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regpye
Yes I noticed that you followed my idea and used a similar design. Works well doesn't it?
When I get it all finished I will post the files for others to use if they want.

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CellJeffe


Thanks, regpye, but I was well into my redesign before I saw that. I'm quite happy so far with this simple fan mount - it works well enough so far without a duct. Though I have to thank you again after stealing your ideas of the long lever arm and short bowden tube retainer for the servoless lever.

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CellJeffe
Hmm. I switch over to all rack-and-pinion last night (and a 0.4.9 update!) and decided to do some speed tests using the speed multiplier of Repetier (base settings Perimeters: 30mm/s, Infills: 40mm/s). Speed was not the problem. The printer could easily go 150% to 200% faster than the base settings. After some sleuthing, I determined that cooling was the main problem with increased speed!
[attachment 35891 IMG_1666.JPG]
Both of these were printed at 150% speed at the indicated temperatures. The both did quite well on the bottom layers, but as it gets to the top of the pyramid, there was just not enough time for a layer to cool before the next layer goes on. Results: slurring of the smaller layers.

I always have a fan running on my J-head to cool down the barrel. It is usually not a problem since I have mostly been printing multi-part plates with large layers. But small objects are obviously a problem. Time to think about adding more fans to cool the print as well. Any pointers to a good ducted fan design that might work well with my servoless J-head mount?

[attachment 35892 IMG_1667.JPG]

My servoless hotend

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BackEMF
Yes i also noticed the new speed that came with the Cura 14.7 update t hought it was me overlooking some settings hehe.

In my case the higher layers now tend to crimp more (a cylinder comes out slightly conical) Am I printing to hot?

The overall result has improved a lot. Thanks Cura!

I'm going to add your Start and End codes too Reg, clever details. :-)

Is there a reason why M82 (set extruder to absolute) is removed?
I noticed that Cura this also added in the default

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MelT
It's just that celljeffe's fan is only 40mm so it looks like it's just big enough to blow on the cold end.

I'm having some level of success on my setup but I believe the best would be a dual fan setup. One dedicated for cold end and a ducted one for the print because as you will discover, you will need cooling only on some parts of the print. I have yet to see someone do this on smartrap though.

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MelT

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duranza
Or you can do what MeIT has done and re-direct some airflow to the print

It's just that celljeffe's fan is only 40mm so it looks like it's just big enough to blow on the cold end.

I'm having some level of success on my setup but I believe the best would be a dual fan setup. One dedicated for cold end and a ducted one for the print because as you will discover, you will need cooling only on some parts of the print. I have yet to see someone do this on smartrap though.

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duranza
Or you can do what MeIT has done and re-direct some airflow to the print

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duranza
Well, last night I had my printer going 100 mm/sec with Reg's geared extruder at 210c with very good finish and not missing any steps. This produced the best looking print from it to date. Very shiny and solid. This also got rid of all the stringing while moving to positions. The z rods do shake a little at this speed, and I had my retraction set to 0 afraid that I would strip the filament. I'll post a picture of the finished product tonight.

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MelT
I hope you guys can come back here and share your nozzle diameter. I believe that affects the maximum print speed which were not shared above. I'm asking becaue after trying the geared extruder, I'm still getting kickbacks.

I printed Regpye's geared extruder from smartrap's github. After 4 hours of printing, I noticed it was pointing the other way :(. Not a problem since I plan to mount it externally anyway using my spare stepper motor. I couldn't find a tap that is being sold individually so I just used the MK8 hobbed drive.

I thought it was the end of my extruder kickback problem but, lo and behold, it still happens. Normally during the first layer. Thinking that my nozzle is too close to the glass on my first layer, I adjusted the offset by 0.2mm and no more kickback so far but only on first layers. I still get it from time to time.

While it didn't cure the kickback, I must say that a geared extruder makes a difference in speed and consistency. I probably have a really bad filament to fix other print issues but I was able to go 40mm/s! Whohoo!
I might slow it down again when I need the absolute print quality but for printer parts and replacement parts, I don't really need top notch quality so I want to push the speed a little.

So why do I still get that kickback? The last thing I did was go extreme and adjusted my flow rate to 70%! It's going well so far without kickback at this setting but I'm wondering why my flow rate is way off that I had to turn it down that much.

My j-head was 0.3mm but I found a 0.5mm drill at an electronics store and used it to drill the nozzle. When I measured it with my cheap caliper, it turs out to be only 0.35mm diameter which I put as my nozzle diameter on slicer. I was hoping to make it at least 0.4mm to make prints a bit faster but even with 0.35mm nozzle, is it realistic to be able to print at 50mm/s?