Hello all. Just getting into 3D Printing and have just got my Taz 5. Having so much fun already!!.
I am a performance car enthusiast and plan on making a hobby of using my 3D printer to make small custom parts for people. An example is a friend has a car (a Lexcen) that he has swapped the motor for an LSx, and would like a custom badge made for it. So the things i want to make will often be quite “flat”.
I am very familiar with 3d modelling, and use Inventor. So I have modeled up the design and produced the STL file.
My question is about the “quality” of the print. The best result i have had so far, is printing the badge upside down on the bed so that the top layer of the badge is smooth is that makes sense. But the lower areas are quite rough, where they have the grooves of the print nozzle in them.
At present i have a roll of ABS and also PLA, the results don’t seem to vary much between the two.
So can anyone suggest any tips on how to make flat areas smoother? below is an image out of Inventor, then one of some of the attempts.
Those are actually pretty good looking prints. Top layer surface is always going to have a bit of roughness to it, and by printing the badges upside down to get a flat upper surface, you introduce bridging or use of support material into the mix for the areas not in contact wih the bed. You can improve some on quality by tuning the machine a little, making sure the fan speeds for bridging are correct (which is one of the few times you use fan with ABS) etc. But you are probably never going to get a 100% smooth on all surfaces 3d print. Part of the problem lies with the controller. As the nozzle makes passes on the top surface, the controller isn’t smart enough to make a complete 180 degree direction change and calculate a variable extrusion rate to allow the surface flow to remain completely constant through that corner. You basically end up with the effect of water sloshing up against the side of a bucket in a sharp turn, only in this case the water is molten plastic, and the bucket is the outer perimiter layer.
The best way to create a uniformly smooth part is either going to be one of the acetone smoothing techniques for ABS, or using modeling putty (squadron green or white modeling putty works great) to fill in the voids, smooth the surface , sand, then spray a primer layer over the whole thing and paint it (or chrome it, etc.) .
Thanks for the reply, that helps alot just to even know what is achievable or to aim at.
Btw I am not sure the terminology but when say I printed the octopus, the inside of his main body was actually hollow with webbing (apologies I am unsure of the correct term). If i make my own parts that are quite thick, what program do I use to make the inside hollow with webs also? Is there a program that will do that automatically or do i need to model them in by hand?
The inside hollow with webbing bit is actually known as “infill” and you can adjust the style and density of it inside Cura or whatever other Slicer program you choose to use to generate your gcode for printing. The main setting is going to be the infill percentage. A 100% infill part is solid plastic, no air gaps. A 0% infill part is a hollow vase. The octopus is probably somewhere around 45% I would guess? Then there are the types of infill, Rectalinear is the most commonly used and easiest to print. It’s that every other layer 45 degree offset pattern. Hexagon based infill looks cool, but is also prone to retraction based filliament gouging issues and can ruin large prints so I never use it. There are probably a couple others as well.
