Making Larger Injection Molded Parts

[@GregsGarage]

I've been watching a lot of your back catalog. I'm trying to decide whether I want to get into injection molding or if I will farm out the work. Your videos do a great job of breaking down the process and making it seem rather manageable. Thank you for sharing your insights and experience.

[@JohnSL]

I'm happy to help you answer that question. Send me an email if you're interested.

[@TheCrafsMan]

This is a really big debate - whether to make the parts yourself, or to hire them out. (It's a debate we've had at our shop and is still somewhat ongoing.) JohnSL will have, I'm sure, some invaluable information for you if you reach out to him.

[@GregsGarage]

@@TheCrafsMan Thanks CrafsMan! John and I have shot messages back and forth. He's INCREDIBLY knowledgeable. I saw the work he did for you as well (I'm a long time fan of your channel too). I bought an injection molding machine about a year ago after I posted this comment! Keep on Steady Craftin!!!

[@danjones4002]

Im wondering what happens when you dont screw it? It seem like a lot of clamping force. How much pressure is the machine pushing the plastic?

[@LumaLabs]

You could probably double the cycle time on the screw reenforced mold. 1- Better/shorter driver. The Milwaukee M12 Instillation driver is excellent. Compact, powerful, precise, inexpensive. I started using them in my machine for clamps and fixtures and it is a game changer. 2- Make the screws 2"+ long, with holes in the spacer plate to accommodate the extra length. Unscrew the fasteners enough to get the part out without completely undoing them, and you reduce the handling count by 8. Massive time savings. 3- Mold jig for the operator. Eliminate the hand-torquing effect with a jig to hold the mold for opening/closing. Faster + Safer. 4- Threaded inserts (KeenSert, Helicoil, etc) to solve the threads in aluminum issue. Great videos BTW! You're making me think we should get into injection molding our own parts!

[@glennedward2201]

What about using a horizontal mounted 10 or 20 ton air over hydraulic jack for clamping? Would you be able to utilize the extra clamping in making a larger part? There are others using steppers and ball screws to clamp their molds who are making significantly larger parts.

[@grahamfrench340]

Thanks John, I've just switched from a manual Travin TP1 to a hydraulic version the same as yours, I'm having trouble as I thought I would as I noticed the hydraulic version moves quite slowly and acts like a ram splitting open my moulds, I seem to have got away with it on my manual machine by pumping in plastic quite quickly this works pretty OK. I thought I would have to resort to bolting them together and you've beaten me to it!

[@loganbrantley7216]

I had a question. You mentioned that the clamping force required is proportional to cross sectional area but it seems that most of the parts you make a quite thin. If the part you are making in this video were say 1in think with the same cross sectional area would you still be able to make it and the clamping pressure would still be sufficient? I am considering getting one but the thickness of the part I want to make is about 1/2in thick with maybe about a 1in squared cross sectional area.

[@3dfabrication]

Thanks John, great content once again. Looking forward to seeing your ejector pin video on the travin, as I have this machine and something I want to do.

[@prototype7970]

Thank you for share you experience with the world ! Interesting rule of thumb for the clamping for molding part. The screw could be made to be remove by sliding of the edge of the mold. Maybe it would make you cycle time a bit faster. But it would need a nut and maybe a ticker plate. Great vid keep at it !

[@glennedward2201]

He could also fabricate a tool that uses a large planetary motor coupled to four gear driven chucks that could run them all in and out the same time but modifying the clamp with an Air over hydraulic ram makes more sense.

[@billstrahan4791]

If you'll take a center punch and angle it into the hole for the dowel pin (without the pin in) you can put in a couple of punch marks, and that will be enough to lightly press the pin into place so it stays put. You can also do it around the edge of the hole if that's easier, but anything that will just slightly deform the hole inwards will take care of it! I had some molds where I got my clearances off and it allowed me to go ahead and use them. When I make molds, I still make through holes for the pins, but I make most of the hole a slip fit for the dowel and a light press fit for only the last 1.5-2.5mm. Then I can easily press the pin in after slipping in most of the way, and the pin stays. But if I need to remove it, a couple of strikes with a punch or drift and take it back out since it only had a couple of mm of press fit. We're still working on our plastic injector. We have electronics working, and have made parts but now are going through a round of redesign. I'll update you when I have an update!

[@JohnSL]

Currently I use 1/4" dowel pins that I mill to very tight tolerances on my Haas. I also have 1/8" diameter through hole that would allow me to press out the pin if I need to. That works much better than these 10-year old molds. Given that I'll probably never have to make these parts again, which I should have mentioned in the video, I figured it was OK to just make the parts. Looking forward to seeing your machine.

[@thatstrami]

Thank you very much for making this video and showing a good general understanding of the way these desktop machines work. Would that travin be able to produce a part like a flat panel that's about 13 in x 8 in and maybe like four or five millimeters thick?

[@valentinsantovena3569]

Thank you for share the experience,very interesting,my best greetings from México.

[@PeckhamHall]

Hi John, if you ever decide to make a injection moulding machine for yourself so you could run fully auto on bigger moulds I love to share some of my ideas. Been in the industry for nearly 30 years as a process technician on machines upto 3250 tons. Great channel. Jim🏴󠁧󠁢󠁥󠁮󠁧󠁿🇬🇧

[@santiagokof]

Id love to see this colaboration. Greetings from Mexico

[@daight12345]

how big of a pneumatic cylinder do your machines have?

[@RobertWelchman]

Have you considered using an over/under reamer set for dowel pins? The undersized reamer is a few tenths below, so the pin has to be pressed in and it will stay there while the oversized reamer is a few tenths over and provides good positioning.

[@JohnSL]

There have been lots of suggestions along this line. These are molds I made 10 years ago before I know what I know today. I don't make molds this way anymore.

[@emel60]

Hi John, Could you please help me identify one very, very old injection moulding machine which I purchased on Ebay near London. The tags exhibit the previous company name and a patent number. Unfortunately, the patent relates only to the way the mould is pushed out from a mould by operating the vice, and not the machine itself. I am interested in an operating manual or blueprints, since some hydraulic parts are missing and the heater energy regulator is not really working as it should. It is always in the ON position, regardless how I turn the knob. Finding a replacement for this is a task by itself, unrelated. So, is there any way you could help me, considering your experience? Any advice is welcome.

[@emilyleone4839]

Great video. 😀Could you make two injected molded parts at the same time? What’s the biggest size part you could make with this machine?

[@JohnSL]

The larger part is stretching what this machine can do. I wouldn't go much larger than that.

[@Oberkaptain]

Have you through about making two parts at a time with the screwed mold?

[@durkashurpala]

Great job and very informative and realistic

[@MrAirsoftmodz]

just a thought why don't you change the pivot point of the clamp to help you produce more force?

[@bennesky4323]

what if we install 20 ton hydraulic or more at this home injection machine (with reinforce structure for sure), do you think it can make even more larger part sir? . How big the part is that can possible with this type home injection molding. I think about more larger part like a size our palm hand. Thanks.

[@JohnSL]

Yes. Some people have done that and it works. The rule of thumb is that you need 2 to 2-1/2 tons of clamping force for every sq. in. of cross section. So using the upper value of 2-1/2 tons, that would give you a maximum cross section of 8 sq. in., or 2.8" by 2.8".

[@bennesky4323]

@@JohnSL I see, the clamp that need to reinforce too as the pressure increase.. thanks Sir..

[@gregederer6945]

Always enjoy your videos.

[@Preso58]

John, do you have to cool the die halves periodically or are the cycle times low enough that the heat doesn't build up?

[@JohnSL]

For larger parts if I keep running them for a while, the mold does get hot. The issue is being able to hold the mold. Because it's aluminum, it doesn't take long for the mold to cool back down. For small parts, the molds never really get that warm.

[@arkandenha811]

Hi there I like your videos I am trying to get into plastic injection to make checker stone or backgammon checkers , I am making them right now in a cnc machine but it takes a long time ! I wish you can help me where or who can make a mold for me I will appreciate

[@nickst2797]

Is it possible to have molded-in parts included, such as power connectors, when do the 3d printed mold approach?

[@JohnSL]

Yes. This is called over molding. The requirement is that the mold is tight enough around the connectors that need to be exposed so the plastic doesn't exit the mold.

[@nickst2797]

@@JohnSL Thank you very much for your answer. Is this something that you could demonstrate? It would make a pretty good video. For example, in the connector example, if they do not come from the front of the hole but they are inside the hole, isn't there danger of plastic covering them up?

[@baptistmonteiro5972]

Interested in making aluminium mold how i can learn making one

[@petergrunwald7706]

Very informative! Looking forward to the ejector pin video.

[@JohnSL]

kzbin.info/www/bejne/momlXoatlst3eNk

[@PaulSteMarie]

I'm a bit surprised you didn't ream the dowel pin holes, with one side being an interference fit and the other side being a slip fit, pressing the pins into the interference fit side for permanent retention.

[@JohnSL]

These are molds I made 10 years ago and, well, there are lots of things about these molds that I would be embarrassed to do in molds I make today. Because of the very low volume, it's not worth redoing the molds. In fact, it was never financially worth making the molds in the first place, but I learned a lot.

[@tbfanling2787]

Thank you, i learn about the pressure of sq inch of injection mold, is that possible to have two or more injection input in same time for large scale mold?

[@JohnSL]

If I understand correctly, you're asking if you can make more than one part in a mold? If so, yes, I've done that. But that would require even more clamping force (or screws).

[@tbfanling2787]

@@JohnSL oh, yeah, i see！the mold need to under take more pressure and damage by pressure.

[@OKeefeist]

What’s the maximum size part you can make on that machine?

[@johnhodges8185]

great video, could you use a large c clamp around the outside of the machine to boost the machines clamp?

[@JohnSL]

Possibly. Although, I'm not sure that would be much faster than the screws. Fortunately, I've now retired the molds that required the screws. Plus, I have my Morgan, which has much higher clamping forces. I'm debating selling the Travin.

[@alleng3968]

Hey John thanks for the injection molding content. I am using a manual plunger style desktop molder. I’m having issues with the nozzle drooling plastic out while I’m removing parts from my mold. It makes a huge mess and lots of strings when I scrape the glob off the vise each cycle. I’ve tried decreasing barrel temp but then my molds don’t fill. How do you handle this? Your process looks so clean (and with less plastic waste!). Thanks and love your videos!

[@cesarmata3787]

I just bought a manual machine, it's supposed to be delivered this month, and I'm making a couple of molds to try when my machine arrives. The question is, how big are your plastic pieces? How many tons of pressure can be generated in a manual machine? Are your pieces bigger than JohnSL's? I am afraid that when my machine arrives, I will not be able to fill my molds, due to lack of pressure. which is the nature of the manual machine.

[@alleng3968]

@@cesarmata3787 mine is an LNS-150A. The parts I’m making are round wheels, 11mm diameter and 6mm thick. My mold makes 4 wheels at a time. I extended the handle on my machine and it still takes a lot of force to fill the molds. My abdominal is sore after a day of molding haha

[@JohnSL]

That's often an issue with desktop machines. All of my machines have a valve in the nozzle that requires the nozzle to be slightly pushed in before the plastic will flow out of the nozzle. That pretty much prevents drooling. Another thing that makes a difference is the type of plastic. These parts are all polystyrene. But I know polypropylene is a lot runnier, and therefore more likely to drool.

[@JohnSL]

Four of those wheels sounds like expecting a little much from the LNS-150A. You might be better off with just two wheels at a time. Sure, it reduces throughput in theory. But it might give you better process reliability.

[@MakerMark]

What happens to all the plastic sprews? Seems like some of your parts is more waste than part

[@JohnSL]

Companies that make a lot of parts typically have a plastic grinder that can grind up sprues for reuse. I don't, and don't really make enough parts for that to be worthwhile for me.

[@Stark324]

I may have missed something in earlier videos, but what happened to the Morgan press? I would have imagined you would have used that machine for your larger parts.

[@JohnSL]

Yea, I mentioned in my previous video that these are molds I made 10 years ago, long before I got the Morgan. These we would super easy to make with the Morgan. But it's not worth redoing the molds because the volume is so low for these parts.

[@DragonflyEngineering]

nice video! Are these more parts for the train model oil tank building from last week? A static vent pin in the middle of the part may help with getting the air pocket out and lower you pressure. if cosmetics allow

[@JohnSL]

They are. I could certainly put a vent pin in the back. That being said, these are molds I made 10 years ago and I expect I'll never use them again, as the kits are being discontinued. So not worth improving. Plus, production volume is tiny--I think on the order of 100-200 parts total for the lifetime of these molds.

[@briangilbert3884]

Hi John- first, thanks for the videos. These are very educational for me and I'm learning a lot. But here's a question, and I apologize if you may not like it, but... What is your take on the Precious Plastic injection machines? We have one here in Savannah, and we like it because it allows us to recycle pretty fair amounts of plastic that would otherwise be landfilled. But we want to up our game. Ours is a manually operated machine that injects a comparatively large volume of plastic. It uses bolt-together molds that are (again, comparatively) fairly crude- simple laser-cut affairs. We make simple coasters and small plant pots, and small sea creature keychains. So my question is this- what improvements would you suggest for these machines? I have a few ideas that I'm mulling over, but I'd LOVE to hear your thoughts. Thanks BG

[@JohnSL]

I have no experience with the Precious Plastic machines. I've used bolt-together molds and try to avoid them when I can because they're so labor intensive. It sounds like the one improvement the machine could use is better clamping. A toggle clamp is probably a good choice, and probably not that hard to design and build.

[@T0tenkampf]

thanks for the info, I would have built a machine that is far to small for what I want to mold...time to rethink

[@patkirk960]

A little tip for holding the packing pieces together is to use double sided tape. I used to swear by the Tesa brand (not cheap!) It's really good at not leaving sticky residue. Used to hold plastic plate onto a milling machine bed for machining! Don't use too much tape! Not sure if you're clamping force would be too much for it? Edit.. wish I knew the Tesa product code.. sorry

[@wizrom3046]

Great channel! 🙂 Have you tried that mold without the screws? Looking at the clamping system and that steel machine body it looks more like 10 ton equipment than 4 ton. Even a decent bench vise is good for 4 ton.

[@JohnSL]

Yup. When I first made the mold 10 years ago, I tried it without screws and I couldn't keep the mold from flashing. So I added the screw holes, which are somewhat crude because of lack of skill on my part back then. The Travin TP-1 states that it's a 4.5 T clamp.

[@motornyiandrii]

what plastic do you use?? ABS ?

[@JohnSL]

These were all polystyrene, which is the most common plastic used for models. I've also used other plastics, including ABS, PP, and Santopreme.

[@w-4258]

Maybe use dowel pins but thread one end so they can be left on one side of the mold?

[@JohnSL]

Thread locker is a lot easier. I should have used that in this mold, and can't give a good reason why I didn't.

[@red62]

Why not just glue the pins in place?

[@oldschoolcars3318]

Thank you for a clear video.

[@Runnerbeandaz]

Hi John iv got a quick question for you on your very small parts have you tried to laser instead of milling?

[@JohnSL]

I started with a laser cutter in around 2004 and got a very good idea of what I could and couldn't do. These are definitely parts that you couldn't produce on a laser because of the rivets and the curved edges.

[@dnjmachine]

Thanks for another injection video. Have you thought about using loctite or super glue on the dowel pins? I would press fit them from now on but to fix your older ones that may work.

[@JohnSL]

That's what I do on my more recent molds. With these molds, I often have more than one cavity and I have to use different holes for different cavities. These are molds I made 10 years ago, when my skills were, shall we say, still developing.

[@dnjmachine]

@@JohnSL ahh I get it. Maybe silly puddy or something sticky like that that can just kinda keep it from falling out. Cheers. -Daniel

[@JohnSL]

What I could have easily done is to use some removeable LockTite since I already have some. But, well, I just wanted to get the parts done. And most of the time I did a good job keeping the pins from falling out.

[@ruitavares3792]

thank you

[@bigbird2100]

Great video 👍John Tool maker's use a half thread trick to speed up jig time assembly disassembly machined at angle half the thread's are used.

[@JohnSL]

That sounds interesting, but I think I need some more information. Can your provide a link or a longer description? I'm intrigued.

[@bigbird2100]

@@JohnSL I used a few drill jigs that had a nut with part of thread cut away I tried to find a link no luck an alternative would be a multi start thread as used by fly presses it moves greater distance for a given motion and multiple load.

[@bobonono8544]

Thunk you 🙏

[@ibrahimkroglu5484]

Super John

[@goglu2]

you have a cnc machine, put some interlocks on your molds.

[@JohnSL]

I could have. But it was worth it. I expect this mold will be retired after this run. I spent an hour making parts from this mold, which is less time that it would have taken to improve the mold. And I'd have to hunt for the mold CAD files, as I did this 10 years ago. That in itself might have taken more time than just running the parts.

[@NeoQJ]

Thanks for the video, very informative💪

[@CAMER_21]

It's an humble request to make playlist of 4th axis machining setup ... Take offsets of xyzA .... Make program...run it... Please make 10 videos with all details if possible....

[@JohnSL]

Yes, it's on my backlog.

[@David_11111]

Yay

[@Brother-live]

Cool video

[@kailashgavai5311]

Machine and dayi praise

[@ikifkif]

..use an impact driver

[@najimgharame4337]

Machine humko chahie

[@dass1333]

A pneumatic actuator on the lever to save wear and tear on your arm and shoulder? Repetitive injury. Keep yourself healthy. If you don't use enough to make it worth making a conversion video. 😉

[@JohnSL]

I didn't have to make very many of these parts, so no where near enough to strain my arms.

[@gregheine404]

The solution to pollution is dilution

[@pauldaniels2179]

You worry to much about the time it takes lol Just joking !

[@zeeshankhan6687]

I am really impressed and your technology is really fruitful for my country Please send your contact number