Arcol blog Just another RepRap weblog

7Mar/10Off

Megalomaniac stupidity 2 — Flatness

I pushed my newly designed heated bed to its limits.
Do you wonder how good it performed?

Looks like until I reach the ultimate goal (ie. using the whole printing area) I will produce a complete soap opera. We are already at episode 2, lets hope we will finish until season two;-)

I repeated my previous try, but this time with heated bed and without raft (spares 2 hours from the 18 hours printing time).

I was fully aware, that the aluminium sheet has 0.2 mm flatness error at one edge, but we hoped for the best: this will not affect the build.

I levelled the bed the best I could, that means, there were part of the bed, where the plastic hardly stick, and parts, where it was really pushed into the polyimide tape.

On the left side, the frame-vertex part hardly stuck to the tape, and on the bottom right corner, the z-driven-pulley part is really pushed into the tape (the photo is upside-down regarding the machine).

Also if you look at this picture:

You can see, that where the frame-vertex part is not really stuck, the z-bar-top-clamp is again pushed too much in the kapton tape.

So I levelled again the bed, and tried to lower a bit the bed from the nozzle.
Also here is a closeup picture of the parts, which didnt really stuck to the tape:

At that point the nozzle blocked, because where the nozzle was too close
to the bed, the plastic could not come out from the nozzle.

When extruder pushed the plastic out, only that few plastic came out:

I tried to pull out the plastic, but it break away, here is a photo
(tip: try to pull out when the extruder is at least 200C hot):

So I dismounted the extruder. Here is the nozzle part:

And here is the ptfe tube part:

I could not push out the plastic from the ptfe tube. I tried to drill it out (pretty bad idea):

The drilling bit came out of the ptfe tube:-(

Thanks god, I bought a spare extruder, and I could use the ptfe tube from it.
Otherwise I could not buy ptfe tube with outer diameter 6.2mm and inner diameter 3.2mm here...
It needs a lathe to fabricate such ptfe tube.

After I tried one more time, to only print four z-motor-bracket:

I could pull out the plastic this time (didnt break away).
With more levelling I would be able to print four z-motor-bracket at once, like on this photo:

The above print had other problem, but this is subject to an another article...

Also remember, the above experience have been done on heated bed, which is available for sale.

If you are interested buying one, drop me an email to order (at) arcol (dot] hu

ps:
By the way if I could build my megalomaniac print, it would result of 14 hours printing, and the generated .gcode file for the machine was about 14MB. Also generating with skeinforge took about two hours, and used almost my full available memory (4GB) of the machine. (in fact my first generating got killed by the kernel because of out-of-memory, ok I forgot the Multiply plugin on (2x2) in skeinforge).
Here is what skeinforge reported:

The text has 426461 lines and a size of 14592.0 KB.
The total build time is 50530 s.
The total distance extruded is 764151.1 mm.
The total distance traveled is 941319.2 mm.
The version is 2009-11-14
The volume extruded is 176.3 cc.