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My Z axis belt keeps sliding over to one side of the top idler bearing. When it rubs there, it produces the black dust and sometimes makes a squeaking noise. I can carefully apply pressure - while printing - to get the belt to move to the center or even the other side. But it works its way back after about 20 min. This weekend I'll try to adjust the idler to be more level.

On the fill > perimeter issue, I'm wondering if playing with the KISSlicer settings for Infill Extrusion Width and also Loop/Solid Infill Overlap (both set to 0.75 in my screenshots) will solve the problem. For example, one time I was playing with the Infill Extrusion Width and by mistake I entered 5 instead of 0.5. I guarantee you'll reach the perimeter with that!

[img]http://farm9.staticflickr.com/8074/8414 ... e844f4.jpg[/img] [img]http://farm9.staticflickr.com/8365/8414 ... d83b77.jpg[/img]

The Infill Extrusion width shouldn't help, because it will change the spacing of the tool paths.
However if you set it too large >> than the free air extrusion width which was about 0.7mm for me then the nozzle has no control over the shape of the bead and there might be enough variance in the output that it appears better. It also increases flow for the extruder which might allow it to correct better for slipping filament (most likely caused by a retract).

The Loop/Solid Infill Overlap is the setting that controls it, however it's supposed to be mostly cosmetic, the full range as I understand it is only moving the path 1/2 of the width of the infill, at 100 % the path touches the perimeter and therefore the extrusion overlaps by 1/2 the width.

The gaps people are posting pictures off look very large to me and look like either backlash in the belts or issues with filament being under delivered, usually an issue with it slipping, or the filament diameter not being set correctly. IME the biggest contributor to slipping is retraction, you can verify if this is the issue by running prints with it disabled and seeing if you see the same thing.

I printed your duct today Highcooley. It turned out really nice, but the support arm is pretty ratty.

I still have a huge infill problem, but other than that it turned out nicely. Now I just need some PLA as an excuse to mount it on the effector.

It's a very nice design!

http://www.geneb.org/images/fan-duct-1.jpg
http://www.geneb.org/images/fan-duct-2.jpg

I printed it in ABS (MakerGear) and sliced it with the most recent beta of Kisslicer.

g.

I printed that fan duct today and got a similar lumpy support arm. I had a 40mm fan that fit perfectly, although I would mention there isn't room for nuts on the screws that hold on the fan. Fortunately I didn't need nuts since the screws tapped into the plastic and held fine.

But when I went to mount the duct, I ran into trouble because according to Highcooley's photos, the support arm mounts on a deep corner of the hot end platform, but that's where my hot end spacers are attached. I suppose I must rotate the position of the spacers before I could mount the fan duct. It's further complicated by LED wires I ran through some of the extra holes, which would have to be cut and rejoined elsewhere to accomplish this rotation.

It was too much for my Sunday afternoon with all the other stuff I had to do.

I was motivated to try it by a closeup video I did of the test pyramid. At the very top, you can see how new layers deform the un-cooled layers below - making the tip top a bit of gooey blob. For now I'll just use a 5 inch desk fan blowing across the bed.

Thank you for your feedback and the pictures. Nice to see, that the fan duct printed well to the tip of the nozzle.
Hmm, I also had some troubles with the support arm on my print. But I thought it was my lousy settings causing this.

I think, I'm going to make the support arm thicker, as it also seems to be just a little too weak to hold the fan duct "gondola" at the right angle. And maybe I try to slice the object into two parts to be able to print the support arm flat on the bed. However, I don't have the perfect solution to attach the two parts after printing yet. My idea was to use a splint pin allowing for fast detachment of the duct from the print carriage. But the part is almost too small to construct a proper connection.

Another change, I am probably going to make, is a flatter angle of the fan. This should lift the lower edge of the fan connection flange further off the print bed, making it easier to level out the fan duct at the nozzle and giving a bit more head room for longer screws or nuts. However, as described by barnett, the screws tap into the plastic, which worked fine for me. Additionally, the flange should not get in contact with the paper clips which are holding the build plate down.

How about, if I design another support arm to clip the duct directly to one of the hot end spacers? Maybe, it would even be possible to design such a clip with another duct altogether, to clip it to a spacer, if they are mounted on the flat sides of the carriage like in my build. I've got to check, if the fan would get into the way of the delta arms or not.

geneb wrote:Inspect your belts! I had that same dust collecting and it turned out a sharp set of gears was eating the belts!

I don't know that it's backlash. The belts on my machine are tight enough to play Jazz Bass on. There's no binding going on either. I'm at my wits end at this point.

g.

Still haven't solved the belt eating. Did you just sand down the sharp edges of the gears, or what was your solution?

Today's approach to minimize backlash will be to apply some silicone grease to the joints. I'll report if that helped.

And finally some good news for all people interested in the fan duct. I altered the design a bit and am going to upload the models onto thingiverse tonight, as soon as I installed it and took a couple of pics. The angle of the fan is a bit flatter now, lifting the fan flange further up from the print bed. And I separated the mounting plate from the duct to be able to print it separately. It is also 1 mm thicker now and I designed a second version for barnett to clip the duct to a hot end spacer. The duct and the mounting plate are attached by a 1 mm pin (bent open paperclip). I was able to print all parts nicely this way and the clip works great.

Thanks Highcooley! I will look for it.

Last night, I downloaded a plugin for sketchup so I could import STLs & modify them. On the train to work this morning, I was getting ready to modify your duct to attach to the spacer ... although I'm sure yours will be nicer than whatever hack I might invent.

You could file down sharp edges on your timing pulleys. But seemecnc would probably send you smoother ones if you needed them.

Voilà!

Version 2 of the fan duct is ready for download: http://www.thingiverse.com/thing:43983

[img]https://lh6.googleusercontent.com/-AHTg ... CF0599.JPG[/img] [img]https://lh5.googleusercontent.com/-argO ... CF0610.JPG[/img]

Wow....very cool...BUT no Onyx bed yet..??!?!?..hehe.....
Looks great..will have to talk with Barnett shortly....thanks.

The picture was taken 5 min before I mounted the freshly arrived Onyx

A very nice bed. However, with the fan duct as well as the other cooling fan attached, it is not possible to use the full build space. The sticking out fans can get caught in the aluminium bars as well as the extruder construction.

Additionally, I am not sure, if the fan duct and the LED ring work together with the new nozzle design. Haven't tested it yet, but unless the nozzle sticks further out of the heating block, it will probably be too short.

Maybe you could move the new nozzle down a bit to allow room by using washers under the head, and using longer tubing inside the hot end. However, this may affect the temperature gradient inside the nozzle.

- dan

Ok, latest update:

- New fan duct design tested - check
- Onyx installed and leveled - check
- LCD module installed - check
- Grease joints - check (smooth like butter)
- Switch to Repetier firmware - check
- Update firmware to 0.81 manually - check
- Print button and beeper cover for LCD module - check
- Automate hot-end cooler fan - check

To-Dos
- Test Repetier firmware
- Test measures against perimeter/infill separation
- Switch to new nozzle design (incl. reconfiguration)
- Design new fan duct for new nozzle, LEDs & multiextruder setup
- Design toolhead change mechanism
- Go for dual extrusion

All right...here we go with the latest development of my Rostock experience:

First a look at my machine with the new LCD module and the onyx bed:


The beeper cover looks crappy on the picture, but is quite nice in reality. It's basically a simple hollow cylinder with three holes in it. Can somebody actually explain the reset button to me? Am I right, that there is no function in Repetier firmware at the moment (I read something about that on github)?

For clarification, the front of the Rostock is facing to the left, as I have limited space for the filament spool holder on my table. Intentionally, I put the LCD door to the right side during the printer assembly, to have perfect access to a potential LCD module. Works great, but I just recognised, that I will run into trouble when adding the second extruder. The holes for two extruders are right in front of the LCD door.
Gosh, I am definitely not going to disassemble the printer base. And rewireing everything also doesn't sound pleasing.


Repetier firmware works great so far. I only have the problem, that the extruder won't work at times. Sometimes even a restart of the printer does not solve this. The first time occuring this, it was the hardest. After trying with several printer and host software restarts, I uploaded Marlin to check, if there was a hardware issue. There wasn't and after switching back to Repetier, it worked again. Does anybody else have this problem?

The perimeter/ infill separation issue got much better with all the measures I took. It was mainly greasing the joints with silicone grease, which did the job. And I highly recommend doing this, as the joints move so much smoother. I don't know if the change to the Repetier firmware helped as well. However, I still had a slight separation. And if the infill does not touch the perimeter, it gets slightly pulled back by the nozzle moving away from the perimeter, increasing the gap. So, I also went for 75% overlap in Kisslicer.

Here we got the result:


From 1: perfectly overlapping...
... to 2: little open spots due to the nozzle radius, but acceptable ...
... to 3: not overlapping and causing the wider gap, luckily only in one spot of the whole print, but still something to work at.

Should I go for 80% overlap? There are spots, where the infill is already being squashed to the perimeter.

is still very variable on long prints. I already showed pics of the differntial gear, which took about 6 hours for the biggest part. The model itself was easy to print, due to a lot of infill and only a few overhangs and sharp corners. Last night's print was a bit different (random vase 1.5:1):


One thing I am still fighting with is first layer adhesion of the starting point as well as of sharp corners. The filament is dragged along by the nozzle. With the starting point, this can be several mm soemtimes. Sharp corners usually only get slightly ripped off by a fraction of a mm and protrude in Z. But this is already enough to get caught by the nozzle with every layer and can even lead to warping like the corner circled in the picture. I print first layers at 200°C on 60°C hotbed in PLA. Which temperatures would you recommend to change and into which direction?

The model was sliced with Kisslicer at 0.2mm layer height and 84% precision, which would be about 17mm/s for perimeters and 24mm/s for infill (I set vase for infill density anyway).

Analysing the print, I started off on the lower left corner of the picture, with the first layer being printed at 60% speed (due to the sharp corner adhesion problem). I then slowly cranked up speed first to 100% and later - about half way through to the first red line - to 120%, all @ 195°C. Suddenly, the nozzle started dripping a little bit, causing little roughness on the surface. It went away for another twenty layers untill it came back and caused holes in the wall for the first time. After closer inspection of the hot-end, I figured out that the heat managed to "climb" up to heat the PEEK part and even the push fit. I assumed jamming, set the temperature down to 186°C, speed to 80% and helped the extruder feeding filament by hand for a couple of minutes. This seemed to help, so I cranked speed up to 100%. The printer managed to print another 20 layers in very good quality without me feeding filament by hand. Then, it came back, this time only extruding very small dropplets, causing them to break off and generating the big hole. Without any clue what to do, I assumed the hotend to be too cold now. So I set the temperature to 190°C and speed to 80%. Again, after helping to feed some filament by hand to unjam the nozzle, I got about 5 mm of perfect print. That's when I left the printer on its own over night. As you can see, the problem keept comming back (the first time after record breaking 25mm) and solving itself for several times.

Does anybody have a clue what I could try? Temperature is constant in a range of 1°C measured by the thermistor. When measuring wall thickness, it seems to be abit on the small side. With 3 walls @ 0.5mm width, I only measure 1.3mm in total. Could the printing problem be something like underfeeding of the nozzle?

Or could it be an issue which is solved with the new nozzle design (internal fluctuation in temperature or something like that)?

That's where my knowledge about 3D printers ends

Thank you for your feedback!

Cheers
Andy

First layer stick problems are not always temperature related. At your temps you should be fine. My first advise is to clean the glass thoroughly with isopropyl alcohol and avoid touching the surface. Second advice is to make sure your first layer height is good. If your initial Z=0 is off, you'll either not get stick or you'll get too much squish (to the point where the extruder is blocked). Finally, try printing on blue painters tape at bed temp of 60°C (and make sure the tape is cleaned with alcohol). Finally, slow down the first layer speed. I would start with decreasing it by half of what it currently is.

I am uncertain about the efficacy of your fan tunnel (but forgive me, I have not been following its evolution closely - it sure looks nice though!). It appears to be blowing air on the hot end. That would not be good! You want to leave the hot end hot! The air should blow on the barrel (PEEK) to cool that area. With PLA the filament melts up the barrel with a long area of unmelted filament to melted filament. It is the length of this transition (and the melt zone migrating up the barrel) that leads to jamming and problems - what you call "climb". The idea of the fan is to cool the barrel above the hot end, thereby keeping a very short melt transition zone down in the hot end and nozzle. Get it right and it works fantastically (and it is not difficult to get right). Your symptoms are classic PLA creep/climb and can be prevented by cooling the barrel area.

Now, the other thing a fan can be used for is to cool the actual extrusion/part itself. Especially with large thickly filled parts, heat builds up in the part and the extrusion doews not have a chance to cool properly. You can then get sagging, warping, etc at the part. A fan / air stream directed down at the part or surrounding the part prevents this. Usually you do not need to run this all the time.

One other thought, I have heard of people etching their glass plates to improve first layer adhesion. This seems like a good idea if not over done. You could etch one side and not the other and simply flip the plate if you need pure glass vs etched!

cheers,
Michael

going back and looking more closely at your fan duct, it seems to be of the second type I mentioned above - to cool the extruded part (although I would be concerned about it cooling the nozzle too). With PLA you really do need a fan above the hot end directed at the barrel to prevent molten creep up the barrel.

cheers,
Michael

Thank you for your reply! Yep, the fan duct cools the part and not the nozzle. Or at least, the air flow is directed towards the print bed...of course, cooling air could be reflected by the bed or the print. I do have another 40mm fan blowing at the PEEK insulator constantly. Due to the delta arm contruction, it is mounted 8cm away from the barrel. I think the cooling capacity is a bit on the low side, hence the heating of the barrel @ 195°C over time (> 3 hours). With the heat turned down to 190°C, the barrel cooled down quickly.

Did you ever get your loops touching infill figured out?

I've sanded my u-joints so they are nice and smooth without friction then I lubed them up. I made sure my belts are tight. I've calibrated the extruder and have set my loop solid infill overlap in KISS to 1.0. I printed the hollow cube for a test. The silver one on the left is from the rmax. The one on the right is from my cartesian. Both sliced with KISS. The cartesian has loop overlap set to 0.75.

Also see the calibration cube I printed with perfect overlap printed on the rmax. For me it seems to be a problem with the inside overlap.

I actually haven't gone any further yet than to sand the joints almost perfectly, lubing them, tightening the belts and setting KISS to 0.75 overlap. It's not a 100% perfect now but I'm close. I probably would have to sand a bit more, but I wasn't in the mood so far, as I was facing other problems, e.g. different layer thickness due to a convex glass plate. So, there is still potential for a perfect overlap. Thanks for your reply!