SoliForum - 3D Printing Community — Help - Where should I wire my Hot End Fan?

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T23:57:24Z

No worries. The carriage upgrade will keep me busy on my vacation. Ahh! Now I know what the fishing line is for in your signature! Great idea, that should keep me in business until the belts come!

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T23:37:37Z

That mount works well I just don't have a fan duct integrated into it for the G-code fan. I actually have a printer running that setup right now and it works fine. BTW fish line will replace a belt real quick.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T23:27:26Z

I have the bulldog mount that is for the stock SD3 carriage design. I'm going to go ahead and print the parts for the Lawsy Carriage as well as your mount for that carriage.. well, as soon as my belts come in.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T19:04:21Z

Try .2963 for a layer height that'll fix you bonding and layering issues.
As far as my carriage goes for the bulldog which mount do you have. The one with bearings and the integrated nozzle fan mount is the preferred mount and all I can say is you can try the stock rods and see or just replace them with known good ones.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T18:57:09Z

wardjr wrote:

The E3d will function just fine with about half the airflow.

In my experience this is true with with ABS, not PLA. With PLA you need all the heatsink cooling you can get.

fdm_process wrote:

printing at a .4 layer height with a .4 nozzle

There's your problem. Layer width needs to at least 1.2x layer height. Otherwise its like stacking spheres on top of each other - there's no surface area for them to bond.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T18:54:08Z

Yes sir, the cold end fan is what I am talking about here. Sorry about the confusion.

I will flip the fan around so it is sucking the hot air out instead of blowing air in, that should fix any air blowing back onto my print.

Also you are correct about having an underlying issue. I was messing around with different layer heights and was doing my first attempt at printing at a .4 layer height with a .4 nozzle, which was causing my prints to barely bond. I didn't realize this until just now. Bringing the layer height back down should alleviate that issue.

I will test these out and report back once I get my belts in, snapped one last night.

Lastly, I should have clarified this as well. I have your Bulldog XL mount for the SD3. I see that you have a mount for a nozzle fan on Thingiverse. Will that mount work if I don't have Lawsy's carriage? Also, if I were to decide to mod up to the Lawsy Carriage design, is there anything I need to order other than the (8) LMU8 bearings? Can I recycle the rods on my current carriage or do I need to order new ones?

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T17:36:46Z

So as to clarify for future readers let's use the correct terminology.
The E3d cooling fan is used to cool the upper (cold) portion of the E3d and is usually run at a full 12v.
The G-code controlled nozzle fan is used to cool the print itself. It is usually ducted to direct cool air directly at the tip of the nozzle. This fan can not only be controlled by the slider in RH. It can also be controlled and speeds varied by Slic3r automatically based on your slice profile. This is a great feature to have for printing not only PLA but overhangs and bridges when using ABS.
If you are under the impression (and results confirm) that the cooling fan is causing layer separation. I would suggest that you have some other underlying issue. That being said the E3d will certainly function fine with less cooling than the included fan provides. You do not however want that cooling fan on the G-code controlled pins.
I might also suggest you flip that fan over and see if that makes a difference. If not find a way to add some resistance to slow it down and set it and forget it. The E3d will function just fine with about half the airflow.
Then check Thingiverse and find a nozzle duct you like. Add a fan and solder up the pins so you can enjoy the benefits of a G-code controlled fan.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T17:10:29Z

Thanks for clearing that up, Ward.

Yes, I do have a printerboard, an E3Dv5, and am running RH. I would like to use the slider in RH to control the fan (the E3D fin cooler) but I am not opposed to making an analog hack if that is necessary. I was having some serious clogging issues without the fan but now I am having some layer separation issues.

I am not running a fan to cool my PLA prints, but maybe I should be. Is there a file out there that allows for both the cold end fan and the print fan?

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T15:31:38Z

So you have a printerboard you think?
You want to install a ducted nozzle fan?
You would like to use the Slider in RH to control the fan?
I am not sure everyone understood the question.
If that is indeed what you are looking to do and you do actually have a printerboard. Then this process has been covered here in the last few posts.
http://www.soliforum.com/topic/182/nozzle-fan-duct/

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T15:12:10Z

Thanks for the suggestion guys, but is that going to just cut my speed by a percentage? It doesn't sound like it has much control.

I do have some extra electrical parts laying around and some arduino stuffs. I'm not the most experienced with electric design but do you think there is a way I can wire in a slider type of control and could anyone possibly point me in the right direction to attempt something like that?

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T07:37:02Z

There is no need to quote my post, it is the one above yours. Doing so just makes more stuff to scroll through.

You can still get plenty of control with an appropriately sized pot, at least varying from 50-100%. You would certainly have better control with a properly sized pot than the 100k pot you suggested.

http://www.blackfiveservices.co.uk/fanspeed.shtml

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T07:25:43Z

elmoret wrote:

That's a poor suggestion, Carl. Fans of this size typically draw 40ma, meaning they have an effective resistance of 300 ohms.
That means that the entire speed range of the fan would be controlled by approximately 1 degree of rotation on the potentiometer you suggested.

Unless the fan is PWM driven you won't have that much degree of speed with any pot regardless of it's resistance. Once you get below 6 or so volts the fan will start stalling.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T07:21:20Z

That's a poor suggestion, Carl. Fans of this size typically draw ~40ma, meaning they have an effective resistance of 300 ohms.

That means that the entire speed range of the fan would be controlled by approximately 1 degree of rotation on the potentiometer you suggested.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T05:28:34Z

fdm_process wrote:

I have a printerboard or whatever comes stock with an SD3. I was hoping I could wire it up somewhere that would allow me to control the speed at which the fan is blowing. I have it wired in with my extruder motor fan now and it's running full speed and I think it's causing some layer separation.

Get a 100k ohm pot rated at a couple of watts and put it on one side of the fan. Then you can vary its speed somewhat.

Re: Help - Where should I wire my Hot End Fan?

2015-03-07T05:25:24Z

I have a printerboard or whatever comes stock with an SD3. I was hoping I could wire it up somewhere that would allow me to control the speed at which the fan is blowing. I have it wired in with my extruder motor fan now and it's running full speed and I think it's causing some layer separation.