I assume (?) there are differences in mechanical strength of the printed item relative to forces exerted along vs. normal to the laminations. Is this a significant difference (i.e., one that would suggest printing in one orientation over another)? Also, does this (?) generality apply to all materials? Or, some moreso than others?
OT: 3D printing
Started by ●March 20, 2023
Reply by ●March 20, 20232023-03-20
Don Y <blockedofcourse@foo.invalid> writes:> I assume (?) there are differences in mechanical strength > of the printed item relative to forces exerted along vs. > normal to the laminations. Is this a significant difference > (i.e., one that would suggest printing in one orientation > over another)?Yes. 3D prints tend to break between layers. CNC Kitchen and Thomas Sanladerer on Youtube have done many videos comparing such.> Also, does this (?) generality apply to all materials? > Or, some moreso than others?Mostly, yes. Some have better layer adhesion than others (PETG is better than PLA, for example, but there are some even better) but it's rare that it's "as good as injection molded strength".
Reply by ●March 20, 20232023-03-20
On 21/03/23 08:14, Don Y wrote:> I assume (?) there are differences in mechanical strength > of the printed item relative to forces exerted along vs. > normal to the laminations. Is this a significant difference > (i.e., one that would suggest printing in one orientation > over another)? > > Also, does this (?) generality apply to all materials? > Or, some moreso than others?Yes.
Reply by ●March 20, 20232023-03-20
On 3/20/2023 2:57 PM, DJ Delorie wrote:> Don Y <blockedofcourse@foo.invalid> writes: >> I assume (?) there are differences in mechanical strength >> of the printed item relative to forces exerted along vs. >> normal to the laminations. Is this a significant difference >> (i.e., one that would suggest printing in one orientation >> over another)? > > Yes. 3D prints tend to break between layers. CNC Kitchen and Thomas > Sanladerer on Youtube have done many videos comparing such.This suggests it is likely more the norm than the exception (?). Thanks, I will chase down their videos to see what specifics they can add.>> Also, does this (?) generality apply to all materials? >> Or, some moreso than others? > > Mostly, yes. Some have better layer adhesion than others (PETG is > better than PLA, for example, but there are some even better) but it's > rare that it's "as good as injection molded strength".I wouldn't expect the same performance as an injected molded part. But, if it is common enough to be a noteworthy problem, then I'm probably better off pursuing a different technology. Thanks!
Reply by ●March 21, 20232023-03-21
On 21/03/2023 01:35, Don Y wrote:> On 3/20/2023 2:57 PM, DJ Delorie wrote: >> Don Y <blockedofcourse@foo.invalid> writes: >>> I assume (?) there are differences in mechanical strength >>> of the printed item relative to forces exerted along vs. >>> normal to the laminations. Is this a significant difference >>> (i.e., one that would suggest printing in one orientation >>> over another)? >> >> Yes. 3D prints tend to break between layers. CNC Kitchen and Thomas >> Sanladerer on Youtube have done many videos comparing such. > > This suggests it is likely more the norm than the exception (?). > Thanks, I will chase down their videos to see what specifics they > can add.I think it will depend a lot on how much sheer force the part is likely to suffer along the planes of printing. You invariably see edge artefacts and on cheaper printers that don't enclose the workspace a cold draft can make some parts much weaker than others. It is a fine line between setting to solid and still being soft enough to bond with the next layer. Enclosed units with heated beds seem to manage this interlayer bonding a bit better than cheaper models. I've not seen any fail this way but the printer I cadge time on is fairly high end heated bed and has a tame skilled operator. He spends most of his time printing archaeological artefacts on it so any foreigners tend to come out bone coloured or black by default.>>> Also, does this (?) generality apply to all materials? >>> Or, some moreso than others? >> >> Mostly, yes. Some have better layer adhesion than others (PETG is >> better than PLA, for example, but there are some even better) but it's >> rare that it's "as good as injection molded strength". > > I wouldn't expect the same performance as an injected molded > part. But, if it is common enough to be a noteworthy > problem, then I'm probably better off pursuing a different > technology.You could always make the master part that way and then use the equivalent of lost wax casting to make a conventional mould from it - provided that you obey the rules for a makable part in a convex mould. -- Martin Brown
Reply by ●March 21, 20232023-03-21
On 2023-03-20, Don Y <blockedofcourse@foo.invalid> wrote:> I assume (?) there are differences in mechanical strength > of the printed item relative to forces exerted along vs. > normal to the laminations. Is this a significant difference > (i.e., one that would suggest printing in one orientation > over another)?Yes.> Also, does this (?) generality apply to all materials? > Or, some moreso than others?Mostly for FDM printers, and then moreso to reinforced material, because it is deposited in a stream parallel to the layer boundaries. -- Jasen. 🇺🇦 Слава Україні
Reply by ●March 21, 20232023-03-21
On 2023-03-21 05:10, Martin Brown wrote:> On 21/03/2023 01:35, Don Y wrote: >> On 3/20/2023 2:57 PM, DJ Delorie wrote: >>> Don Y <blockedofcourse@foo.invalid> writes: >>>> I assume (?) there are differences in mechanical strength >>>> of the printed item relative to forces exerted along vs. >>>> normal to the laminations. Is this a significant difference >>>> (i.e., one that would suggest printing in one orientation >>>> over another)? >>> >>> Yes. 3D prints tend to break between layers. CNC Kitchen and Thomas >>> Sanladerer on Youtube have done many videos comparing such. >> >> This suggests it is likely more the norm than the exception (?). >> Thanks, I will chase down their videos to see what specifics they >> can add. > > I think it will depend a lot on how much sheer force the part is likely > to suffer along the planes of printing. You invariably see edge > artefacts and on cheaper printers that don't enclose the workspace a > cold draft can make some parts much weaker than others. > > It is a fine line between setting to solid and still being soft enough > to bond with the next layer. Enclosed units with heated beds seem to > manage this interlayer bonding a bit better than cheaper models. > > I've not seen any fail this way but the printer I cadge time on is > fairly high end heated bed and has a tame skilled operator. He spends > most of his time printing archaeological artefacts on it so any > foreigners tend to come out bone coloured or black by default. > >>>> Also, does this (?) generality apply to all materials? >>>> Or, some moreso than others? >>> >>> Mostly, yes. Some have better layer adhesion than others (PETG is >>> better than PLA, for example, but there are some even better) but it's >>> rare that it's "as good as injection molded strength". >> >> I wouldn't expect the same performance as an injected molded >> part. But, if it is common enough to be a noteworthy >> problem, then I'm probably better off pursuing a different >> technology. > > You could always make the master part that way and then use the > equivalent of lost wax casting to make a conventional mould from it - > provided that you obey the rules for a makable part in a convex mould. >My late lamented 1992 Saturn had an engine block that was cast using a lost-foam process--the core was injection-moulded from polyurethane foam, then investment cast to make the aluminum block. The level of detail was impressive--you could see the characteristic starburst dot patten of the foam, reproduced in aluminum. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●March 21, 20232023-03-21
DJ Delorie <dj@delorie.com> wrote: >Mostly, yes. Some have better layer adhesion than others (PETG is >better than PLA, for example, but there are some even better) but it's >rare that it's "as good as injection molded strength". I did some printing with TPU. That material is unbelievable strong. I can print handcuff with 5mm diameter and you can not break them. .-) Olaf
Reply by ●March 21, 20232023-03-21
Don Y <blockedofcourse@foo.invalid> wrote: >I wouldn't expect the same performance as an injected molded >part. But, if it is common enough to be a noteworthy >problem, then I'm probably better off pursuing a different >technology. It is possible to print with carbon fiber loaded nylon or PETG if money is not your first problem. Olaf
Reply by ●March 21, 20232023-03-21
On Mon, 20 Mar 2023 14:14:16 -0700, Don Y <blockedofcourse@foo.invalid> wrote:>I assume (?) there are differences in mechanical strength >of the printed item relative to forces exerted along vs. >normal to the laminations. Is this a significant difference >(i.e., one that would suggest printing in one orientation >over another)?There is a difference. Whether or not it is significant, does, of course, depend. The problem is often referred to as "layer adhesion", should you want to research it further. Choosing the orientation also depends. Strength is not always the only parameter to worry about. Sometimes, a part can be printed without support material in one direction, but not in another. Other times, the part will only fit inside the print envelope in one particular orientation. As with any manufacturing process, it is a big advantage if the part can be designed with 3D-printing in mind (design for manufacture). That way, compromises can be balanced to get the best possible result.>Also, does this (?) generality apply to all materials? >Or, some moreso than others?There is definitely a difference between materials. I seem to remember having heard that PA (Nylon) offers very strong layer adhesion. -- RoRo
