tonyno
Posts: 168
Joined: Sat Jan 31, 2015 5:46 pm

Not-a-Raft

Sat Feb 21, 2015 6:53 pm

I have designed a few parts to compensate for the first-layer-thickness increase and they worked well (simple bevel). This came after trimming the "flash" from my first batch of parts.

Can anyone think of a way to do this automatically via the vast amount of settings in S3D? Maybe a second Process using the new, horizontal size compensation for the bottom layers?

JFettig
Posts: 72
Joined: Tue Dec 30, 2014 3:13 pm

Re: Not-a-Raft

Sat Feb 21, 2015 8:11 pm

I frequently design in a small 30 degree chamfer to the bottom of some of the parts. I prefer printing on a raft for this reason actually. I usually skip the base layers unless its a large print.

dunginhawk
Posts: 39
Joined: Mon Jan 19, 2015 10:15 am

Re: Not-a-Raft

Sat Feb 21, 2015 8:25 pm

i use 123ddesign and just create .4mm high 15mm wide strips that fit the sides of my parts.
import them in to S3d and connect them essentially to the edges of the prints. works perfectly and they cut/ bend right off

JoeJ
Posts: 1436
Joined: Sun Feb 16, 2014 10:52 am

Re: Not-a-Raft

Sun Feb 22, 2015 5:44 am

You could add the bevel to the original STL file, or your idea about using 2 processes with the horizontal size compensation would also work fine.

tonyno
Posts: 168
Joined: Sat Jan 31, 2015 5:46 pm

Re: Not-a-Raft

Sun Feb 22, 2015 10:59 am

Thanks. Since I can't specify a Process by layers, would I just use the layer height? In this case, 0.4mm, or, the 150% first-layer height? Is it actually 50%, or, 0.2mm for that first, flattened layer? Then, the compensation would be half the layer height?

JoeJ
Posts: 1436
Joined: Sun Feb 16, 2014 10:52 am

Re: Not-a-Raft

Sun Feb 22, 2015 12:02 pm

Yes, you need to account for any adjustments to the first layer height. You can also use the cross section tool to verify the correct location.

tonyno
Posts: 168
Joined: Sat Jan 31, 2015 5:46 pm

Re: Not-a-Raft

Sun Feb 22, 2015 2:33 pm

This seems to be a bit counter-intuitive... Shouldn't Process 2 (top) start where Process 1 (bottom) ends? I'm getting gaps between the two. :?

tonyno
Posts: 168
Joined: Sat Jan 31, 2015 5:46 pm

Re: Not-a-Raft

Mon Feb 23, 2015 8:37 am

This is interesting. 1" cube, cut short, printed with no compensation. Check that taper on the lower 2.6mm!

Image

User avatar
BaronWilliams
Posts: 159
Joined: Tue Jul 15, 2014 8:30 pm

Re: Not-a-Raft

Mon Feb 23, 2015 4:37 pm

tonyno wrote:This is interesting. 1" cube, cut short, printed with no compensation. Check that taper on the lower 2.6mm!
Over extrusion could cause that if the cube is hollow with a solid floor. The floor of the cube, if over extruded, is going to bulge out more than the side walls because there's more plastic extruded there. I would look at lowering the extrusion multiplier first by a little bit.

Also, a heated build plate can cause this, especially if its too high, and you are very slightly over extruding.

On my FlashForge Dreamer I print ABS using 110 C for the first layer and then drop to 105 C. On the MakerBot Replicator 2X I start with 115 C and drop to 110 C.

If I don't drop the temperature on the second layer, I get this bulging problem for a few layers, especially if I'm very slightly over extruding.

JoeJ
Posts: 1436
Joined: Sun Feb 16, 2014 10:52 am

Re: Not-a-Raft

Tue Feb 24, 2015 5:25 am

Yup, I agree. It looks like you are over-extruding a bit. This is much more visible in your first 3 layers, since those are all 100% solid filled layers. You won't notice it as much higher up since you have a lower infill percentage, which is likely why those are closer to the true dimensions.

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