Bridging problems with PLA

Hello!

I'm quite new to the 3D printing area, but I still have some experiance. Today I tried to do a complete calibration of the Prusa Mendel printer as described here: Calibration When I came to the point Bridging I tried to print the 20mm hollow box, but it was not possible to close the box (top layers). For me it seems that the PLA does not stick on the edges of the box. I also tried to use different layer heights (0.1 and 0.3mm) but with the same result. The box is just filled up with plastic.

So at first I have to tell you which configuration I'm using: Prusa Mendel Printer, Wade Extruder, Arduino Mega including Ramps 1.4 with Merlin Firmware and Repetier Host SW with Slic3R V 0.9.7.
I'm printing PLA using a temperature of 160 degrees (I know this is a little bit low, but the results were the best.. If I'm increasing the temperature, I get bubbles and crosshairs (I hope everyone understandy what I'm meaning).

Has anybody tried to print this part and with which setup?

Cheers,
Christoph

Hello Christoph,

I have printed that same box with PLA with decent results. You can see my progress images here: [forums.reprap.org]

Prusa Mendel V2 Linear, Wades Extruder, Printrboard, Marlin, Slic3r

I messed around with a lot of settings, but my biggest improvements came from the addition of a 40mm fan. You can find fan mounts on thingivese that allow you to position a fan so that it is blowing on the hot-end and the print. This helps a lot when printing with PLA. You can see the vast improvements in my 50mm tower print.

Good luck,
Bobby

Hello Bobby,

Thans for your reply! Can you tell me at which temperature is your extruder working?

Cheers,
Christoph

Hey Christoph,

Sorry for the delay. Extruder temp is a standard 185C, bed temp is 60C. My hot-end is .5mm and I typically print a .25mm layer height.

I'm using 3mm PLA purchased from onlinefilament or makerfarm.

I've heard that some colors can require different temps, but I have not found that to be the case so far.

Bobby