Bridging to nowhere

After last night’s efforts I had a pretty good cube, on five of six sides. Unfortunately, the top looks terrible, honestly more like a net than a side. Bridging is the act of printing over an open space without support structures, and there are custom settings for it in slic3r. I decided to focus on bridging next.

Even more cubes

After many different settings and even more cubes, I have begun to think that I am doing something wrong. I got back on google and did some more research.  I followed different settings from several different blogs and none of them worked. The only thing that they recommended that I cannot do out of the box is control the speed of the extruder fan. The TwoUp printer does not have an extruder fan.

Actual bridging test

My best results seemed to involve very low-speed and reduced flow rates.  Getting tired of cubes, I got a bridge test object from thingiverse and printed out a few.  By lowering the extrusion temperature to the minimum for my filament (190°C), lowering my print speed to 10mm/s and decreasing the bridge flow rate to 0.85, I was able to get a bridge. bridging torture testMy best bridge had only a few layers that sagged, then firmed up by the top of the span, and even had its little circular thing in the center.

I am mostly happy with the bridge, many objects where I will use bridging, it will be internal so a little sagging may weaken the top, but not be visible. Unfortunately, although I can change the speed and flow rates for bridges, I am not able to change the temperature in slic3r. I am able to increase the fan speed to 100% for bridges, but as I mentioned, my TwoUp doesn’t have one.

Time for an upgrade

This is now the second thing I have found that is just not acceptable if I want to create objects that I might be able to share, or possibly even sell.  My only option is to replace the inadequate parts with ones that can do the job well. The best thing about this is I can print them and upgrade as I go, which will allow me to track the improvement (or lack thereof) for the different things I change. I’m a nerdy numbers guy so this naturally appeals to my sensibilities.

Before designing my own replacements for parts, this time I started on thingiverse and found a page that collected upgrade parts for the OneUp/TwoUp printers. As I continued searching on this page I noticed that a particular user name kept popping up with his own designs or as part of collections that other we making.  I then searched for “Proto-Plastik” and found the start for what I had in mind, his A5-1Z upgrade for the TwoUp.

No time to sleep tonight, must get printing…

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