Plastic Injection Molding 

Nothing better after a day's work than to have dinner, pour a glass of wine and watch a video about plastic injection molding.

I made plastic injection molds for 35 years, and that was the most precise description of the process that I could wish for. Great work!

This guy is the David Attenborough of engineering!

What separates us from other animals? Plastic injection molding.

This guy is THE epitome educator! Clear, concise, and informative! Always a pleasure to watch his videos!

After spending 200 years making injection plastic I can say for sure this guy knows what he's talking about!

I’m a maintenance mechanic at a plastic injection molding plant. I rebuild and maintain these machines. If someone asked to explain the principles involved I don’t think I would have done it as well. Our molds don’t have hot runners, or date stamps so I actually picked up some knowledge. Good video sir.

First aluminium cans and now plastic molding, what's next RU-vid?

After spending over 25 years as an injection mould toolmaker I thought I knew just about all there was to know. This is an excellent educational video that I have benefitted from watching and learnt much more than I expected. Many thanks for posting this.

As an industrial designer, I wish they would have taught this information in college as thoroughly as this video did in less than 10 minutes… would have saved me the trouble of piecing it together on my own bit by bit over a couple of years.

I work in the Injection-mold department, assembling products. Love it!

Something about these videos is just so therapeutic and relaxing, yet so rich with information

I'd just like to add that the water pumped round the tool isn't always cold. Where I work we regularly use water anywhere between 20*C and 80*C depending on the mould size and the material used for that job. We've even had moulds go up to 130*C for glass filled lens housings.

Absolutely agree with the Lego part. Our teachers often tell us how incrediblely complex and well-constructed the Lego parts are and what huge amount of engineering know-how went into making them. This year we even got the challenge to construct a mold for a Duplo part (A little bit easier but still great to build up knowledge as a student). On of our class even had to construct one for a Duplo slide. It took him and two teachers about 3 hours to find out how to construct the cavity in the mold in order to eject it from it.

I designed injection molded parts for over 38 years. This video is on of the most thorough presentations of the molding process. This video with help new designers and engineers explain why it will take weeks to complete a mold due to strength of the pressures and the precision, and complexity of cooling the mold. Hats off!

As a process technician in Injection Stretch blow molding and Injection molding, this is such an informative and accurate video on our industry. Thank you.

WOW...the dedication on the quality and details of this video is just amazing! You guys are true heroes to those who love to learn!

Hey Bill. Thank you for returning to RU-vid, I enjoy the way you explain things I normally don't think about. Have a fantastic day

I'm a mechanical engineer and I just discovered your channel with this video, I had so much fun watching it, the description so accurate, and it seems the only thing left for me to do now is to binge the rest of your content

I never thought this subject would be so interesting yet here I am on the edge of my seat to learn how legos are injection molded…

I can watch you explain anything and be completely entertained and educated. Love your videos.

worked in a molding plant for 5 years, very good introduction.

I am glad I stumbled upon this video BEFORE my chapter test on "Molds" in Solidworks. This video helped me understand and visualize the process soooo much better than it was ever explained to me in class! The lightbulb in my head has exploded and now I understand why I have to design with drafts and cavities on every single assignment. :-) Thank you!

Man I've been in high speed plastics for 8 years. Specializing in closure and preform injection molding and PET blow molding. I was so excited to watch this. Couldn't wait to make a comment about hot runners, but then he brought them in!! Having toured multiple injection press and mold shops, this really hit a special note for me.

this is insane. valuable information is so cheap these days.

Please be my professor, instead of the lunatic I have now

Been in Injection Molding since 1994, started as a operator and is now the Plant Manager. I always loved injection Molding,.

As a professional injection moulding productions sales in this field，i can surely say this is the most clearest video to the explanation of injection machine

As a kid, I studied the marks of injection molding on household objects without knowing how they were poured. Thanks for revealing the mystery.

Your videos are always perfect.

This is one of the best videos I've watched describing injection molding. Great job simplifying the process so most can understand it and opening the door to the more intricate side of mold making and processing.

His voice , his tone, .... so relaxing and immersive. Bill, you are the greatest..

underrated and forgotten beauty of Mechanical Engineering.

How on earth does this guy make something as ordinary as plastic seem infinitely interesting? Thanks for the videos Bill!

Thanks Bill for the explanation. In my apprenticeship we had injection molding machines, I used to feed the hopper. Back in the 70's the Italians were the "kings" of molders. We had a big tool shop that made so many molds.

I've been in the business since 1994 and I agree, that was the most concise description I have ever heard or watched. Well done! Thank you!

8:06 "Look around you and see how many injection molded objects you can find." 'I'm pretty sure my laptop's case is injection molded.' 8:10 "Likely the device you are watching this on has injection molded parts" 'wow'

I work in a factory that does injection molding of ABS, PS and rubber too, used for shoes manufacturing, mainly soles and heels The machines are indeed very simple despite looking overly complex! To think that we still have fully functional 1970s machines that work only on relay logic and nothing more, and nearby computerized machinery, doing exactly the same job, every day 24hrs a day

Once upon a time, I was to be a U of I student. I chose a different path, and never found my way back to school to get a degree. I feel like if I would have had teachers like this, I would have stayed in school. Thank you for making these amazing videos. I appreciate your work because it shows how amazing even simple household objects are. Thanks again.

This is exactly what I needed. I was interested to learn more about how injection molding works, and this video could not have been more perfect! Thanks for this!

Very nice. I am an injection molding process technician with 30 + years in the business. Your breakdown is a very informative approach to basic injection molding - great for the new guy/gal to gain an overall viewpoint of the process. Cudos to you for a clear and concise look into the process!

The diagrams and animations are the best I've seen when it comes to manufacturing processes.

I am just starting at Plastic industry as a maintenance at Engel Global machines, this video helped me a lot in my first steps. Thank you Bill Hammack

Its just perfect, this guy is going into such a detail in very limited time frame without making a single mistake. There is no room for improvement.

Love your animations. Thank you for putting so much thought and research into your videos.

I used to work at a CD/DVD manufacturing plant. This is exactly how we did it.

He gets right down to it. No introduction except what is necessary for the topic at hand. Then on to the details. Wonderful.

Excellent description of the injection molding process!

“If you cut a lego in half.” Yeah, you’re gonna need the Hacksmith for that. Those things are unbreakable.

I know everything I'm going to write is obvious but I just wanted to leave a comment in case you haven't heard these things lately. I hope you know how absolutely great your videos are! Your ability to take complex subjects and break them down for dummies like me shows your absolute mastery over not only the topics at hand but of teaching, video acoustics, filming, editing, animation, writing, and so many other things I'm sure go unnoticed. Your visuals are amazing; plainly drawn, distinctly labeled, and animated clearly. Thank you so much for what you do! Also, thanks for taking the time to add in links to videos/podcasts with more information on the subject!

My father designed moulds and manufactured them. He also had a production line with numerous machines, British built (Newbury) and had the distinction of being able to convert imperial measures to metric and vice versa in his head. This was because we moved to the U.S. in the 1980's. Thanks for the video, it's a great reference to a life I lived long ago.

I only assemble parts after they have been molded, but I always found this whole process fascinating.

I enjoy the way you explain things as well. The 3d animation of how the parts work is amazing. Thank you for taking the time to make these videos.

Well done Professor, from one engineer to another, I say bravo. Your educational work is top notch, inspiring, and consistent with the rearing nature of someone who cares for his fellow man. Bravo!

Now I am engaged in the business of plastic injection molding. I am very grateful that this video has let me know this great industry. I am looking forward to cooperating with more mold projects

I did know the technical solution, but this explaining is on a lvl that even people never have been in contact with it can understand it easily. Great.

Clear, concise, and full of amazing details!

Thank you a lot, engineerguy. I've got a homework about this great process and I didn't found better information than this video. You helped me to know an excellent info and valorate the extrusion process.

Thank you very much for your video sir! I currently work as a procurement guy for a company selling electronic products and this video really helps me a lot know the fundamentals of the injection molding especially in this Covid hard times. Thank You!

I used to operate a heavy mold machine at PMI when I was 18. I was so amazed at that simple process and all the parts we made.

This was way more enthralling than I thought.

This guy could take Mr Wizard and Bill Nye in a fight I bet.

That's a wonderful explanation and visualization. Every person working in plastic industry should watch this. We did not have such videos back in my time. This is so valuable.

I love that this is as informative and thorough as it is. I didn't expect him to cover hit runners in such a short video. He did miss the fact that celluloid is flammable and volatile, though.

great explanation! It would be a good companion series to discuss roto-molding, vacuum forming, and blow molding. ;-)

Hi Bill, This is the first of your videos I've viewed. Very informative! I've been in the plastics business for about 20 yrs. and had no idea that's how injection molding started. I knew that celluloid was invented to replace Ivory, but not that this was the start of injection molding. I'm afraid you wouldn't find ejection pin marks on the product the Co. I work for produces. The parts are too thin, so are ejected by air. Think yogurt or butter containers. Other than that, you're spot on. Thank you from a new subscriber!

Absolutely superb! This is one of the best explanatory videos I've ever watched. Bill is a wonderful teacher. Thank you Bill!

Just recently discovered this channel and I am already completely hooked! The soothing voice, the clear explanations, no "sponsor shout outs", no "hit the subscribe" demands. Just pure knowledge and information! Great job!

It's like listening to a story. Great job!

never thought I'd watch this on a Sunday night... and enjoy it. Thank you.

Beyond awesome, educational, intuitive learning video! Like my own mechanical, gearhead, brain, I can mentally see how things work. I've always loved step,by, step instruction books, and videos on how things work. Thank you!👍😀

I'm a mechanical engineer and I've designed many injection molded consumer products for over 40 years that are very well known to everyone. I just want to say that this presentation is marvelous. Keep up the good work.

Lately I've been designing parts for plastic injection molding; at first I only knew the general idea but over time I've had to get more and more technical in my understanding. Even after reading a lot about the topic, this video has taught me more. There are some things I've learned recently that aren't specifically mentioned in this video: One is how to figure out which side is the core and which side is the cavity on a part. The core is the side of the mold with the ejector pins, and the cavity is the side with the injection gates. In practice, the ejector pins are never on the same side as the plastic is injected from. The core, which has the ejector pins, will be whatever side the mold engineer thinks the part is more likely to stick to when it shrinks during cooling. In practice this means that the core will be the side that has the most tooling enclosed by the part, or it will be the side that has the shallowest draft angle. I recently designed a part and was surprised that the vendor didn't want to put the ejector pins on the side that I was expecting, and then again I was surprised when the injection points couldn't be on the side I was expecting either. Another thing: the vendor used what are called submarine gates, which come in at 90 degrees to the pull direction and are designed to shear the sprue off of the part as the mold opens. Learning about this was fascinating.

wow, so throughly explained !! Even with the history, I'm ready for a test paper !

This is amazing. In ten minutes he explained what took 2 classes of Design of plastic products, and way clearer.

No one has made a better video explaining this in the last 7 years, thank you for this explanation!

I'm in the plastic model kit building hobby, and I'm very used to speak about "sprues" to which the parts are attached. Today I learned they are actually called runners :)

I never thought injection molding would be so interesting!

What didn't occur to me but recently is that the 3D design most allow for the object to be pushed out of the mold. There can't be overlapping structures that would obstruct the line of draw.

Was a machine operator for a while. This video is so entertaining, and really educational. Makes me want to get back into the industry.

One thing I love about this channel is the number of really smart commenters that can provide various answers to the questions!

can't believe I watched this whole thing and enjoyed it

I am my shift's maintenance guy at a plastics plant where we do both injection and blow molding. Injection is by far my favorite and this was a tremendous explanation. On the subject of part ejection and vacuums: depending on the desired product design the mold manufacturer may add air poppets that open ever so slightly to blow air into the molded part to release the vacuum. We make 5 gallon/20 liter pails that require aie because the vacuum is too strong for a mechanical ejector. In fact our molds don't have mechanical ejectors at all, they use pressurized air to blow the buckets off the mold and onto a conveyor belt. These molds don't require a hot runner (but the mold that makes the lids does). Super cool stuff honestly, I love my job!

Thank you so much for the explanation. The animation make the process of plastic molding easy to understand.

SO WHO WON THE BILLIARD BALL CONTEST?!

Hey Bill, One of my favorite things about your videos are your super clear animation models. As a 3D modeler myself, do you model these pieces yourself? How do you do it? Thanks, and keep going!

You need to bring back this style of videos again. They are much more entertaining to watch and the views on these videos speak for themselves.

This video is very well done, I have worked in an injection molding company for quite some time as a mold tech meaning I have to know a lot about the process. And he even taught me a good bit. Perfect.

Wow, this is my new favorite channel! I wish this would have been around when I was a young man, just interested in all things mechanical and electrical. What a great resource. Thanks for sharing your knowledge.

Your voice is so calming! Loved the video and the narration!

I've learnt all this in school about 8 years ago, but if I saw this video back then, I'd understand it much better and faster. I think there's a lot to be changed in the educational system.

I wish you were a professor in my college because your explanation is simple,clear and to the point, just the way it should be explained. You helped me for my exam sir. Thank you!

These videos are just marvelous. Very well done as always.

Once again - awesome video!

Couldn't find anything about how they were venting the air of the empty mold cavity until this video. Thank you!

Absolutely phenomenal overview of injection molding - thank you for the video!

Very good explained, just one correction regarding "Lego Molds". Actually those were standard Hot Runner molds but no more in use in Lego. They are now returned to improved sprue tecnology in energy saving manners. Improved sprue means that it is basicly a "Stack" Mold meaning that during opening midle plate is also detached and robot removes the sprue with comlete gates.

Probably my favourite channel on RU-vid!!

Great video. Many many years ago, I use to be a shop lead that was responsible for making sure 4 to 5 injection molding machines were producing products. This included material and mold changes, heater / chiller set ups. We had molds that also had screw elements that had to unscrew before ejecting the parts. The inside edges were razor sharp, and I have scars from removing stuck parts. If you use a phone that was made in Alberta in the early 80s, chances are, I was involved. Ever since, when I look at plastic parts, I try to understand how they are molded. The most complicated parts that I see now a days are printer frames with multiple sliding inserts and cavities. Extreme precision molds are required.

This is the best lecture of injection molding. Thank you for sharing.