Heat block to ABS parts clearance?

I am designing a Kossel effector for the E3D V6 that maximizes build height. I am looking and the clearance between the heat block and bottom plate of the effector is pretty tight (1.5mm). what kind of clearance do I need to allow to avoid melting ABS?

Like with most things, it depends. How hot are you planning on running the extruder, is the heat block going to be insulated? You can use aluminum tape to help reflect heat from critical areas if things are marginal. How come the heat block is so close to the plate - you're putting the heatsink on the topside? I have the fan shrouds for my hotends printed in abs at the moment and they sit a couple of mm from the heatblocks. One has aluminum tape on, one doesn't, neither show any signs of softening, but the heatblocks are insulated and the fan ducts are continually cooling themselves, so maybe not a good comparison. I typically run the heatblocks at 260C

yes, the heatsink is sitting above the base plate. That is how I am maximizing build height. that is the current configuration of my printer, but it uses a modified E3D V5 with a super long heatbrake (probably 2cm longer then stock) and aluminum effector plate. Basically, the heatsink acts as the top nut and the effector plate is sandwiched between the heatsink and a nut on the heatbrake. I want to redesign the effector to incorporate cooling fans and to use standard E3D parts to make replacements easier to come by. I think i will run some tests with my hot end.

Sounds like a neat design. I was taking some measurements along the length of the heatsink on my hotend and I was quite surprised how little gradient there was from top to bottom - only about 4C with an average of about 38 with the hotend at 170. I was in a hurry to start a print so I didn't let it soak, so I should repeat the test with a higher hotend temp and let it reach equilibrium.

I used an ABS part clamped around the bottom of the heatsink on my V6. I print at 260c and I have a layer of aluminium foil tape stuck onto the abs to reflect radiant heat, the whole thing is in an enclosure that normally runs at 50c. I've not had any problems with it so far except for one time when the thermistor broke and the hot end reached 350c+




Moriquendi