Change filaments on the fly

Here is my process I put this alert bar at the top so I can at least try and prevent people who are new to 3d printing from attempting something that could cause issues on their printer. To use this process a recessed hobbed bolt is almost required as it helps in the alignment of things. This process can also help in the dreaded might run out of filament scenario as well.

The process is quite simple as many have stated it is simply pausing the print and replacing the filament the trick is not to let the extruder move. The main difference in this method and the one I used on the color cube is that this can be done on the fly where as that other one had to have the gcode adjusted prior to the beginning of a print.This one requires no modification to gcode at all.

This is how I do it and in the print below I did it seven times with success.
Some of the procedures used are not best practice when 3d printing so proceed with caution


1. -- Pause the print
2. -- Raise Z axis about 10mm (this prevents excessive melting of the print)
3. -- Set manual extrusion rate to about 300
4. -- set retraction to about 135mm and hit retract button (this pulls out the old filament)
5. -- Now Keeping the extruder closed feed the new filament into the hole at the top where it normally goes down until it hits the RECESSED hobbed bolt. This process mandates the the center of the recessed hole is in line with the hole on the top of the hot end assembly.
6. -- set extrusion to about 135mm -150mm the variance in length is depends on how are accurate you are with guiding the filament. Hit the extrude button now by guiding it (blindly) into the proper position the hobbed bolt will grab the filament and center it in the recessed area and then guide it into the hot end.
7. -- When you feel the extruder has gotten hold of it you can do a quick visual check to make sure it is not coming out side ways but check quickly then grab your small cricut spatula and place it between the nozzle and the print and angle it so it deflects the extruded filament away from the print. as soon as the filament stops extruding use the spatula to scrape off the nozzle. If the extruder stops extruding and you saw no new filament get extruded that you may not have had it extrude long enough. The key here is you need to learn what the distance is so that you can do it in one pass time is kind of critical so in this case too much is better the result would be a bit more filament lost in the transition.
8.-- Lower Z axis by 10mm to bring it back to the print and let it rest for two seconds there to remelt the last bit of filament it had extruded previously.
9. -- Continue the print

and you are done.

I am sure this would work with materials to you just have to add in the temp changes required as well probably
step 1-A, -- Change temp


So you have to be very familiar with the workings of the components of your printer and the right pieces in place the RECESSED hobbed bolt probably being the most critical.

I have to save good luck but I take no responsibility if you jam up your extruder or have other issues related to trying the process out BUT I do take full credit for the idea and the steps to do it. LOL

Again good luck and have fun with it.
I hope to see some very creative new prints come out because of this.

Jeff

 

Just for clarity and for those who did not know we think the chemicals that need to be in the list of ingredients in the hairspray are these two

VA/Crotonates/Vinyl Neodecanoate Copolymer,
Acrylates Copolymer

If either one is in it it seems to work well if both are in it it works really well if neither is then it usually doesn't work too well

Our Aquanet has both as seen here

 

I was going to say one thing but I just thought about it and I think the answer is I am using the E3d hotend and it is very simple in how the filament flows no nooks and crannies to get caught in flow seems to be quite good throughout the hotend.

I have a transition period where it is one color and the is a mixture and then is the second color of maybe 50 to 100mm of extruded material. Once it transitions I never have seen a patch of the original color.

In my process I retract the material out and then insert the filament and extract until one of two conditions occurs and I continue down one of two paths at that point if I want a short seemless transition as soon as I see filament begin to extrude I return to printing it will continue for a short time in the original, then the mix, then the new as mentioned, but again this is only for about 100mm max.

If I want an abrupt change I keep extruding until I see the transition is fully to the new color and then I continue the print and the color change is how you see it in the pics.

Actually when I was doing these I may have always continued when I saw filament extrude regardless of color so you may see some transition (short though they may be) and abrupt changes. Both are hard to see though

 

OH by the way upload some pics of your color changes I have not seen anyone else color changes at all I thought I was the only one doing it and was wondering why.......

 

none at all just hairspray and the correct initial height for starting prints(that is the biggest part of it)

 

If you are using teh standard rep rapLCD controller it has the pause print and I though you could manipulate the motors after things are started mine is off so I cannot check but I was moving the motors manually all the time when working on the dual just can't remember if it was during a print LOL

 

That is an excellent starting point but as the bases of the prints get to be larger, contiguous and flatter there will be tendency to lift even with PLA but IMO the hairspray can only help