No, in fact cooling the plastic is not wanted. You want as much temperature in the print as possible. What happens is that the bottom layers start to cool and shrink. As more layers get put on, they are being placed hot and shrink as well. It starts to act like a bow and starts to pull the edges off the glass/tape.
Only time fans get used is when doing bridges and when doing small repetetive motions over the same spot. This repetion doesnt give the filament time to solidify and starts to mess with the print.
The controller has an output for the fan, i just havent hooked one up as i dont do a lot of bridging and if i do use repetitive motions over the same spot i slow the print down, or make sure the print head moves over to another spot before coming back to print at the original position.
You learn to work around the deficiencies in the system. learn to design your models to avoid issues.
For instance, my slicer program sometimes doesnt recognize walls thinner than 0.5mm...it simply doesnt write code for it. So i've learned to make sure my prints dont have thin walls...other times a wall thickess is such that it leaves an empty void instead of filling it. Nature of the open source beast. All the software is free and there are many different versions. In fact i use two different versions of the same slicer depending on how i want it to turn out. As one version will create different gcode from the same 3d file. Weird huh?
I can load the 3d printer software, load the gcode and line by line preview what the tool path will be, this lets me spot any issues before i start to print. If i see an issue i just alter the file in sketchup and redo the gcode.
Well I started this thread to learn and I'm glad that I did, because I certainly am. So my assumption about the purpose of the fan was correct, but I was wrong in assuming that it's use is universal. I had thought that the heated bed would minimize the curling of the plastic, but obviously everything is a balancing act.
Are you finding that you're constantly tweaking your settings and how you use the slicer programme, or have you pretty much gotten your output to be as good as it's going to get at this point? Do you keep looking for another programme that will work better for you?
Are you doing any smoothing of your prints with acetone, or are you satisfied with the surface results that you're getting already?
If you are smoothing with acetone, wat is the surface like? Does it become waxy and easily damaged?
Interesting timing... just started my Mendel build the other day. Working on the frame now, still gotta source and order all the bearings and then the electronics... I have an Arduino Mega kicking around here somewhere, so I think I'll be going the RAMPS route. I'm hoping to be done in January.
Rob, if you ever want to meet up to have a chat about this stuff at Ryerson just give me a shout.
I'm looking at something more like a complete setup, rather than building my own. I doubt that I'd make it any tougher than buying a complete kit. If I went the CNC route, instead, then I might consider building a rig. At this point I'm just kicking this idea around, but I might take you up on that offer in the future.
I started looking into this stuff because either technology would have been very useful in helping me to build the tools I'm using for another hobby; chainmail armour and jewellery making. I built my own coiling and ring cutting rigs using acrylic, high density polyethylene block, and high density fibre board and rather than using hand tools, CNC or 3D printing would have made their creation far easier and neater. Either would also be useful for making actual custom jewellery pieces by either creating positives for mold making, or actually creating the pieces.
