Hello,
I’m trying to print a stl file design with holes in it PLA.
My problem with it it has not the right hole sizes. The inner holes are smaller, I use slic3r and I can’t solve this by changing settings in the slicer configurations.
This has major impact when making holes for screws etc and plastic bricks.
Any ideas?
Regards!
Hi cognito,
this problem has been described by other people before. Most likely your extrusion multiplier isn’t calibrated, so that more filament is pushed through the hotend then necessary.
You’ll need a calliper for this, preferably one with 0.01 mm resolution. And some simple stl file, like the second (solid!) box in here http://www.thingiverse.com/thing:5573, or this http://www.thingiverse.com/thing:152672 one, or design a simple cube or so yourself.
Next, create a special profile for slicing with the following adaptions from the standard parameters: perimeters 1, infill 0, top solid layers 0. You can also reduce the bottom solid layers if you want. When slicing, this will generate a hollow box with a wall that’s only a single line thick.
Set the extrusion multiplier to 1 for the beginning and measure the diameter of your filament, it may be 2.85 or 2.9 instead of 3.0. Enter that value in Slic3r as well.
Take a look at the extrusion width for perimeters. If it’s in percent, the resulting width is your layer height (0.25 mm?) times the percentage, e.g. 0.25 mm * 160% would be 0.4 mm. If the value is very low (below 0.4 mm), you better adapt it for this test. 0.5 mm, like the nozzle diameter, is a good start. The value is also written in the top lines of the generated G-code, in case you want to recheck what Slic3r has calculated.
Slice the box, check that the G-code really gives you a single-wall object and then start the print. You can probably stop it early, once the wall is a few mm high. Note that the printed surface should have only few (even better: no) errors, otherwise the whole printing process isn’t stable enough yet.
If the print looks ok, measure the wall width with the calliper at several positions. If one value is far off from the others, leave that one out. Average the other values. If this average matches the set extrusion width in Slic3r, you’re done. If not, calculate a new extrusion multiplier from both values, e.g. with 0.5 mm set, 0.47 mm measured, and 1.0 as extrusion multiplier:
(0.5 / 0.47) * 1.0 = 1.06, which is your new extrusion multiplier. Enter the new value in Slic3r, then do the same test again, until you have the correct values on your print.
There’s also a couple of other calibrations that you can do if the print dimensions, surface quality etc. are not satisfactory. Some are described in the instructions to the first thingiverse link up above. Apart from that, https://github.com/alexrj/Slic3r/wiki/Calibration and also the RepRap wiki are good resources. The descriptions, used stl files etc. all vary a bit, but in the end they all will help you to get a feeling about how all those slicing parameters influence your prints.
Cheers,
kuraasu
Hello,
Thanks for your reply, kuraasu!
I’ll try again with this calibration.
Regards!
Hi,
My outer dimensions are spot-on, but I always end up having smaller inner holes.
It’s very frustrating a hex nut doesn’t fit.
Any ideas?
Regards!
Hi cognito,
which Slic3r version are you using? The older ones (0.9.* etc.) are known to have this “difference” between inner and outer perimeters. The new versions, v1.0.0RC1 and RC2, should be a bit better, at least to my knowledge. Apart from that, I’m afraid you can only a) change the model to enlarge the holes slightly or b) try another slicer.
Cheers,
kuraasu
[quote=“kuraasu”]Hi cognito,
which Slic3r version are you using? The older ones (0.9.* etc.) are known to have this “difference” between inner and outer perimeters. The new versions, v1.0.0RC1 and RC2, should be a bit better, at least to my knowledge. Apart from that, I’m afraid you can only a) change the model to enlarge the holes slightly or b) try another slicer.
Cheers,
kuraasu[/quote]
Hi,
I use Slic3r v1.0.0RC1 and also Cura 14.01 prints 0.5mm to small holes!!!
options a) and b) are no solutions. If it can print outer dimensions spot-on it can print inner holes too, looks like we do something wrong in software settings… Is there anyone printing STL dimensions = real dimensions?
Does Velleman support have a solution for this?
Regards!
Only 0,5 mm? This is only 0,25 on each side, this could be from a little movement in the construction or the belts combined with some other minor effects. Is each layer affected or is it a pattern
Hi,
Just to inform users…
The problem is known and a solution is called ARC COMPENSATION.
reprap.org/wiki/ArcCompensation
dl.dropboxusercontent.com/u/377 … Errors.pdf
There was ARC COMPENSATION in Slic3r but they removed this due complaints.
github.com/alexrj/Slic3r/issues/1613
Skeinforge could be an option
fabmetheus.crsndoo.com/wiki/inde … ge_Stretch
Regards!
Suprised to find this thread here & to see that this hasn’t been picked since the last post in 2014. After all, Arc Compensation is still required for the Velleman printers & their slicers (both K8200 & K8400).
It would be great, if Velleman Support would be able to pick this up?
At the moment, we’re producing modified designs - so we draw our models with oversized holes, hoping they come out at the right size.
When I make a post in Thingiverse, I have to state that the Velleman series are troubled by this - to avoid someone that doesn’t have the issue tries to print it & the product then doesn’t fit.
It would be so much better, if this could be handled in the slicer? Is there something we or Velleman Support could do?
Thanks!