CTC Bizer Dual Extruder Desktop 3d Printer

[simonm]

1st off .. Hi all .. i'm new to the 3d printing world.
i'd been following the technology for a long time and its now withing the reach of normal users to experiment with ..

so last week .. i bought myself a CTC dual extruder printer. vendors description CTC Bizer Dual Extruder Desktop 3d Printer, Mk8
out of the box it was 'fun' . nothing would stick to the bed .. in the end i solved that.
heated bed temps seem to report wrong , being approx 30-40c to low .. seems a common issue on this printer.

i have it all working .. 1st on the right hand extruder.. then after much adjusting and stripping the extruders and steppers down a few times i now have it printing from the left also. i have both the hot end heights just right (that was fun !)

my problems that i have been unable to solve start here
filament does not flow as quick on start up as it should . not an issue on single color as once it does a raft the flow is ok.
on dual color when it changed from one to the other it then leaves gaps or does not work at all .
i also need to calibrate the 2 extruders but because of the change of color it makes printing the calibration thing in repg a problem.

does anyone have one of these printers who could give some advise

[JoeJ]

1) you need to prime the extruder before starting the print. The easiest way to do this is to add a skirt in Simplify3D. Using 1 or 2 skirt perimeters is usually enough for me to make sure that the extruder is flowing cleanly.

2) use an ooze shield. This is built in S3D and will help prime each extruder after the switch. Has worked wonders for me on my dual extrusion prints.

3) you can set toolhead offsets on the LCD menu. So try to print a dual-extrusion object and then adjust the offsets as needed until everything lines up properly.

[TimEdwards]

I am having a similar problem. I am trying to print a dual extrusion object, and need to prime each extruder before it prints. I have an experimental setup with hardware wipers where I am trying to avoid the use of an ooze shield or wipe tower. But I still need to have a skirt printed by each extruder before it starts printing the object itself. Version 3.0 claims to support skirts being printed by both extruders. But I have tried to set this up in the left and right processes every which way, and all the toolpath ever shows is a skirt being printed with the first (left) extruder. The right extruder is not printing a skirt. How can I make this happen?

[TimEdwards]

Well, since nobody is answering this one, and help from Simplify3D support comes at the excruciatingly slow pace of one email a day, I'll go ahead and post a partial answer to my own question.

First off: The way to get both extruders to print a skirt is to make sure that both extruders are defined in both processes. That is, I had my left process defining the left extruder only, and the right process defining the right extruder only. Seems reasonable to me, and it appears to work perfectly---until you attempt to print a skirt with both extruders.

Okay, so I got my processes defined "properly" with the obscure and unintuitive feature of having each extruder process define the other ("so that the left and right processes will know about each other", according to Simplify3D support. Apparently parts of their software are not on speaking terms with each other).

Now I get a skirt that is printed with both extruders. But apparently some Simplify3D programmer decided that it would be really cute if the skirt was printed in alternating rings of left and right. And that each perimeter of the skirt would be printed in sequence by alternating extruders. And that the last extruder to print a skirt outline would go inactive while the other one goes and prints the first layer. All of which completely undermines the main reason for drawing a skirt. The point of drawing a skirt is not for decorative purposes. Getting the first layer to stick to the bed is always a challenge, and drawing a skirt gives a way to get the filament primed on a throw-away bit, not connected to the model, but close enough that it can jump quickly from the skirt to the model and start printing while the filament is primed.

Stopping the skirt and going idle for a while before printing the object is a great way to completely mess up the first layer. You will get a bad first layer every single time. With this particular method of alternating left and right perimeters in the skirt, you get the worst of both worlds. Neither the left or the right sides are going to stick the first layer to the bed properly.

Now I know that skirts have other uses; they can hold a print down that has a very small area contact with the bed. But this can be done just fine if printing the left side skirt all at once, and printing the right side skirt all at once. It would be up to the end-user to set the distances for each skirt individually to make sure that the right one contacts the model to give it support. As far as I can tell, the current version of Simplify3D ignores any difference between the skirt parameters. I'm not even sure how it decides which set of parameters to use.

[CompoundCarl]

I have a feeling your issues are because you're trying to use options in S3D for things they weren't necessarily designed for. As I understand it, the skirt is typically used to help purge the nozzle on the first layer or to act as a brim to help hold the model down. If you choose to print the skirt with the "all extruders" option, then it primes every single extruder you are using. So that's exactly what I would expect it to do, since that's what the skirt was designed for.

If you want to purge the toolheads through out the print, then there are 2 options that are designed for that purpose - the ooze shield and the prime pillar. They work beautifully, and I personally prefer the ooze shield since that does double-duty grabbing oozing filament after the purge.

So that's probably how those things are intended to be used. It sounds like you're trying to use the skirt in place of an ooze shield, which I'm sure will create some problems. But that's not unexpected if you're trying to do an "experimental setup"

[TimEdwards]

As I understand it, the skirt is typically used to help purge the nozzle on the first layer or to act as a brim to help hold the model down.

Yes, that's exactly what I want. But to have the nozzle purge on the first layer be effective, the head must move immediately from printing the skirt to printing the model, with no time lapse in between, or you end up needing to do the purge all over again.

In this weird interleaved skirt, even if you print just one skirt outline, the sequence will be: Left extruder print skirt outline, right extruder print skirt outline, left extruder print model, right extruder print model. That puts a time lapse between the skirt and model printing for both of the extruders. Neither one will start printing the model properly.

What you really need here is to print in this order: Left extruder prints skirt outline, left extruder prints model 1st layer, right extruder prints skirt outline, right extruder prints model 1st layer. No other order makes any sense.

Additionally, if I want to use the skirt to hold the print down, I would still need to purge both nozzles but I certainly would not want to waste a huge amount of time having the skirt switch back and forth between the two nozzles. I would just want to print the first skirt with, say 10 outlines at a distance of zero from the model with the left extruder, then print the second skirt with the right extruder with, say, 3 outlines at a distance of 4mm from the model. Because I don't need both extruders to hold the part down, I don't want to wait that long for the skirt to print in an absurdly complicated and unnecessary way, and I do need both extruders to purge, and I need each extruder to purge as the very last thing it does before starting to print the model. Preferably with the delay between skirt and model measured in milliseconds.