Provide a simple measurement tool
On Saturday 28 August 2021 20:51:21 Gareth Chen wrote:
If your printer is printing 5.98mm parts to be 6.51mm tall it's
seriously out of calibration...
Its a Prusa mk3S, has about a 25 minute calibration using markers on the
bed for xy references. But other that running z against to top stops and
hammering on the top for a while, I don't see where it calibrates the z
range. XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it hit.
If the same circuit is used for detecting the top of travel, then its
failing as its dual z motors and useing a default because it hammers the
top of travel for about a full second. I'll ask prusa monday. And get
the m command to change it too.
Thank you..
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
It almost sounds as if your printer profile is messed up. Are you using
defaults in PrusaSlicer, or did you change something, or are you using Cura?
On Sat, Aug 28, 2021 at 9:24 PM Gene Heskett gheskett@shentel.net wrote:
On Saturday 28 August 2021 20:51:21 Gareth Chen wrote:
If your printer is printing 5.98mm parts to be 6.51mm tall it's
seriously out of calibration...
Its a Prusa mk3S, has about a 25 minute calibration using markers on the
bed for xy references. But other that running z against to top stops and
hammering on the top for a while, I don't see where it calibrates the z
range. XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it hit.
If the same circuit is used for detecting the top of travel, then its
failing as its dual z motors and useing a default because it hammers the
top of travel for about a full second. I'll ask prusa monday. And get
the m command to change it too.
Thank you..
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
I'm not sure what you mean about a calibration for xy reference. When I
start a print using gcode produced by PrusaSlicer, it does a 49 point z
calibration before anything else. I don't think you're supposed to try to
detect the top of travel. Certainly I've never seen that happen. And I
don't know that it would help much wtih z cal unless you were really far
out. It seems like z cal depends on two things: accurate determination of
the z=0 point and accurate motor operation. I've just always printed on my
Prusa MK3 (now S) using PrusaSlicer with just minimal changes to suit the
model (e.g. turning brim on, adjusting infill, and changing the number of
perimeters) and things just always work and come out accurately sized. I
just printed some screw tests where the thread pitch is around 1.25 mm and
I printed the bolt .2mm smaller than the nut (nominal sizes) and the two
parts engage. I previously printed 1/4-20 bolts that engage with standard
metal hardware. It just works. Note that Prusa has 24/7 tech support by
chat, which I've found pretty helpful at figuring out issues I have had. I
had a situation where the magnets in the base came loose and moved around
and interfered with the motor operation, which messed up the Y
calibration. It would try to travel behind the back of the build plate.
When the machine goes right and left until it hits the sides I think it's
testing belt tension. (I'm not sure how that test works.) I had an issue
early on after I first assembled my machine with insufficient belt
tension.
On Sat, Aug 28, 2021 at 10:24 PM Gene Heskett gheskett@shentel.net wrote:
On Saturday 28 August 2021 20:51:21 Gareth Chen wrote:
If your printer is printing 5.98mm parts to be 6.51mm tall it's
seriously out of calibration...
Its a Prusa mk3S, has about a 25 minute calibration using markers on the
bed for xy references. But other that running z against to top stops and
hammering on the top for a while, I don't see where it calibrates the z
range. XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it hit.
If the same circuit is used for detecting the top of travel, then its
failing as its dual z motors and useing a default because it hammers the
top of travel for about a full second. I'll ask prusa monday. And get
the m command to change it too.
Thank you..
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
Calibration is something you need to do, not the printer.
You need to slice & print calibration objects and get your callipers out.
Then adjust slicer settings, rinse, repeat, until you get physical objects matching the specification of the calibration object.
You will need to have profiles for different materials with settings from a calibration run for that material (usually just extruder settings being different).
I haven't calibrated for a long time as I use Shapeways, but Google coughed up these which look reasonable.
https://all3dp.com/2/how-to-calibrate-a-3d-printer-simply-explained/
Then do some torture tests
https://all3dp.com/2/best-3d-printer-test-print-3d-models/
There is little point printing functional objects until you can print a calibration object accurately.
https://www.thingiverse.com/search?q=calibration https://www.thingiverse.com/search?q=calibration&type=things &type=things
From: Father Horton [mailto:fatherhorton@gmail.com]
Sent: Sun, 29 Aug 2021 12:36
To: OpenSCAD general discussion
Subject: [OpenSCAD] Re: Provide a simple measurement tool
It almost sounds as if your printer profile is messed up. Are you using defaults in PrusaSlicer, or did you change something, or are you using Cura?
On Sat, Aug 28, 2021 at 9:24 PM Gene Heskett gheskett@shentel.net wrote:
On Saturday 28 August 2021 20:51:21 Gareth Chen wrote:
If your printer is printing 5.98mm parts to be 6.51mm tall it's
seriously out of calibration...
Its a Prusa mk3S, has about a 25 minute calibration using markers on the
bed for xy references. But other that running z against to top stops and
hammering on the top for a while, I don't see where it calibrates the z
range. XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it hit.
If the same circuit is used for detecting the top of travel, then its
failing as its dual z motors and useing a default because it hammers the
top of travel for about a full second. I'll ask prusa monday. And get
the m command to change it too.
Thank you..
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
--
This email has been checked for viruses by AVG.
https://www.avg.com
On Sat, 2021-08-28 at 22:22 -0400, Gene Heskett wrote:z
XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it
hit. If the same circuit is used for detecting the top of travel,
then its failing as its dual z motors and useing a default because it
hammers the top of travel for about a full second. I'll ask prusa
monday. And get the m command to change it too.
If you have sensorless homing X and Y, that will work fine. It detects
stall current. But I seriously doubt that your machine came equipped
with sensorless Z homing, for the simple reason that the Z axis will
not give a high enough stall current to stop the bed in time, due to
the flex in the Z axis while driving a screw, with its (for want of a
better word) gear reduction of the screw.
I am quite certain that your endstop for the Z axis is some sort of
sensor, be it mechanical (like a microswitch), electronic (capacitive,
inductive, piezoelectric, etc.).
So for the Z axis, you want the Z homing to NEVER hit the bed. That's
usually a mechanical adjustment, moving the sensor toward/away from the
bed. When the Z axis homes, you will have a gap between the nozzle and
bed, and that's when you adjust your Z offset such that z=0 is when the
nozzle touches the bed.
As for your bad height of prints, that's a result of configuring the
wrong setting for Z axis steps/mm or step distance, depending on how
it's specified.
Thank you..
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
On Saturday 28 August 2021 22:36:09 Father Horton wrote:
It almost sounds as if your printer profile is messed up. Are you
using defaults in PrusaSlicer, or did you change something, or are you
using Cura?
cura 4.10.0, I could't make sense out of prusaslicer.
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
Hi Gene,
MK3S(+) has an z-calibration.
Activate factory restart.
You can find procedure here :
https://help.prusa3d.com/en/article/xyz-calibration-mk3-and-mk3s_112351
I had to do it also in the near past by controlling all calibration by
'benchy'.
After that it's much better now.
example 59.8 -> 59.7 to 59.9
Hope you can somehing with it.
Regards,
Harm Jeurink.
PS I want to start new item on here but cannot find anymore how to make
1st message.
Anyone can tell me?
Gene Heskett schreef op 2021-08-29 04:22:
On Saturday 28 August 2021 20:51:21 Gareth Chen wrote:
If your printer is printing 5.98mm parts to be 6.51mm tall it's
seriously out of calibration...
Its a Prusa mk3S, has about a 25 minute calibration using markers on
the
bed for xy references. But other that running z against to top stops
and
hammering on the top for a while, I don't see where it calibrates the z
range. XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it hit.
If the same circuit is used for detecting the top of travel, then its
failing as its dual z motors and useing a default because it hammers
the
top of travel for about a full second. I'll ask prusa monday. And get
the m command to change it too.
Thank you..
[...]
Cheers, Gene Heskett
On Saturday 28 August 2021 23:21:21 MichaelAtOz wrote:
Calibration is something you need to do, not the printer.
You need to slice & print calibration objects and get your callipers
out.
Then adjust slicer settings, rinse, repeat, until you get physical
objects matching the specification of the calibration object.
You will need to have profiles for different materials with settings
from a calibration run for that material (usually just extruder
settings being different).
I haven't calibrated for a long time as I use Shapeways, but Google
coughed up these which look reasonable.
Yes, I dl'd several of them, should be helpfull, thank you.
https://all3dp.com/2/how-to-calibrate-a-3d-printer-simply-explained/
Then do some torture tests
https://all3dp.com/2/best-3d-printer-test-print-3d-models/
There is little point printing functional objects until you can print
a calibration object accurately.
https://www.thingiverse.com/search?q=calibration
https://www.thingiverse.com/search?q=calibration&type=things
&type=things
From: Father Horton [mailto:fatherhorton@gmail.com]
Sent: Sun, 29 Aug 2021 12:36
To: OpenSCAD general discussion
Subject: [OpenSCAD] Re: Provide a simple measurement tool
It almost sounds as if your printer profile is messed up. Are you
using defaults in PrusaSlicer, or did you change something, or are you
using Cura?
On Sat, Aug 28, 2021 at 9:24 PM Gene Heskett gheskett@shentel.net
wrote:
On Saturday 28 August 2021 20:51:21 Gareth Chen wrote:
If your printer is printing 5.98mm parts to be 6.51mm tall it's
seriously out of calibration...
Its a Prusa mk3S, has about a 25 minute calibration using markers on
the bed for xy references. But other that running z against to top
stops and hammering on the top for a while, I don't see where it
calibrates the z range. XY home apparently senses motor current to
detect just touching the left and rear stops. Not even hard enough to
obviously hear it hit. If the same circuit is used for detecting the
top of travel, then its failing as its dual z motors and useing a
default because it hammers the top of travel for about a full second.
I'll ask prusa monday. And get the m command to change it too.
Thank you..
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law
respectable. - Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
On Sunday 29 August 2021 00:23:08 larry wrote:
On Sat, 2021-08-28 at 22:22 -0400, Gene Heskett wrote:z
XY home apparently senses motor current to detect just touching
the left and rear stops. Not even hard enough to obviously hear it
hit. If the same circuit is used for detecting the top of travel,
then its failing as its dual z motors and useing a default because
it hammers the top of travel for about a full second. I'll ask prusa
monday. And get the m command to change it too.
If you have sensorless homing X and Y, that will work fine. It detects
stall current. But I seriously doubt that your machine came equipped
with sensorless Z homing, for the simple reason that the Z axis will
not give a high enough stall current to stop the bed in time, due to
the flex in the Z axis while driving a screw, with its (for want of a
better word) gear reduction of the screw.
I am quite certain that your endstop for the Z axis is some sort of
sensor, be it mechanical (like a microswitch), electronic (capacitive,
inductive, piezoelectric, etc.).
So for the Z axis, you want the Z homing to NEVER hit the bed. That's
usually a mechanical adjustment, moving the sensor toward/away from
the bed. When the Z axis homes, you will have a gap between the nozzle
and bed, and that's when you adjust your Z offset such that z=0 is
when the nozzle touches the bed.
the printer has a test pattern for that, and the sensor is 1.065mm above
the bed for a .18mm nozzle gap. Adhesion with petg is generally good,
and a single line is .17 mm thick. No interline gaps in the little patch
at the end when held up to the light with a very strong glass for a
close look. Prusa MK3S lets you trim that in extremely small increments,
1/20th the increments possible with other printers, and does it without
bed leveling wheels.
As for your bad height of prints, that's a result of configuring the
wrong setting for Z axis steps/mm or step distance, depending on how
it's specified.
I expect dimmensional accuracy to generally print at about the target
move plus the nozzle dia, and generally write my code to be .2mm approx
undersized on each edge to come out with a decent press fit where parts
come together. Currently that value seems to be closer to .3 than .2.
for a .2mm layer, indicating over extrusion.
Thanks.
[...]
Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/gene
Getting back on track, it took me a while to grasp the idea that the
programming part of Open SCAD is just an elaborate script producing
interface, and when the programming side of it finishes, the scripts
that are produced, are forwarded to the graphics engine to create the
3-D model. The programs and the rendering do not run simultaneously. The
first cannot communicate with the second. So the program is not in the
position to access geometric dimensions that are then produced and
rendered afterwards.
Producing a script that maps the transformation of the graphical objects
before they are calculated through the CSG Tree is in fact running a
parallel universe that involves far more effort for any degree of
complexity for my designs than I believe it is worth. Is this
frustrating? Yes. Is it trivial solving this problem? No.
The penny dropped when I understood the significance of:
Compiling design (CSG Tree generation)...
Rendering Polygon Mesh using CGAL... in the console.
The "CSG Tree" becomes a static list of graphical transformations. I
calmed down substantially when I got it. So while it may seem the
addition of the "ruler" idea would be easy (given all the other amazing
stuff OpenSACD allows us to do), it will take a very crafty programmer
to do it in the first place, and really crafty one to retain
compatibility with the existing processes. So I listen to the experts on
how they "work around" this issue, the quality of their work attests to
the fact they know what they are doing.
My simple approach is to usually draw in any critical extras (eg bolts,
bearings axles etc) my creation has to work with, or position easily
"checkable chunks" of known dimensions, to test my model with and then
remove them when the final model is created. This will not be convenient
for all situations but there other really good ideas that have helped
others.
Rob