Using retract to change filament

[Boundless]

Hey guys,

I am probably NOT doing this the right way, but when I change filament, in Reptetier manual control, I am using the retract button set to 100mm. After which... i hit the button again, and again, and... you get the idea. Until the filament has popped out of the ezstruder above the red lever.

I have tried manually pulling the filament with and without the red lever pushed with no luck. The bowden tube is also set in the PTF connectors like a rock. Rather not remove it everytime for a change anyway.

How is it suppose to be done?

Thanks.

[Polygonhell]

I heat the hot end to a bit less than extrusion temperature, then depress the red release lever and pull the filament out by hand, I also feed the new filament in the same way.
But there is nothing wrong with what you are doing.

[nitewatchman]

Me too, I will also roll it out with the manual feed.

nitewatchman

[atoff]

For PLA, I heat up the hotend to 110c then retract manually, for ABS I heat it up to 130c.

[Boundless]

I have been heating the plastic up to the extrusion temp and then using the retract button, but when its free of the hotend, and I depress the red lever, I still get nothing when I pull on it.

Thats why I have been using retract all the way... I wonder if something is wrong with my red lever. Appreciate the help guys.

[atoff]

I have been heating the plastic up to the extrusion temp and then using the retract button, but when its free of the hotend, and I depress the red lever, I still get nothing when I pull on it.

Thats why I have been using retract all the way... I wonder if something is wrong with my red lever. Appreciate the help guys.

I think if you heat it to extrusion temps you're going to leave a lot of the molten plastic sitting in the nozzle/chamber. Try heating to 110/130c, then retract until it's free of the hotend and see how you like the results... you'll end up seeing all of the filament, including tip.

[geolupulus]

Do you experience resistance when you depress the red lever?

When I change filament, most times the end of the filament is a bit thicker than the rest of the filament, just because it partially melted in the hotend. I just do a quick tug and it pops out. I do notice that sometimes it takes quite a bit of force to pull the filament out when I have the red lever depressed.

I hold the lever down, and rotate the filament spool to pull the filament up and out.
If you pull harder do you feel any filament at all come out?

[nitewatchman]

This is the reason why I bring the hot end to full temperature. I usually get a nice long pointy end when the filament is withdrawn. There is no plug or knob attached to drag back and it loads freely next time.

I insert the new filament and manually crank several turns on the extruder gear to purge the melt chamber, retract a half turn and we are ready to go. I turn the gear manually because it is quicker and easier that stabbing the retract button.

Works well for me but YMMV.

nitewatchman

[Tinyhead]

I do mine the exact same way as nitewatchman. It never even occurred to me to only heat it up to around 130 and pull out the plug. I like the operating temp as it's a nice easy pull. Even if you have to extrude more to get the old filament out of the end, I feel like it's easier on some of the parts.

[Boundless]

Yeah, I am pretty sure something is wrong with the red lever now. I heat the nozzle up to 190, retract 100mm, 100mm more till I see all of the plastic pulling up through the tube and once I know its free from the hotend, I press the lever down. It goes down with normal spring pressure I assume, and then I pull on the filament with no movement at all. I can pull pretty hard and still nothing.

Its kinda funny how many times I have to hit the retract 100mm button. I try changing that 100 to 1000 or even 200 and it doesn't go anywhere. Seems 100mm is maxed out.

Is there any G-code I could write that would let me retract it faster?

By the way guys, thanks for all the good replies and tips. Awesome to be working with ya'll.

[Polygonhell]

It's a pretty simple mechanical device, should be obvious if the red lever is not working, all it does it remove pressure from the idler bearing.

[RAMTechRob]

I would take parts the Red lever mechanism. There must be something jammed.

For my retract, I unscrew the bowden tube and allow about 2 inches of filament to show. I then cut the filament and pull out those 2 inches from the extruder. Tighten the bowden tube back on. I depress the red lever and pull out rest of the filament for another day.

Occasionally, I get a rough spot where the stepper drive wheel has worn away the filament, and that makes it a little harder to retract. But that only happens when I am really pushing the machine for speed, and you hear the clicking noise coming from the stepper.

[Boundless]

You were right, it was jammed. Found some broken off plastic inside. Don't know how it got there, but it was jamming the lever when pressed. Now its cleared out, filament is coming out just fine.

Thanks for your help diagnosing the problem.

[Demolishun]

Thanks for bringing up this subject in the first place. I kept wondering what the "proper" way was to do this. It gives me some ideas of how to approach this when I change filament. I have been: heating up the hot end, undoing the bowden tube at the hot end, pulling out the filment, and snipping the end off before pulling all the way back through the tube at the EZStruder. I just toss the wasted end piece in my ABS slurry or my "to be extruded as filament" box.

[Boundless]

Yeah, I think unhooking the bowden tube is just extra hassle that's unneeded.

For me, (now that the red lever is working properly) the easiest way is to change filament is....

1) Heat hot end to temp
2) Use retract button 100mm twice.
3) Push red lever and pull the filament up and out.

I have noticed that very little filament is left in the hot end this way. After adding a new color and starting a new print, the old color fades to the new color during the first outer loop or skirt, or whatever its called.

[Boundless]

Also, a quick side note.

I find it easy to feed and extract the old filament when the Z=0 (the hotend is at print level, not home)

This straightens the bowden tube somewhat which helps the new or old filament to feed easier.

[RAMTechRob]

So what does the retract button look like?

[Mac The Knife]

Here's a screenshot of where it is on the Manual Gcode tab of Repetier.