Talk:Wildseyed Simple Hot End

From RepRap
Jump to: navigation, search


The documentation is good, but certain details are missing.

What diameter is the copper welder tip, for example? I assume it's 6mm rather 5mm - as this is closer to the 7/32" drill-hold. Would this be correct? --Dslc 18:19, 1 September 2011 (UTC)

Update:after ordering 6mm tips, I realise they are not the right diameter. Something closer to 7mm would probably work. --Dslc 18:05, 6 September 2011 (UTC)
I bought both the welder tips and the brass air fitting in a hardware store at the same time. I could check that the 1/4" OD of the "0.6mm (0.023") MIG contact Tip" ( ) did interfere with the UNmeasured ID of the 1/4" NPT female air fitting before comitting. I don't know if the 1/4 NPT quick-release air fittings are common worldwide DaveX 15:44, 15 February 2012 (UTC)

Metric vs. imperial

Would it be possible to somehow specify the metric dimensions alongside the imperial ones? Or would that require a separate set of instructions/page? --Dslc 15:59, 3 September 2011 (UTC)

Air hose Adapter machining

Do you cut off or trim the locking fin from the brass fitting? The cross section does not show the brass fin. In the shop last night, I cut off the fin and the smaller diameter, and cut the threads off of the welding tip. It looks pretty compact, and it looks like it keeps the working end close to the heating block. It does require a bigger hole in the Al heating block to take the larger round section of fitting though. Maybe my air fitting is different than yours. Yes: my brass air fitting ID chamfers at ~45 degrees from the end of the threads down to the (now) 7/32" ID, so I'm trying chamfering the PTFE to match, otherwise there's be a 7/16" OD cone-shaped shoulder cavity adjacent to the filament path. In my first iteration necking down the PFTE to about 0.488 at an eyeballed taper of 1/16 inch/inch to get about 1/2 way down the 1/4 NPT threads per DaveX 15:29, 15 February 2012 (UTC)

Heat Transfer simulation cartoon

I was fiddling with matlab's pdetool to see how the heat would flow through the brass fitting, since the diagram on the main page didn't seem quite right, and even if it was, it wouldn't match my fitting anyway. The things to take way from this cartoon is that the copper is about twice as thermally conductive as the aluminum, and pulls a bunch of heat up and around the PTFE. It might be a good idea to drop a washer & heat shield around the bottom of the PTFE barrel to separate the cold end from the hot end convection-wise. (I know this isn't close to an accurate cross section-- Matlab's PDEtool is 2D and is pretty awkward in the geometry specification. I wanted to model the Al wrapping all the way around the brass, so I took it around the bottom. You could to other 2D adjustments to make it more analogous to the 3d part.) Working through some FEM models (not shown) makes the effect of thermal breaks apparent. Maybe carving a deep groove out of the fitting would be helpful. DaveX 18:48, 16 February 2012 (UTC)