26 Reply by carl_m1968 (edited by carl_m1968 2015-12-14 03:18:12)

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Re: Finaly fitted my E3D hotend

Landin81 wrote:

My extrusion multiplier is set to 0.90 on PLA, and on ABS profile its set to 1.0, can that be a different for the prints?

mark.burton wrote:

Generally I don't recommend changing the steps per mm. That is calculated off the  gear size. you run into compounding error compensation if you do that.

Instead you should use the xy size compensation located in your slicer.


In your slicer there is a compensation setting to ad X size to the dimension or remove X size from the dimension that is not where you want it. Of course this will change with each roll.

The standard practice is to load a roll then print an calibration object of known size. I use a 50mm cube that has a 20mm hole bored in each axis.

Once printed and fully cooled you ,measure that object to find out what your shrinkage factor is for that roll. Then you go into your slicer and set it to compensate for that shrinkage factor by +/- x mm.

I don't use RH or Slic3r, but here is the setting in Simplify3d..

http://soliforum.com/i/?KFxYmMH.jpg

Printing since 2009 and still love it!
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Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

27 Reply by wardjr

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Re: Finaly fitted my E3D hotend

Extrusion multiplier is just a fudge factor for extrusion.  I would agree that changing steps/mm will create a compounding issue.  I also agree with Carl in that what is skewing your measurements is mostly due to shrinkage.  To properly measure that dimension it needs to be of one layer as it is layed on the build platform.  The other thing to try is a cube or several of different dimension.  Try a 50mm cube and see how close that is.  Extrusion width can also play a roll as the Slicer at some points needs to round to the nearest divider of the width.  You can do that math assuming that width is set at a proper .48 mm.  I know you're thinking that it shouldn't matter as it isn't filling that area but that doesn't mean the slicer isn't making room for those paths even though they are unused.  If what you truly need is a perfect 20x20 you'll need to design in all of these factors.  It really isn't a problem but by making your cube design say 20.09x20.09 in your case it should yield that near perfect measurement.  Or do like the rest of us and accept it as it is.

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28 Reply by carl_m1968 (edited by carl_m1968 2015-12-14 17:41:41)

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Re: Finaly fitted my E3D hotend

As long as all the items you print are made to the correct dimension and then printed at the current settings they will all shrink at the same ratio for the given roll and should fit. You ask for a 20mm cube you get a 19.9 cube you then ask for a 20.1 hole for that 20mm cube to fit in you get a 20.0 hole which still fits your original design dimensions.

3d printers are not at a level to give you the precision of much passed .1mm so if you need that precision you may want to look into a different prototyping technique or different 3d printing such as litho printers using resin and laser or laser sintering of powder and or metal. Of course none of this tech is affordable for the average hobbyist but there are printing services that offer these types of printing for a lower price than owning such a machine.

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

29 Reply by Landin81

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Re: Finaly fitted my E3D hotend

Thanx guys alot for all the help!!

appreciate it alot!

30 Reply by mark.burton

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Re: Finaly fitted my E3D hotend

Extrusion multiplier affects how much plastic is pushed out. it can very depending on the plastic but I would not think it would be that much different between pla and abs. Mine are the same. this doesn't generally affect dimensional accuracy. it does affect over or under extruding, which can affect layer bonding and create blobbing.

The dimensional accuracy in your firmware must be calculated according to your belts, pulleys and leadscrews. The xy size compensation takes care of the small variances. Use Josef Prusa's Calculator. http://calculator.josefprusa.cz/

The xy size compensation is meant to calibrate the size in software and is the correct way to fine tune your calibration.
most slicing software has this now.