DIY Aluminium 3D-Printer, build 2 (page 4) (Page 2 of 7)

Yep, I tried to look max rpm for this kind of motor before planning, but didn't found any information. Sadly this is too slow for now, and I'm not happy at all! Atleast it works, but still

I actually checked some planetary gears from ebay and they are too expensive. Also I want to get rid of threaded rod I can't do gears so making planetary gear is not an option.

Instead, this threadless ball screw is very interesting and I probably try to do one. I already did some plans for clamping to the lathe Lets see how it settles

Belt system is the last thing I'm going to try. Well, it works for shure but I want to try alternative things. If I can't get anything else working good, then I add it. Need to change motors place etc.

Oooh... Given a choice we like GT belts here: with the round teeth they're designed for maximum accuracy (rather than power / strength / wear resistance etc.). They can get pricer if you leave the safety of 3d-printer-land 2mm pitch / 6mm width. Do you reckon you need the extra power/strength properties of the HTD? MXL (trapezoidal teeth, 2.03mm pitch x 6mm width) is probably the most common / cheap variety of course, but they say these are a little less accurate than GT's. In any case, pretty much any timing belt will be good. In general smaller pitch will be smoother. Only go up in width if you definitely need the additional load capacity - otherwise it just requires more force to tension properly (and associated friction in bushings etc.). If you can go metric for reasonable money this is also a good idea as the numbers come out exact.

Have you looked into using spectra line instead of belt? Some users here have had great success with that stuff, and given you can machine round things pretty accurately with your CNC lathe I'd guess you could do all the running gear yourself (instead of having to buy pulleys).

The threadless ballscrews are probably not a good option for the x/y axes as they are not symmetric or deterministic in their travel. The can vary their distance/rev with load even (tiny wee microscopic slips)!!

If you want to keep the threads, have you considered multistart acme threads (they're surprisingly cheap on ebay, and might give you sufficient speed - pitches in the order of a few mm / rev instead of about 1)?

In any case, given you've experimented with the maximum RPM of your motor you can probably work what kind of steps-per-mm you need to target to get a given max printing speed (sky's the limit but if I was building my own I wouldn't settle for much less than 100 mm/sec).

+1 you're who I was thinking of... I think it's definitely worth a look.

0.9° steppers will be slower and less torquey (for the same size and current) than 1.8° - stick with what you've got. In the end I think the step resolution in x/y is well overshadowed by backlash, rigidity of the printer (probably not in your case though... hehe) and the inherent inaccuracies of squirting plastic around.

Probably the best way to proceed here would be to compare your belt options to existing printers in terms of mm per revolution and aim for something similar out of your options. That should at least avoid worrying you're operating way off the chart in motor speed for example!

e.g. my slightly modified solidoodle has 20t pulleys on 2mm pitch belt for a grand total of 40mm/rev. It happily jogs around on linear bearings at 100mm/s, which by my calculations is about 150 RPM. This seems quite serviceable, but I won't go as far as saying it's definitely optimised though.

I bought 1,5m 10mm wide T5 belt and 8pcs small bearings for belt rollers! Belt is somekind of polyuretane with steel strings inside it. It should stand the tension

Yep, I will try fishing line system some day! Today morning I got message which said that I have three pulleys waiting (fourth arrives maybe next week). So after shift I made couple parts in hurry, hoping pulleys would have 5mm bore. But I didn't have enough time to make all the parts for converting Y-axis to belt system. Luckily it doesn't matter because pulleys had only center hole for boring. I Need to bore them tomorrow. So, I made two holders for pulleys and "plug" for empty end of Y-axis. A bolt comes to hole in the plug and gets attached to pulley holder. Then I can set tension for belt by just tightening nut in bolt! Maybe I should put spring in there?

Pulleys feels good quality. With belt I bought yesterday, I bet there will be very small backlash if nothing!

I don't really know, should I do couple more parts for x-axis to get whole new holders for engine and pulley or should I make just one part more and use exiting parts..

+1....

And I thought I was a good Machinist!

Actually, I didn't even think about closed loop! I have bought already 1.5m straight belt so closed loop is not possible(unless I buy new belts). There is just bolts as tensioner in my desing so I am pretty sure there is suitable closed belt. Since I can change distance of pulleys about 30mm.

Here is what I've planned for X-axis. Y will have something similiar.

Thanks! Yes of course I upload a video Maybe tomorrow or day after tomorrow. I'm a bit busy on this week, so there is not so much progress as last week

What's your voltage the motor is rated for? What voltage are you driving it with? Better yet: what inductance is your motor, if that's available?

600rpm is somewhat fast for a stepper but you can go alot higher with a strong enough driving voltage. Maybe as it seems you are aware you are having a current dropoff. Try running an amp-meter inline if you have one that can measure AC current (since the phases alternate direction DC won't give you a useful measurement.)

EDIT:! I was responding to the post "shoot can't go fast, maybe should give up on threaded rod" but you've gotten much farther since then. My mistake.

Hey! I did today almost last parts! So Y- and Z-axis have their parts. I'm going to assemble them tomorrow and upload photos then! Made also dial indicator holder so I can measure movements precisely. And I'm pretty satisfied with results!

Biggest difference is about 0,05mm and that is pretty good IMO.