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PLA doesn't produce fumes - with ABS you need some ventilation.
For PLA a dilute solution of PVA applied to the glass bed helps it to stick and the parts come off quite easily when the bed cools.
Operating in a warm environment helps minimise warping.
If you are printing fine detail or small objects a cooling fan helps - it should be turned on after the first layer has been deposited.
Be prepared for some experimenting....
Excellent, thanks for that info.
Will switch direction to PLA to start with.
I take it that the PVA is applied and allowed to dry first on the glass?
I will need to upgrade the stepper on the head as my drivers can only go down to 1.5A and the teeny little motors supplied only run 0.84A, luckily motors are cheap and standard Nema17's
I use Slic3r as well, it's a good piece of code. Also runs on Windows and Ubuntu so I can use it for printing indoors from a laptop and in the garage using my LinuxCNC machine, in conjunction with Pronterface for printer control.
The extruder stepper needs next to no current so should be fine off the ATX psu.
PLA is a good starting point but I would disagree that you need to mess about with PVA, etc, on the bed. I use a heated bed running at about 60C and don't have any problems. However, the top layer of my bed is a glass trivet from a local discount shop which has a ground finish. Getting the "squish" of the first layer on the bed is critical so you need the bed to be level to, maybe, better than 0.05mm so the layer is uniform across the piece. The bed gets cleaned with a quick wipe with acetone between prints to make sure it's grease-free.
Don't need PID for the bed as the temp isn't that critical and there's lots of thermal inertia but PID on the hot end is really useful. I reckon that I need to hold the temp to within 2-3C and without PID that's difficult. Took a little while to tune the PID parameters but I seldom see the temp move by more than a degree or so during a print. I built my favourite hot end with about 24W of heater power so about 2A on 12V. I think the heated bed (about 200x200) takes about 120W off the same 12V supply as the rest.
Just my experience, though - there are as many religious debates in the 3D printing world as, say, the Mach3/LinuxCNC world!
I used clean glass at first and it was a bit hit and miss - I would think the frosting is an improvement.
The PVA is quite dilute (5:1), applied with a tissue and will dry while the bed heats up. It lasts for several prints and I find it easier than cleaning the glass each time.
I agree with the bed flatness - I use a DTI gauge to make sure it's flat.
The other side of my heatproof glass was plain and didn't work too well; I flipped it over and used the ground surface and it's very good. If you can find someone with a sandblaster I gather it is trivial to lightly frost the surface.
Great, makes sense too, should be able to find frosted glass somewhere.
Could you not get some glass etching solution and frost the glass that way?
Yes - it just depends on whether you have access to a glass frosting solution or happen to know a glass-worker with sand-blasting kit! Although in my case, the heatproof glass I bought just needed little plastic feet scraped off and it was ready to go. Very minor problem is that there is a pattern of narrow unfrosted lines in the otherwise frosted surface which comes out on the printed parts, but there's enough frosted to ensure good adhesion while printing. What's not obvious is that you have to do a lot of playing around with print speeds, extrusion rates, layer heights, hot end temp, etc, before you start getting halfways-decent prints. There are a lot of interdependent parameters to be played with, maybe even more than for CNC routing. Very satisfying when you get there, though.
Twiddling software settings is the easy bit I think, once the mechanics and electronics are fixed, the rest is just fine tuning as with many DIY subjects.
having a good forum is a big help.
I was getting all excited (sad I know!) about adding a 3D print head to my router (when I finish it...) and then I remembered that I'll be mounting it nearly vertically....doh! Ok so I'll have to make a second CNC machine :)