Builders/Metalab

Blog

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Things that turned out to work

PEEK instead of PTFE for the thermal insualtor

PTFE is just to soft. PEEK has too disadvantages: it has more friction so its harder to unscrew the M6 winding which was once a problem because the heating barrel broke when we headcrashed into the base. Because we could not get a grip on the broken part we could not unscrew it. but a PTFE part would have bent and would also be destroyed. Next thing i want to try out is a PEEK PTFE mix so it should have better friction. The other problem is cost. It costs about 200euro per kg. we got a 20mmx30cm zylinder for 60euros. We only lost on PEEK part so far. We destroyed about 8 PTFE parts in accidents before. More info on our blog: http://reprap.soup.io/?search=peek

Acrylic base plate

a milled acrylic base plate provides good sticking for ABS. http://reprap.soup.io/post/6602231/Current-Extruder-Setup

Heated base plate

If you can heat the object, the internal stresses that normally build up while each layer cools off seperatly gets reduced and so you can make relly flat objects. We have not tried out adrians fan solution but that might be an even simpler solution. That would also be easier to use with the acrylic base plate that provides better sticking than the heated copper plate. http://reprap.soup.io/?search=heated+base

CSG Evaluator - A usefull plugin for AoI for doing multiple boolean operations - A mini tutorial

First lets create a cube positioned at the origin with a side length of 10mm. I named it "My Cube"

Now lets create a sphere with a radius (in all three dimensions) of 6mm. Also positioned ath the

origin. I named this sphere "Inner Sphere"

Now lets open the CSG Evaluator Dialog by chooing it from Tools->CSG Evaluator...

It should appear in the lower left corner. Notice thats its always on top. It can also be toggled

by pressing the c-button.

Now select the cube and the sphere we just created (hold the Ctrl button to select multiple

objects) and press the "difference" button in the CSG Evaluator dialog. This might take some time

to calculate.

Now the screen should look like this. What happened? The CSG Evaluator created a new object called

"difference" which is the cube with the sphere subtracted. But the original objects are still here.

They are children of the "difference" object. You can see this when you click on the small triangle

next to the "difference" object. So click on the small triangle to verify it yourself.

So the cube and the sphere are children of the "difference" object and they are greyed out because

they are hidden.

Although the cube and the sphere are hidden you can still change their parameters. For example lets

make the radius of the sphere large. Lets increase it to 6.5mm (in all three dimensions).

Huh? Nothing happened? Why? Well the sphere is hidden - so you cant see the changed radius and the

difference does not get updated automaticly. To recalculate it you have to select the "difference"

node and click at the "evaluate" button in the CSG Evaluator dialog.

Ah! Now the difference got re-evaluated and so the resulting object changed. But maybe blindly

editing properties of hidden objects is not your thing. Would it not have been much nicer if you

could have seen the sphere to choose the right radius? You can do this. Make sure the difference

node is selected and click at the "devaluate" button.

Now the "difference" node is hidden and its consituents (the cube and the sphere) are visible

again.

Now you could visually change the cube or the sphere, move them around and so on. But we (or at

least I) are already satisfied with the way they are so lets just "evaluate" them again. This might

take some time to calculate.

The object we created looks nice but it still has sharp edges. Children might get hurt! So lets

greate another sphere also positioned in the origin with a radius of 8mm (in all three dimensions).

Lets call this one "Outer Sphere" and just for visibility lets change the display mode to

transperent (Scene->Display Mode->Transparent) at least in one view so we still see whats going on.

Now select the "difference" node and the "Outer Sphere" and click at the "intersection" button in

the CSG Evaluator dialog. This might take some time to calculate.

Now the object is finished. CLick on the small triangle next to the newly created "intersection"

node to see the consiuents of the final object.

As you can see you can hierarchically create complicated objects. In this tutorial we didnt use the

"union" operation but I guess you can figure out what this one does by yourself. Also I should

mention that each of the three operations (union, intersection and difference) can have as many

children as you like! Try it out! Have fun! Be excellent to each other! And create cool RepRap

objects.