Design fault or low quality printing
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail for Windows
Sounds like someone printed it for you, what type of printer?
The thin thread,
a_picture = 1000* words;
From: Hendrik [mailto:blindguydiy@gmail.com]
Sent: Sun, 13 Mar 2022 16:03
To: discuss@lists.openscad.org
Subject: [OpenSCAD] Design fault or low quality printing
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for Windows
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Hey Hendrick:
An important aspect of 3d printing for real world items is to ensure your 3d printer is tuned as accurately as possible. I’m happy to give you details on how to accomplish that, but that’s somewhat off the focus of this group which I believe is 3d modelling generally, not 3d modelling for 3d printers specifically.
Anyway, you may have already tuned your printer as accurately as can be expected.
As far as OpenSCAD is concerned, i would not be surprised that you are getting tripped up with the way works with the triangles it creates to approximate the diameter of a circle.
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/undersized_circular_objects https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/undersized_circular_objects
As you can see in the link provided, OpenSCAD defaults to providing undersized holes for internal object differences. The link provided gives you some calculations that provide more ‘accurate’ inner hole diameters, but you will also need to determine or guess at the engineering fit and tolerance between the bearing and your printed cylinder. Do you want to have to hammer your bearing into your cylinder (interference fit), do you want to be able to push it in with a little bit of tightness (transition fit), or do you want it to fit loosely to that if you tip your cylinder over, the bearing falls out (clearance) fit.
This wikipedia page gives a good description of tolerance and fits… https://en.wikipedia.org/wiki/Engineering_fit https://en.wikipedia.org/wiki/Engineering_fit
The consequence is that even if your circle diameter is calculated appropriately for your difference cylinder, you may still have the issue of fit to resolve until you get a print of the cylinder you’re happy with.
On Mar 12, 2022, at 9:03 PM, Hendrik blindguydiy@gmail.com wrote:
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for Windows
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org mailto:discuss-leave@lists.openscad.org
Do not know what make printer. The image in the mail not helping me for I am blind. Thanks Just want to know if I have to make my inner of my pipe not 16mm in diameter rather 16.5 or 17mm, But it Does not make sence for if the bearing is 16mm outer mm it should fit into a 16mm pipe?
Sent from Mail for Windows
From: MichaelAtOz
Sent: Sunday, 13 March 2022 07:24
To: OpenSCAD general discussion
Subject: [OpenSCAD] Re: Design fault or low quality printing
Sounds like someone printed it for you, what type of printer?
The thin thread,
a_picture = 1000* words;
From: Hendrik [mailto:blindguydiy@gmail.com]
Sent: Sun, 13 Mar 2022 16:03
To: discuss@lists.openscad.org
Subject: [OpenSCAD] Design fault or low quality printing
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail for Windows
Virus-free. www.avg.com
On Sunday, 13 March 2022 00:03:00 EST Hendrik wrote:
because this concerns 3d printing Hendrick, I am blocked from posting to
openscad list, hence this CC to you.
Hi all
I want to find out if it is my design or the printing. I designed a
hollow cylinder where a bearing would fit in and then a shaft that
will go through the bearing. Bearing size outer diameter = 16mm,
inner diameter =8mm. But when I received the part the bearing did not
fit inside and also the shaft was to big to fit in the inner of the
bearing. I created my cylinder with a 16 inner and the shaft with a 8
outer diameter.
In printing, it is common to remove about half the printers nozzle
diameter, because the printer prints to the center of the nozzle, so
outside of shaft is then nominally .2mm big on both near and far
surfaces. So an 8mm shaft should be reduced to around 7.6mm and a bearing
seat expanded by about the same amount. Exact fit will depend on your
slicer settings.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my
bearing should fit in. Or must I make it larger the inner diameter to
get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner.
But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it
makes some places a thin thread that can be pulled of. Like a thin
plastic thread if you pull it it start running all around the
cylinder.
Hope I make sence.
Thank you
Sent from Mail for Windows
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
You have a design problem and possibly a 3D printing problem.
Assiuming the 3D printer is perfect, meaning everything prints exactly the size it is supposed to:
If you design a 16mm hole for a bearing with a 16mm outer diameter, the bearing won’t fit. Even if you somehow make it fit, removing it will be next to impossible. The same goes for the shaft. If you print an 8mm shaft for a bearing for an 8mm inner diameter, everything will be too tight.
-
The printer needs to be calibrated so that the parts come out to be the sizes expected. If you are using Cura, you need to print out test pieces and use the "Horizontal Expansion” and “Hole Horizontal Expansion” settings to get everything dialed in.
-
Once the printer is calibrated, the hole size for the bearing and the diameter of the shaft will need to be adjusted so that they fit. The hole will need to be slightly larger than the bearing and the shaft slightly smaller than the hole. Start with 0.25mm and go up or down from there.
I occasionally design parts to support bearings. Bearings are hard because too loose is bad and too tight is bad. They need to be just right. I never get them right the first time, but getting the printer dialed in is critical. You will need to calibrate again if you change the nozzle and if you change material. Tuning the printer will allow you to settle on the hole and shaft sizes with a reasonable expectation that your design will work on different printers and with different materials.
On Mar 12, 2022, at 11:03 PM, Hendrik blindguydiy@gmail.com wrote:
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for Windows
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org mailto:discuss-leave@lists.openscad.org
So I presume you ordered it from somewhere? Knowing the type can help with tolerance suggestions.
The type of printer affects how the material is laid down.
A basic hobby 3D printer sort of squishes the plastic so if not well tuned the inside bulge reduces the diameter,
they also cut corners with the inside line segments,
if you imagine a circle, join two dots on the edge with a line, the middle of the line is always inside the circle.
Even high $fn will do so.
I high-end Shapeways printer can be much more accurate.
From: Hendrik [mailto:blindguydiy@gmail.com]
Sent: Sun, 13 Mar 2022 16:55
To: OpenSCAD general discussion
Subject: [OpenSCAD] Re: Design fault or low quality printing
Hi
Do not know what make printer. The image in the mail not helping me for I am blind. Thanks Just want to know if I have to make my inner of my pipe not 16mm in diameter rather 16.5 or 17mm, But it Does not make sence for if the bearing is 16mm outer mm it should fit into a 16mm pipe?
Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for Windows
From: MichaelAtOz mailto:oz.at.michael@gmail.com
Sent: Sunday, 13 March 2022 07:24
To: OpenSCAD general discussion mailto:discuss@lists.openscad.org
Subject: [OpenSCAD] Re: Design fault or low quality printing
Sounds like someone printed it for you, what type of printer?
The thin thread,
a_picture = 1000* words;
From: Hendrik [mailto:blindguydiy@gmail.com]
Sent: Sun, 13 Mar 2022 16:03
To: discuss@lists.openscad.org
Subject: [OpenSCAD] Design fault or low quality printing
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for Windows
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Thank you.
Sent from Mail for Windows
From: David Schooley
Sent: Sunday, 13 March 2022 08:01
To: OpenSCAD general discussion
Subject: [OpenSCAD] Re: Design fault or low quality printing
You have a design problem and possibly a 3D printing problem.
Assiuming the 3D printer is perfect, meaning everything prints exactly the size it is supposed to:
If you design a 16mm hole for a bearing with a 16mm outer diameter, the bearing won’t fit. Even if you somehow make it fit, removing it will be next to impossible. The same goes for the shaft. If you print an 8mm shaft for a bearing for an 8mm inner diameter, everything will be too tight.
1. The printer needs to be calibrated so that the parts come out to be the sizes expected. If you are using Cura, you need to print out test pieces and use the "Horizontal Expansion” and “Hole Horizontal Expansion” settings to get everything dialed in.
2. Once the printer is calibrated, the hole size for the bearing and the diameter of the shaft will need to be adjusted so that they fit. The hole will need to be slightly larger than the bearing and the shaft slightly smaller than the hole. Start with 0.25mm and go up or down from there.
I occasionally design parts to support bearings. Bearings are hard because too loose is bad and too tight is bad. They need to be just right. I never get them right the first time, but getting the printer dialed in is critical. You will need to calibrate again if you change the nozzle and if you change material. Tuning the printer will allow you to settle on the hole and shaft sizes with a reasonable expectation that your design will work on different printers and with different materials.
On Mar 12, 2022, at 11:03 PM, Hendrik <blindguydiy@gmail.com> wrote:
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail for Windows
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& p.s. if it has a thin thread coming off, it sounds like a poorly tuned FFF/FDM (https://en.wikipedia.org/wiki/Fused_filament_fabrication) printer.
From: Hendrik [mailto:blindguydiy@gmail.com]
Sent: Sun, 13 Mar 2022 16:03
To: discuss@lists.openscad.org
Subject: [OpenSCAD] Design fault or low quality printing
Hi all
I want to find out if it is my design or the printing. I designed a hollow cylinder where a bearing would fit in and then a shaft that will go through the bearing. Bearing size outer diameter = 16mm, inner diameter =8mm. But when I received the part the bearing did not fit inside and also the shaft was to big to fit in the inner of the bearing. I created my cylinder with a 16 inner and the shaft with a 8 outer diameter.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my bearing should fit in. Or must I make it larger the inner diameter to get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner. But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it makes some places a thin thread that can be pulled of. Like a thin plastic thread if you pull it it start running all around the cylinder.
Hope I make sence.
Thank you
Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for Windows
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Gene,
I'm not sure if you posted to the Mailing-list AND CC'd, but you did post.
You are not blocked, you are moderated, due to ignoring warnings to stay on topic.
However due to time zones, moderation can take a while.
All,
There is interplay between design, expression of that design as .scad code, and the printed result.
Such interplay can be discussed here.
Hendrick's question is clearly asking about design/scad tolerances and printed outcomes.
This can be a spectrum though; straying to the dark side of pure printing related topics is
discouraged.
MichaelAtOz
Admin
-----Original Message-----
From: gene heskett [mailto:gheskett@shentel.net]
Sent: Sun, 13 Mar 2022 17:00
To: OpenSCAD general discussion
Cc: Hendrik
Subject: [OpenSCAD] Re: Design fault or low quality printing
On Sunday, 13 March 2022 00:03:00 EST Hendrik wrote:
because this concerns 3d printing Hendrick, I am blocked from posting to
openscad list, hence this CC to you.
Hi all
I want to find out if it is my design or the printing. I designed a
hollow cylinder where a bearing would fit in and then a shaft that
will go through the bearing. Bearing size outer diameter = 16mm,
inner diameter =8mm. But when I received the part the bearing did not
fit inside and also the shaft was to big to fit in the inner of the
bearing. I created my cylinder with a 16 inner and the shaft with a 8
outer diameter.
In printing, it is common to remove about half the printers nozzle
diameter, because the printer prints to the center of the nozzle, so
outside of shaft is then nominally .2mm big on both near and far
surfaces. So an 8mm shaft should be reduced to around 7.6mm and a bearing
seat expanded by about the same amount. Exact fit will depend on your
slicer settings.
difference() {
cylinder(d=20, h=10, $fn=100);
translate([0,0,-1]) cylinder(d=16, h=10+2, $fn=100);
}
Now this should give me a cylinder with a inner of 16mm where my
bearing should fit in. Or must I make it larger the inner diameter to
get a 16mm to fit my bearing in when it is printed.
Bearing shaft
Cylinder(d=8, h=10, $fn=100);
This should give me a shaft of 8mm to fit into the bearing 8mm inner.
But is to large for my bearing. Must I make this smaller?
Does it matter if I use r for radius or d for diameter?
Also why I think it could have to do with quality of print is that it
makes some places a thin thread that can be pulled of. Like a thin
plastic thread if you pull it it start running all around the
cylinder.
Hope I make sence.
Thank you
Sent from Mail for Windows
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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