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kevin-osborn

Help me beat makerbot!

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I went to the Makerbot store the other night (for a networking event... really)

and picked up:

http://www.thingiverse.com/thing:230139

which is a print in place hinged toy.

So far, all my attempts to print it have failed.

fidget

One thing I noticed, was the print from makerbot (replicator 2, black in photo) had bigger hinges than the default in the SCAD, so I increased the hinge size.

I've tried printing slower 30mm/sec .1 layer

Most of the failures are when trying to free the hinges.

The only thing I haven't tried yet is printing colder, or trying other filament.

Any clues?

 

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The type of filament and settings used are probably making your problem.

I noticed that fine-tuning is much more important than it seems. Also, I noticed that depending on the type of filament I use, there can be quite some difference in the resulting print. For example, holes for M3 screws can vary a lot in diameter between various filaments.

I guess the flow parameter is one of the most important things here, because if you have a slight underextrusion, your lines will be thinner (or thicker with overextrusion) than they should be - making holes slightly smaller or bigger.

That should translate 1:1 to the hinges...

You could try to simply decrease your flow (not flow rate!) a little, maybe 5 to 10%, and see if it helps.

 

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Thanks, I'm trying again with different filament, slightly bigger hinges still, and more clearance around the hinges.

I'm not sure what the best distance for the separated parts, that part seems to work ok, but requires a bit of cleanup. I didn't see them take the part off the makerbot, but it looks very clean.

I'm thinking about trying it printed a little colder, thinking that would help with the overhangs?

Previous prints were at 240, currently printing at 230.

I'll post the files up on youmagine (is that allowed?) if I get closer.

Here are my current parameters for scad:

// Decide whether you want the pieces to be full cubes or snub on one side

snub = "yes"; // [no:Cube Pieces,yes:Snub Pieces]

// Choose a side length for the cubes, in mm

cube_height = 20;

// Choose a stacking clearance factor, in mm (controls distance between cubes)

stacking_clearance = .4;// default .3

// Choose a hinge radius, in mm

hinge_radius = 3;

//hinge_radius = 1.5;

// Choose a hinge clearance factor, in mm (controls distance around hinge parts)

hinge_clearance = .8; //.45

 

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For really good prints, print at 210 or 220C (depending on filament). And print slow - say 35mm/sec. Make sure retraction is on. Increasing hinge_clearance was probably smart but .8 is huge. I've printed parts with only .1mm clearance and they worked okay. 100% fan is critical when you get to the hinges.

Retraction issues:

If it doesn't retract when it jumps that .45mm gap then you will get problems. So go into expert settings and under retraction set both distances to 0 (min travel, min extru).

 

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Ah that's cool. I made some progress, but like you say, the hinge clearance is too big, it makes it quite wobbly.

I made the hinges a bit bigger (6mm dia) and printed at 230. I started another print at 220, but got underextrusion (probably printing too fast.)

fidget working

Makerbot print on the right. The non-ripped apart layers look much better on the ultimaker (that might just be filament surface...)

I'll implement your suggestions and see where it takes me. This is fun!

 

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This is a subject I do not understand; maybe someone can explain? I downloaded a hinged box recently, out of interest on how it would work. Going through the hinge was a bolt. Now in order to work the bolt cannot be fused to any part of the hinge – can you print that?

I printed the box, tried to close it and it broke – unsurprisingly to me.

 

Edit: OK it depends on hinge design; at least one part of the hinge cannot be fused to the bolt

 

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I printed the box, tried to close it and it broke – unsurprisingly to me.

 

These are not easy parts to print, but it is possible to get great results once you know your printer really well. Try the settings I mentioned in my previous post above. Also if you have heated bed keep it cool - no hotter than 60C.

 

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I've made a working version...

Fidgetcube from www.thingiverse.com, file "day147_fidgetcube_red.stl".

Printed at 225 degrees

0.2 mm first Layer, rest 0.15mm

wall/bottom/top 0.8 mm

speed 30 mm/s, 1h45m print

fan 25% in Cura, lowered to about 16% with UC during print.

 

 

 

first part is print in timelapse, the actual working cube starts @3:20 mins.

 

Regards, Kees

 

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