Note I haven't tried solvent welding with it yet but I have dissolved PLA with it and I use to clean my glass bed when printing PLA. On Sat, 20 Jul 2019 at 16:23, Dan Shriver <tabbydan@gmail.com> wrote: > gewoods3 that works, and was stated before. nop_head was also reporting > ethyl acetate works; ethyl acetate has a MUCH lower to toxicity, and is > easier on the environment. You could probably substitute many other ester > solvents (though ethyl acetate is probably the least expensive). Solvent > welds will have a lower strength than a continuously cast part, but > considering PLA is not exactly known for durability probably a good option. > > On Sat, Jul 20, 2019 at 11:04 AM gewoods3 <gewoods3@gmail.com> wrote: > >> I have not read this entire thread, so I hope this is not duplicate >> information. The active ingredient for bonding PLA parts is >> dichloromethane >> or methylene chloride, same thing. Search "PLA dichloromethane". 3D Gloop >> PLA (https://www.3dgloop.com/shop/pla-gloop) and SCIGRIP 16 (Amazon) have >> dichloromethane. I prefer SCIGRIP 16. Either of these products don''t just >> glue PLA, they bond PLA as one part. 3D Gloop might send you a sample if >> you >> ask nicely. >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> Discuss@lists.openscad.org >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

Has anybody experimented with these pins or pins like them? I just printed out the pins at the 3 recommended sizes (in PLA on a Prusa MK3) and with the defaults the "standard" pins make a snug joint. The "small" and "tiny" pins make a looser joint with less tension. I wonder what adjustment would tighten up the smaller pins (more preload? less clearance?), or how I would pick parameters for medium sized pins in between the "small" and "standard" ones. There are a few things I'm not sure I understand about the design, such as the "preload" which both moves the nubs and shrinks the length. Shouldn't these be independent? (Shrinking the length seems like it should be a function of clearance rather than another parameter.) acwest wrote > The best way to find out how the snap pins work is to print Emmet's gear > cube https://www.thingiverse.com/thing:213946 > There are two versions of the hole inset, one which allows rotation and > one > which is fixed. They hold very solidly, but can be pulled apart with > enough > effort. The smallest I have been able to make useful pins is 4mm long with > a 2.5mm diameter, anything smaller than that is too fragile to use. > The fully customisable pins are at > https://www.thingiverse.com/thing:3218332, > and the output options include a test socket you can print to try it... > The > code generates an STL for the pin, which is printed flat, and an STL for > the socket, which is difference'd from the surface you want to embed the > pin in. -- Sent from: http://forum.openscad.org/

I would probably have to look over my code again, my printer has been offline for a while due to reorganising my apartment and replacing my main board. Generally increasing the preload should help, though. Some of the problem is that the smaller pins can't generate as much spring force due to physical constraints On Tue, 21 Jan 2020, 21:27 adrianv, <avm4@cornell.edu> wrote: > Has anybody experimented with these pins or pins like them? I just printed > out the pins at the 3 recommended sizes (in PLA on a Prusa MK3) and with > the > defaults the "standard" pins make a snug joint. The "small" and "tiny" > pins > make a looser joint with less tension. I wonder what adjustment would > tighten up the smaller pins (more preload? less clearance?), or how I > would > pick parameters for medium sized pins in between the "small" and "standard" > ones. > > There are a few things I'm not sure I understand about the design, such as > the "preload" which both moves the nubs and shrinks the length. Shouldn't > these be independent? (Shrinking the length seems like it should be a > function of clearance rather than another parameter.) > > > acwest wrote > > The best way to find out how the snap pins work is to print Emmet's gear > > cube https://www.thingiverse.com/thing:213946 > > There are two versions of the hole inset, one which allows rotation and > > one > > which is fixed. They hold very solidly, but can be pulled apart with > > enough > > effort. The smallest I have been able to make useful pins is 4mm long > with > > a 2.5mm diameter, anything smaller than that is too fragile to use. > > The fully customisable pins are at > > https://www.thingiverse.com/thing:3218332, > > and the output options include a test socket you can print to try it... > > The > > code generates an STL for the pin, which is printed flat, and an STL for > > the socket, which is difference'd from the surface you want to embed the > > pin in. > > > > > > -- > Sent from: http://forum.openscad.org/ > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

I tried printing a few test cases and found that with "small" got got a better fit with preload=0.16. This was a tighter fit than with preload=0.2, the default, and also tighter than 0.1 and 0.0. I predicted this by matching up the geometry for overlap compared to the "standard" size. For "tiny" they were all sort of loose, even the one I predicted to be tight. The way the overlap occurs is pretty sensitive to the preload number, so I suppose it might be highly printer dependent. There are questions I have about design choices which seem obscure. Like is it intentional that the pin lacks rotational symmetry (because the nub is scaled down by 0.9)? It seems like especially for smaller pins, having more engagement would be better. It might also be easier to code by doing a 2d model with rotate_extrude. On the other hand, maybe the lack of symmetry makes it easier for the pin to engage because it has a leading point. acwest wrote > I would probably have to look over my code again, my printer has been > offline for a while due to reorganising my apartment and replacing my main > board. > Generally increasing the preload should help, though. Some of the problem > is that the smaller pins can't generate as much spring force due to > physical constraints > > On Tue, 21 Jan 2020, 21:27 adrianv, &lt; > avm4@ > &gt; wrote: > >> Has anybody experimented with these pins or pins like them? I just >> printed >> out the pins at the 3 recommended sizes (in PLA on a Prusa MK3) and with >> the >> defaults the "standard" pins make a snug joint. The "small" and "tiny" >> pins >> make a looser joint with less tension. I wonder what adjustment would >> tighten up the smaller pins (more preload? less clearance?), or how I >> would >> pick parameters for medium sized pins in between the "small" and >> "standard" >> ones. >> >> There are a few things I'm not sure I understand about the design, such >> as >> the "preload" which both moves the nubs and shrinks the length. >> Shouldn't >> these be independent? (Shrinking the length seems like it should be a >> function of clearance rather than another parameter.) >> >> >> acwest wrote >> > The best way to find out how the snap pins work is to print Emmet's >> gear >> > cube https://www.thingiverse.com/thing:213946 >> > There are two versions of the hole inset, one which allows rotation and >> > one >> > which is fixed. They hold very solidly, but can be pulled apart with >> > enough >> > effort. The smallest I have been able to make useful pins is 4mm long >> with >> > a 2.5mm diameter, anything smaller than that is too fragile to use. >> > The fully customisable pins are at >> > https://www.thingiverse.com/thing:3218332, >> > and the output options include a test socket you can print to try it... >> > The >> > code generates an STL for the pin, which is printed flat, and an STL >> for >> > the socket, which is difference'd from the surface you want to embed >> the >> > pin in. >> >> >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> > Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- Sent from: http://forum.openscad.org/

The pin model has some historical artifacts in its development, as it was originally based on the pin in Emmet's gear cube and hearts(the standard pin still fits the sockets made for that) I'm not sure what you mean by rotational symmetry in this case. I've been arguing with kubernetes deployments all day so my brain may be a little slow... On Wed, 22 Jan 2020, 18:58 adrianv, <avm4@cornell.edu> wrote: > I tried printing a few test cases and found that with "small" got got a > better fit with preload=0.16. This was a tighter fit than with > preload=0.2, > the default, and also tighter than 0.1 and 0.0. I predicted this by > matching up the geometry for overlap compared to the "standard" size. For > "tiny" they were all sort of loose, even the one I predicted to be tight. > The way the overlap occurs is pretty sensitive to the preload number, so I > suppose it might be highly printer dependent. > > There are questions I have about design choices which seem obscure. Like > is > it intentional that the pin lacks rotational symmetry (because the nub is > scaled down by 0.9)? It seems like especially for smaller pins, having > more > engagement would be better. It might also be easier to code by doing a 2d > model with rotate_extrude. On the other hand, maybe the lack of symmetry > makes it easier for the pin to engage because it has a leading point. > > > acwest wrote > > I would probably have to look over my code again, my printer has been > > offline for a while due to reorganising my apartment and replacing my > main > > board. > > Generally increasing the preload should help, though. Some of the problem > > is that the smaller pins can't generate as much spring force due to > > physical constraints > > > > On Tue, 21 Jan 2020, 21:27 adrianv, &lt; > > > avm4@ > > > &gt; wrote: > > > >> Has anybody experimented with these pins or pins like them? I just > >> printed > >> out the pins at the 3 recommended sizes (in PLA on a Prusa MK3) and with > >> the > >> defaults the "standard" pins make a snug joint. The "small" and "tiny" > >> pins > >> make a looser joint with less tension. I wonder what adjustment would > >> tighten up the smaller pins (more preload? less clearance?), or how I > >> would > >> pick parameters for medium sized pins in between the "small" and > >> "standard" > >> ones. > >> > >> There are a few things I'm not sure I understand about the design, such > >> as > >> the "preload" which both moves the nubs and shrinks the length. > >> Shouldn't > >> these be independent? (Shrinking the length seems like it should be a > >> function of clearance rather than another parameter.) > >> > >> > >> acwest wrote > >> > The best way to find out how the snap pins work is to print Emmet's > >> gear > >> > cube https://www.thingiverse.com/thing:213946 > >> > There are two versions of the hole inset, one which allows rotation > and > >> > one > >> > which is fixed. They hold very solidly, but can be pulled apart with > >> > enough > >> > effort. The smallest I have been able to make useful pins is 4mm long > >> with > >> > a 2.5mm diameter, anything smaller than that is too fragile to use. > >> > The fully customisable pins are at > >> > https://www.thingiverse.com/thing:3218332, > >> > and the output options include a test socket you can print to try > it... > >> > The > >> > code generates an STL for the pin, which is printed flat, and an STL > >> for > >> > the socket, which is difference'd from the surface you want to embed > >> the > >> > pin in. > >> > >> > >> > >> > >> > >> -- > >> Sent from: http://forum.openscad.org/ > >> > >> _______________________________________________ > >> OpenSCAD mailing list > >> > > > Discuss@.openscad > > >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > >> > > > > _______________________________________________ > > OpenSCAD mailing list > > > Discuss@.openscad > > > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > > > > > -- > Sent from: http://forum.openscad.org/ > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

I suspected that historical artifacts could be an issue. I cleaned up the code substantially and saw things like "difference" called with just one child. (I can post my revised code, but note that it depends on BOSL2.) By rotational symmetry I mean that the model could be generated by rotate_extrude. Now obviously the pins have flat faces, so that isn't rotationally symmetric, but the way the nubs are scaled on the pin also breaks this symmetry. acwest wrote > The pin model has some historical artifacts in its development, as it was > originally based on the pin in Emmet's gear cube and hearts(the standard > pin still fits the sockets made for that) > I'm not sure what you mean by rotational symmetry in this case. I've been > arguing with kubernetes deployments all day so my brain may be a little > slow... > > On Wed, 22 Jan 2020, 18:58 adrianv, &lt; > avm4@ > &gt; wrote: > >> I tried printing a few test cases and found that with "small" got got a >> better fit with preload=0.16. This was a tighter fit than with >> preload=0.2, >> the default, and also tighter than 0.1 and 0.0. I predicted this by >> matching up the geometry for overlap compared to the "standard" size. >> For >> "tiny" they were all sort of loose, even the one I predicted to be tight. >> The way the overlap occurs is pretty sensitive to the preload number, so >> I >> suppose it might be highly printer dependent. >> >> There are questions I have about design choices which seem obscure. Like >> is >> it intentional that the pin lacks rotational symmetry (because the nub is >> scaled down by 0.9)? It seems like especially for smaller pins, having >> more >> engagement would be better. It might also be easier to code by doing a >> 2d >> model with rotate_extrude. On the other hand, maybe the lack of >> symmetry >> makes it easier for the pin to engage because it has a leading point. >> >> >> acwest wrote >> > I would probably have to look over my code again, my printer has been >> > offline for a while due to reorganising my apartment and replacing my >> main >> > board. >> > Generally increasing the preload should help, though. Some of the >> problem >> > is that the smaller pins can't generate as much spring force due to >> > physical constraints >> > >> > On Tue, 21 Jan 2020, 21:27 adrianv, &lt; >> >> > avm4@ >> >> > &gt; wrote: >> > >> >> Has anybody experimented with these pins or pins like them? I just >> >> printed >> >> out the pins at the 3 recommended sizes (in PLA on a Prusa MK3) and >> with >> >> the >> >> defaults the "standard" pins make a snug joint. The "small" and >> "tiny" >> >> pins >> >> make a looser joint with less tension. I wonder what adjustment would >> >> tighten up the smaller pins (more preload? less clearance?), or how I >> >> would >> >> pick parameters for medium sized pins in between the "small" and >> >> "standard" >> >> ones. >> >> >> >> There are a few things I'm not sure I understand about the design, >> such >> >> as >> >> the "preload" which both moves the nubs and shrinks the length. >> >> Shouldn't >> >> these be independent? (Shrinking the length seems like it should be a >> >> function of clearance rather than another parameter.) >> >> >> >> >> >> acwest wrote >> >> > The best way to find out how the snap pins work is to print Emmet's >> >> gear >> >> > cube https://www.thingiverse.com/thing:213946 >> >> > There are two versions of the hole inset, one which allows rotation >> and >> >> > one >> >> > which is fixed. They hold very solidly, but can be pulled apart with >> >> > enough >> >> > effort. The smallest I have been able to make useful pins is 4mm >> long >> >> with >> >> > a 2.5mm diameter, anything smaller than that is too fragile to use. >> >> > The fully customisable pins are at >> >> > https://www.thingiverse.com/thing:3218332, >> >> > and the output options include a test socket you can print to try >> it... >> >> > The >> >> > code generates an STL for the pin, which is printed flat, and an STL >> >> for >> >> > the socket, which is difference'd from the surface you want to embed >> >> the >> >> > pin in. >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> Sent from: http://forum.openscad.org/ >> >> >> >> _______________________________________________ >> >> OpenSCAD mailing list >> >> >> >> > Discuss@.openscad >> >> >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> >> >> > >> > _______________________________________________ >> > OpenSCAD mailing list >> >> > Discuss@.openscad >> >> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> >> >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> > Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org acwest wrote > The pin model has some historical artifacts in its development, as it was > originally based on the pin in Emmet's gear cube and hearts(the standard > pin still fits the sockets made for that) > I'm not sure what you mean by rotational symmetry in this case. I've been > arguing with kubernetes deployments all day so my brain may be a little > slow... > > On Wed, 22 Jan 2020, 18:58 adrianv, &lt; > avm4@ > &gt; wrote: > >> I tried printing a few test cases and found that with "small" got got a >> better fit with preload=0.16. This was a tighter fit than with >> preload=0.2, >> the default, and also tighter than 0.1 and 0.0. I predicted this by >> matching up the geometry for overlap compared to the "standard" size. >> For >> "tiny" they were all sort of loose, even the one I predicted to be tight. >> The way the overlap occurs is pretty sensitive to the preload number, so >> I >> suppose it might be highly printer dependent. >> >> There are questions I have about design choices which seem obscure. Like >> is >> it intentional that the pin lacks rotational symmetry (because the nub is >> scaled down by 0.9)? It seems like especially for smaller pins, having >> more >> engagement would be better. It might also be easier to code by doing a >> 2d >> model with rotate_extrude. On the other hand, maybe the lack of >> symmetry >> makes it easier for the pin to engage because it has a leading point. >> >> >> acwest wrote >> > I would probably have to look over my code again, my printer has been >> > offline for a while due to reorganising my apartment and replacing my >> main >> > board. >> > Generally increasing the preload should help, though. Some of the >> problem >> > is that the smaller pins can't generate as much spring force due to >> > physical constraints >> > >> > On Tue, 21 Jan 2020, 21:27 adrianv, &lt; >> >> > avm4@ >> >> > &gt; wrote: >> > >> >> Has anybody experimented with these pins or pins like them? I just >> >> printed >> >> out the pins at the 3 recommended sizes (in PLA on a Prusa MK3) and >> with >> >> the >> >> defaults the "standard" pins make a snug joint. The "small" and >> "tiny" >> >> pins >> >> make a looser joint with less tension. I wonder what adjustment would >> >> tighten up the smaller pins (more preload? less clearance?), or how I >> >> would >> >> pick parameters for medium sized pins in between the "small" and >> >> "standard" >> >> ones. >> >> >> >> There are a few things I'm not sure I understand about the design, >> such >> >> as >> >> the "preload" which both moves the nubs and shrinks the length. >> >> Shouldn't >> >> these be independent? (Shrinking the length seems like it should be a >> >> function of clearance rather than another parameter.) >> >> >> >> >> >> acwest wrote >> >> > The best way to find out how the snap pins work is to print Emmet's >> >> gear >> >> > cube https://www.thingiverse.com/thing:213946 >> >> > There are two versions of the hole inset, one which allows rotation >> and >> >> > one >> >> > which is fixed. They hold very solidly, but can be pulled apart with >> >> > enough >> >> > effort. The smallest I have been able to make useful pins is 4mm >> long >> >> with >> >> > a 2.5mm diameter, anything smaller than that is too fragile to use. >> >> > The fully customisable pins are at >> >> > https://www.thingiverse.com/thing:3218332, >> >> > and the output options include a test socket you can print to try >> it... >> >> > The >> >> > code generates an STL for the pin, which is printed flat, and an STL >> >> for >> >> > the socket, which is difference'd from the surface you want to embed >> >> the >> >> > pin in. >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> Sent from: http://forum.openscad.org/ >> >> >> >> _______________________________________________ >> >> OpenSCAD mailing list >> >> >> >> > Discuss@.openscad >> >> >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> >> >> > >> > _______________________________________________ >> > OpenSCAD mailing list >> >> > Discuss@.openscad >> >> > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> >> >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> > Discuss@.openscad >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > > _______________________________________________ > OpenSCAD mailing list > Discuss@.openscad > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- Sent from: http://forum.openscad.org/