Tip: Ambient temperature effects on clearance setting

K8200 3D Printer K8200 - Assembly and user manual
1

I have noticed that the extruder head clearance varies substantially with changes in ambient temperature. I set the clearance early in the morning when the temperature was around 17 degrees © and in the afternoon when the temperature was around 28 degrees the gap had increased to almost double; this is due to the vertical support arms expanding; perhaps someone can do the math on the expansion of aluminium as I have forgotten the formula.

Moral to this story: move the printer into a more stable atmosphere, set the clearance at that temperature and pray to whichever God that you got it right again! Well, it gives me the excuse to move the printer in next to the TV but away from the radiator . . . in my dreams!!!

2

The thermal expansion coefficient of aluminium is 23,1 * 10E-6 per Kelvin, that is, an aluminium rod of 100 cm length increases for about 0.0231 mm per Kelvin.

With 9 Kelvin of temperature difference, this sums up to roughly 0.2 mm.

Since the vertical support is about 0.5 m high, the expansion is just 0.1 mm.

What you’re noticing is most presumable temperature-related warping of the printing bed or it’s supports.

A really nice feature would be an autocalibration feature, where the printer actually measures the distance between extruder and printing bed, but this won’t be that easy to construct …

3

The thermal expansion coefficient of aluminium is 23,1 * 10E-6 per Kelvin, that is, an aluminium rod of 100 cm length increases for about 0.0231 mm per Kelvin.

With 9 Kelvin of temperature difference, this sums up to roughly 0.2 mm.

Since the vertical support is about 0.5 m high, the expansion is just 0.1 mm.

What you’re noticing is most presumable temperature-related warping of the printing bed or it’s supports.

A really nice feature would be an autocalibration feature, where the printer actually measures the distance between extruder and printing bed, but this won’t be that easy to construct …[/quote]

Thanks for that, I was being lazy as I could have looked up the expansion coefficient! I did not measure the difference but guessed it was about double; 0.2mm is almost twice. Also, the bed remained level. Today, I was looking at the auto-focus system used on laser cutters but, as you surmised, this is quite complex.

4

Keep in mind that this is a hobby 3D printer, not the hubble telescope :slight_smile: However, we endorse any theories that result in moving the printer next to the TV.