Injection mold design for desktop machines is easier than for the larger, industrial machines. But it can be very intimidating when you first start. I talk about the basics of gates, runners, sprues, and air vents.
Great job. I've been designing parts for injection molding for many years, but never actually designed the mold itself. The way you showed the basics of the mold really made it easy to understand. The industrial molds that are so complicated its hard to get your bearing on what you are looking at. Thanks.
The channel I needed. I’m an Engineering student and haven’t found videos technical enough. Beagle and Craftsman only go to a 1/16 lvl Knowledge and mini injection molding machines can be tuned to the thousands.
Wow! That video covered everything that took me about 4 months to learn via trial and error on my own! That part about shearing pellets at the edge of the barrel took me a while to realize was causing my occasional random under injection! Great video!!
hola amigo me gusto mucho la explicación, apenas empiezo en esto de las maquinas de inyección de escritorio y quiero aprender mas sobre moldes para este tipo de maquinas, puedes hacer mas videos para aprender mas, saludos y muchas gracias .
Hi John, Really well done. Question: This is about the dynamics of the air escaping the mold. As the plastic comes into the mold it most likely has a spaghetti shape at first until the material starts to get squished. But as the ratio of the amount of plastic versus residual air increases some air may not be able to make it to the escape port as the hole will eventually get covered. What happens to this trapped air? Can it make small bubbles on the surface? Can it be trapped inside the part and cause weaknesses? Many thanks as there are many people learning from you!
Hi John & thankyou for your very informative videos. I notice your molds do not have a chamfer at the entry port as some do. I was wondering what sort of design your molder nozzles are. How do they form a seal on the mold block? Do they have some sort of shut off valve or are they just an open hole in the bottom of the tube. Keep up the good work. Its nice to see you love what you do.
Very nice breakdown. I preheat some of my more challenging desktop molds to help with flow using a small coffee cup warmer. I have one mold for a product made of lustran that needed a dedicated heating element to fill completely. I noticed on your emco molder there's a piece of sheet metal bolted to the rear clamping face, what is that for? That bolt hole is typically for the mold stop.
I've thought about adding heaters or a heater plate but never gotten around to it. As to sheet metal plate on the Emco, I don't know why it's there. The only thing I can think of is that it helps space a 1/2" thick mold out so it centered under the nozzle. But that's just a guess.
Very interesting video as always. Question: what are the strategies for dealing with shrinking? Do you ever make molds with exaggerated geometries, to let the part shrink to dimension?
I didn't cover this, but generally one step is to scale up the design to counteract the shrink rate. This varies from one plastic to another, and isn't important for all designs.
This is a bit off topic but it does have to do with mold design. I believe injection molding may one day have a rise in popularity just like 3D printing had a few years ago. Once people start buying machines like the LNS or Bruster Beagle machines then the Chinese knockoffs will follow. This will be a good thing for injection molding. Some people will buy more advanced machines like yours but a lower barrier to entry gets more people involved. However, I believe there is one major thing holding this popularity back. Molds.. Right now I don't think there are any molds readily available that people actually want to make. LNS has one mold that I would consider and honestly I still don't want to make heart keychains. I know the common rational is that you should have a part in mind first and then get the machine. But that's not how common people work. Personal computers, video game consoles, and even smartphones all needed a "killer app" before they were widely adopted. Before people will buy a injection mold machine I think they need a "killer app" mold. I know there's a lot to consider with molds. The type of plastic, and the Machine itself being the most important. But if a popular mold can be designed for generic low entry machines, then I think that will go a long way towards getting people to adopt injection molding. I do have some ideas as to what parts to make. I've been thinking about making a video that's an open letter towards mold makers. Would you have any interest in these ideas?
Sure, I'd love to hear more. I'm planning to set up a web store sometime this year to sell products. You can contact me via email using the email address you can view on the about section of my RU-vid channel.
@@JohnSL I made that video. It was a bit of a mess so you can skip straight to about 20 min in to get to my ideas. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6GvSUuIPaXI.html
Thanks for your knowledge sir! Does overall surface area of a mold matter as well? For example, I'm considering injection molding some glasses frames. According to the volume and weight estimations from the CAD model, they should be within the "shot capacity" of a desktop injection machine I'm looking at, but I'm doubtful. I fear that the long path of the cavity wouldn't be filled by one pull of the lever, or that the extra surface would cool the plastic before full injection. Do you have any advice on estimating an injection machine's limits?
You absolutely can. In fact I use round gates for molds I make for my Morgan (which has injection through the "back"). But if you want the gate to be twice as wide as tall, which is useful when you're injecting into a thinner part, it can't be round. So using rectangular gates is pretty standard.
Hello. Could you tell me please, how much maximum pressure your compressor can supply on your desktop termoplast machine which model 100. And how much pressure actually do you use of it?
I have two compressors. The one under the machine, which is what I typically use, is rated for 225 psi. But I keep the pressure to the injection molder at about 130 psi and then don't use more than 120 psi for injection or clamping.
Yes, that can be done. The mold maker did this with the large throttle sold by TCS, as the part distorted when molded too much. So they did a detailed 3D scan of the part as molded and then adjusted the mold to compensate.
