My custom Cartesian

Phaedrux · 7 Sept 2018, 16:04

I would prefer to see the print time estimates without having to save the Gcode first

This is coming apparently. Although keeping it seperate has kept the slicing speed up.

I can confirm that the triangle labs titan clone is quite good. The hob bolt is hardened steel. And it had less alignment issues. Though the cover plate didn't fit as nicely and did rattle a bit.

wilriker · 7 Sept 2018, 18:42

@phaedrux said in My custom Cartesian:

This is coming apparently. Although keeping it seperate has kept the slicing speed up.

I would not mind to have to click a button to get this calculated and displayed. But saving a file first is too much of a disturbance in the workflow. It drags your focus to another opening window and away from the slicing.

I can confirm that the triangle labs titan clone is quite good. The hob bolt is hardened steel. And it had less alignment issues. Though the cover plate didn't fit as nicely and did rattle a bit.

At least while just moving parts by hand there is no rattling on mine. Will see once the motor is working.

wilriker · 9 Jul 2018, 18:55

So, today I have printed a Benchy that was sliced with Slic3r. I have to admit that the quality is great. No more visible infill on the hull. Also some other areas around the cabin look better.

Though there are three things that I never saw with Cura sliced Benchies so far. Stringing is a lot more pronounced due to different travel paths. My stringing got worse after enabling Pressure Advance and I have to retune retraction again but the Benchyi printed two days ago was also with PA enabled and stringing was less. But this does not bother me too much.
But there are also two artifacts on the hull that I never had before. A strange blob on the front side and something that looks like some kind of ringing on the back side. Unfortunately I am writing in my phone right now and cannot upload images this way. Instead here is a link to a Google Photos album.

Phaedrux · 7 Sept 2018, 19:25

You may have travel combing enabled in Cura. It tries to stay within the model during travel. Slic3r has that option to avoid crossing perimeters. I don't tend to use it because it creates longer travel paths and has a tendency to increase underruns at restart because the plastic has oozed out during the travel. There are also a few retraction settings you can tweak in slic3r.

Here's my optimized profile. You might have to adjust some speeds, but otherwise it prints quite well.

0_1536348222810_Optimized config.ini.txt

wilriker · 9 Jul 2018, 19:42

@phaedrux Travel combing is once again something that is enabled by default in Cura so I used it.

Thanks for your profile, I will check it and see what I can adapt into my profile from it.

Re stringing: I think I need to tune this independent of the slicer. Mainly because I use firmware retraction but also as I think that I could use much faster retraction speed than I currently do. But I have to find out how fast I can retract.

I need to tune a lot of things on my printer still. Acceleration, jerk, retraction... So good that I don't need this printer for anything but tinkering on the printer. I mean seriously, that's how it is.

wilriker · 12 Sept 2018, 06:59

New motors were delivered yesterday. I originally had planned to change my Z axis to belt-n-pulley setup with a 2:1 gearing (via different sized pulleys) but then there was this package waiting for me when I came home.

I measured their lengths and interestingly they differ. 3 of 4 are 46.98mm long and the remaining one is 47.16mm long. Very strange for being the same motors from the same manufacturer delivered in one box.

I then filed flats on all shafts of the motors and started with replacing X motor (as it is easiest). Now my X axis can run 250mm/s - which at 220mm axis length + 3000mm/s² accel means it takes around 1s to get from one side to the other. Looks totally crazy as I am not used to these speeds!

So far I cannot tell that (at same speeds as before) this motor is quieter (or louder) than the original Anet motor.

I have wired connectors to all other motors already and will replace them today as well.

In the process of re-tensioning my X belt I though saw that my (printed) belt tensioner was partly broken so currently printing a new one. I wanted to do this last night but all attempts failed due to an "improvement" I added to my extruder earlier last night. It was supposed to achieve better internal guiding but instead it just resulted in filament jams.

stewwy · 27 Oct 2018, 15:54

May i recommend a bondtech style extruder, night and day compared to a titan clone or mk8.

Much less grinding of the filament, which is highly constrained, and I'm sure my extruder motor runs cooler

pretty cheap if you buy just the gears and bearings and print the rest

P.S. how did you get on with the motors I have some on the way?

wilriker · 27 Oct 2018, 18:02

@stewwy Thanks. In fact, Bondtech is on my list in case I ever run into problems - which I did not yet even with the MK8. But I never printed anything but PLA and some PETG so far. I guess once I get into flexibles this will be another story. Still I have not yet even mounted my Titan clone. Lately I have no time for tinkering on the printer at all (and this won't change before November at best) and still some modifications that I will revert - and I did not yet even post details about the mod in the first place in this thread.
But once I get that done I will update here anyway.

Regarding the motors: I am very happy with them. They are not much quieter than the stock Anet ones (which would have been a nice bonus) but they have so much torque they just don't care about the weight they throw around.

wilriker · 27 Nov 2018, 10:00

Here are two small updates. In the second to last image above one can see that the plug was still exposed and I also wrote that it does no longer look like that already at the time of posting the image. So here is how it looks now:

Also I did some experimentation with my Z axis. I changed it from direct-driven via flexible coupler to a belt-driven approach where I also introduced a 2:1 reduction ratio to get my 8mm lead down to a 4mm lead. The motor is shifted to the front and attached with a separate motor holder bracket. The lead screw sits inside a printed base with a thrust bearing in the bottom and a 608ZZ bearing to take the radial forces from belt tension.

But as I mentioned earlier I will revert this approach. The main reason for this decision is that it is virtually impossible to get the motors well aligned because the screws that fix the holding brackets to the frame are covered by the motor once it is installed. So this is an extremely tedious mount-check-unmount-adjust-loop that so far has not yielded the results I am very happy with. The belt tension is influenced a lot more than I would ever have expected by moving the motor only 10th of a millimeter. So this is no fun to do.

I already have all the parts on my desk because I will not simply go back to how it was before but will also replace the lead screw by a 2mm lead and the coupling will be replaced by a zero-backlash jaw coupling that will eventually be suspended on a thrust bearing that sits on the motor housing so the motor shaft gets relieved of the axial downward forces. Images will follow once this is done.

deckingman · 27 Nov 2018, 10:21

@wilriker

Manuel,

Is that motor mount bracket slotted where it fixes to the extrusion so that you could raise it a bit higher? If so, you could turn the motor 180 degrees so that the shaft is pointing down, and mount the motor on top of the bracket. Then you would be able to get at the fixing bolts to set the belt tension. Or would that mean that you lose too much travel in Z due to the bed hitting the motor? Just a thought.........

Edit. If you fitted the pulley the other way round on the motor shaft, you probably might need need to move the bracket vertically (but that won't help the bed hitting the motor).

2nd Edit. Just scrolled up to see your original pics and it looks like the gantry moves in Z not the bed, so it might work if there is enough clearance to fit the motor that way.

wilriker · 27 Nov 2018, 11:12

@deckingman

Hi Ian,

Thanks for this idea. It might work. The brackets are slotted and also mounted at the outside of the frame. And the bed runs strictly inside the frame (with some clearance) so there is no way the bed could ever collide with the motors - if it does I guess I have a whole different set if issues. And yes, it's an i3 style Cartesian where the X gantry moves in Z. Whether or not the extruder carriage collide with the Z motor I cannot say right now but I don't think this would be an issue - could also be solved by just using longer belts to get the motors a little bit more to the front.

Anyway this approach might still not work due to some reinforcement struts (no idea how to describe this better) that are part of the bracket and makes sure it cannot fold on itself. In the image below you can see a little bit better what I mean (sorry for the bad quality, just have nothing better at hand right now)

They might be in the way of the belt path and I do not know whether the slots will allow me to move the motor high enough up so that an upside-down mounting approach would be able to align with the pulley on the lead screw horizontally. I might compensate a little bit by making the lead screw base a little less tall (my English is not at its best today ) but there is not much to gain there. I guess 1mm max to not risk the structural stability of the base since it is not supported at the bottom (because usually this is where the motor is mounted).

Also having the motors where they are now also makes it very hard to get to my leveling screws since the motors are perfectly aligned to in the way. Turning them upside-down is probably the only way to make this situation even worse.

And last I am looking forward to a 2mm lead. Not that I ever had any issues with 8mm lead.

EDIT: Looking a little bit closer on the image above I don't think these struts are in the way of the belt path. But from what I can tell the slots for mounting won't allow me to raise it enough to get a good alignment of the belt horizontally.

OBELIKS · 28 Nov 2018, 11:09

Do you need to move it up?
I think that if you move the bearing on the screw above the pulley (attach it to the vertical extrusion), both pulleys will be roughly aligned.

wilriker · 28 Nov 2018, 11:18

@obeliks said in My custom Cartesian:

I think that if you move the bearing on the screw above the pulley (attach it to the vertical extrusion), both pulleys will be roughly aligned.

I think this might result in a very odd and unfavorable angle to fix the bearing. If you look at the picture of the full printer in the second post you can see that it is quite a distance from the vertical extrusion to the lead screw.

Still, reverting-with-improvements will give me the best solution, I think. I will get an even finer Z resolution and free access to my leveling screws again. And from what I read in another thread these jaw couplings should also reduce noise a little bit (which is nice but honestly not really important on the Z axis).

OBELIKS · 28 Nov 2018, 11:24

Oh, I didn't notice the distance.

wilriker · 28 Nov 2018, 11:50

@obeliks Yeah, the recent images are misleading in this aspect.

stewwy · 1 Dec 2018, 13:57

Just converted to a 2mm lead screw, now I can print at any layer height to 2 significant digits without worrying about height accuracy.

i.e. 0.10, 0.11, 0.12..... etc

Previously, with a 'normal' lead screw, the only accurate heights where , 0.1, 0.15,0.2....etc.

first print is on as I type

oops, meant to mention, you are unlikely to need a reduction ratio because the torque needed is much reduced from an 8mm pitch.

Torque needed should be about 25% of what is needed for an 8mm pitch, the number of steps has changed from 400 to 1600.

wilriker · 1 Dec 2018, 15:32

@stewwy said in My custom Cartesian:

Just converted to a 2mm lead screw, now I can print at any layer height to 2 significant digits without worrying about height accuracy.

i.e. 0.10, 0.11, 0.12..... etc

Just did the same today. Images will follow.

Previously, with a 'normal' lead screw, the only accurate heights where , 0.1, 0.15,0.2....etc.

That seems odd to me. What lead did your lead screw have previously? On 8mm lead it would be 0.04mm increments. To get to 0.05mm increments it would have needed a lead of 10mm. I rarely came across this type of lead.

oops, meant to mention, you are unlikely to need a reduction ratio because the torque needed is much reduced from an 8mm pitch.

Torque needed should be about 25% of what is needed for an 8mm pitch, the number of steps has changed from 400 to 1600.

I never used the reduction ratio because of lack of torque. I only used it to convert a physical 8mm lead into a logical 4mm lead.

stewwy · 1 Dec 2018, 16:04

@wilriker said in My custom Cartesian:

That seems odd to me. What lead did your lead screw have previously? On 8mm lead it would be 0.04mm increments. To get to 0.05mm increments it would have needed a lead of 10mm. I rarely came across this type of lead.

You are right, we had a party last night so still a little hazy!

Note to self: don't press submit without thinking it through lol

deckingman · 1 Dec 2018, 16:49

As well as better resolution, you get other benefits too from using a finer lead. Effectively you get better gearing so can use a smaller motor or a single motor to drive say 3 screws via a single belt. The shallower helix angle also means that if you have a heavy bed, it will be less likely to drop under it's own own weight. I did a bit of a write up on my blog almost two years ago which explains things https://somei3deas.wordpress.com/2017/01/31/z-axis-lead-screws/

stewwy · 1 Dec 2018, 16:51

@deckingman said in My custom Cartesian:

As well as better resolution, you get other benefits too from using a finer lead. Effectively you get better gearing so can use a smaller motor or a single motor to drive say 3 screws via a single belt. The shallower helix angle also means that if you have a heavy bed, it will be less likely to drop under it's own own weight. I did a bit of a write up on my blog almost two years ago which explains things https://somei3deas.wordpress.com/2017/01/31/z-axis-lead-screws/

That write up is one of the things that prompted me to order one, so thanks