RAMBO Fans Questions

[theverant]

Where are people plugging in extra fans with the RAMBo board? I'd like to have one cooling the PEEK and another to blow the printed object. Suggestions?

I know in Repetier Host there is a Fan button with ramping, what does that correlate with on the RAMBo? Also, should this be used for the PEEK cooling, or the object cooling? I read something in the Repetier/RAMBo mega thread about fan turning on associated with extruder heat. I assume this is for the PEEK cooling and is completely automated. Does this connect with the Fan in the Host software, or is it firmware only?

As always, very appreciative of any input!

[mhackney]

The fan control on Repetier host controls the single fan connecor on RAMBo. It's up to you how to use it. I have a fan on my hot end for cooling the barrel when printing. I have it direct wired with a switch. I use it for both PLA and ABS. My logic is that the barrel should be kept continually cooled when needed. The fan output I have hooked to a larger fan that blows on the part. It is controlled by the gcode and turned on and off by the program. I have not mounted this fan permanently yet. Right now I aim it from the side of the base top.

[theverant]

Thanks, I was thinking along the same line - having the hotend fan hardwired to the power supply. I just know on the MBI replicator I have used the hotend fan comes on automgaically when the hotend hits 50oC, and shuts itself off when the hotend cools, which is a nice no need to think about it setup. I was pretty suprised that the Max hotend did not come with a fan and/or heatsink. Are other people finding they don't need it, or is this considered an essential upgrade? (In which case the SMCNC guys should think about including it in the kit).

[mhackney]

It's essential if you print PLA not do much for ABS. But even with ABS if I need to crank up the heat it keeps the Teflon tube from getting clogged.

I have a 25mm fan up top. It fits between the 2 hot end mount plates perfectly.

[Av8r RC]

Mhackney, do you have a pic of your 25mm fan mounted? And does one do a good enough job cooling the peek insulator for PLA? I just bought two this weekend to mount up on the hotend. I got two cause I didn't think one would be enough.

[Highcooley]

I currently have two 40 mm fans attached, one cooling the PEEK and one cooling the print. The print fan is configured to the FAN1 port of the RAMBO in both Marlin and Repetier firmwares by default. That's also the fan which can be controlled in the repetier host by the fan button with the ramping slider. I currently use a bracket similar to this one: http://www.thingiverse.com/thing:28412 with a more flat angle as this version doesn't work with our hot-end and the fan touches the print. However, with the flat angle, a 40 mm fan is almost too little to provide enough cooling.

The second fan is aiming at the PEEK part with my simple 90° fan bracket http://www.thingiverse.com/thing:40845. However, recent thin wall prints show slight deformations on the side where this fan blows towards the hot-end. I assume, it is due to air swirls from this fan passing underneath the hot-end carriage. I am probably going to shield the fan off with some plastic foil along the bracket. I configured this fan to the FAN2 port of RAMBO and am using the described function to switch the fan on automatically when heating and off when the hot-end reaches a temperature below 50°C. Since Repetier fixed a minor issue with this function, it works just perfect, even when I reset the printer. Should the need for a third hot-end ever arrise, I am going to solder a little amplifier circuit together and use an unused Arduino port.

HOWEVER, controlling the hot-end fan with the RAMBO also means that it won't go on automatically, if you use a different firmware than Repetier. Unless it has this distinct function. I don't know if the latest Marlin by ErikZalm supports a hot-end cooling function. for the moment, I just added a line in the setup void, switching the fan on during boot up.

[theverant]

I currently have two 40 mm fans attached, one cooling the PEEK and one cooling the print. The print fan is configured to the FAN1 port of the RAMBO in both Marlin and Repetier firmwares by default. That's also the fan which can be controlled in the repetier host by the fan button with the ramping slider. I currently use a bracket similar to this one: http://www.thingiverse.com/thing:28412 with a more flat angle as this version doesn't work with our hot-end and the fan touches the print. However, with the flat angle, a 40 mm fan is almost too little to provide enough cooling.

The second fan is aiming at the PEEK part with my simple 90° fan bracket http://www.thingiverse.com/thing:40845. However, recent thin wall prints show slight deformations on the side where this fan blows towards the hot-end. I assume, it is due to air swirls from this fan passing underneath the hot-end carriage. I am probably going to shield the fan off with some plastic foil along the bracket. I configured this fan to the FAN2 port of RAMBO and am using the described function to switch the fan on automatically when heating and off when the hot-end reaches a temperature below 50°C. Since Repetier fixed a minor issue with this function, it works just perfect, even when I reset the printer. Should the need for a third hot-end ever arrise, I am going to solder a little amplifier circuit together and use an unused Arduino port.

HOWEVER, controlling the hot-end fan with the RAMBO also means that it won't go on automatically, if you use a different firmware than Repetier. Unless it has this distinct function. I don't know if the latest Marlin by ErikZalm supports a hot-end cooling function. for the moment, I just added a line in the setup void, switching the fan on during boot up.

This sounds exactly like the setup I want for my printer. Auto cooling the PEEK always, and a controllable fan for the print, since ABS won't want it the same as PLA. Am I reading correctly that the Repetier firmware already has the FAN1 and FAN2 ports set up as you describe them? I just need to plug in some fans?

[Highcooley]

You need to define the pin in configuration.h. Look for the line: #define EXT0_EXTRUDER_COOLER_PIN -1 and exchange -1 with the pin you want the fan to be on. I set mine to pin 6, which is the MOSFET section marked as FAN1 on the RAMBO (left of the bed_heating section).

However, this is not very consistent with firmware development. So, I put #define FAN2_PIN in pins.h in the motherboard 301 (RAMBO) section and defined EXT0_EXTRUDER_COOLER_PIN as FAN2_PIN.

In addition, I also wired my electronics fan to the same pin, as usually the stepper drivers don't move a lot if the hot-end is off and therefore don't need to be cooled.

[mhackney]

@Av8r RC - Here's a post with a photo and description of my 25mm fan: http://forum.seemecnc.com/viewtopic.php?f=54&t=1202

[mhackney]

Posted temp measurement results in my thread: http://forum.seemecnc.com/viewtopic.php ... 5813#p5813

[mhackney]

@Highcooley - when you describe FAN1 and FAN2 I think you are referring to the locations marked Extruder 0 Fan and Extruder 1 Fan on the RAMBo RepRap page:

[img]http://reprap.org/mediawiki/images/thum ... nn-all.jpg[/img]

correct? The fan control section on Repetier host only controls the fan configured at Extruder 0 Fan on the RAMBo. Even if you enable a second extruder, no additional support for fans is available.

Cheers,
Michael

[Polygonhell]

FWIW There is support in repetier for a hotend fan that runs when the hotend is turned o.
In my copy of the firmware I have that set as I think the extruder2 output (note not the fan), you can change it in pins.h.

[mhackney]

I'm not sure that I follow Polygonhell. In pins.h I only see 1 pin assignment for a fan (pin 8). Are you saying that there is an option that anytime the hotend is being heated, a fan appropriately configured, will automatically come on? And you have that fan hooked to Extruder 1 Heat terminal in the diagram above?

regards,
Michael

[Polygonhell]

I'm not sure that I follow Polygonhell. In pins.h I only see 1 pin assignment for a fan (pin 8). Are you saying that there is an option that anytime the hotend is being heated, a fan appropriately configured, will automatically come on? And you have that fan hooked to Extruder 1 Heat terminal in the diagram above?

regards,
Michael

Then the pin number is specified in configuration.h.
It's hooked up to Heat 1 I think, the Fan and Heat pins are all identical electrically, when I split the wire I didn't have enough leeway to reach fan 1.

[mhackney]

Yup, that's it in configuration.h:

/** The extruder cooler is a fan to cool the extruder when it is heating. If you turn the etxruder on, the fan goes on. */
#define EXT0_EXTRUDER_COOLER_PIN 7

Perfect! Thanks.

[Highcooley]

Yup, that's it in configuration.h:

/** The extruder cooler is a fan to cool the extruder when it is heating. If you turn the etxruder on, the fan goes on. */
#define EXT0_EXTRUDER_COOLER_PIN 7

Perfect! Thanks.

Yep, that's exactely it.

[theverant]

Okay, lemmie see if I get this. Plug the PEEK cooling fan into Extruder 1 HEAT, plug the Reptier Host controlled fan into Extruder 0 FAN?
Host controls FAN0 by default and the posted changes to firmware enables the auto control of fan on the Extruder 1 HEAT port?

Yeah I plugged my fans in this way and it works, no changes needed in firmware (if using Polygohell's Repetier FW), for those who might want to try it.

My first PLA thin wall calibration thing with fans is coming out great!

Thanks all!