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With the digipot set to 255, you need quite a good cooling for the stepper driver on the Rambo. Even the heat sinks I mounted on the back side are not enough, I had to add a fan.

Literally seconds after the print was finished:

[img]http://mhackney.zenfolio.com/img/s8/v81 ... 2548-3.jpg[/img]

You can still see the tiny filament coming from the top where the nozzle headed home at the end of the print. This is in natural PLA and is a little difficult to photograph. I tried to illuminate it to really highlight the issues - which were very minor in person. This is much better than any pyramid I've ever printed on my H-1s and my friend's Prusa.

Here is a closer view off the printer. Again, no touching the part. Just in moving it the little hair (which was ever so fine) "blew" off by movement through the air:

[img]http://mhackney.zenfolio.com/img/s9/v87 ... 4618-4.jpg[/img]

I claim victory and am going to move on! But I am getting some RED PLA tomorrow so will likely print another in red (translucent).

At this point I am VERY pleased with the Rostock. It definitely outperforms my H-1 and H-1.1. I will refine things i'm sure and the slicers will improve things too. There is a real balance between the mechanical aspects and the slicing aspects to get great prints. My first attempt at this was with a 180°C nozzle. It was a bit stringy. I increased it to 195° and wa-la, no stringing.

As for parameters:

KISSlicer 1.1 RC2 (released today on Mac)
.5mm skin
2 loops
50% infill
.55mm extrusion width and infill extrusion width
.25mm layer thickness
1.0 / 45° Jitter (new feature as of today, just learning how to use it!)
195°C nozzle
60°C heated bed on blue tape
10mm prime/suck
5mm wipe
20mm/s speed
1.5mm min jump
5mm trigger

On the printer side you can get the accel and extruder speeds on my EEPROM screen shot:
stepper digipot 175

Let me know if I missed anything!

Oh yeah, while it was printing I was dancing up and down with a counter clock wise spin!

That looks awesome! I am going to try your settings and see if I can replicate. I have a few questions. Did you use a fan at all to cool the PLA? Are you using Repetier firmware? Are you using the default 0.5mm nozzle (I would think you are from your kiss settings). Are you using 1.75mm PLA? Again I'd like to say congrats on excellent work!

edit: what is your min layer time set to? and your destring speed? Is it really only set to 20mm/sec or is that the print speed?

Thanks!

Yes .5 nozzle and repetier firmware and host. I print the first layer and then turn on three 40mm fans (wait till you see my fan mount accessory!). This is 1.75mm PLA.

20mm/sec is the print speed set in KISS.

mhackney wrote:Thanks!

Yes .5 nozzle and repetier firmware and host. I print the first layer and then turn on three 40mm fans (wait till you see my fan mount accessory!). This is 1.75mm PLA.

Thanks! I'll post pics of my fans as well (I am using os1r1s mounts with 2 squirrel fans) . I'd love to see how you have yours mounted. What is your destring speed set to?

The prime, suck and wipe settings I posted above are the destiring settings. Min layer time is 10 seconds. I did reduce that from the default I recall. You either haven't go pretty slow or blow lots of air to cool the part. PLA as you know stays plastic for quite a while.

mhackney wrote:The prime, suck and wipe settings I posted above are the destiring settings. Min layer time is 10 seconds. I did reduce that from the default I recall. You either haven't go pretty slow or blow lots of air to cool the part. PLA as you know stays plastic for quite a while.

Wow 20mm/s is slower than what I was using (30). I will try it now

Those little pillars have to have time to cool. The natural PLA seems to stay plastic longer than the colored material so I slow down.

mhackney wrote:20mm/sec is the print speed set in KISS.

Thanks. What are you using for loop/solid infill overlap in the printer section? I found with the 0.35mm nozzle I really had to turn it up to 0.95 to get the loops to touch the infill.

mhackney wrote:Those little pillars have to have time to cool. The natural PLA seems to stay plastic longer than the colored material so I slow down.

Sorry I meant the 20mm/s for the destring speed. I was using 30mm/s and was wanting to get it running at 60mm/s. Correct me if I am wrong but I believe this is the speed the extruder moves when it is priming or sucking.

Ah, my extruder is 100mm/s. loop solid infill overlap is set to "1"

mhackney wrote:Ah, my extruder is 100mm/s. loop solid infill overlap is set to "1"

Thanks...I am asking about the "Speed" setting in the destring tab. If you are able to get 100mm/sec I am seriously impressed and at the same time bewildered. If I go above 30mm/s I will get occasional skipping. Perhaps it is because your acceleration is set much lower than mine was. I am going to give it a try with your accel values. Getting excited

I'm sorry! I'm a bit tired. My destring speed is 55mm/s in the destring tab.

Yes, I systematically decreased accel until I got no missed steps but have good accel for retraction.

Here are my fans. I am considering adding a 3rd squirrel fan.

Unfortunately I just cant get 55mm/s on the destrings. I have active cooling on rambo and my digipot is at 255. I get occasional skipping which can be seen in the print

My digipot is lower and what's your accel setting for the extruder?

aehM_Key wrote:Anybody tried it with ABS? I think it's quite hard..

My posted first print and pyramid test was in ABS

mhackney wrote:My digipot is lower and what's your accel setting for the extruder?

my accel setting is 2250. Do you have the newest Rambo? Apparently they changed the digi pot settings. 175 on the old rambo is now 255 on the new one.

Yes, ver 1.1 RAMBO. 175 on the digi pot. I started at 255 and backed off.

mhackney wrote:Yes, ver 1.1 RAMBO. 175 on the digi pot. I started at 255 and backed off.

Interesting. I was considering backing down. I started at 235 and still had occasional skipping. I will give 175 a try.

the other thing I'd like to work on is shielding my hotend from the fans. I'm finding now with the 2 fans its hard to maintain the hot end temp at higher fan speeds. I'm going to design a printable deflector. Do you have one of you 3 fans blowing at the peek on the hotend to cool it? If you have a chance can you post the details on your fan setup with some pictures?

Brendin

xnaron,

Current and acceleration play a part in stepper stalling. Try my values and see how it goes. If it works, great, if not, back down accleration or up current.

I have a small 1" fan mounted on the delta head pointed at the PEEK. It's only job is to cool the cool end. I run it all the time for every type of filament. Have had "zero" plugging issues.

I then have three 40mm fans attached to the towers. They can slide up and down and in and out to direct the airflow directly at the part from 3 sides. This gives me better 360° coverage around the part and allows me to lower the amount of airflow and that helps keep the nozzle cooler.

The other thing is, with head mounted fans directed down, they are always blowing on the hot end. And since they follow the nozzle, as soon as it moves away from the print area, less air is directed on the place just printed. This pyramid is a good example - consider printing the pillars. As soon as a layer on a pillar is complete, the nozzle moves all the way to another pillar. Unless the fan is quite large or blowing a loot of air, the pillar just printed is not cooling well. With my arrangement the PART gets cooled with air. I've been testing and refining this for a month and it makes a difference. I am not ready to share photos quite yet but I will. I am actually working on changing the mounting system from steel rod to printed parts so folks can make these. I am also experimenting with a fan duct to get even more controlled cooling.

mhackney wrote:xnaron,

Current and acceleration play a part in stepper stalling. Try my values and see how it goes. If it works, great, if not, back down accleration or up current.

I have a small 1" fan mounted on the delta head pointed at the PEEK. It's only job is to cool the cool end. I run it all the time for every type of filament. Have had "zero" plugging issues.

I then have three 40mm fans attached to the towers. They can slide up and down and in and out to direct the airflow directly at the part from 3 sides. This gives me better 360° coverage around the part and allows me to lower the amount of airflow and that helps keep the nozzle cooler.

The other thing is, with head mounted fans directed down, they are always blowing on the hot end. And since they follow the nozzle, as soon as it moves away from the print area, less air is directed on the place just printed. This pyramid is a good example - consider printing the pillars. As soon as a layer on a pillar is complete, the nozzle moves all the way to another pillar. Unless the fan is quite large or blowing a loot of air, the pillar just printed is not cooling well. With my arrangement the PART gets cooled with air. I've been testing and refining this for a month and it makes a difference. I am not ready to share photos quite yet but I will. I am actually working on changing the mounting system from steel rod to printed parts so folks can make these. I am also experimenting with a fan duct to get even more controlled cooling.

Yes I will give your current setting a try. I am already running your accel setting of 2250 which was a pretty big drop from the 4500 I was running.

As for my fan setup I am not blowing down but rather at the hot end. I am using squirrel cage fans and the flow is directed at the nozzle. Right now I have 2 fans but I am going to add a 3rd so I get 360 degree coverage. The one issue I'll have to overcome is the the 3rd fan will hit the extruder for larger prints. I can lasercut a new extruder mount to help with that.

Thanks for posting your settings. I'm looking forward to see if I can replicate your results. I'm also looking forward to seeing your fan setup once you are ready to share.

thanks,
Brendin

mhackney wrote:Yes, ver 1.1 RAMBO. 175 on the digi pot. I started at 255 and backed off.

I forgot to ask. Are you running the stock stepper motor that comes with the kit?