Multiple processes for Dual Extrusion?

[grindeddown]

Hello,

I just bought S3D after much frustration using makerware and I have to say that so far I am very pleased. I am however having one issue.

I work with dual extrusion prints quite frequently and in a few of my designs I have features on the model that are recessed from the roof. The problem with this is that when quick printing using low infill %'s, there often isn't internal support for these recessed features. So one way I have discovered of possibly combating this is to use multiple processes.

Up until the recessed feature prints, I would like to print at a low infill. So I turn off the roof layers, keep the infill low and move on. Then right before the feature, I create a process with 0 top and bottom layers and rafting turned off. I then select an infill of 50% for several layers using the 'start print' and 'stop print' options in the advanced dialog. I then create a third process with 0 bottom layers and 3 top layers, rafting off, and 15% infill to finish out the print.

The problem I am having is that the first process works according to the preview, but then with the second and third processes, it only prints using T0 (right extruder) and ignores any future dual extrusion commands.

Is there a way to create multiple dual extrusion process groups so dual extrusions will continue to print seamlessly? Is there something I am missing? Can it not be done as of now?

[grindeddown]

So I have solved part of the problem. I simply copied the two items in the process group created by the dual extrusion wizard, pasted them into the process window, which rendered two separate processes, and then grouped them together. A few of the small issues I have been able to solve with this method. The problem I have then, which is major, is that after the first process (the group created by the dual extrusion wizard, the print fails to utilize both extruders and instead finishes the print only with the right (T0) extruder.

I have tried to create multiple instances of the dual process group using the dual extrusion wizard, but it removes any previous groups from the process window. Basically, the software seems to only allow one instance of the dual extrusion group.

I suspect that there is where the problem lies since that is where the different stl files are assigned to a toolhead. Since I can only do this process once essentially, I cannot have multiple processes for the entire dual extrusion print?

Any workarounds for this or is this just a current limitation of S3D's ability to handle multiple processed for dual extrusion prints?

[KeyboardWarrior]

Hello,

I just bought S3D after much frustration using makerware and I have to say that so far I am very pleased. I am however having one issue.

I work with dual extrusion prints quite frequently and in a few of my designs I have features on the model that are recessed from the roof. The problem with this is that when quick printing using low infill %'s, there often isn't internal support for these recessed features. So one way I have discovered of possibly combating this is to use multiple processes.

Up until the recessed feature prints, I would like to print at a low infill. So I turn off the roof layers, keep the infill low and move on. Then right before the feature, I create a process with 0 top and bottom layers and rafting turned off. I then select an infill of 50% for several layers using the 'start print' and 'stop print' options in the advanced dialog. I then create a third process with 0 bottom layers and 3 top layers, rafting off, and 15% infill to finish out the print.

The problem I am having is that the first process works according to the preview, but then with the second and third processes, it only prints using T0 (right extruder) and ignores any future dual extrusion commands.

Is there a way to create multiple dual extrusion process groups so dual extrusions will continue to print seamlessly? Is there something I am missing? Can it not be done as of now?

It's probably best to keep your dual extrusion prints to two processes for simplicity reasons. I would recommend using a low infill % throughout and then just using more top-solid layers to help close things up on top.

[grindeddown]

To be honest, thats not exactly the answer I am looking for as some of the models that I am printing have features that leave certain features unable to adhere to the infill. The solution is seems is to have a process that has a few layers of increased infill density to ensure that these floating walls have something to adhere to.

I have potentially found a a solution to this problem of having multiple processes although there is still one last piece that I am finding to be finicky and I cannot solve.

So, multiple processes are indeed allowed. I can copy and paste the original dual extrusion process and then group the pasted processes. Inside of the process dialogue box and selecting the advanced menu, I can select each of the colors and then on the very bottom, there is an option to 'Select Models', which allows me to assign the model to a toolhead.

Problem almost solved. At first it was giving me problems that looked as if the print would stop using the second toolhead after the first process, but I have discovered that that is not the case. In my case, the issue is with having a raft turned on for the first process. For some reason, what happens is that the first toolhead will complete the print as normal, including the raft dimensions into the objects overall build height. The problem is that this additional height that stems from the raft is only calculated and added to the right toolhead and not the left toolhead. This essentially offsets the model to be printed from the left extruder by a negative amount along the Z axis that is equal to the thickness of the raft.

Turning the raft off in the first process seems to solve this offset issue, but that also is not a favorable option as I am looking to print a fairly large model in ABS.

I am making progress and am hoping that I can find a solution, but if not (or even if), I am hopeful that the S3D team will take a look into this and attempt to fix this behavior. It's probably the biggest reason I bought the software license.

I'll post more if I find anything.

[CompoundCarl]

Can you post your factory file? The software will elevate both parts of you place them too close together. So if you want one to use a raft and another to be without, then the parts need to be spaced far enough apart.

Try separating them by another 10mm

[grindeddown]

Hey compoundcarl, I understand what you are saying, but that is not the behavior I am witnessing. It is almost the opposite. The two stl files are aligned properly and when finished, should appear as one object. The problem I have had is that the software is only elevating one part and not the other, despite being aligned and effectively stacked.

I have tried various ways around this to no avail and it appears that it really is software related issue, but I could be wrong. If you would still like me to post the factory file, let me know.

Cheers!

[TomL71]

I just recently came upon a similar issue.

My solution was to split the model in to several STL's. Broken into pieces, I could use the wizard to pick which toolhead printed which piece. Also had to use reset position on each stl to get them stacked properly.

This way I could use the dual extrusion wizard, instead of the start/stop option, to determine what stl was printed with which extruder.

Of course it was some work ... YMMF of course...