what nozzle height do tou guys use with your BuildTak platform?
I tried different heights but none of them are 100%.
I measured the twicely folded A4 sheet. It’s 0.3mm. This height gives me corner warping when printing ABS.
I tried .10mm and .15mm but this made the ABS so extremely sticky that it destroyed my brandnew buildtak sheet
.20mm gave me still a sleight warp at one corner (right-front)
Today i spoke a representative from Velleman. He also ownes a K8400 and had no warping problem when printing larger ABS things. He said is must be possible to print warp free without a heatbed. He also told there is no heatbed comming available for the K8400.
What i also noticed is the the aluminium plate isnt flat. The glassplate is flat but when mounted on the aluminium with the clips it is under tension. And this lightly warps the glass.
My printsettings (Velleman Host with Cura)
Temp 220
Speed first layer 15mm/sec
Extrusion 70%
Cooling On (Velleman told me or the nozzle holder wil be burned)
Now I’ve installed a heated bed.
With the Buildtak I used a nozzle-bed height of 0.2 mm.
[quote=“basvaningen”]This height gives me corner warping when printing ABS. [/quote]To limit this : add a brim (at least 0.5 cm) and use low infill. Set the fan speed to 50%.
[quote=“basvaningen”]this made the ABS so extremely sticky that it destroyed my brandnew buildtak sheet[/quote]So did I:( -> another reason to install a heated bed.
[quote=“basvaningen”]The glassplate is flat but when mounted on the aluminium with the clips it is under tension. And this lightly warps the glass.
[/quote]I noticed this too. When I installed my heated bed I checked the aluminum plate and it is perfectly flat. The clips must cause the glass plate to bulge in the center.
I’d try a bit hotter than that. I print at 240 with 50% fan, so the nozzle temp is around 237 (at least that’s what it’s claiming - who knows what the real temperature is?!). ABS / PET does stick really well to buildTak, but on long prints it may eventually lift off, especially at the corners where you just can’t get the print head as close. You’ll just have to experiment with what you’re printing until you get a distance and a bed position that works for that print.
The reason for the centre ‘bulge’ has been hotly debated - even with Velleman. There doesn’t seem to be a definitive answer. But I can tell you that I padded mine at the corners and found I could slip a feeler gauge between the aluminium plate and the glass in the centre (so it wasn’t touching) and the bulge was still there. It’s a bit smaller, but it’s still there! I thought it might be possible the weight of the head is causing the 8mm bars to deflect slightly at the centre, but Velleman declared this to be nonsense! So we’re all still left with the mystery of what is causing it - everyone has it, but no one has found out why or how to cure it. It’s a real annoyance.
