As we have earlier posted we have now a beta casted Wallace 3D printer available in our shop. And as some people questioned how good this printer prints, i made some efforts to show how good the print quality of this printer can get.
So i connected a RAMPs 1.4 and a arcol.hu 3.0 hotend to this printer and started calibrating. After adjusting the configuration values of the sprinter firmware to this printer, i started the first testprints.
But it quickly showed that the PID values in the sprinter firmware where not really good for this particular hotend. The temperature varied up 40°C around the requested temperature, which ofcouse causes some printing difficulties. As you can see in the following picture, there are parts of the model where temperature got too high and the whole object started to melt.
So to analyse this, i used the output of pronterface to plot the achieved temperature and find out how to tune the PID values better. In the next picture you can see how the temperature response was in the beginning. The blue curve is the current temperature and the red curve is the heater pwm value. The target temperature was 180°C and you can see how it always over- and undershoots the target temperature.
Some experimentation then got me to this curve. Where it still overshoots in the beginning, but it quickly gets to a pretty stable temperature value with a variation of only a few degrees after the first peak. This was good enough for the next experimentations.
The next print then looked like the following picture. As you can see the temperature problem is solved, but the prints look pretty wobbly.
I quickly found out that this is caused by the x-axis not beeing completly level. As the Wallace uses two motors for the z-axis, a not completly level x-axis causes uneven lift on the z-axis. That means the x-axis is lifted on one side first and then the other side. Fixing this made the z-axis going up smoothly and the next print looked much better:
If you look at it in detail, you can see that there is still a little bit of wobble, but much less then in the blue statue.
Finally i made a short video of this last print, take a look and enjoy a Wallace 3D printer printing:
If you now like to get this printer, all parts are available at www.2printbeta.de