cut and test my bearings.

if I don't print circles after this ill probably set my solidoodle on fire. joking, but if this doesn't work the next step is the Y motor. I've already checked the case for squareness--have you checked yet? I forget.

I'm honestly shocked that gluing the rods in did not fix this. it did stop my belts from dancing like they were on a balance beam which means it is a step in the right direction. sadly i can't do any more testing until i find a way to put my X pulley in place. the stock carriage design broke on me when i took the X belt off. I guess it broke a while ago and was being held together by tension . that's why you don't use harsh angles in moving parts, bad idea Solidoodle.

if after replacing the y motor and the carriage i still have imperfect circles then the x motor goes as well. beyond that, it must be the frame or the rear bushings. ive already tried removing the stock pillow. im very ... excited ... to find out what the culprit is.

if my belts come from solidoodle before the carriage pieces ill put on new belts too.

I was going to test all of that before my Y carriage snapped.

There must be some difference because wardjr has owned a couple SD3s at least, and immediately pointed out the inferiority of the right side of the design on the SD4. There must be something different about it, otherwise he wouldn't have thought it was such a potential point of failure.

Im starting to wonder if the closed-loop belt design is also to blame. Taking that all apart again today, I realized that there is a huge potential for that to fail, what were they thinking? Open-loop would've been MUCH SMARTER. If those belts slip even a little bit inside that holder, all hope of perfect circles is lost. The parts they printed don't even perfectly match the teeth on the belt.  The lawsy carriage uses open loop, and so does the SD3.

You could print a part, glue it on to the existing belt holder, cut your belts, punch holes and hold them down with M3 bolts and an M3 nut. It certainly won't make your situation any worse to try this. Just cut it, punch a hole and match up the belts. It's what I'd try next, in fact I might as well if I can get my printer running again without swapping carriages.

All I can say is I'll try it if I get my printer going. I have to cut mine anyway for the lawsy carriage. The belts are only held down on one side with the existing design, I could see that being an issue. They should've used two screws, one on each side. The current design clamps harder on one side of the belt than the other. It has to--the screw is closer to one side than the other.

That's one difference between the SD3, which prints great circles, and the SD4, is the belt design.

I'm brainstorming. The number one rule of brainstorming is you throw stuff at the wall until it sticks. Why don't you counter my argument with an experiment? I'll do this test myself if I can get my X pulley secure enough. It won't be hard to do. You won't lose a thing by cutting those belts, your printer will still work, hundreds of printers before ours have worked with open loop belts.

Stop countering ideas with unwarranted skepticism and try something. anything! i do research for a living, i know the process of getting results and you aren't following it very well . you won't solve this problem if you don't experiment. you might break your printer. big deal. everything is replaceable on the cheap. 99.9% of the parts can be found at a hardware store, including these timing belts.

Does it? Maybe I missed it but I only saw wardjr's SD3 print and his SD3 has upgraded carriages.

"Unwarranted skepticism"? jagowilson, I'm trying to help and want to get this fixed as much as you do. I have had this problem probably longer than you and you've seen how many tests I've done, photos and videos and illustrations I've made. I just think we should have all of our facts before moving to deductions. It's just my opinion, sorry if you don't like that.

Why am I not trying anything myself? Because I don't think I have gathered enough information to create a new theory now, and then try it. I do have a plan, it's just different from yours.

every idea we've proposed so far you've had a counterargument for, but you haven't actually tried any of them, or posted results that show it does not work. you won't learn more about the issue unless you try something. i did some designs to test it but they weren't quite on par with wardjr's suggestion. i noted in previous posts that they didn't work. so far we know that a semicircle over the rod doesn't work.

unless you're a mechanical engineer (neither of us are, right?) thinking won't help you because neither of us understand the true mathematics or forces at play.

i'm not trying to be a jerk, i'm really not. but you aren't experimenting enough. try something and post results please, so many ideas have been thrown at you. did you even take the belts off and check for play in the rods? I did this step already, and it's fixed on mine, as far as I know right now. I'll do further testing after I get up and running if I can get running again at all with this broken Y carriage.

this is the reality i've come to accept yes.