Injection Molding DIY
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- Опубликовано: 4 янв 2025
- One of my projects requires some plastic injection molded parts. Quotes for the molds came in around $15,000 which was way over budget for prototype parts. My solution was to build an injection molding machine to mount on my arbor press. I tested the machine with a simple spinning top mold before attempting to make the more complex molds for my original project. I used a cheap PID temperature controller, two 300 watt elements and a thermocouple. To use, I just set the desired temperature, drop in some plastic pellets or recycled parts, and press the melted thermoplastic into a mold.
Main body: machined from 1" thick plain carbon steel
Plunger: machined from 3/4" drill rod
Solid state relay: amzn.to/2u2oOi3
Two 120 VAC, 300 watt cartridge heating elements
Thermocouple: amzn.to/2uKOlts
PID temperature controller: amzn.to/2u6RPZu
Note: I highly recommend the book, "The Secrets Of Building a Plastic Injection Molding Machine" by Vincent Gingerly. Although I didn't follow his plans, it was a great resource to get started: amzn.to/2uKYJSc
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This is brilliant, it's basically the hot end from a 3d printer but larger. The simplest and best design I've seen yet. Thank you! It's inspired me to try making my own.
Can you PLEASE make a tutorial of how you hooked this up?
Great Job ❤❤
How would you recommend making molds on a budget for something like this, may I ask?
Very ingenious,I really like the use of the cartridge heaters for the melting chamber.
The arbor press works very effectively, providing plenty of extruding force.
An elegant solution to what could be a very complicated machine.
I had less flashing with a resin printed mold.
You've got either way too little pressure on it or poor machining tolerances.
I think you have the best DIY machine I’ve seen so far. Nice job! I’m looking for one of those arbor presses now, but all I can find at the moment is a 1 ton... not sure if it’ll be large enough.
Thanks Dan, that's kind of you to say. My press is a 2 ton but I think 1 ton might be sufficient (I'm just judging by the force I applied and the leverage of the arbor press handle and gear). Of course, bigger is usually better when it comes to shop equipment so if you can find a 2 ton then go for that.
dude how you setup the eletronic part... im struggling to understand
Good evening, great project !! A question of what diameter is the bar that pushes the plastic and what diameter is the hole in the heating block where the bar enters? Thank you !!
I used 3/4" drill rod and reamed the bore to a close sliding fit. However, I think the fit can be less accurate as the plastic squeezes between the rod and the bore which seals the gap and soon holds the pressure needed for the injection process.
@@blainemcfarlane Very kind to answer my questions, I want to build one in Argentina, best regards !!
So are the pop bottle caps a different plastic than the body of the pop bottle they go on, and so why you're only using/showing the pop bottle caps for the object youre making?
Yes, they are different materials. The caps are high density polyethylene (HDPE) and the bottles are typically polyethylene terephthalate (PET).
@@blainemcfarlane Oh ok :o) So this is just a matter of your preference to not use the PET (pop bottle itself) because of an unwanted property that will/may result in the object your making and/or the application the object is for?
From just recently having started using a 3D printer that uses PLA plastic, I've been seeing where PET is pretty common plastic for making 3D prints but not sure about using it for injection molding
what temperature does plastic have to be to inject? good vid thanx
Here in Brazil, I will begin the manufacture of these machines
Please may I know what it takes to make the heating element? I am trying to build one for my lab but I dont have any experience in plastics. Thank you for the nice demo.
Hi akshayd211, I didn't make the heating elements. I bought them off Amazon. At the time I found them for $4 each but I can't find any for that price anymore. Do a search for "cartridge heater" on amazon or eBay and try to find something around 300 watts and 120 VAC (or your local mains voltage). I would also highly recommend the book mentioned in the video description as it is a good beginner resource for learning about the different types of plastic that you can use for injection molding. I didn't really follow those plans at all but it was a big help to point me in the right direction.
@@blainemcfarlane oh okay. :) please could you share your schematic of the connections for the temp. Monitor, to the heating element?
I basically wired up the injection molding equipment so it would work but do not have enough experience to consider electrical best-practices and safety implications (fusing, etc.). As I am not an electrical engineer / electrician, I can't guarantee that what I did was 100% safe. Therefore, I won't share the details of what I did electrically. Once you source the components and do a bit of research on them, you will be able to figure it out quite easily.
@@blainemcfarlane fair enough. That helps though! Thank you
@@blainemcfarlane Ok I found the Rex C100 PID and some solid state relays that work with the PID. However, I found an array of cartridge heaters on McMaster Carr. I have no idea how to wire them up though. Could you let me know where I could find the wiring diagram? I have to present a proof of concept to my boss soon.
I think the main issue most people would have is, sure you can inject heated plastic into a mold BUT creating the mold would be an issue. Additionally most hobbyist or even semi-pro builders are not pumping out multiple parts so creating a mold to knock out 100s of parts, to make a mold practical, is not really a consideration.
I have a couple questions, not for this type of application but that you may be able to help with. Do you have an email I could send questions to?
Get a blender and stick the pop lids in. Instant granules.
Great advice! Thank you.
Sir I am interesting about the assembly, parts , measures etc..thank you.
Thanks for your interest. I've added a few details to the description.
Where did you get the heating elements?
Hi Patrick, I bought them from Amazon for about $4 each. Unfortunately, they’re not available from that vendor anymore or I’d share the link. Do a search for “cartridge heater” on amazon, eBay, etc. and you might find a reasonable deal.. you want something close to 300 watts and 120 VAC (assuming you’re in North America).
Ok, Thanks. Also, how hot does it get?
It depends on the plastic you are working with and takes some experimenting. I usually set it between 180 C and 220 C.
@@ptschrems they can get extremely hot. If you dont monitor the temperature, they can get so hot that they melt your 3d printer (im saying that becsuse 3d printers use them), and burn your house down.
If the thermistor falls out when your printer is heating, if there is no protection it will keep applying power to the point it can melt metal (or so ive heard).
Not trying to scare you away, but just becareful.
I confirm it. I had a thermal runaway a while ago because of a faulty thermistor, and the heating cartridge melted through the extruder metal block like butter and fell into the printer bed.
Those things are pretty dangerous when uncontrolled.
how do you cnc machine your molds, and how would i do it if i wanted to get into this. do you have your own cnc or do it at a makerspace or a company. can i even milling aluminum like this on a budget machine at home?
Hi Luke, I don't have any CNC equipment. I only have a manual lathe and a manual mill. You can do just about anything you need with this equipment other than some free-form shapes. A maker space is a great option if you don't have the equipment.
Thanks for the help. Keep making!
Very nice build! How did you make the green part?
The green part is an arbor press. You can sometimes pick them up at yard sales or the local classified ads for a reasonable price.
Can I make the barrel (main body) and plunger from machined aluminum block, or does it have to be stainless steel?
I actually just used plain carbon steel but you could use whatever you have available. Aluminum might wear out faster but it would be better at transferring heat.
hi, just want to find out what you used as a nozzle?
II just machined a nozzle with an included angle of 60 degrees where it mates with the mold and a 0.25” (6.35 mm) hole. When I made the mold, I used a center drill with a 60 degree taper to match the nozzle which make a good seal. You can use whatever angle iis convenient based on the tools you have.
Thanks, will post my build as soon as its done.
Excellent
What's the Solid State Relays used for? Is there a diagram showing how everything is connected?
Also the SSR you posted is unavailable, is there another one you can recommend from Amazon? I am trying to order the parts :)
If this puzzles you, then perhaps you should not play around with mains voltage on your own, you'll shock yourself or burn something down if you have no idea about what you are doing. It may not be rocket science, but some prerequisite knowledge is required before you attempt something like this. Your questions reveal your lack of experience in anything of the sort, if you really want to do this, ask a friend who does know what he is doing to help you out on the electrical side of things. Next time you'll have some experience, but first time to wire anything up with mains voltage, you should have someone there to hold your hand and to make sure you don't make any big mistakes.
Mains voltage is not a toy, know what you are doing, or don't do it.
aleksander suur he’s learning here so he does it right
@@hacklabdesign nothing wrong with learning, but this topic is definitely something where you need someone to show you the ropes in person to get you started, for safety reasons. It's as if someone on youtube was asking how to start a car and get it moving, or how to perform appendectomy. Some things you absolutely should not try to learn on your own, you should get someone to show you how to do it correctly, because the price of failure can be just too much.
A fantastic way of producing injection parts at low cost, will have to try this for one of my project, what metal is the mould made from ?
RetroCable.com Looks like aluminum...