Hobby Injection Molding

By injection molding do you mean a machine that can melt the plastic and inject it into a cavity in the mold?

I cannot see the required components (heater, screw, die etc.)

Sorry, Yes i did mean an injection molding machine. A hobby design that can heat plastic and then inject it into a die. The picture on my site doesn't have the handle attached. The element and attachments are protected to prevent burns and the die is not evident in the picture. I will be sure to be more clear on my next post, as well as show a better picture. Thank you for the heads up. If you check my site http://www.backyardengineer.com after saturday I should have the handle attached. Thank you for your feed back and I hope that is a little clearer of a question. Please feel free to email me at

kevin@backyardengineer.com

Kevin

Hi Kevin -

You obviously must have experience in injection molding. Please register as a member and become one of the family.

I will surely watch your site. Best of luck with the project.

What is the intended maximum volume or size of parts?

Are you making your own die´s ?

I concur completely, he should join CR4 asap!

Not quite sure how relevant this is: but have you checked out polymorph plastic? It's very strong when set but melts at a very low temperature. You get it in granule form; tip it in boiling water; fish it out with tongs; shake off the water, and then you can mold it in your hands like plasticine.

Hello Randall:

Just a note to say thank for the 'Putty' link.

Looks like the stuff I could have done with on several occasions!

Take care, and happy holiday.................

Hello Randall, here across the pond the trade name is Friendly Plastic, Here is the google link .

Thanks for the info. I like to prototype.

Brad

Thanks for the link. I, too, have been looking, and am on the same side of the pond as you. I just couldn't spring for the VAT, and the shipping, to send for it from the other side.

Mike

Anytime Mike,

Snowing like mad here and blowing wind chill below 0 Global warming bah cool summer and cold winter.

May you happy holidays be warm and cozy.

Brad

I saw this website: http://www.techkits.com/pim/index.htm

They are selling a low cost plastic injection molding machine for home or small business use.

Looks interesting...

Ed

Nice!

Hi, there are two suitable approaches:

either use a cold polymerisation of precursors that can be cast as being very fluid,

(http://www.chemyq.com/En/xz/xz6/53114uapeh.htm)

or try a small hydraulic unit (hand operated) to force a melt out of a second hydraulic cylinder. Melt to be molten from ordinary plastic powder or chips or granulates without screw type extruder by simple thermal contact. This is requiring better than usual evacuation to prevent excess oxidation and pores from water vapor.

If shot weight is small (micro injection molding) then commercial machines use this approach!

Second hydraulic cylinder may be exchanged to a very big diameter, very small stroke cylinder so heating up is fast and without problems.

Why using plastics. Metal casting is much easier?!

RHABE

Instead of an injection mold machine where cost of dies can become prohibitive for a backyard engineer, try this:

http://www.fabathome.org/wiki/index.php?title=Main_Page

Fab at Home 3D printer. Kit costs $2750US and quality of parts are first rate.

UFG

That is a great machine!

Years back I saw an HP Deskjet converted into something similar. It used a UV reactant paste which hardened when the UV light came on. Always wanted one.

Or cheaper still:

http://www.reprap.org

I think you may have something here.

To make it viable, the ability to create the dies easily should be considered. A ceramic kit or something???

I wouldn't give away all your tricks though. Like developing a low temp process and only use your own "hobby" plastic. Money is in the future supply.

You could have a whole cottage industry of home created plastic stuff based on your machine.

Don't forget to package it pretty and get on the shopping network.

Cold ceramics is not too expensive.

Gypsum may do the job too.

Particle filled epoxi is good if some outer bandage takes the circumferential stress.

Fine sand fired with glass powder or clay or porcelaine?

RHABE

Hello Guest,

yes you should join, like now! This is a really interesting thread, thank you.

Take care.........and happy holiday.

Thanks guys, I didn't realize that there was even an interest. I was kind of just crossing my fingers. In response to a persons question about creating dies. I planned on two forms. One way to go would be to use molding epoxy. The material is strong enough to make the shapes quickly, so one would not need heavy equipment. The second way was by using a thermoforming machine to make plastic baking cavities. Hot glue which is what I used for my first experiment has a low melting temperature and I am able to make what I call 2 dimensional shapes with it. I plan on posting those results on saturday. After being in this thread for a few minutes, i had never even heard of a raprep machine. However, if an individual were to combine my thermal injection capabilities and a raprep machine, I think we might have a winner. Thank you guys so much for the feedback. I will look into using, clay, gypsum and any other ideas you guys might have. Is there any chemists out there who might want to delve into creating a mid temperature high viscosity plastic. I am amazed at how knowledgable everyone here is. Thanks again guys, if any of you want to see the results of my machine can do first hand send me your mailing address to kevin@backyardengineer.com . l will send you all some samples of what it can do. Maybe you guys have some ideas of your own. I don't see why we can't have some fun with this stuff. Thanks again

Kevin Regan http://www.backyardengineer.com

p.s. I will make sure to get myself all registered and a part of the team.

Thank you and Welcome to CR4. You could post here to let us know your avitar etc.

Brad

Yes I would like learn more about this. Pics and all...Share please.

Sean_rashti@yahoo.com

Hey Guys,

Ok so based on some of the emails you guys sent me. Everyone wanted to know if I could get it to do polystyrene and or harder plastics. So this weekend I tested polystyrene with some success. Anyway If you guys want to take a look I made a couple of modifications to allow for higher tonnage and clamping pressure. Also the picture on the right of my homepage shows parts I made with my injector. Red is Polystyrene and Blue is hotGlue. Anyway Does anyone have any ideas for other additions or things that I could try. Feel free to check out my site. http://www.backyardengineer.com

Thanks again,

Kevin

Hello Kevin R:

You ask about 'other things you can make'. How about molding a key in plastic that is not brittle, so it does not break in the lock?..........Polyproperlene? Not sure of the spelling.

I have got to your site a couple of times, and it is interesting!

Take care and have a wonderful holiday!...............

Hello babybear:

Yes it is possible to mold a key. Currently the only two types of plastic i have tested are hot glue and polystyrene. One is to soft, the other is to brittle. I will try polypropylene and or ABS in my next experiment. Thanks so much for checking out my website. I will be sure to test out key making and send you the results or post them when I have done it. Take care and have a wonderful holiday as well.

Kevin

http://www.backyardengineer.com

Hello Kevin R:

I see you have tried metal casting. Is pewter too soft to make a key with?

I'd guess that Pewter will just wind you up with a big locksmith's bill, as it has a very poor shear strength (what it takes to keep it from breaking while twisting it in any lock that hangs even a little bit). On the other hand, I know that the AAA Auto Club here in the US used to offer a key to its customers for one-time use (all it was good for, but it was GOOD for that!) that was made out of something called FRP, for Fiberglas Reinforced Plastic. I don't know how moldable that is under pressure, but I know it is extruded for into 4 foot by 8 foot panels for making carport and shed roofs out of, and it holds up tremendously well as a roof, as long as no one walks on it. It does crack if you step on it, since it has a kind of "running w" shape to it, and if you step on the peaks, it breaks them down into the valleys (trying to flatten it out) which makes it crack. Then it leaks in a rainstorm and starts to break down rapidly. Probably that last is due to UV rays in sunlight, I'd guess.

But it might work, if it is extrudable. I don't know.

Kevin, I wanted to point you to Lindsay books, as a publisher of a lot of fairly esoteric and hard to find how-to books that are probably right up your alley. Their web-site is www.lindsaybks.com. Their catalog is free, and it has a bunch of useful stuff in it, most at pretty good prices, and most short on text, and long on detail drawings of how to do, or build to do, whatever is of interest to you.

Micahd02,

Thanks for the tips on good books, I will be sure to get their catelog. I have come across their site a couple of times and I have asked my girlfreind to get me some books from their site. Thanks for the information though. I wonder are you also interested in esoteric plans as well, being that you have pointed me toward them??

Baby Bear,

I apologize baby bear for not answering your pewter question. I will have to look into it, currently I do not know the answer.

Kevin

http://www.backyardengineer.com

Hmmm. Kevin, I thought I answered you on this one. Yep, I am interested in esoteric plans and information. Remember a conversation you had with another CR4 reader about "housekeeping engineering?" Well, that wasn't another reader. It was I.

I have another couple of sites that might interest you. One is for a magazine, and it isn't all that cheap. But I just subscribed again, for my third year. It IS worth the price. Its at www.makezine.com.

The other is free, and has more information about things I KNOW you are looking at (plans for 3D printers, plans for injection molders, a lot of stuff like that, and detailed how to build its, along with discussions from both us wantabes, and the guys who already built one and have comments on it, or improvements to it). That one is at www.instuctables. com

Enjoy.

BTW, I looked at you site links again last week, haven't had time this week, and its looking better by the day. Let me know what questions you might be looking for answers too, related to our earlier e-mails. If you want, I'll try to answer them here. It might spark some good discussion, to further both our knowledge bases.

Micah

I apologize. I didn't realize Ha ha yes you did answer me on this one. Your email and your User name here are similiar but not identical. That mistake wont happen again. Thanks for your input. I will be sure to check out the sites that your recommended and I will be sure to post some questions here for you and everyone when I am having some difficulties. Again I am sorry. Thanks for the compliment on the site. I am trying to spend some time everynight but the bulk of the work is done on the weekends.

Be well and happy holidays if i don't talk to you.

Kevin

http://www.backyardengineer.com