Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
On Fri, 27 Feb 2026 11:32:52 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
It's true, but "pretty good" is not a number.
The heated nozzle is smaller than the feed filament, but cannot be
that small or the printing speed suffers too much to be economical.
Joe, known to possess a biggish hot melt gun
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
On 2/27/2026 9:12 AM, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
That would fall in the realm of dimensionality.
One typically uses "plastic parts" for more than just
cosmetics.
I'm concerned with *mechanical* aspects -- tensile
strength, ability to withstand shear forces, ductility,
behavior under compression, etc.
E.g., if I print a part and then expect it to support
a mass (or, be supported by an aspect of its shape/design),
will the layers delaminate if the force is orthogonal to
the printing plane? If I "print" a mounting hole and a
user uses a screw to secure the device to a surface
THROUGH that hole, will the plastic crumble or splinter
as force is applied to tighten the screw? If I print a
boss with the intent of fastening to it with a self-tapping
screw, will the penetration of the boss splinter (or
delaminate) the boss (depending on print orientation)?
If force is applied to printed surfaces, will their
deformation be elastic or catastrophic?
How do materials and filament diameter effect each of these
issues?
Or, should I just use 3D printing for non-functional *mockups*
and not rely on them to perform comparably to molded/cast
parts?
Yer kidding.
On 2026-02-27 12:59, Joe Gwinn wrote:
On Fri, 27 Feb 2026 11:32:52 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
It's true, but "pretty good" is not a number.
Really? Whoda thunk? ;)
Resin printer resolution varies with the resolution of the LCD display
it's based on, but can easily be 20 microns, which is a lot smaller than
the nozzle you're going to be using with a filament printer.
The heated nozzle is smaller than the feed filament, but cannot be
that small or the printing speed suffers too much to be economical.
Joe, known to possess a biggish hot melt gun
Cheers
Phil Hobbs
(Known to possess one of the first 3D printed objects, circa 1992 or
1993--a hollow sphere, made from Sears hot melt glue)
Fri, 27 Feb 2026 15:11:57 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
Yer kidding.
On 2026-02-27 12:59, Joe Gwinn wrote:
On Fri, 27 Feb 2026 11:32:52 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is >>>>> melted and applied. In some cases the surfaces are made smoother by >>>>> melting the surface, this being the equivalent of flame-polishing of >>>>> glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
It's true, but "pretty good" is not a number.
Really? Whoda thunk? ;)
OP wanted numbers.
Resin printer resolution varies with the resolution of the LCD display
it's based on, but can easily be 20 microns, which is a lot smaller than
the nozzle you're going to be using with a filament printer.
This sounds like a 3D printer that works like a Xerox printer with
funny ink. Sounds very precise but very slow. Don't think OP was
talking about this.
<snip>
On Fri, 27 Feb 2026 13:31:49 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 2/27/2026 9:12 AM, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
That would fall in the realm of dimensionality.
One typically uses "plastic parts" for more than just
cosmetics.
I'm concerned with *mechanical* aspects -- tensile
strength, ability to withstand shear forces, ductility,
behavior under compression, etc.
E.g., if I print a part and then expect it to support
a mass (or, be supported by an aspect of its shape/design),
will the layers delaminate if the force is orthogonal to
the printing plane? If I "print" a mounting hole and a
user uses a screw to secure the device to a surface
THROUGH that hole, will the plastic crumble or splinter
as force is applied to tighten the screw? If I print a
boss with the intent of fastening to it with a self-tapping
screw, will the penetration of the boss splinter (or
delaminate) the boss (depending on print orientation)?
If force is applied to printed surfaces, will their
deformation be elastic or catastrophic?
How do materials and filament diameter effect each of these
issues?
All of these things depend on a thousand details, far too complex for
a few rules of thumb.
Well, save one rule: 3D printed components are far weaker et al than components made by the traditional methods. Maybe this matters, maybe
not.
For making only a few units of each design, a 3D printer is very
attractive.
Or, should I just use 3D printing for non-functional *mockups*
and not rely on them to perform comparably to molded/cast
parts?
What people do is to print a prototype and see if it works well
enough. I have bought a number of such components, which have so far
worked.
But it will be a long time before 3D printing can be used for
automobile suspension components.
On 2/27/2026 4:33 PM, Joe Gwinn wrote:
All of these things depend on a thousand details, far too complex for
a few rules of thumb.
I disagree. E.g., interlayer bonds seem to be less strong than
the layers themselves -- suggesting how one could arrange for stresses
to be distributed in the object. Nylon and PLA are more ductile
than materials like SLA so expect less "catastrophic" (more plastic) deformation.
I wouldn't want to experiment with a material (or build orientation)
only to discover these sorts of things would have been obvious on
initial inspection.
Well, save one rule: 3D printed components are far weaker et al than components made by the traditional methods. Maybe this matters, maybe
not.
For making only a few units of each design, a 3D printer is very attractive.
It seems most suited to verifying form but likely not for actual
*use* in a generalized "real product". E.g., imagine printing
something that the user would fasten to a wall surface -- how
can you be sure the user won't tighten the fastener just a bit too
much and crack the part? I imagine this is exacerbated by smaller
parts where you can't just throw extra "material" into the product.
Or, should I just use 3D printing for non-functional *mockups*
and not rely on them to perform comparably to molded/cast
parts?
What people do is to print a prototype and see if it works well
enough. I have bought a number of such components, which have so far worked.
But it will be a long time before 3D printing can be used for
automobile suspension components.
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
Cheers
Phil Hobbs
On Fri, 27 Feb 2026 11:32:52 -0500, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
Cheers
Phil Hobbs
PCBs are now roughly 80 years old. They are stiil made from a smallish
number of parallel planes.
If 3D printiing could ever make decent conductors, we might have true
3D circuits. It might take an AI-scale compute farm to do the place-and-route.
Parts inside?
Don Y <blockedofcourse@foo.invalid> wrote:
On 2/27/2026 4:33 PM, Joe Gwinn wrote:
All of these things depend on a thousand details, far too complex for
a few rules of thumb.
I disagree. E.g., interlayer bonds seem to be less strong than
the layers themselves -- suggesting how one could arrange for stresses
to be distributed in the object. Nylon and PLA are more ductile
than materials like SLA so expect less "catastrophic" (more plastic)
deformation.
I wouldn't want to experiment with a material (or build orientation)
only to discover these sorts of things would have been obvious on
initial inspection.
The problem is that those things depend on a thousand details, which could
be different between each print.
For example, the slicer software sets how the path of the print head moves
to draw the object. Suppose the slicer makes the head push down harder
into the previous layer - result will be stronger interlayer bonds. Then
the next version of the software comes out and changes the slicing algorithm >- changing all the properties.
Then you have the problem that the filament differs from manufacturer to >manufacturer and sometimes batch to batch.
Well, save one rule: 3D printed components are far weaker et al than
components made by the traditional methods. Maybe this matters, maybe
not.
For making only a few units of each design, a 3D printer is very
attractive.
It seems most suited to verifying form but likely not for actual
*use* in a generalized "real product". E.g., imagine printing
something that the user would fasten to a wall surface -- how
can you be sure the user won't tighten the fastener just a bit too
much and crack the part? I imagine this is exacerbated by smaller
parts where you can't just throw extra "material" into the product.
There are things you can do with that - eg orient the layers so they're >parallel with the load, rather than perpendicular. Then you are applying >force along the layer rather than between layers. Again that's a function
of how the part is printed, which is a function of both the software and its >hundreds of settings.
Or, should I just use 3D printing for non-functional *mockups*
and not rely on them to perform comparably to molded/cast
parts?
What people do is to print a prototype and see if it works well
enough. I have bought a number of such components, which have so far
worked.
But it will be a long time before 3D printing can be used for
automobile suspension components.
It's already happening: >https://www.voxelmatters.com/new-ferrari-f80-to-integrate-metal-3d-printed-parts/
Theo
Don Y <blockedofcourse@foo.invalid> wrote:
On 2/27/2026 4:33 PM, Joe Gwinn wrote:
All of these things depend on a thousand details, far too complex for
a few rules of thumb.
I disagree. E.g., interlayer bonds seem to be less strong than
the layers themselves -- suggesting how one could arrange for stresses
to be distributed in the object. Nylon and PLA are more ductile
than materials like SLA so expect less "catastrophic" (more plastic)
deformation.
I wouldn't want to experiment with a material (or build orientation)
only to discover these sorts of things would have been obvious on
initial inspection.
The problem is that those things depend on a thousand details, which could
be different between each print.
For example, the slicer software sets how the path of the print head moves
to draw the object. Suppose the slicer makes the head push down harder
into the previous layer - result will be stronger interlayer bonds. Then
the next version of the software comes out and changes the slicing algorithm - changing all the properties.
Then you have the problem that the filament differs from manufacturer to manufacturer and sometimes batch to batch.
Well, save one rule: 3D printed components are far weaker et al than
components made by the traditional methods. Maybe this matters, maybe
not.
For making only a few units of each design, a 3D printer is very
attractive.
It seems most suited to verifying form but likely not for actual
*use* in a generalized "real product". E.g., imagine printing
something that the user would fasten to a wall surface -- how
can you be sure the user won't tighten the fastener just a bit too
much and crack the part? I imagine this is exacerbated by smaller
parts where you can't just throw extra "material" into the product.
There are things you can do with that - eg orient the layers so they're parallel with the load, rather than perpendicular. Then you are applying force along the layer rather than between layers. Again that's a function
of how the part is printed, which is a function of both the software and its hundreds of settings.
Or, should I just use 3D printing for non-functional *mockups*
and not rely on them to perform comparably to molded/cast
parts?
What people do is to print a prototype and see if it works well
enough. I have bought a number of such components, which have so far
worked.
But it will be a long time before 3D printing can be used for
automobile suspension components.
It's already happening: https://www.voxelmatters.com/new-ferrari-f80-to-integrate-metal-3d-printed-parts/
john larkin <jl@glen--canyon.com> wrote:
On Fri, 27 Feb 2026 11:32:52 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-02-27 11:12, Joe Gwinn wrote:
On Fri, 27 Feb 2026 03:57:35 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
Can anyone recommend a good text that covers the mechanical
characteristics of 3D printed objects related to the
*process*, itself? Then, anything additional specific to
the various printing materials that can be used and how they
mitigate/amplify these characteristics?
I'd like ot be able to gauge just how accurately 3D printed
prototypes would reflect the characteristics of injection
molded parts -- before paying for their tooling.
Good luck. The current rule of thumb is that the accuracy of the
printed item is at best the diameter of the plastic filament that is
melted and applied. In some cases the surfaces are made smoother by
melting the surface, this being the equivalent of flame-polishing of
glass articles.
Joe
Resin prints can be pretty good, and the printers are nearly free.
Cheers
Phil Hobbs
PCBs are now roughly 80 years old. They are stiil made from a smallish
number of parallel planes.
If 3D printiing could ever make decent conductors, we might have true
3D circuits. It might take an AI-scale compute farm to do the
place-and-route.
Parts inside?
Well, Murata is shipping those DC-DC modules with the toroid core inside
the board. Folk have been putting ceramic decaps inside PCBs for over 20 >years that I know about.
Cheers
Phil Hobbs
(Former member of the packaging research group at IBM Watson)
On 28 Feb 2026 22:50:57 +0000 (GMT), Theo
<theom+news@chiark.greenend.org.uk> wrote:
Don Y <blockedofcourse@foo.invalid> wrote:
On 2/27/2026 4:33 PM, Joe Gwinn wrote:
All of these things depend on a thousand details, far too complex for
a few rules of thumb.
I disagree. E.g., interlayer bonds seem to be less strong than
the layers themselves -- suggesting how one could arrange for stresses
to be distributed in the object. Nylon and PLA are more ductile
than materials like SLA so expect less "catastrophic" (more plastic)
deformation.
I wouldn't want to experiment with a material (or build orientation)
only to discover these sorts of things would have been obvious on
initial inspection.
The problem is that those things depend on a thousand details, which could >>be different between each print.
For example, the slicer software sets how the path of the print head moves >>to draw the object. Suppose the slicer makes the head push down harder >>into the previous layer - result will be stronger interlayer bonds. Then >>the next version of the software comes out and changes the slicing algorithm >>- changing all the properties.
Then you have the problem that the filament differs from manufacturer to >>manufacturer and sometimes batch to batch.
Well, save one rule: 3D printed components are far weaker et al than
components made by the traditional methods. Maybe this matters, maybe >>> > not.
For making only a few units of each design, a 3D printer is very
attractive.
It seems most suited to verifying form but likely not for actual
*use* in a generalized "real product". E.g., imagine printing
something that the user would fasten to a wall surface -- how
can you be sure the user won't tighten the fastener just a bit too
much and crack the part? I imagine this is exacerbated by smaller
parts where you can't just throw extra "material" into the product.
There are things you can do with that - eg orient the layers so they're >>parallel with the load, rather than perpendicular. Then you are applying >>force along the layer rather than between layers. Again that's a function >>of how the part is printed, which is a function of both the software and its >>hundreds of settings.
Or, should I just use 3D printing for non-functional *mockups*
and not rely on them to perform comparably to molded/cast
parts?
What people do is to print a prototype and see if it works well
enough. I have bought a number of such components, which have so far
worked.
But it will be a long time before 3D printing can be used for
automobile suspension components.
It's already happening: >>https://www.voxelmatters.com/new-ferrari-f80-to-integrate-metal-3d-printed-parts/
Theo
Yeah. Being pioneered by the aerospace community, who can afford such >things. But it's largely research except for simple things. But they
will get there.
Military aerospace are the folk that built the equipment to forge the
F-22 fighter aircraft airframe of titanium.
Joe
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