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Wrong size of printig objects  

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hetterich
(@hetterich)
Eminent Member
Wrong size of printig objects

Hello,

i habe a little problem with the xy size of my printed objects.
As test object i use a washer with following sizes
inside diameter: 20mm
outside diameter: 40mm
z = 2,5 mm.
The washer after printing:
inside: 19,5mm
outside: 20,4mm

What's going wrong?
I try Cura, slic3r, KisSlizer to generate gcode.
It's always the same result.
If i use SX Size Compensation = -0.2 in slic3r the result is better but not exact.

What can i do?

Peter

Postato : 15/03/2016 9:00 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Hi Peter

A few things

You say the outside printed at 20.4? that's almost half the size. Should that be 40.4mm?

When slicing are the perimeters being printed before or after the loops? Is the fill before or after the perimeter/loops?

What extrusion width are you printing at? What material and what temps?

Have you calibrated the filament feed?

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 15/03/2016 9:06 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Sorry , after printing the outside diameter is 40,4

I print with PLA 1,75 Printer Notzle = 0,4
Temps 210/52
I use the default settings from Prusa in slic3r
Default extrusion width, First Layer, Perimeters, ... = 45, only support material is 0,35
No i have not calibrated the filament feed.
I can't find something about to calibrate in manual

Thank's for your help

Postato : 15/03/2016 9:26 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

OK, so try the following settings:

Bed: 50
Extruder: 195 to 200
Extrusion width: 0.4 (same as nozzle...)
Perimeters first, then loops then infill - this ensures that the outside measures are correct

Try printing that. If you don't have any luck, then upload the STL which I will slice for you to print.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 15/03/2016 9:30 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Thank you, printer works.

Postato : 15/03/2016 9:44 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Hey, now it's better
inside 19,89
outside 40,10
without xy size compensation
Thank, you very much.

Peter

Postato : 15/03/2016 10:10 pm
fl0PPsy
(@fl0ppsy)
Eminent Member
Re: Wrong size of printig objects

I had this issue when I first got my printer.

After making sure that everything mechanical was correct (ie bed calibration etc) I was still getting prints that werent 100% to scale.

I ended up making a change to the following parameter in the firmware:-

#define DEFAULT_AXIS_STEPS_PER_UNIT

If you google that parameter you'll find some guides on how to set how many steps the motors turn for 1mm of travel.

After 3 quick test prints and adjustments the printer is now 100% accurate.

I use my printer mainly to print parts for Quadcopters so having accurate prints was really important otherwise screw holes just wouldnt line up. I dont have any issues now.

Postato : 16/03/2016 8:29 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Markus

In this instance your suggestion will not help; the inside diameter is small (oversized) and the outside large (oversized); therefore as with most other printer builds, Peter's step values are correct.

In this case, I believe that the remaining error is simply due to the perimeters not being printed first (this is an option only available in certain slicers).

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 16/03/2016 9:56 am
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Hello,

fill perimeters first is a default setting in slic3r. I didn't change it. The decisive improvement was to switch the default extruder extrusion from 0,45 to 0,4mm. Now i have a difference from 0,1 inside and outside. It is significantly better but not perfect. (smile)
Peter, must i change it in all printversions (0,05-0,1-0,2) to 0,4?
Is it possible to change it in Cura too?
Each Idea to perfection is helpfully.
Sorry for my bad English
Peter

Postato : 16/03/2016 11:42 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Hi Peter

Sorry, I don't use Slic3r, so I can't advise on that. Cura (15.04.2) has the setting "Shell Thickness", which I have set to the nozzle width (0.4mm).

From the outset, I have always had the extrusion width set to the nozzle width with all the slicers I use. I am aware that Josef has extrusion widths set to a value greater than the nozzle width; I don't know why, but I would have thought there would be some benefit (for him) in doing this.

Equal widths works well for me, and I also find it simpler when working out how wide to make a thin wall (2 mm walls = 5 paths @ 0.4mm).

I was unaware of the "perimeters first setting within Slic3r and it is unusual for many prints to print the perimeter first; any overhangs require the printing order to be inside to outside (loops then perimeter).

You will also find that different slicers will generate different accuracy and quality. I mainly use KISSlicer as I find this generates the best results for me.

One final thought; you may find that your printer is slightly over-extruding and causing the expansion of the inner and outer perimeters and you may need to calibrate your filament feed (this should be done for each filament type and colour in order to get the best precision).

To calibrate the filament feed:

Heat extruder and insert filament
Measure and mark the filament at 110mm from the top of the extruder housing
Feed 100mm (use pronterface/octoprint terminal): G1 E100 F100
Measure the distance from the top of the extruder housing to the mark you made on the filament; it should be 10mm
Tweak the filament flow rate in the slicer for any different in filament fed

If the distance is less than 10mm, then you decrease the flow, if greater, then increase flow

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 16/03/2016 12:05 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Peter

One more thing: ensure that the filament is actually 1.75mm. Measure the diameter of the filament in two direction (90 degrees apart) across a length of 5 metres - get a few measures and then average them out. Use the average value in the slicer.

I have had some Chinese filament vary between 1.6 and 1.8mm across the length of a spool. Where possible, buy known filament brands (such as Prusa Research 😉 ).

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 16/03/2016 12:10 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Ok, i try it tomorrow. Today i have Guests from another Company. I will show them my Town Ingolstadt.
Can you send me a Profile for KisSlicer with settings for my printer and material? Then i can test it with KisSlicer too.

Postato : 16/03/2016 1:48 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Peter

My current KISSlicer settings are attached. Please note that some of the settings are quite specific to what I am printing at the moment.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 16/03/2016 2:02 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Thank you,
i will try it (tomorrow in the evening) and tell you my results.
By the way, i only use original Filaments from Prusa.
It's exact 1,75 - 1,76 mm.

Peter

Postato : 16/03/2016 2:27 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Hello Peter,
the Command in Pronterface works, but i think it's to much speed.

Postato : 17/03/2016 7:05 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Hi Peter

F100 is 100 mm/min. The printer should be able to feed PLA at 210 degrees.

A good maximum volume for the Lite6 is 6 to 8 mm^3/sec; linearly about 2 to 3mm/sec (120 to 180 mm/min).

Not a problems slowing it down; try the same command with F60 - that will feed at 1mm/sec (2.4 mm^3/sec).

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 17/03/2016 7:33 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

The Motor from Extruder blocked and sounds like tictac

Postato : 17/03/2016 8:23 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Wrong size of printig objects

Peter

Either you are not getting the extruder hot enough or you need to do a clean: https://ultimaker.com/en/manuals/149-atomic-method - from the third point.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Postato : 17/03/2016 8:29 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Sorry, i think i have the 2 screws tightened too much.

Postato : 17/03/2016 8:41 pm
hetterich
(@hetterich)
Eminent Member
Topic starter answered:
Re: Wrong size of printig objects

Hey Peter

now all Sizes are 100%
I set the extrusion width to 0,35 and the next problem was that the Glass-Bed in the middle is higher then the corners. (Why?)
I calibrate only the corners before. Now i take a mean from both.

I hope i don't have the same problems when i try a Layer hight from 0,1 and 0,05
But i have learned many things from you. So i will be confident that i can do this.

Thank you so much.

Postato : 17/03/2016 9:29 pm
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