The indents and cutouts in the injection moulded part aren't only originally there to save on material cost but more importantly to preserve shape when casting, since the demoulding shrinkage causes thick parts to dimple and warp. Just something engineers get drilled into them pretty hard to always design with near-constant wall thickness. Absolutely love your redesign.
@@joserafael9913 When injection molding parts you need to keep in mind how they will cool after injection. If a part has a thick section, it will cool slower than a thinner section and this can cause warping. To prevent this, during design, a part that will be injection molded should be designed to have close to constant wall thickness wherever possible to prevent or reduce warping during cooling.
Imagine a sphere that can fit inside your part and grows or shrinks so that it always touches the outside. This sphere represents the shortest cooling path for the plastic at the center and the radius of the sphere is pretty indicative of how long it will take to cool. You want your part to cool at the same rate because as it cools it shrinks and if you have leftover hot pockets those end up shrinking late and creating areas of internal tension. If the internal compression and tension aren’t perfectly balanced the part will warp.
"... vor allem der Formerhaltung beim Gießen" stimmt sicher im Prinzip, aber im Fall dieses speziellen Teiles nicht. Im Gegenteil, eine leichte Delle auf den beiden Seiten würde das Herausziehen aus der Werkbank erleichtern. Bei Modellbauern zählt aber Gewichtsersparnis und so ist dieses Video sehr hilfreich. Meine B&D-Werkbank stammt noch aus den 1970er Jahren und restlos hinüber sind nur die Kunststoffteile an den Füßen. Bei Thingiverse gibt es dafür STLs, aber bei der Wahl des Kunststoffes muss man sehr wählerisch sein. Ich habe mir Gussformen gedruckt und will mit Heißklebern experimentieren.
I have spent the last couple weeks trying to find a process for 3D printing a replacement fan blade that has a larger radius but kept have rubbing issues with parts I cannot remove and adding material to the fan itself kept making it untenable to 3D print. Finally I realized I just needed to print a mounting plate to got between the motor and the fan blade. The (hopefully) final version is printing right now. Design for the process indeed.
just fyi, injection molded parts are required to not have large areas of plastic, as they will take too long to cool and cause sink marks on the surface, thats why there are "lightening cuts" its not because of material cost.
I love the mad scientist experimentation. So glad to see you redesigned it, because the first thought I had was it was a bad design with weak points. Chamfers and fillets are our friends. Great work.
Excellent video, as an industrial designer & professional model maker in the past, that was one of my first takeaways when I started designing for my first 3D printer 10 tears ago. I love making replacement parts and fixing stuff using my design skillset, and working with the limitations of FDM printing to achieve results. You're doing a great job of educating the masses, with those subtle bits of trickery.
@@albarqak Never noticed the typo, but funny though, as mistakes are what you often learn the most from aka the "tears" :) I must admit I often 3D print stuff before I commit to CNC. It's surprising despite your best efforts, how much you can improve after looking at a model, especially when it's an assembly
I made a button like that to replace my broken microwave door button. Mine had the same problem with weak tangs but all I needed to do was to change the print orientation so that the layer lines are in the long dimension so if turned out very strong. The side effect was that the face of the button was now lined instead of the prefect flat face it previously was. But that was not a big issue and the button has been in my microwave for months now. It actually did break once but I adjusted something (I forgot what, some dimension) to make it more reliable and now it's good. One of the things I added was to fillet the base of the tang to give it a little bit more material and that made a big difference.
Thats cool! Actually did some "remelting" experiments some months ago as well. I tried embedding printed parts into one-time-use "temporary" molds, being a) compressed salt powder and b) heat-resistant silicone. interestingly, my primary issue as well was plastic "bubbling" out of the form. So I am pretty sure this was not related to the release agent you used. I was able to minimize the issue by tempering the part at 90°C , moisture seems to be the primary issue. But also any air caught inside will expand! And the plastic itself too, to some degree. PC and PETG was affected heavily by this. PLA worked much better. But I never got rid of it entirely. I stopped further experiments because I think I've found an alternative solution for my use case. But I really hope to see more insight and progress on this topic in the future. Would be so powerful to reach isotropic/injection molded quality!
As you mentioned salt you got me curious! I've seen recently some experiments on annealing 3d printed parts and I've been thinking about trying that but with the part suspended in fine salt and heating the salt around it as evenly as possible with temperature sensors close to the part, have you tried something quite like this or was the setup different? Does it anneal the part in a similar manner as they do with injection molded parts?
A couple of comments - as an industrial designer it is common to add some "jack screws" to the mold half to facilitate disassembly. If you added a couple of threaded inserts into the your molds you could use them to separate the two halves instead of hammering on a screwdriver. Alternatively, you could mold a couple of reliefs into the joint area to provide a place for the screwdriver to slide into. 2nd - I can see extending this idea to create some custom clamps to hold specific shapes more securely. Great video.
I’m impressed with your matte PLA version. Matte filament typically has worse layer adhesion than standard PLA, but with your design improvements, those kicked ass. I’d probably used something with glass or carbon fiber though, particularly for a workshop part like that.
Instead of printing moulds you could use salt annealing. You pack the part in salt and then put it in the oven. That way you don't need a mould for each different part. CNC Kitchen tried this with good results. The biggest problem was the coarseness of the salt patterning the surface of the part. Maybe there is a finer material that could replace the salt. Or as you say just design the parts better for 3D printing. Great video. Keep up the good work.
Good call. You could just grind the salt finer in a spice grinder to fix the surface quality issue. Plus it would help it pack better. It would be interesting to test the new design in PLA and PTEG CF/GF and salt anneal it to see the strength difference.
I used the salt method to remelt and fuse printed PETG parts with success. You should give it a try if you haven't already. Small features became rather tough and stretched quiet a bit instead of snapping off.
I haven't tried this, but for separating those molds, you might try designing in some jack screws. Put some more threaded inserts into the face that touches the other half of the mold, but put the clearance hole for the screw through the same half instead of the opposite half. On the opposite half, you might want to put a recess to glue in a bit of metal for wear resistance (a washer for a smaller-diameter screw perhaps). Then, when demolding, thread in a screw and use it to bear against the opposite half.
I will say when it comes to annealing or reforming parts temperature and rate is everything. It's not universal either for those unclear about this process, it is material specific and can be very finicky. Petg does expand when heated, that's why it warps and changes translucency if it is clear. The stress is so great in petg sometimes it really can't be fully relieved. The only way around it is high printing temps and a heated chamber. The cooling causes it to shrink at the outside quicker so if you can slow that down you get a much more stable part. It's fun stuff to play with because it is such a challenge.
I personally would love a way to injection mold stuff not because I need something that can only be injection molded but because I have dozens of kilograms of support material and failed prints that I could recycle that way
Have you watched the Teaching Tech videos about his journey with this? Wasn't a huge success if I recall but was quite interesting. It seems like turning the scraps into new filament might be a better way, but you have to have kept your different plastics separated otherwise you have issues in the extrusion and then printing process.
@@BenWolkWeiss the problem with recycling back to filament is that even if it's clean it's still going to be much lower quality than from a manufacturer, and unless you want to convert an old 3d printer to a filament machine you'd be spending way more than you're ever going to make back. I've seen a few creators attempt both filament extrusion and injection molding, and it never seems useful enough to invest money in sadly
Make 2 part molds from plaster of paris or other dedicated casting plasters, or casting rubbers/silivones made for low temp metal or wax castings. Bake clean plastic scraps into molds in a convection oven. Profit (rather reduce loss). I bake HDPE/LDPE scraps with some virgin plastic in non stick pans to make big blocks of recycled plastic.
thanks for posting failures. it is a valued lesson learnt that not often seen on YT. now I know a superior design works better than going through tough methods of enhancing the material. we all kind of learned from the failures in this video and I find value in it. thanks for sharing
Seeing how you re-designed this to be more appropriate for it's fabrication method was really helpful as a mindset to keep in for the future - especially with such impressive results after!
I learned a neat new trick to heat set inserts, Press the side of the soldering iron (or use a chisel tip) against the insert but dont push it in. When it starts to melt the plastic and falls into it a little use a flat block (like wood) to press it in and it should fit flush without trimming. If I was to guess why its hollow is because there was air in the part and it expanded during heating. As in it wasn't solid (I've found 100% infill isnt always solid)
That's a cool idea and I'm glad you tried it even though it failed. It seems making a silicone mold of the part you want to reproduce and casing it in polyurethane would be a better way to go than a 3d printed annealing mold. Your final solution to redesign the part for optimal strength when printed is great.
I like the redesign features. Those tabs look significantly stronger with the curve to distribute the stress. The added spring was a cool idea as well.
when modeling the mould you should include a slot on each side which lets you get a screwdriver in between the halves on each side to lever them apart rather than having to hammer it in. if you use two screwdrivers at once (one on each side) then you're also not applying any twisting force so it should come apart easier
I feel like you could make silicone molds for annealing that would work pretty well. Just pour around your part, cut it in half, put it back together, and anneal. As long as you don't go super liquid it should hold everything together well enough. Bonus points for making the mold in a box that can be heated originally, so that you have even less chance of any pressure pushing the mold out of shape.
The fundamental design problems with the red snap piece is the that the snap tabs have HUGE stress points where you have a right angle. You need to chamfer the sides of the snap tabs so that the stress is distributed and there is more reinforcement at the tab-base transition.
I am really impressed by this idea and the execution! Obviously plenty of room for improvement, but this is so cool. Redesigning the part before using the "mold" would also make the "molding" process easier I think. Don't really need the injection molding voids anymore for example. The results of the melted PETG were surprising to me and also the look was very unsettling. I would like to see some ABS tests with some tweaks to the execution. I was wondering if the part partially melting and getting into all the voids and rough surface of the mold would be an issue. Dialing in the temperature just right may be important. Good stuff!
Don't forget too, there are geometries you can't get with injection molding you can get with 3d printed parts, like serious undercuts and threads. Some molded parts with these features are VERY expensive to make molds for. Strengthening 3d printed parts is a cool exercise.
I use Plaster of Paris to mould my parts. Print the part, completely encase it in plaster, dry the plaster thoroughly, then bake at the melting point of the printed plastic. Chip away the plaster bulk, then soak the part in baking soda to dissolve the remaining plaster. Works great, but requires about a week total and is a total loss for the moulds. You don't get the part distortion that is common with salt or sand baths, and you don't get mould fouling. Still, it's a huge time investment, so you really have to want the parts re-flowed to eliminate the weak layers.
for the removing process: instead of just holes Inwould try the heat inserts, so that a longer bolt will slowly push out the part. maybe even backed by a plate to spread the bolt pressure does that make sense?
Why would you even use the pins in the first place ? They are there to make an injection molding process possible but since you 3D print the part, just change the geometry instead. Your final design though is pretty good, well done.
Using a resin printer with a rigid high temp resin might make for a good injection mold, but you’ll need the molding machine for that too. Ultimately design intent is the best thing for adapting to 3D printing since you need to make very different compromises from injection molding.
Great video. I have a workmate with not enough dogs so this will be great to try printing. I think I'll do it in PTEG though for the increased ductility vs PLA.
thanks for this! interesting approach to "reworking" a 3D print into an injection moulded one... 🤔 I wonder if it would be worth trying to seal the 3D printed PLA part in a 2-part silicone mold for remelting... I imagine it'd be rigid enough & a lot easier to demold ... hope you can give this a shot & looking forward to your next informative video!
I think you can increase the process efficiency if you add a flow channel pointing up that is filled with plastic, compensating the shrinkage and allowing bubbles to excavate. Also, would be great if you add a weight of some kind in the flow channel that puts pressure on the plastic.
When annealing you should probably use a temp below the printing temp. If you use 140C for printing, try annealing at 100-120C. Remelting is not really the goal, increasing layer adhesion is. A better option is usually to print multiple parts in different orientations and glue them together to get strength. It will never beat injection molding but is sometimes good enough.
Very interesting process. I took the simple road to replacing mine by making and/or replacing dogs using a hardwood block for the "Head" and hardwood dowel. I also made custom shaped "heads" for various holding methods. Made a box full in a hour. If they get chewed up, they go in the garbage.
Well on print where you need strength on both direction you should consider splitting the part and print the loaded section facing horizontal on the build plate. Then reinsert it into the original carcass and glue it tight. That way you have the strength of both worlds.
Love your vids man. Interesting idea. But I’ll just say I printed these in petg and they were fine, and if you printed in a high hardness tpu you’d never be able to break them! But I get that this was just a proof of concept for other future projects too.
@needitmakeit Take high Temp silicone. Print the part. Make a mold from silicone with the printed part. Take a 3d printer Toolhead. Drill a hole on the upside of the oven. Place the mold into the oven. Heat up the oven. Place the Toolhead on the drilled hole. Extrude the filament directly into the silicone mold.
One trick for stronger studs that have to be printed vertical is to design a small hole in it, far below the surface. Normal stud with fail by ripping the top layers it is printed on, by embedding a small hole it has an anchor point and you get the full strength of the layer adhesion.
Interesting. Would have been nice to see the same parts printed in regular PLA and tested as well. Carbon fiber supposedly makes everything more brittle.
All my comments/recommendations were actually adressed in the last redesign. It shows that in order to work as necessary, parts need to be redesigned for the manufacturing process.
Maybe another weak point to eliminate: Make the cylinder Solid to where the latches are and add an "inverted" Spring mechanism afterwards. This way, the clamping forces will not act on the Spring. 😊 Not sure if I described clear enough...
For part shrinkage could you do a calibration cube with a precise Z height setting to actually measure the shrinkage? If you print at a higher than ambient temp then the chamber temp shouldn't be a variable.
Have you tried casting the mold out of silicone and using that as the high temp mold for the 3D printed part mold? oomoo makes different 2part silicone molds that you can bake to higher temp.
As riba2233, what if we used this high temp plastic just as mould. With maybe a cone on the top to serve as a buffer for material, we could just put some plastic granulats and leave it melt and fill the mould in the oven with gravity.
@riba2233 I'm afraid it would start to make the thing complicated and it will reach the injection molding trigger what isn't a so easy task in diy I think. Anyway these new High Temp 3D printable polymers seems really cool.
Would've been interesting to strength test the injection molded parts for a baseline. In your tests the prongs broke along the layer lines - shouldn't you have had the layer lines perpendicular to the direction of force?
Engineering and problem solving in action! 💪💪💪 CF infused filament seems to be the way to go for absurdly strong parts but if it breaks, how safe is it to handle; will the fibres be problematic even after being printed?
I wonder if we can make a more "flex" mold, by using a strong metal box filled with sand, we can put the part into the sand box, compress the part with sand and put it inside the oven? If this method work, it will allow annealing with a little more complex part.
as a 3d printing project, this is pretty great. as a wood working fix, just use a hard wooden dowel that fits in the hole. most normal dogs are round dowels anyway, and the workmate only uses that weird shape so that you can get a very low edge on one side.
Wow neat I wonder if you built the mold from a diy cnc and aluminium, would the surface quality also resemble a professionally made injection molded part, without layer lines and all
My good guess is that PET-G expands a great deal when heated. Expanding and pushing out when heated...then when it cools and attempts to retract..it can't since the outer shell hardened..so that creates a negative pressure inside the cavity. This negative internal pressure can cause one or both of the following defects in a molded part. 1. Recessed surface or "sunk-in" appearance. : This is caused by negative internal pressure pulling in "frozen" (no longer) plastic from the cavity wall in away from the mold surface. Indicated by the surface texture of void or sink. And/-Or- a cavity or internal area void of plastic..like air..or other product gasses. AKA A hollow part.
You might be able to pull it off inside a pressure cooker (so to speak) The issue is handled in injection molding with "pack pressure" along with temperature. It's been a few decades..but I do believe an air compressor would provide sufficient pressure to potentially help resolve voids and hollows.🤷♂
Мне кажется формы для литья лучше делать на фотополимерном принтере, можно просто поэкспериментировать с закалкой - довести чуть выше температуры стеклования и плавно остудить, например для pla около 70 градусов на пол часа - час. Если страшно за форму можно поместить в соль или мелкий песок)
Very interesting.. but why not creating a rib between the two endpoints? They need to flex just a bit, but they do not need to be exact copy of the original molded part. However, love the experiment…thanks you for sharing?
To me, PLA is best suited for decorations and toys. I wouldn't make anything functional out of anything less than PETG but typically I'd move to to engineering filaments such as PA-GF, PA-CF or maybe even PC.
Need to dry the parts before putting into your annealing chamber, something much lower in temperature so only the moisture dissipates and doesn't cause shape changes. Also where did the 150°C annealing temperature come from? Should be doable 30-40°C less than that. If looking to reflow the material than designing oversize for shrinkage is critical since even at 100% infill, its not truly homogenous like an injection molded part due to many small interstitial spaces.
The indents and cutouts in the injection moulded part aren't only originally there to save on material cost but more importantly to preserve shape when casting, since the demoulding shrinkage causes thick parts to dimple and warp. Just something engineers get drilled into them pretty hard to always design with near-constant wall thickness. Absolutely love your redesign.
Hi, i dont understand the constant thickness relation with shrinkage, would you mind to explain, Thanks!
@@joserafael9913 When injection molding parts you need to keep in mind how they will cool after injection. If a part has a thick section, it will cool slower than a thinner section and this can cause warping. To prevent this, during design, a part that will be injection molded should be designed to have close to constant wall thickness wherever possible to prevent or reduce warping during cooling.
Imagine a sphere that can fit inside your part and grows or shrinks so that it always touches the outside. This sphere represents the shortest cooling path for the plastic at the center and the radius of the sphere is pretty indicative of how long it will take to cool.
You want your part to cool at the same rate because as it cools it shrinks and if you have leftover hot pockets those end up shrinking late and creating areas of internal tension. If the internal compression and tension aren’t perfectly balanced the part will warp.
"... vor allem der Formerhaltung beim Gießen" stimmt sicher im Prinzip, aber im Fall dieses speziellen Teiles nicht. Im Gegenteil, eine leichte Delle auf den beiden Seiten würde das Herausziehen aus der Werkbank erleichtern.
Bei Modellbauern zählt aber Gewichtsersparnis und so ist dieses Video sehr hilfreich.
Meine B&D-Werkbank stammt noch aus den 1970er Jahren und restlos hinüber sind nur die Kunststoffteile an den Füßen. Bei Thingiverse gibt es dafür STLs, aber bei der Wahl des Kunststoffes muss man sehr wählerisch sein.
Ich habe mir Gussformen gedruckt und will mit Heißklebern experimentieren.
The last ~5 minutes are the most important part. Design for the process!
Да! Вступление затянулось )
I have spent the last couple weeks trying to find a process for 3D printing a replacement fan blade that has a larger radius but kept have rubbing issues with parts I cannot remove and adding material to the fan itself kept making it untenable to 3D print. Finally I realized I just needed to print a mounting plate to got between the motor and the fan blade. The (hopefully) final version is printing right now. Design for the process indeed.
just fyi, injection molded parts are required to not have large areas of plastic, as they will take too long to cool and cause sink marks on the surface, thats why there are "lightening cuts" its not because of material cost.
I love the mad scientist experimentation.
So glad to see you redesigned it, because the first thought I had was it was a bad design with weak points. Chamfers and fillets are our friends. Great work.
While using PPS-GF as a mold was cool, highlight of the video was seeing your approach to redesigning the part for 3D printing :)
Excellent video, as an industrial designer & professional model maker in the past, that was one of my first takeaways when I started designing for my first 3D printer 10 tears ago. I love making replacement parts and fixing stuff using my design skillset, and working with the limitations of FDM printing to achieve results. You're doing a great job of educating the masses, with those subtle bits of trickery.
I agree; Real experience is measured in "tears" not years 👍🥲🥲🥲
@@albarqak Never noticed the typo, but funny though, as mistakes are what you often learn the most from aka the "tears" :) I must admit I often 3D print stuff before I commit to CNC. It's surprising despite your best efforts, how much you can improve after looking at a model, especially when it's an assembly
Last redesign montage put a smile on my face. [ Chef's kiss ]
In conclusion, redesigning for FDM is better than annealing. Easier too, since if one breaks you can just print another one. Great work.
I made a button like that to replace my broken microwave door button. Mine had the same problem with weak tangs but all I needed to do was to change the print orientation so that the layer lines are in the long dimension so if turned out very strong. The side effect was that the face of the button was now lined instead of the prefect flat face it previously was. But that was not a big issue and the button has been in my microwave for months now. It actually did break once but I adjusted something (I forgot what, some dimension) to make it more reliable and now it's good. One of the things I added was to fillet the base of the tang to give it a little bit more material and that made a big difference.
Thats cool! Actually did some "remelting" experiments some months ago as well. I tried embedding printed parts into one-time-use "temporary" molds, being a) compressed salt powder and b) heat-resistant silicone. interestingly, my primary issue as well was plastic "bubbling" out of the form. So I am pretty sure this was not related to the release agent you used.
I was able to minimize the issue by tempering the part at 90°C , moisture seems to be the primary issue. But also any air caught inside will expand! And the plastic itself too, to some degree.
PC and PETG was affected heavily by this. PLA worked much better.
But I never got rid of it entirely. I stopped further experiments because I think I've found an alternative solution for my use case.
But I really hope to see more insight and progress on this topic in the future.
Would be so powerful to reach isotropic/injection molded quality!
As you mentioned salt you got me curious! I've seen recently some experiments on annealing 3d printed parts and I've been thinking about trying that but with the part suspended in fine salt and heating the salt around it as evenly as possible with temperature sensors close to the part, have you tried something quite like this or was the setup different? Does it anneal the part in a similar manner as they do with injection molded parts?
What was your alternative solution?
Why not just print a master, and use silicone molds and polyester/polyurethane casting resin to cast the part?
A couple of comments - as an industrial designer it is common to add some "jack screws" to the mold half to facilitate disassembly. If you added a couple of threaded inserts into the your molds you could use them to separate the two halves instead of hammering on a screwdriver. Alternatively, you could mold a couple of reliefs into the joint area to provide a place for the screwdriver to slide into.
2nd - I can see extending this idea to create some custom clamps to hold specific shapes more securely. Great video.
I’m impressed with your matte PLA version. Matte filament typically has worse layer adhesion than standard PLA, but with your design improvements, those kicked ass. I’d probably used something with glass or carbon fiber though, particularly for a workshop part like that.
I think what you are thinking of as matt is fiber filled.
Modern matte filament isn’t the same as older filaments and is otherwise tougher than regular PLA in a lot of cases
I think this could work great with the part cast in plaster instead of a printed mold.
Not working well, cnckitchen tried this already and it was a f*n mess 🫨😵💫
Instead of printing moulds you could use salt annealing. You pack the part in salt and then put it in the oven. That way you don't need a mould for each different part. CNC Kitchen tried this with good results. The biggest problem was the coarseness of the salt patterning the surface of the part. Maybe there is a finer material that could replace the salt. Or as you say just design the parts better for 3D printing.
Great video. Keep up the good work.
Good call. You could just grind the salt finer in a spice grinder to fix the surface quality issue. Plus it would help it pack better. It would be interesting to test the new design in PLA and PTEG CF/GF and salt anneal it to see the strength difference.
@@BenWolkWeiss You can buy flour salt.
Those tabs break because they unconstrained, add an additional tab between the two flextures to limit how far they can bend.
and he did if you watched the whole video - but very good point!
I used the salt method to remelt and fuse printed PETG parts with success. You should give it a try if you haven't already. Small features became rather tough and stretched quiet a bit instead of snapping off.
I haven't tried this, but for separating those molds, you might try designing in some jack screws. Put some more threaded inserts into the face that touches the other half of the mold, but put the clearance hole for the screw through the same half instead of the opposite half. On the opposite half, you might want to put a recess to glue in a bit of metal for wear resistance (a washer for a smaller-diameter screw perhaps). Then, when demolding, thread in a screw and use it to bear against the opposite half.
I will say when it comes to annealing or reforming parts temperature and rate is everything. It's not universal either for those unclear about this process, it is material specific and can be very finicky.
Petg does expand when heated, that's why it warps and changes translucency if it is clear. The stress is so great in petg sometimes it really can't be fully relieved. The only way around it is high printing temps and a heated chamber. The cooling causes it to shrink at the outside quicker so if you can slow that down you get a much more stable part. It's fun stuff to play with because it is such a challenge.
I personally would love a way to injection mold stuff not because I need something that can only be injection molded but because I have dozens of kilograms of support material and failed prints that I could recycle that way
Recycling companies are slowly coming up with ways to recycle failed prints and unused filaments as a service but its so slow...
Have you watched the Teaching Tech videos about his journey with this? Wasn't a huge success if I recall but was quite interesting. It seems like turning the scraps into new filament might be a better way, but you have to have kept your different plastics separated otherwise you have issues in the extrusion and then printing process.
@@BenWolkWeiss the problem with recycling back to filament is that even if it's clean it's still going to be much lower quality than from a manufacturer, and unless you want to convert an old 3d printer to a filament machine you'd be spending way more than you're ever going to make back.
I've seen a few creators attempt both filament extrusion and injection molding, and it never seems useful enough to invest money in sadly
Make 2 part molds from plaster of paris or other dedicated casting plasters, or casting rubbers/silivones made for low temp metal or wax castings. Bake clean plastic scraps into molds in a convection oven. Profit (rather reduce loss). I bake HDPE/LDPE scraps with some virgin plastic in non stick pans to make big blocks of recycled plastic.
thanks for posting failures. it is a valued lesson learnt that not often seen on YT. now I know a superior design works better than going through tough methods of enhancing the material. we all kind of learned from the failures in this video and I find value in it. thanks for sharing
Seeing how you re-designed this to be more appropriate for it's fabrication method was really helpful as a mindset to keep in for the future - especially with such impressive results after!
I learned a neat new trick to heat set inserts, Press the side of the soldering iron (or use a chisel tip) against the insert but dont push it in. When it starts to melt the plastic and falls into it a little use a flat block (like wood) to press it in and it should fit flush without trimming.
If I was to guess why its hollow is because there was air in the part and it expanded during heating. As in it wasn't solid (I've found 100% infill isnt always solid)
The newly design part looks perfect for me. Thanks!
Not a failed experiment. You succeeded at showing the best way to handle this, which in this case was to re-design the part.
I like the way you redesigned the part to print it and have it function better.
Fascinating. TY for putting in the time and effort in the experiment, as well as producing a video to share it with us.
That's a cool idea and I'm glad you tried it even though it failed. It seems making a silicone mold of the part you want to reproduce and casing it in polyurethane would be a better way to go than a 3d printed annealing mold. Your final solution to redesign the part for optimal strength when printed is great.
I like the redesign features. Those tabs look significantly stronger with the curve to distribute the stress. The added spring was a cool idea as well.
Thank you for sharing this fantastic video and 3D print design!
Outstanding design and really interesting results!
Great Video, I can't believe I never seen one of your videos, this one definitely made me suscribe. Good job!
Oh boy you were so close to my idea, using pps-cf as a mold for sunlu pla meta which prints as low as 170c, very cool vide0
when modeling the mould you should include a slot on each side which lets you get a screwdriver in between the halves on each side to lever them apart rather than having to hammer it in. if you use two screwdrivers at once (one on each side) then you're also not applying any twisting force so it should come apart easier
I feel like you could make silicone molds for annealing that would work pretty well. Just pour around your part, cut it in half, put it back together, and anneal. As long as you don't go super liquid it should hold everything together well enough. Bonus points for making the mold in a box that can be heated originally, so that you have even less chance of any pressure pushing the mold out of shape.
improved model didn't have complete failure, very good sir.
The fundamental design problems with the red snap piece is the that the snap tabs have HUGE stress points where you have a right angle. You need to chamfer the sides of the snap tabs so that the stress is distributed and there is more reinforcement at the tab-base transition.
I am really impressed by this idea and the execution! Obviously plenty of room for improvement, but this is so cool. Redesigning the part before using the "mold" would also make the "molding" process easier I think. Don't really need the injection molding voids anymore for example. The results of the melted PETG were surprising to me and also the look was very unsettling. I would like to see some ABS tests with some tweaks to the execution. I was wondering if the part partially melting and getting into all the voids and rough surface of the mold would be an issue. Dialing in the temperature just right may be important. Good stuff!
Good example why functional design is most important. Thanks for the experiment. I would have never considered exploring that option
Thank you for taking the time to make this part. Like you, I love my Workmate but can't always keep track of the dogs.
Don't forget too, there are geometries you can't get with injection molding you can get with 3d printed parts, like serious undercuts and threads. Some molded parts with these features are VERY expensive to make molds for. Strengthening 3d printed parts is a cool exercise.
I use Plaster of Paris to mould my parts. Print the part, completely encase it in plaster, dry the plaster thoroughly, then bake at the melting point of the printed plastic. Chip away the plaster bulk, then soak the part in baking soda to dissolve the remaining plaster. Works great, but requires about a week total and is a total loss for the moulds. You don't get the part distortion that is common with salt or sand baths, and you don't get mould fouling. Still, it's a huge time investment, so you really have to want the parts re-flowed to eliminate the weak layers.
for the removing process: instead of just holes Inwould try the heat inserts, so that a longer bolt will slowly push out the part. maybe even backed by a plate to spread the bolt pressure
does that make sense?
Why would you even use the pins in the first place ? They are there to make an injection molding process possible but since you 3D print the part, just change the geometry instead.
Your final design though is pretty good, well done.
Save material too maybe.
Tho the same could be achieved with modifiers instead. Make the thing that flexes 100% solid and everything else hollow.
@@Splarkszter Exactly, for 3D printing, ribs and such are irrelevant.
Using a resin printer with a rigid high temp resin might make for a good injection mold, but you’ll need the molding machine for that too. Ultimately design intent is the best thing for adapting to 3D printing since you need to make very different compromises from injection molding.
Great video. I have a workmate with not enough dogs so this will be great to try printing. I think I'll do it in PTEG though for the increased ductility vs PLA.
thanks for this! interesting approach to "reworking" a 3D print into an injection moulded one...
🤔 I wonder if it would be worth trying to seal the 3D printed PLA part in a 2-part silicone mold for remelting... I imagine it'd be rigid enough & a lot easier to demold ... hope you can give this a shot & looking forward to your next informative video!
I think you can increase the process efficiency if you add a flow channel pointing up that is filled with plastic, compensating the shrinkage and allowing bubbles to excavate. Also, would be great if you add a weight of some kind in the flow channel that puts pressure on the plastic.
When annealing you should probably use a temp below the printing temp. If you use 140C for printing, try annealing at 100-120C. Remelting is not really the goal, increasing layer adhesion is. A better option is usually to print multiple parts in different orientations and glue them together to get strength. It will never beat injection molding but is sometimes good enough.
Very interesting process. I took the simple road to replacing mine by making and/or replacing dogs using a hardwood block for the "Head" and hardwood dowel. I also made custom shaped "heads" for various holding methods. Made a box full in a hour. If they get chewed up, they go in the garbage.
Well on print where you need strength on both direction you should consider splitting the part and print the loaded section facing horizontal on the build plate. Then reinsert it into the original carcass and glue it tight. That way you have the strength of both worlds.
Love your vids man. Interesting idea. But I’ll just say I printed these in petg and they were fine, and if you printed in a high hardness tpu you’d never be able to break them! But I get that this was just a proof of concept for other future projects too.
Was this 3d printed or injection molded?
Needitmakeit: Yes
It’s such a good channel, I’m so glad it’s not another cooling nozzle video.
@needitmakeit
Take high Temp silicone. Print the part. Make a mold from silicone with the printed part. Take a 3d printer Toolhead. Drill a hole on the upside of the oven. Place the mold into the oven. Heat up the oven. Place the Toolhead on the drilled hole. Extrude the filament directly into the silicone mold.
Instead of whacking it open, use compressed air.
One trick for stronger studs that have to be printed vertical is to design a small hole in it, far below the surface. Normal stud with fail by ripping the top layers it is printed on, by embedding a small hole it has an anchor point and you get the full strength of the layer adhesion.
Can you elaborate more on that idea?
Sounds interesting
Interesting. Would have been nice to see the same parts printed in regular PLA and tested as well. Carbon fiber supposedly makes everything more brittle.
All my comments/recommendations were actually adressed in the last redesign. It shows that in order to work as necessary, parts need to be redesigned for the manufacturing process.
You probably didnt need the spring loaded mechanism. Just a solid round peg with friction fit
Maybe another weak point to eliminate: Make the cylinder Solid to where the latches are and add an "inverted" Spring mechanism afterwards. This way, the clamping forces will not act on the Spring.
😊 Not sure if I described clear enough...
Thank you I will print some for my workbench!
Instead of printing the final piece flat, I'd try printing it at 45 degrees with tree support so that the layers aren't the weak point.
For part shrinkage could you do a calibration cube with a precise Z height setting to actually measure the shrinkage? If you print at a higher than ambient temp then the chamber temp shouldn't be a variable.
why not just change the orientation so that potential layer breaks would be less likely to occur?
Because that wasn't the purpose of this experiment.
excellent work!
Thanks for the video and the files!
Could you use casting sand or something similar to anneal the parts?
I like your way of teaching great video o will be following you from now on
Have you tried casting the mold out of silicone and using that as the high temp mold for the 3D printed part mold? oomoo makes different 2part silicone molds that you can bake to higher temp.
As riba2233, what if we used this high temp plastic just as mould. With maybe a cone on the top to serve as a buffer for material, we could just put some plastic granulats and leave it melt and fill the mould in the oven with gravity.
Or just use a powerful extruder to pump it in :)
@riba2233 I'm afraid it would start to make the thing complicated and it will reach the injection molding trigger what isn't a so easy task in diy I think. Anyway these new High Temp 3D printable polymers seems really cool.
I've seen lower quality filaments with CF having many voids, that may have been your PETG-CF expansion issue.
What if you just cast plaster around it before baking? Having a material you can soak off would avoid the oil, however you are exposing to water.
Would've been interesting to strength test the injection molded parts for a baseline. In your tests the prongs broke along the layer lines - shouldn't you have had the layer lines perpendicular to the direction of force?
You might want to look into powdered salt annealing, instead of printed molds
That wasn't the point of this video.
Engineering and problem solving in action! 💪💪💪
CF infused filament seems to be the way to go for absurdly strong parts but if it breaks, how safe is it to handle; will the fibres be problematic even after being printed?
What about making a silicone mold for the annealing?
IMHO this is high temp resin's best use case.
I wonder if we can make a more "flex" mold, by using a strong metal box filled with sand, we can put the part into the sand box, compress the part with sand and put it inside the oven? If this method work, it will allow annealing with a little more complex part.
Why would you use PETg or PLA for the clamps that will need force? Why not print is in PETF-CF or ABS-GF or the Nylon filament?
as a 3d printing project, this is pretty great. as a wood working fix, just use a hard wooden dowel that fits in the hole. most normal dogs are round dowels anyway, and the workmate only uses that weird shape so that you can get a very low edge on one side.
Using carbon fiber dowels (wood) in your projects is pretty useful. Adding dowel inside your 3D print can make it very strong.
Is that oven accurate enough?.... Usually the temp control on those ovens is pretty bad. They can fluctuate by plus or minus 25 degrees.
Can you do the same thing with a complete captured plaster of Paris cast?
you are gem man im glad that i found your chanell
the last parts of the video
were amazing
Smart re-design ! 3D printing requires more brain than printing in itself.
Wow neat
I wonder if you built the mold from a diy cnc and aluminium, would the surface quality also resemble a professionally made injection molded part, without layer lines and all
My good guess is that PET-G expands a great deal when heated. Expanding and pushing out when heated...then when it cools and attempts to retract..it can't since the outer shell hardened..so that creates a negative pressure inside the cavity. This negative internal pressure can cause one or both of the following defects in a molded part. 1. Recessed surface or "sunk-in" appearance. : This is caused by negative internal pressure pulling in "frozen" (no longer) plastic from the cavity wall in away from the mold surface. Indicated by the surface texture of void or sink. And/-Or- a cavity or internal area void of plastic..like air..or other product gasses. AKA A hollow part.
You might be able to pull it off inside a pressure cooker (so to speak) The issue is handled in injection molding with "pack pressure" along with temperature. It's been a few decades..but I do believe an air compressor would provide sufficient pressure to potentially help resolve voids and hollows.🤷♂
Great video Mike. Always look forward to your next video. And...Thanks for the improved work clamp/dog. How is that QiDi holding up?
You should consider using a screw as rebar
Devil Scooby Doo 😂.
I am satisfied with the strength of the parts printed without any filling at all. I fill them with epoxy resin with filler and reinforcement.
What kind of filler? Thanks.
@@michaels3003 Portland cement
My question is why you didn't also try using a master mold made from metal. I would imagine you could do the oven bake with them very effectively.
it could be usefull to use this methond on a small scale parts, when there is no much room for redesigning or finding best orientation to 3d print
Мне кажется формы для литья лучше делать на фотополимерном принтере, можно просто поэкспериментировать с закалкой - довести чуть выше температуры стеклования и плавно остудить, например для pla около 70 градусов на пол часа - час. Если страшно за форму можно поместить в соль или мелкий песок)
Very interesting.. but why not creating a rib between the two endpoints? They need to flex just a bit, but they do not need to be exact copy of the original molded part. However, love the experiment…thanks you for sharing?
Haha… I should have waited until the end of the video…;-)
To me, PLA is best suited for decorations and toys. I wouldn't make anything functional out of anything less than PETG but typically I'd move to to engineering filaments such as PA-GF, PA-CF or maybe even PC.
Really interesting ideas
Need to dry the parts before putting into your annealing chamber, something much lower in temperature so only the moisture dissipates and doesn't cause shape changes. Also where did the 150°C annealing temperature come from? Should be doable 30-40°C less than that. If looking to reflow the material than designing oversize for shrinkage is critical since even at 100% infill, its not truly homogenous like an injection molded part due to many small interstitial spaces.
Injection mold dies are highly polished and that does make a huge difference when it comes to part release.
PPS parts really need to be annealed to allow all layer lines to fuse together.
An interesting continuation of this would be investment casting the printed part, then baking and dissolving the investment away