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I think we will need to do more precise measurements in order to see if cooling has an effect on retraction and hence quality. I'm not there yet but should be at some point. But I think conventional wisdom is that there is no effect other than the clogging issue correction.

Ok, I am about ready to go machine this and test it. In concept, this fix is the same as Polygonhell's in that the idea is to eliminate space between the rollers and the filament entry point for the Bowden adapter. I am using a piece of 3/16" acetal/Delrin with a 2mm hole bored in it. One end is milled to form a point to match the radius of the rollers. Acetal has very good mechanical wear and low friction properties so I intend to have it just barely clear the rollers.
It will simply be friction fit in a 3/16" hole .5" deep in the aluminum adapter.

Edit: no comments on the visual similarity of this drawing to certain anatomical features please.

mhackney wrote:
@Av8r RC - I actually make my plates 12 1/8" diameter. I'll machine a few this weekend and offer them on my site on Monday. I have enough material to fabricate 6 (had enough for 10 but 4 are already spoken for). The bolt hole pattern looks to be on a 285mm diameter. I just looked at the ROSTOCK dxf files but they do not have the Onyx holes on them. The SeeMeCNC site says: Six 3mm diameter mounting holes spaced 300mm center-to-center so there you go!

You will need to cut out for the electronics pad area too.

Ah thank you sir.

I posted this in the current Onyx heated bed discussion but wanted to capture it as part of my build - it's pretty important!

--

Let me start with the backstory, when I first installed the Onyx it was heating up very quickly - sub 2 minutes to 90°C. Then I removed it, resoldered the power leads so they "bend back" the opposite direction to route nicer through the slot in the base. I noticed that it took a little longer to heat - maybe 3 - 4 minutes but didn't really think anything of it. Then this thread got started as well as other Onyx discussions and I measured my voltage, etc. But I was perplexed why it was taking longer than original. I went back and looked at a screen shot of the heat curve and sure enough it was heating nearly twice as fast back then.

So, tonight I removed the Onyx and what do you think I found? Well, actually nothing - I like suspense. However, I decided to solder a third wire to each of the leads. So now I have three 18 gauge wires running from (+) and three from (-). I also made sure the connection at the connector was nice and tight. Then, for grins, I tuned my power supply down to 12.0 volts to see what would happen. The results are astonishing! I just took a screenshot with my clock/calendar overlaying the temperature curve display so you can see there are no shenanigans...
I am getting heat up to 90°C in 2 minutes and 15 seconds with my 12 volt 30 amp supply!

and as if that isn't enough, I kicked it up to 110°C to see what would happen.
As you can see, about another minute and a half and I reached 110°C.

Now I am not suggesting your results with the stock supply will be similar BUT I would highly recommend trying three 18 gauge wires to each terminal to make sure you are getting full current!

With heated beds the wires to them can easily become a significant portion of the resistance and as a result sink a lot of the supplied power.
A single bad solder joint can drop the rate it heats at dramatically, so can wire that's to high a gauge I've seen a loose screw on the heated bed connector to a RAMPS board cause the connector to melt because the loose connection caused the connector to be a significant portion of the resistance and therefor it became a sink for a significant portion of the power.
If your wire to the bed is getting hot/warm, you could probably benefit from lower gauge wire.

Rate of change of temperature is dictated by the power to the board and is simply V^2/R, for a given bed/wiring combination R is more or less constant (technically it changes as the board gets hotter), if the power supply is struggling to supply sufficient current the voltage will drop, if you don't see a voltage drop when the bed turns on a more powerful power supply at the same voltage will make no difference. You need to either increase the voltage or decrease the resistance which is what the extra 18 Gauge wire does in this case.

Polygonhell wrote: I have Budda and a JHead, on other machines, both are good hotends, but they are very different.
The Budda has a very short nozzle, and requires very little pressure to exrude, the JHead is a lot closer to the Steve's with the current nozzle.
I've heard bad things about the QU-BD (I know they use a different design in the printer they sell), but don't have one, and have no first hand knowledge.
I would really like to pick up one of the all stainless hotends that seem to be coming into vogue, notably Prusa's.

I really liked the way my buda performed in my other printer, it takes so little force to extrude. Have you ever tried swapping out the nozzle on it?

I'm using 12 gauge stranded, which should be equivalent to four 18 gauge wires, so that's not it, at least not for me.

- dan

My JHead hot end kit came in (3 days ship to arrival) and I assembled it last night. It has a .35mm orifice, they were out of the .5mm. I do have a set of drills and may drill this one out so I can do a better comparison to the .5mm hot end on the Rostock.

[img]http://mhackney.zenfolio.com/img/s2/v73 ... 7950-3.jpg[/img]

It was a pretty easy thing to put together but surprisingly, there is very little information out there on how to do a "clean build" with shrink wrapped wiring, etc. Now need to make a mount to fit the Rostock and JHead and I'll be good to go.

Ok, so I hooked up the new JHead to my RAMBo on Heater 1 and the appropriate thermistor connector. I enable 2 hot ends in the host printer set up AND in Repetier firmware. I also edited pins.h:

#define HEATER_1_PIN 7
#define TEMP_1_PIN 1

I pulled the heater pin assignment out of the RAMBo pins table. When I attempt to test, I switch to extruder 2 and hear an audible beep (each time I change the extruder I hear a beep). If I turn on the heater at a low temp, say 50°C, I see the status line show hot end 2 and its temp and set point. However, I do not see the red LED on the RAMBo come on and I do not get any heating. Just for grins, I changed the pin assignment to FAN_1_PIN (which is 6) and moved the connector to the fan port. Now, low and behold, the hot end heats up properly and temp is read properly. So, either I have the wrong pin assignment (7) for HEATER_1_PIN or there is a problem with the RAMBo on that port. Anyone have any experience with setting up 2 extruders?

regards,
Michael

A while back didn't you have a mishap with the alum plate and short something out?

It's probably the fact that I set the extra Fan on the heater 1 pin, you need to disable that or change the pin mapping in configuration.h.
The reason it will cause an issue is it will likely configure the pin differently for the heater vs the fan (PWM vs Digital).

@Av8r RC - yup, I screwed my hot bed thermistor port earlier but worked around that

@Polygonhell - ah yes, I remember you saying that and discovering that it is assigned in configuration.h and not in pins.h. I'll disable the fan in configuration.h and see what happens. Thanks!

@Polygonhell - and that worked perfectly! I just set

#define EXT0_EXTRUDER_COOLER_PIN -1

in configuration.h and now the hot end works great. Unfortunately, I won't be able to use the auto fan on when heater on tip you posted. I should investigate what other pins might be available, if any, to use for that.

mhackney wrote:@Polygonhell - and that worked perfectly! I just set

#define EXT0_EXTRUDER_COOLER_PIN -1

in configuration.h and now the hot end works great. Unfortunately, I won't be able to use the auto fan on when heater on tip you posted. I should investigate what other pins might be available, if any, to use for that.

FYI you should be careful of the 5A fuse on the RAMBO it's at best borderline if you turn both hotends on simultaneously.
Assuming you have 2 Hotends and 2 Fans, you're out of pins with mosfets, you can probably drive the fan directly from the signal level on the arduino, BUT I wouldn't.
I'd probably just run my cooling fans from one output in parallel, the Mosfets are more than up to the job.
The other easy solution is to wire the fan cooling the peak directly to the 12V line, that's how I run the fan on my RAMBO board.
If you really want control the fan from an arduino pin on one of the expansion headers, you'll want either a solid state relay or a little circuit with a Mosfet in it like the existing hotend outputs.

Thanks. I do already have my first hot end fan on a switched 12v directly from the supply. It also turns on my LEDs. I'll just add the 2nd fan to this circuit when the time comes. I have several RAMPS laying around that I might move over to when I am ready for dual extruders on the Rostock. I use one with duals on my H-1 and that has gone well.

I posted the CAD for my idea to prevent "filament ejection" from the Steve's extruder yesterday. Today I machined the parts and put it back together. Here's what it looks like:

Machined Bowden adapter and Delrin insert:
[img]http://mhackney.zenfolio.com/img/s2/v70 ... 4322-3.jpg[/img]

Assembled:
[img]http://mhackney.zenfolio.com/img/s8/v75 ... 4262-3.jpg[/img]

The Delrin is a nice friction fit in the adapter and is about 5/8" long overall. I installed it and pulled up a part that always gives me trouble to print. All I can say is - "Wow, I immediately noticed a difference!" Firstly, retracts actually sound different. And they are obviously much "crisper". I didn't have any issues with the filament jamming and I've always had to abort printing this object with these settings. I am printing one of the cool single piece bearings now to show off photos.

I have designed a new replacement adapter that mounts in from the top so it is much easier to install, remove any damaged filament, start new filament, etc. It will have this guide insert integrated. I plan to offer these on my site in a week or so. But whatever you do, some sort of a guide like Polygonhell's or this one is a required upgrade to Steve's extruder.

I now have over 20 hours of actual print time with the new extruder guide insert mod and it has been working flawlessly! In fact, it works so well that I have been able to test and collect data on what I call "hydraulic jamming". I'll do a full report on this later but, basically, as I tried to achieve the Holy Grail of print quality I went down a path that looked like this (after basic debugging of mechanical issues):

• First calibration prints looked blobby and noticed nozzle drag but X, Y, Z motion looks great. Blobbyness appears to be the result of nozzle ooze.
• Added some Z lift to prevent dragging - conducted a set of experiments to optimize the lift amount. 1-2 mm works well and doesn't slow things down too much.
• Introduced some retract to minimize/prevent nozzle ooze - again conducting a set of experiments to find a good retract value. 5mm gave good results.
• With things apparently tuned, began printing "real world" things. immediately experienced two issues: 1) filament starving and 2) filament ejection from the extruder.
• Slowed things way down and started diagnosing problems by going back to original calibration objects (single perimeter cube) and notice problems disappear.
• Ask self, "self, what's different between the calibration objects and real things?"
• Realize that some of the things I'm printing have many short bursts of rapid retracts - almost like a machine gun - in some parts of the print. Also correlate filament starving and ejection to these retracts.
• Decided to attack the ejection issue first using basic idea presented by Polygonhell (his extruder roller cap). Fabricate my guide insert (see previous post).
• Test guide insert on real things. Absolutely no extruder ejection occurred. Unfortunately, the filament starving problem worsened.
• Ask self, "self, why would filament starving get worse after fixing ejection problem?"
• Hypothesize that the pressure that was causing filament ejection might be now transferred to the hot end of things during these rapid retraction cycles.
• Devise plan to test - write simple gcode to retract/advance extruder a specified # of times with short extrusion segments in between. Conduct test and discover, yes, these rapid retracts jam the extruder - temporarily. If pressure is backed off for a few seconds (t=3 or more) then extrusion would restart. Validated this test multiple times. Several (<5) rapid retracts in a short period are not too problematic, anything more than 5 create problem I affectionately call "hydraulic jamming".
• Realize that retract is problematic. Hypothesize that the Bowden tube introduces a little "backlash" in the filament retraction cycle and requires a little more aggressive movement to minimize blobbing, leading to the hydraulic jamming issue.
• Recall earlier experiments with KISSlicer and its "wipe" feature. A feature that minimizes blobbing due to nozzle ooze WITHOUT retracting. Decide to do some research on slicers and investigate gcode output.
• Print real world things using KISSlicer gcode. No rapid retracts results in no hydraulic jamming and the consequential filament starving. Wipe feature (and other KISS gcode optimizations) minimize/eliminate blobbing due to extruder ooze.
• Drink "victory beer" to celebrate a deeper understanding of print quality.
• Purchase KISSlicer Pro.

You printing out anything difficult while your enjoying your victory beer?

I need one of those today. Going on 11 hrs with no lunch right now, prob about 2 more to go. Here's where I'm at now. Edti: sorry the pics upside down
This bastard has 578 holes, of 6 different sizes, all held to a tolerance of +/-0.001. Half of it is held to a tolerance of +/-0.002, the rest 0.005. And that pocket is on both sides.

Sorry for posting some BS in here. Had to get my mind of this long cycle.

Hopefully when I get home I'll have the initiative to finish up some Onyx heat bed tests I've been doing. And put my new belts, I got today:D, on my MAX.

Ok, very very cool looking, but no fair, you gotta tell us what the .... it is!

Yes, I am printing out a customized (via its OpenSCAD parameters) "gear bearing" as featured on thingiverse earlier this week. I'm on layer 34 of 50. .2mm layers, .5mm nozzle, KISSlicer (of course!) and it looks mahvalous. As a special treat, I used Clairol Herbal Essences on my heated bed for sticktion. It smells mahvalous.

@Av8r RC - if you are going to show off your metal work, I might have to show off mine!

Flateric wrote:Ok, very very cool looking, but no fair, you gotta tell us what the .... it is!

It's a gas diffuser, vapor not liquid. It goes into a machine that makes computer chips. That's about all I know. Lol

It could be making chips for anything from a missile that's gonna kill some Taliban's to a calculator. No clue.

That is cool!

Mhackney, cool I'd love to see it.

I like the way this one looks. Just hate making it. Lol And we are about to get an order to supply at least 20 a month.

1780 holes

Ok, here are some of the reels I machine.

[img]http://mhackney.zenfolio.com/img/s2/v61 ... 3740-3.jpg[/img]

These are the parts I machine that go into it (it's a kit I sell):

[img]http://mhackney.zenfolio.com/img/s4/v62 ... 2208-3.jpg[/img]

[img]http://mhackney.zenfolio.com/img/s3/v42 ... 0714-3.jpg[/img]

[img]http://mhackney.zenfolio.com/img/s3/v40 ... 0444-3.jpg[/img]

[img]http://mhackney.zenfolio.com/img/s8/v14 ... 3958-3.jpg[/img]

And this one is sort of special. It is a recreation of an 1850s New York style reel that I hand crafted (screws, gears, everything). It is in the Martin Van Buren National Historic Site in Kinderhook, NY. Sitting on President Van Buren's writing desk in his study.

mhackney wrote:I now have over 20 hours of actual print time with the new extruder guide insert mod and it has been working flawlessly! In fact, it works so well that I have been able to test and collect data on what I call "hydraulic jamming". I'll do a full report on this later but, basically, as I tried to achieve the Holy Grail of print quality I went down a path that looked like this (after basic debugging of mechanical issues):

• First calibration prints looked blobby and noticed nozzle drag but X, Y, Z motion looks great. Blobbyness appears to be the result of nozzle ooze.
• Added some Z lift to prevent dragging - conducted a set of experiments to optimize the lift amount. 1-2 mm works well and doesn't slow things down too much.
• Introduced some retract to minimize/prevent nozzle ooze - again conducting a set of experiments to find a good retract value. 5mm gave good results.
• With things apparently tuned, began printing "real world" things. immediately experienced two issues: 1) filament starving and 2) filament ejection from the extruder.
• Slowed things way down and started diagnosing problems by going back to original calibration objects (single perimeter cube) and notice problems disappear.
• Ask self, "self, what's different between the calibration objects and real things?"
• Realize that some of the things I'm printing have many short bursts of rapid retracts - almost like a machine gun - in some parts of the print. Also correlate filament starving and ejection to these retracts.
• Decided to attack the ejection issue first using basic idea presented by Polygonhell (his extruder roller cap). Fabricate my guide insert (see previous post).
• Test guide insert on real things. Absolutely no extruder ejection occurred. Unfortunately, the filament starving problem worsened.
• Ask self, "self, why would filament starving get worse after fixing ejection problem?"
• Hypothesize that the pressure that was causing filament ejection might be now transferred to the hot end of things during these rapid retraction cycles.
• Devise plan to test - write simple gcode to retract/advance extruder a specified # of times with short extrusion segments in between. Conduct test and discover, yes, these rapid retracts jam the extruder - temporarily. If pressure is backed off for a few seconds (t=3 or more) then extrusion would restart. Validated this test multiple times. Several (<5) rapid retracts in a short period are not too problematic, anything more than 5 create problem I affectionately call "hydraulic jamming".
• Realize that retract is problematic. Hypothesize that the Bowden tube introduces a little "backlash" in the filament retraction cycle and requires a little more aggressive movement to minimize blobbing, leading to the hydraulic jamming issue.
• Recall earlier experiments with KISSlicer and its "wipe" feature. A feature that minimizes blobbing due to nozzle ooze WITHOUT retracting. Decide to do some research on slicers and investigate gcode output.
• Print real world things using KISSlicer gcode. No rapid retracts results in no hydraulic jamming and the consequential filament starving. Wipe feature (and other KISS gcode optimizations) minimize/eliminate blobbing due to extruder ooze.
• Drink "victory beer" to celebrate a deeper understanding of print quality.
• Purchase KISSlicer Pro.

Since you purchased the Pro version of Kisslicer, I assume you feel it is the best slicer to be using, is this correct? I have read about the pluses and minuses of all the various slicers and have a hard time deciding which one I want to use.
I do not want a hodgepodge of slicers and having to pick one based on what I am trying to print. Do you feel that kisslicer pro is adequate for all of your printing?