need escape path for air and excess plastic

Hey Stephan do you have spare shredder? I need one shredder but I have financial problems 😅

I did the same using 3D printing methods towards injection molding. And I have learned ups and downs. I have been in your road using resin printing and no success. the reason is the material selection of the mold. it has to be metal to accomplish this. I tried resin with basic and heat resistance. However, the heat of the melted plastic that your injecting will weaken the resin structure and the resin will brittle over time and use. So, I used resin mold to do the casting method and the direction I did was spot on but still working on closing it. Right now, I am having issues with the injection machine, but I got good tips and do another method. hope this helps out.

It has been my experience that Calcium Chloride (DampRid) in a airtight container under slight vacuum Works exceptionally well. I put it in a small plastic container that has a perforated top with a sponge in the bottom because it turns to liquid as it absorbs moisture. You can recycle this stuff if you let it dry out in the sun or put it in an oven. I have considered trying to use displacement gases but I haven't found any good generators

I'd suggest using the Artme3D extrusion auger from your filament recycling line. Comes close to the real stuff an you can achieve more pressure and flow. +using scraps. I currently think about buying the artme 3d kit just for the extrusion mechanism, as i wanted a desktop injection molder for a long time. Just there was no extrusion auger.🎉

at this point why not just cut fillaments and bake it with the mold in oven?

I agree with all the other comments to improve this, but I don't see anyone saying to drill out/increase the printer heads injection hole size.

What about the holipress ? Test it 😉

Try heating the mold. This would be a great use for peltier heater, and you would be less dependent on the extruder temp.

Moulds need a breather hole to allow the air to escape, rather than just trying to compress the air in the mould

Would adding vent holes help the plastic flow to the far ends and corners?

Can you use a vacuum to pull the pla through the form quicker?

Did you take into account the need for a micro-riser? I think as the PLA is cooling, a very small release in pressure would assist in filling the "bottom end" of the mold.

1. You can use a drilled screw instead of a regular nozzle and a thread, printed on the mold, to make the seal better. 2. Making vent holes, to prevent air pressure building up inside the mold. 3. Putting the mold inside a glass of boiling water (heated up with the print bed), to ensure constant 100 degrees of heat, that should be enough, for the PLA or PETG to stay a liquid. You can also add salt to the water to slightly increase the boiling tempreture. Or even switch to glycerin instead of water, since it has significantly higher boiling point (about 290 degrees). 4. Using multiple extruders and multiple plastic input ports may help with complex shapes, but it would require something more than a regular glass as a liquid container, probably some ceramic dish with drilled holes for input "nozzles".

How about an injection mold machine that can use purged filament? Thinking this may be a good DIY type project...

Also if you make your molds with the injection point in the middle of the model instead of top or bottom, maybe in the middle would give better results, by cooling more evenly, it seems that the plastic is cooling to fast in the molds after a certain distance, by placing the injection point in the middle of your molds you should be able to increase the distance that the plastic will travel before it cools! 😊 Just a thought!

Without sanding the molds, and having the lines from the printer on the pieces, would that create stress fracture points? Would they be stronger if the molds are smooth and sanded?

Die Idee schwirrt sein jahren in meinem Kopf. Endlich machts mal jemand.

Now that we have "bricks", all we need is to figure out "mortar" to fill the spaces that are still left.

Make a mold you can heat up and don't forget a vent hole! 👍 Awesome idea!!

As a fan of Lego who loves custom stuff... This could turn out to be a game changer for my hobby.

I wonder if it would make sense to design the mould with a void at the sprue so you can clamp it around the hot end. This would potentially increase the working pressure as the mould would stay in contact with the nozzle. Along with an air vent at the opposite end as others have suggested, so that you will know when the mould is completely filled.

I was wondering throughout the whole video this question. Wouldn’t it make more sense to use a basic screw and nut system in each corner instead of clamping the mould?together

you need some holes for air release. If dont have them, the plastics try to compress the air inside the mould and you have to make so much more effort for inject the plastic inside of the mould.

Suggestion, have a screw table to hold the mold up in place or rebuild an 'injection only' device from an old printer using its parts. Make the jaws 'active heat plates' that hold the mold in place with the clamp like you are currently using, and have a small bleed hole to let air out of the print cavity near the extreme portions of the part. Possibly make sacrificial spew to get material to 'far away' portions of the mold. For larger parts, set up to use multiple extruders with multiple ports on the mold to accept hot material. Great project and yet another set of rabbit holes to follow.

0:21

try to leave a small hole on the Mould to allow air leak for the pressure developed inside. Also smaller sprue helps to fill it faster before it solidifies halfway.

airlocks?

make a custom abs keycap

2 things. At the end of your hook, create a tiny air channel so the air can escape as you push plastics in. Otherwise I think the fluid plastic needs to fight the air pressure if the mold is to airtight. Secondly, put the mold against the build plate and turn its temp up real high, this will ensure longer fluent filament. Then lower the nozzle till it locks the nozzle against the molds entry point. This way you don't need to rely on your muscle strength for the pressure. It also allows for the pressure to go straight down and not diagonally. As added bonus, you don't risk hurting or burning yourself. As a bonus suggestion, calculate the volume of the object to mold and just push that amount of filament in.

how does the air inside the mold escape? maybe create a exit hole on the opposite end to reduce pressure requirement?

Here is a thought I had, what about the AIR still inside the mould itself, once you are injecting into this, that air that is still inside the mould is going to prevent the injected plastic from flowing better (much like how air can stop water from moving, causing air-lock on certain water pumps). I would recommend finding a way to add a small hole at the other end of the mould to allow this air to be pushed out as the plastic in being injected in, this should allow for less pressure being needed and will only need a small amount of clean-up once done. I do not 3D print stuff myself, but I do deal with AIR-LOCK quite often, which even on powerful machines can aften cause issues and could ruin the pump, to trying to remove the AIR-LOCK is a start.

Lol Looks like everyone beat me to the breather hole comment. But with no knowledge of 3d printing or injection molding it’s cool to see that my hypothesis was valid

Loved the banjo kazooie music reference!

Mvyed yzbi

Great video, make me think about the following: Why not make the mold of see through type plastic and surround the mold with high power UV LEDs. replace the hot end with a small peristaltic pump, pumping in UV sensitive resin. Once filled up you blast the fluid with UV light. This way you tackle the following problems: no extreme heat required and no high pressure.

oh man, wait until 3d printing companies start watermarking their prints

you need an air hole exit to allow the hot filament to make its way out with the air

Hello from Prague, I think orientation could be changed especially for the hooks. rotating 90° will shorten path that filament must flow. Preheating of form to correct melting temperature. Extruding from multiple sources could also help. Very interesting and definitely usable for some small parts. You could also fill inside of form with filament, heat to melting temperature and inject new mold into it to make pressure.

Why not have a custom nozzle to screw into the head, and also U need a vent

Can be ground down and used to make more filament? I really want to see that, but I can't find it anywhere. Just people making spools out of cardboard so they can be recycled the boring way.

you need a bigger nozzle, heat is not a factor as most injection molds are liquid cooled anyway but a higher nozzle temp will make the plastic flow better.. they rely on injection pressure and cycle times.(i have 10 years in plastics industry btw)

I'm curious why you choose to vertically stabilize the mold during injection by hand. Why not determine a Z coordinate which best inhibits material escape around the nozzle? Everything squared up and calibrated I think the stable bed would best provide a firm, even seal between the mold and the nozzle.

Does keeping the resin mold sufficiently hot to keep plastic fluidity mostly the same during the whole injection process? Enclosing the resin mold into some bakery aluminum mold should help here.

For the M4 screw mold where the head never completely fills, try a couple of well-placed weep holes through which air can escape as the head portion gets filled. The weep holes should be tight, perhaps 1/3 mm, because you want the air to escape the head allowing the head to fill with plastic, and you do not want a lot of plastic escaping through the weep holes. The goal is to fill the head portion and quickly plug the weep holes so that you can build pressure as quickly as possible. You may even experiment with weep holes that don't fully reach the edge and allow air to escape. Maybe the weep holes should have just enough empty volume to contain the air that isn't escaping your current M4 screw mold.

Injection machine are under pressure and mold have hole for air chasing, some mold are heated because the plastic need to stay liquid for going everywhere in the mold before it cools. It’s very fun this test, I like it 🎉

How does it affect compressive strength?

Make a vent hole at the end of flow of the mold.

Pre-heat the heat resistant mold