3D Printing - Tips and Tricks

Hi all! I got a FlashForge Finder in December and have been printing and learning as I proceed on a free-standing tonearm design. I thought it might be worthy for us to have a dedicated 3D printing thread.
 
As I proceed with my tonearm designs, I've used the Boolean Modifier quite a bit. Much of what I've needed to do is subtract cavities in my design to make way for inserts. Along the way, I've also used Boolean additions to the design. At times I seem to reach a limit... model has 17 subtractions and one addition... adding another Boolean or even changing radius for some inserts causes the base model to disappear, leaving only smaller elements free-floating without the primary base visible. I've found ways to do things, but those have taken a lot of time to implement. I feel like, at times, I've found the limit of the Boolean Modifier or hit upon a bug. Talking in generalities here - not ready to share my design at present - I may offer it as a kit for purchase.
 
My printer doesn't have a heated platform, and doesn't have magnetic front and side covers to hold in the heat as some printers offer, so printing when it's cold or when there's air movement with our fans on can cause problems. I've ordered some duvatyne fabric to make a wrap for the printer sides that can velcro into place when needed.

Printing a large object that has a wide base can present issues. I always cover the printing bed with blue painters tape and, even when using the supplied glue stick to give the PLA (I use Hatchbox PLA+) extra hold, the heat can cause the tape loose its tack and come up as the plastic cools, which can warp the print. I found that I can wrap the tape around the platform sides and have it held tightly, which helps. I add a couple of strips of duct tape front and back to keep those non-clamped sides down. I then use the glue stick and print with a raft, which seems to keep the model from warping. It's way cold outside today and the print looks good so far! I also found 4" painters tape, which keeps the tape seams from imprinting into the face of the print if I don't use a raft. Learning every day.
 
Anyone used MadHackers "3D Gloop for PLA" yet? While it's meant for glass bed adhesion, I saw a video of it being brushed on a model to smooth the sliced appearance of a printed model. A crude application process, but it worked not he model he used. The person in the video said they are looking into developing a spray formulation.

 
Tip#1: for using a FlashForge Finder: When inserting filament, don't stop when you feel a little resistance, keep pushing for about 2 inches 40-50mm) until you can't push any more.

Tip#2: If you get the "Something went wrong during slicing" error, try changing the location of your saved .fpp and/or .gx printing files. Mine were initially going to the MacintoshHD... changing the file location to Desktop fixed the issue.

Tip#3: To determine if a model is causing a slicing error, load one of FlashPrint's internal testing models under File/Examples - if the file prints, the issue is with your model OR where you're exporting the .fpp and/or .gx printing files, not with the FlashPrint software.

Tip#4: Most people recommend fixing a layer of blue painters tape to the platform surface, allowing for easier removal of your print. My printer came with a purple (dried clear) glue stick - liberal application on the painters tape helps smaller prints adhere nicely. I almost always print with a raft or brim. When printing larger, denser models, the painters tape can and does lift up due to the concentrated heat (the PLA and extruder head are both 220º... that's hot!), causing the PLA to be applied at a different heights, resulting in distortions in the printed piece. i.e.: one of my pieces is a 4" cylinder with a center 2" hole that I first printed upside down. With the painters tape and glue stick, the entire top printed with a slow curved top, tallest in the center. It looked cool, but it was uneven and no part was the actual designed height. It wasn't until I got brave and printed directly to the platform that my model retained its true dimensions. The flat bottom of a smaller 2" diameter piece, even with a raft, painters tape and glue stick, continued to print the bottom in a slow arc - I have to print it directly on the platform's unheated surface, adhered with glue stick.

FlashForge's tech support person, Tang, is friendly, helpful and responds in a day or so. While having an issue, I made a suggestion regarding their set up and the process of motor removal when checking for a clogged extruder. I also told him about the Cheetah3d forum and it's helpful members and suggested FlashForge create an open user forum. It seems you learn by experience with 3d printing... an open user forum might help speed everyone's process. When I recommend Cheetah3d to others, I tell them the real reason to try Cheetah3d is the forum. I really appreciate all of your efforts.
 
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As I proceed with my tonearm designs, I've used the Boolean Modifier quite a bit. Much of what I've needed to do is subtract cavities in my design to make way for inserts. Along the way, I've also used Boolean additions to the design. At times I seem to reach a limit... model has 17 subtractions and one addition... adding another Boolean or even changing radius for some inserts causes the base model to disappear, leaving only smaller elements free-floating without the primary base visible. I've found ways to do things, but those have taken a lot of time to implement. I feel like, at times, I've found the limit of the Boolean Modifier or hit upon a bug. Talking in generalities here - not ready to share my design at present - I may offer it as a kit for purchase.

I've been using Cheetah to make models for 3D printing as well and I also encountered the "disappearing body" problem.
It's not a bug. I found the problem (at least in my case...)
The object I was subtracting from the "body" overlapped the outer edge of the body in a very hard to see place.
I changed the view to wireframe and was able to see the overlap. Once I moved the object completely inside the body object, everything worked fine :)

J
 
Great idea to have a 3d printing thread. Ender 3 here printing organic (radiolari style) structures and designing with cheetah3d.

So what is important when it comes to final model for 3d printing and slicing (Cura)?
 
Great idea to have a 3d printing thread. Ender 3 here printing organic (radiolari style) structures and designing with cheetah3d.

So what is important when it comes to final model for 3d printing and slicing (Cura)?
= = =
Hmm, I don't know Cura - perhaps someone here can speak to its use. I continue to use the FlashPrint software that came with my Finder printer. I try to make all my changes in the Cheetah3d file rather than scaling in FlashPrint - more to be able to load the model and print than anything else. I check to make sure all my meshes are connected and that anything hidden from view is deleted.
 
While I originally purchased Cheetah 3d for designing objects for games I now use it almost exclusively for 3D printing. There are some issues with booleans but, so far, nothing that I can't get around. It's nice to know I'm not the only one.
 
Here's a view of my tonearm project. Time to epoxy and wire things up!
 

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Hello, I need advice to optimise objects for 3D printing and stumbled on this 3D printing thread.

This thread seems a great idea and I hope someone can help me and other users like me.
I sometimes print objects from Cheetah on a Ultimaker. The objects are exported as .stl and prepared for print with Cura. My knowledge of Cheetah3D is limited, although I use it on and off since 2005. More off than on, I admit.

I run in 2 major kinds of problems when 3D printing Cheetah generated .stl-files:
1. Wall thickness
2. Auto Intersections/Internal Overlapping/Self-Intersecting Surfaces

1. A typical object in Cheetah3D has only surface visual purposes and thus do not have wall thickness. However, 3D printers need information about how thick I intend the wall of my object to be or if I want to print a completely solid model.
I can use the Shell-modifier for creating a wall thickness, but that changes my object. I want to define the thickness only to the inside and negative values are not accepted. So, the Shell-modifier is not an option, I think.

2. A model to print is often a mix of different objects. It looks like one piece, but it 's made from several bits. And that shows on the generated .stl that is imported in Cura. It's full of intersections. And Cura tries to print those even if these are somewhere inside the object. That's really unwanted because this causes extra print time and waste of material. And in some cases it affects the quality of the print result with parts falling off.

Any solutions?
 
FWIW, I use Cheetah 3D for a lot of printed parts. I don't know what your design process is, but, in general, you should stay away from using planes for anything. Use solid objects and boolean operations to modify shapes. My parts are normally very complex and Cheetah generally can deal with them. When there are issues I can normally post-process the STL files with other utilities to correct them.
 

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1. A typical object in Cheetah3D has only surface visual purposes and thus do not have wall thickness. However, 3D printers need information about how thick I intend the wall of my object to be or if I want to print a completely solid model.
I can use the Shell-modifier for creating a wall thickness, but that changes my object. I want to define the thickness only to the inside and negative values are not accepted. So, the Shell-modifier is not an option, I think.

I suspect that the model interpretation of 3D printers works entirely off of the idea that one side of a surface faces the air, and the other side faces solid 3D material - so putting a plane (which is only 2D) inside a solid 3D shape would screw up its math tremendously since in 3D digital formats each polygon has a predefined exterior surface only on one side of it (this is referred to as the 'normal').

1) A Plane is only a two-dimensional object, so it definitely needs to be extruded in order to gain the third dimensions a 3D printer requires. I would try converting your plane(s) to polygons and flipping the normal(s) ( Tools->Polygon->Flip Normal ), THEN applying the extrusion.

2) I would assume the second issue is that 3D printers require only the exterior surfaces, and finding those polygons inside a solid shape tells the printer to stop printing where it shouldn't. So you would need to delete those interior polygons. making it a boolean solid should do it, but the edge alignments would have to be really tight.
 
FWIW, I use Cheetah 3D for a lot of printed parts. I don't know what your design process is, but, in general, you should stay away from using planes for anything. Use solid objects and boolean operations to modify shapes. My parts are normally very complex and Cheetah generally can deal with them. When there are issues I can normally post-process the STL files with other utilities to correct them.
Actually I don't use planes. The model is a solid object, for instance a lowpoly rubber duck.
In C3D the object is fine and solid, but when the STL is imported in Cura, some polygons seem to get extra thickness. But I wonder if I do prepare the stl properly. Wich utilities do you use to prepare and correct stl-files?
 
I suspect that the model interpretation of 3D printers works entirely off of the idea that one side of a surface faces the air, and the other side faces solid 3D material - so putting a plane (which is only 2D) inside a solid 3D shape would screw up its math tremendously since in 3D digital formats each polygon has a predefined exterior surface only on one side of it (this is referred to as the 'normal').

1) A Plane is only a two-dimensional object, so it definitely needs to be extruded in order to gain the third dimensions a 3D printer requires. I would try converting your plane(s) to polygons and flipping the normal(s) ( Tools->Polygon->Flip Normal ), THEN applying the extrusion.

2) I would assume the second issue is that 3D printers require only the exterior surfaces, and finding those polygons inside a solid shape tells the printer to stop printing where it shouldn't. So you would need to delete those interior polygons. making it a boolean solid should do it, but the edge alignments would have to be really tight.
Thanks for your answer and the tip about 'Normals'. I will look into it further.
But I already use solid objects, no planes.

Here's an example of a problems with intersections.

The object. ((Rendered jpg in C3D.)
example-solid-object.png


Wireframe in Cheetah. You can see the intersections in the "e". (Wireframe view is C3D.)

example-solid-object-wireframe.png


And the effect of the intersection in Cura. (3D Printpreview.)

example-solid-object-cura.png


Any advice on how to clean those intersections?
 
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