I was wondering about some of these DIY Injection molding machine books I've seen on Ebay. Anyone have any insight on these or maybe have made one. I'm considering making one anyone have any insight.

thanks,
Rob

yes I bought one of those books.
It seems pretty good but I may double the size as it can
only handle 2oz of plastic.
It will cost about 400 bucks to build. not bad.
As someone who knows a bit about plastics I think its a
good deal.

my opinion
Hope it helps

Tony

I purchased and read the Gingery book... http://www.lindsaybks.com/dgjp/djgbk/index.html

These are neat, old fashioned how-to books.. Sort of like John Kleinbauers plans(YES i bought some... 3 or 4 years ago.. I like them. They are funny)


Anyways! The machine described in the book is interesting and looks easy to build.. Could be built cheap if you happen to work around alot of angle iron.. I read it, and then fatasized about using the general design, but using cartridge heaters and pneumatic cylinders and other odds and ends off ebay to make a pretty nice benchtop injection molding machine for around $1,000.00

I may do it one day.. The drawings are around here somewhere.. But, I definiately recomend the Gingery book. Its fun and interesting and only around $15.00. I am not sure you will want to build the machine described, but it will be of interest if you want a DIY machine-shop aproach to building a demonstration IJ machine.

Note: Check out the site. They have lots of books, and on amazon there are some pages, including, i think, a page with a diagram of the whole machine.

Cheeers

I bought a Jiffy Shot sample injection molder off ebay thinking it could be used with plastics. Turns out you're only "supposed" to use it with their proprietary blue stuff for "testing molds" I have other plans. This model has 2 handles which can be attached to pneumatics and mounted to a base. The nozzle can be exchanged im guessing if using for plastics dosent work. The shot size im guessing is much larger than 2 oz. The beautiful thing is it wont inject until the nozzle is pushed down!!! it uses around 65 to 70 psi, ive only used mine to clear the blue stuff out but it works. theres one on ebay right now, and its as cheap as if ya built your own:http://cgi.ebay.com/Jiffy-Shot-Mold-Sampler_W0QQitemZ7600512632QQcategoryZ36351QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

does anyone know the consequences of using ordinary plastics in this unit? IE dripping or cloggin?

$450 dosent seem 'cheap as if you built your own'

if you have the proper tools, you could make a pretty neat injection unit with ebay crtridge heaters, a piece of steel rod, ebay pneumatic items(cylinder, solenoid valve, regulators, etc)...

Plastic pellets can react very violently under pressure and excessive heat, do you know what these pressures and heat thresholds are? If not, steer clear of messing around with these "chemicals". Being spattered with 400+ deg of sticky plastic will leave a mark! Have 30 + years as moldmaker/molder, you must always respect the high heats and pressures involved, they WILL react with no warning!!

Djplast, I understand these are some warnings I had read about a while back, as the "Blue" wax has certain properties that are supposed to keep it within the DME Jiffy Shot (and not all over the floor or in one's eyes) a more dense plastic should be retained as easily as the wax's properties do?

The "home brew" Injection molder assembly schematics were available on ebay, I happened to buy one before my purchase of the Jiffy. The folks at www.hobbyinjectionmold.com sold them, and the completed machines. Not just anyone should actually build these things. I have chosen the DME because the only difference it has (other than holding more plastic than home brew) is the all in one package. AND www.hobbyinjectionmold.com stopped making home brews because of potential lawsuits, no longer a registered domain!

I picked the jiffy for a lot less than the one in the link I posted earlier. Its just for example of whats available, and similar machines are or were up for grabs on ebay for around $320-450.

Plastic pellets can react very violently under pressure and excessive heat, do you know what these pressures and heat thresholds are? If not, steer clear of messing around with these "chemicals". Being spattered with 400+ deg of sticky plastic will leave a mark! Have 30 + years as moldmaker/molder, you must always respect the high heats and pressures involved, they WILL react with no warning!!

If you work with this Molds something a little more constructive would be helpfull.

Mills and lathes are just as dangerous as IJ machines, but more information on the danger is common knowledge. So they seam less dangerous.

A general warning to someone who is researching a project is usually uneeded as thats one reason they are researching. But what IS NEEDED is information on how to SAFELY do this are where to get this information.

So if you have good info... Give it up man! :D

Miljnor, sorry to come across as negative, just wanted to make a point of the dangers involved with this type of experimentation. These plastic chemicals are the basis of plastic explosives, they can be deadly, even in small quantities. The gases that can build up in a barrel (on a molding machine) can blow hoppers through the roof, and even crack the barrel with a 1" thick wall. I have personally witnessed the latter, not a pretty sight! Just be extremely careful.
My suggestion is to stay with a local molder to do your molding.

......These plastic chemicals are the basis of plastic explosives,......

This is an exaggeration that is chemically inaccurate. Plastic explosives are a class of compounds which contain the element nitrogen in a form of chemical bond known as a nitrate bond with oxygen atoms or as an azide bond which is between multiple nitrogen atoms; these chemicals bonds are unstable and can react explosively. Many of the thermoplastics used for injection molding do not even have nitrogen atoms in their chemical make up and those that do have the nitrogen in totally different forms of chemical bonds which are stable and non-reactive.

This is not to say that the temperatures and pressures used in injection molding are not dangerous; they are. Overheated thermoplastics can de-polymerize and form flammable and/or toxic gases which can under the correct conditions explode. But this is not any different to the explosion hazard of propane gas or natural gas. The pressures and mechanical forces used in injection molding are comparable to those in heavy duty hydraulic systems and require similar attention to correct and safe procedures.

Using exaggeration and inaccurate analogies to dramatise dangers is not helpful. Sometimes it can be counterproductive because an inexperienced person does not have sufficient knowledge to know what is an exaggeration and what is not. When they discover that part of a warning is indeed exaggerated the tendency is to discount the whole warning including the parts that are reliable. There was a fable written many generations ago about the dangers of 'crying wolf' too often.

And "Stay with you local molder to do your molding" roughly translates to don't do any molding for a DIY'er because this is a hobby for alot of folks and spending 20k on a mold is just a little outside most peoples pocket books.

So personaly I would ignore your "suggestion" and being since I read as much as possible and try to know the dangers inherent in anything I do. I will proceed as I do on all things knowing that everything is dangerous to the uninformed and ignorant.

Well, as Ive expressed my thoughts earlier that its difficult for a individual or group to sell books that help others possibly harm themselves. So, the guy that ran the above mentioned website before it was closed down mentioned melting legos and YOU CAN TELL THAT PLASTIC IS TOO HOT, based on the color of smoke emitted. Correct me if i'm wrong but isn't it grey or white? So a good temperature should be around what for melting for example, legos? Answering these two questions should clarify some confusion here and get some gears crankin.

My suggestion, Keep an eagle's eye on ebay for "plastic injection mold," "plastic mold machine," and the like. I came across 3 or 4 machines within the 350 to 500 range, even a larger what I would call medium scale machine. that one went for nearly 800 if I can remember.

I'd like to make an all electric machine using ac motor, power steering pump to move hydraulic cylinder and a PLC to controll sensors of various locations. too occupied at the moment.

DJplast

there are many thigns more dangerous for sale (guns, power tools, automobiles) to the common public than a set of plans for an injection molding machine. In fact, a common disclaimer 'this is for information al purposes... ...etc.' would be enough. There is a long history and tradition of pamphlets, books, web sites, etc teaching others how to do dangerous things in their back yards, possibly in the presence of women and children.

Checkout the gingery book. He describes a 'hobby machine' that uses a lever and plunger, a single cartridge heater, and some simple machining to make a machine.. using some really low-pressure penuamtic tubes(not even hydraulic), some heavy-duty frame material (3030 80/20?), an air compressor, 2 or 3 cartridge heaters, etc, etc... someone could build a 'low pressure injection molder'

using some of the neato low-temp IJ plastics, it could even be rather safe, around the temperature of a glue gun... and those low-temp IJ plastics, I have used them - they are much like nylon - great for prototype molding 'nylonesque' parts...

Dont be so skeptical. People have built guns, helicopters, motorcycles, wooden cnc machines, doddads, flamethrowers(i built one. it used pressurized kerosine), tesla coils, van degraff generators, etc. etc, all with the aid of either publications, public forums, or both... the danger is obvious to ALMOST anyone who is going to do these sorts of things.

'i know best, i once saw a man loose his face to a 200ton injection molding machine.. the injection pin sheared it right off, then the bloody pulp was coated with molten plastic chemicals, overmolded in bright orange TPE for grip'

otherwise, feel free to share your thoughts..

The D-M-E Jiffy shot is Professionally manufactured, comes with everything to at least allow some creativity. What I mean by this is the handles can be modified with some pneumatics and base can be modified with a vise for holding mold. Shot size is more like 4 to 6 oz I am guessing but is large and has a sealed pressurized "can" style that has versatility of 70 to 125 psi. 90v to 350v heater core is HUGE!

This saturday, I'll try melting some plastic without air pressure to see if she leaks from the nozzle. Then I will try with pressure for same results. Finally, injecting into a cavity to conclude my curiosity!

for those who must know, I got it for 300 on ebay, another 79 for my compressor and hose from harbor freight tools www.harborfreight.com totalling under 400 bucks to inject me molds ..........arrrrrrrrrr(pirate tone.)

awsome man!

Take some pictures, PLEASE!

that does sound cool.. not having to machine the injection parts would save lots of time... 300 puts it in the barely hobby range, for me.. but interested in results..


i would really like to see stuff made with a gingery machine..

Here are some machines to take ideas from.. It really seems like a cnc machine that can cut aluminum, and a $400 or $500 ebay splurge could result in the linear rod and bearings, pneumatic tubes or other linear actuator, solenoid valves, heat cartridges, PID temperature controler device... etc.

http://www.rondolusa.com/im/im.hf5.shtml

http://www.mini-jector.com/products.html

http://www.nhsouth.com/crafts/workbench/injector.htm

i wish i had time... but i have so much else going on..

'i know best, i once saw a man loose his face to a 200ton injection molding machine.. the injection pin sheared it right off, then the bloody pulp was coated with molten plastic chemicals, overmolded in bright orange TPE for grip'


Jesus!! Not to get off-topic, but, did he live??

Here is the machine I bought plans for, I cant find the webpage, this one is in canada:
http://cgi.ebay.com/Injection-Machine-Plastic-Part-Neumatic-110v-Molder_W0QQitemZ7622448839QQcategoryZ92081QQrdZ1QQcmdZViewItem
its selling for 200, plus 75 for shipping, im curious of the final price....

they had demos that made my mouth drool. the thing worked quite well and quickly, imagine automating it. I took pics of my D-M-E Jiffy Shot teardown that I will post soon, purging the old plastic out will be the turning point. Any suggestions for purging?

leberen.

this is very close to what i was imagining when isaid ebayed pneumatic parts could lead to an inexpensive and functional bench IJ machine..

if that machine dosent go above $400, it is probably a rather good start...

neato.

if anyone reading this thread has done some of this stuff, a few photos would be great...

and where did you get the plans and for how much leberen?

Here is the machine I bought plans for, I cant find the webpage, this one is in canada:
http://cgi.ebay.com/Injection-Machine-Plastic-Part-Neumatic-110v-Molder_W0QQitemZ7622448839QQcategoryZ92081QQrdZ1QQcmdZViewItem
its selling for 200, plus 75 for shipping, im curious of the final price....

they had demos that made my mouth drool. the thing worked quite well and quickly, imagine automating it. I took pics of my D-M-E Jiffy Shot teardown that I will post soon, purging the old plastic out will be the turning point. Any suggestions for purging?


the company that made that model is no longer in business. the website was www.hobbyinjectionmold.com

bobert, this I understand, I tried to search during an earlier post on this thread but hobbyinjectionmold is no longer a registered domain - not necessarily not in business.

The plans were 29.00 on ebay. For the sake of the owner's efforts, I can try to find the plans and submit contact to those interested. give me till sunday to find the plans.....

i suppose if the company is, in fact, completely kaput, it would be ok to 'release' the plans?

hmm. just looking at the machine again, those metal rods sure look light compared to that massive actuator... which brings up another possibility - an electric actuator, for those without air\a preference for an 'all electric' machine?

electric actuators are sloooooooooooooooooooooooooooow, right?

found the 30 pages of plans, the creator of the machine is Gary Periard, I cant find an email anywhere.... www.hobbyinjectionmold.com is owned by a computer company domainsbyproxy, whois by godaddy.com status is "registrar-lock" whatever that means?

ı want to fınd some şinformatıon about cnc workbenches for my summer practıce please help me!!!!

Well, as Ive expressed my thoughts earlier that its difficult for a individual or group to sell books that help others possibly harm themselves. So, the guy that ran the above mentioned website before it was closed down mentioned melting legos and YOU CAN TELL THAT PLASTIC IS TOO HOT, based on the color of smoke emitted.

I've still got the videos showing the hobby injector that you used to be able to purchase plans for. I also still have the PDF file describing the molding process using the home built machine. Everywhere throughout the PDF file it refers to the original home page of "hobbyinjectionmold.com" but I find that web address is now being used for nothing but advertisement for vendors. What happened to the orginal site? Are the plans availible elsewhere? I also remember one of the original hobby built units used a digital temperature controller from the westek company. I purchased the controller and planned on getting the plans later but now I can't find the source. Anyone got a new source for these plans.

I too have the book on making a hand press injection machine and although the book is good, I prefer the semi-automated air powered design that used to be availible from the "hobbyinjectionmold.com" site before it changed to an advertisement site.

Brad

I bought this book a year ago and I already made this machine but I didn't use it yet. Instead of mechanical thermostat I am going to use a digital one with thermocouple. This book is quite informative and provides also all the resources for the required parts. I will send some pictures of this project on this week.

Please do very interested to see outcome.
Thanks

I was wondering about some of these DIY Injection molding machine books I've seen on Ebay. Anyone have any insight on these or maybe have made one. I'm considering making one anyone have any insight.

thanks,
Rob
Yes If you like to e-mail me on "hbaldacc@bigpond.net.au" I shall give you any information that you want.
Harry

I was wondering about some of these DIY Injection molding machine books I've seen on Ebay. Anyone have any insight on these or maybe have made one. I'm considering making one anyone have any insight.

thanks,
Rob
Yes If you like to e-mail me on "hbaldacc@bigpond.net.au" I shall give you any information that you want.
Harry

Hi,

In Pakistan we can find brand new hand injection moulding machines at arround 150 USD. + shipping and handling.
If any one interested i can help.

Ahmed

hi ,
You shaould get in touch with (Rob_M) as he may be interested in such
cheap machines.

pictures of these machines would be cool to.

I will put the pictures in few days.

Ahmed

Hey Ahmed, hit us up. I'd love to see that little injection machine. Wonder what shipping from Pakistan is?

Actually shipping i think will be more expensive other wise you find lot of small machines made in Pakistan at low price let the machine come to me i will let you know the dimensions and weights.
Cheers

Ahmed

I have started a new thread for 150usd low cost injection machine and have put pictures there:

http://www.cnczone.com/forums/showthread.php?t=28305

Ahmed

Yes If you like to e-mail me on "hbaldacc@bigpond.net.au" I shall give you any information that you want.
Harry

Harry, do you still have the plans, I am looking for either a copy or a picture. I am going to build a machine, but am looking at what is out there first. Thanks in advance, Eric

Yes I still have plans for one, it will be cheaper to build one,but you must have the nessary equipment, or get the parts made , and put it together yourself. If you like to e-mail me your address ,I shall put together someplans for you.
Harry

Yes I still have plans for one, it will be cheaper to build one,but you must have the nessary equipment, or get the parts made , and put it together yourself. If you like to e-mail me your address ,I shall put together someplans for you.
Harry

It would really help me also if you could perhaps send them to me as well?
I sent you a pm yesterday with my email address, any help would be most welcome thankyou as im just about to build my own.

Yes I still have plans for one, it will be cheaper to build one,but you must have the nessary equipment, or get the parts made , and put it together yourself. If you like to e-mail me your address ,I shall put together someplans for you.
Harry

Harry,
Would you please send me one as well?
I am in the process of build one from David Gingery's book, but it is too small for my need.
I sent you a private message with my email address.
Thanks
Roland

Harry,
Would you please send me one as well?
I am in the process of build one from David Gingery's book, but it is too small for my need.
I sent you a private message with my email address.
Thanks
Roland

I need your home address, as the plans are all made on discs
Harry

yes I bought one of those books.
It seems pretty good but I may double the size as it can
only handle 2oz of plastic.
It will cost about 400 bucks to build. not bad.
As someone who knows a bit about plastics I think its a
good deal.

my opinion
Hope it helps

Tony

-

Hey Guys,
I came across this thread a while back and figured I would spend some time and actually complete a DIY injection molder. I tried a bunch of designs and I finally finished it a couple of weeks ago. I created a Hobby Injection Molder, it does approximately 2 ounces of em900 thermo plastic also known as hot glue. I figure most hobbyists can get away with lower melting temperatures and higher flow rates. I am in the process of testing out hotter plastics, including polypropylene and polystyrene. I spent a lot of time and effort working on this thing and I made a few things with it. I don't know if you guys are interested but I would love some input from you guys on its design. Anyway if you want to check it out that would be great. http://www.backyardengineer.com or feel free to email me: Kevin@backyardengineer.com

To all wanaby build a Plastic injection molder, I have build 2 machines that will do polipropolene and up to Nylon 6 and glass filled nylon, the machine has the capacity of a 26 ton large molder, it makes professionally made parts, and has acapacity of 500grams.I have e-mailed many plans to most guys like you all over the world for this machine, soon the owners of these plans will surely want to talk about this. As for you guys, Plastic molding requires high pressures of 6500 tons approx and heating capacity of no less than 200degress celcies, so unless you want to mold choclate ,stay away from plastic

Its a monster

Plastic molding requires high pressures of 6500 tons approx and heating capacity of no less than 200degress celcies, so unless you want to mold choclate ,stay away from plastic

wow! words of wisdom! maybe i should pack all my toys and go home? NOT

unless your words are constructive or informative, please keep em to your self!

As we on this forum will Adapt, improvise and over come almost all obstacles! which really is the purpose of these forums and others like them.

To all wanaby build a Plastic injection molder, I have build 2 machines that will do polipropolene and up to Nylon 6 and glass filled nylon, the machine has the capacity of a 26 ton large molder, it makes professionally made parts, and has acapacity of 500grams.I have e-mailed many plans to most guys like you all over the world for this machine, soon the owners of these plans will surely want to talk about this. As for you guys, Plastic molding requires high pressures of 6500 tons approx and heating capacity of no less than 200degress celcies, so unless you want to mold choclate ,stay away from plastic

Okay, I'll bite send me a copy of the plans.

Thanks,
Paul

I would love some input from you guys on its design. Anyway if you want to check it out that would be great.

I can not find any details on your site about your injection moulder, all i can find is marketing stuff for whatever you sell. Hot glue isnt great to use because to isnt strong and it re-melts so easily.


To all wanaby build a Plastic injection molder, I have build 2 machines that will do polipropolene and up to Nylon 6 and glass filled nylon, the machine has the capacity of a 26 ton large molder, it makes professionally made parts, and has acapacity of 500grams.I have e-mailed many plans to most guys like you all over the world for this machine, soon the owners of these plans will surely want to talk about this. As for you guys, Plastic molding requires high pressures of 6500 tons approx and heating capacity of no less than 200degress celcies, so unless you want to mold choclate ,stay away from plastic

With respect you sent me a set of drawings recently and although impressive it isnt a home machine, its a home made industrial machine, your machine does require care and attention and uses great forces but a small homemade bench mounted machine can easily be made and made to work extreemly well,

High pressures are only needed if you are injecting stiff plastic into tight moulds a smal bench mounted machine making parts of up to 2 ounce requires very little effort to operate if made well,

Temps of 200'c? i was/am under the impression that you need to cover temps up to and over 400'c if you want to mould a range of materials.

My own machine when finished will mould just slightly over an ounce of material and will be operated by a simple hand lever to push the shot in, i am going to be posting up a guide and procedure of how i made it and how someone else can copy it so you will see for yourself home made bench mounted moulders are possable and common.

Incidentally you have seen the bench mounted hand powered moulders you can buy over the counter havent you? they dont use a million pounds of presure etc.

As i say this is with respect because you was so kind enough to send me the drawings and your machine is impressive although massive, your machine is a big machien that can handle bigger numbers than a bench machine but it doesnt lessen the effevctiveness of a bench machine also a shot of 500 grams is simply not wanted by a garden shed experimenter.

Hey guys,
Scooby I apologize for not putting any specifications on my website, i will be sure to give more information. I just made the website on wednesday. I spent the past few months building it on weekends in my garage. Hot glue was the only plastic I had available. I actually found a plastics source that can send me Polypropylene resin crystals in 5 pound quantities. http://www.kelvin.com. I believe my machine using a lever will be hot enough and have enough pressure to inject PP and PE into simple molds. For example, scenary for train sets, or debree from a war era. It was meant to be fun, I wasn't trying to offend anyone with my posts and my lack of injection molding knowledge. I can say that I spent considerable amount of time building it as well as considerable amount of money. I am merely suggesting that I can send you my machine for in some cases cheaper and sooner then someone could have built one. The real waste in this project was the time. It is very clear to me that it is not designed to be used industrially although, I have designed it to be modifiable for later versions. I plan to make it run continuously, and maybe i can find a chemical company to make higher melting temperature plastics that are also high flow. Anyway Thanks for sticking up for me guys. Kevin Regan P.S If you guys would like to see the machine we are referring to please visit my site. http://www.backyardengineer.com or as always please feel free to shoot me an email: Kevin@backyardengineer.com

Sorry If I have offended anybody, I just wantedf to help out, My machine is benchtop type, and it is not an industrial machine iether, the machine was originally build for a
lab, and I have also build a rotary molding machine .

With due respect scooby, the machine is just a meter high and can be lifted from place to place with ease, and only a cheap 150 psi compresser is needed to operate it.the deis are closed by hand, a small air cylinder is needed to push the plastic through. Most similar machines that are available are not far different from my machine, it is that it has been refined to do the job better and more versatile, but it is still a bench machine. the fact that it looks more sofisticated is that it has been improved. for those that have asked me for the plans , I have spend 3weeks to find the old drawings and redraw them on a cad so that people like yourself would learn a little about the subject, I am 74 years old, I have been retired for sometime, I have no ambition to become some sort of hero or expert on the subjuct, but to forward my experience to others.

With due respect scooby, the machine is just a meter high and can be lifted from place to place with ease, and only a cheap 150 psi compresser is needed to operate it.the deis are closed by hand, a small air cylinder is needed to push the plastic through. Most similar machines that are available are not far different from my machine, it is that it has been refined to do the job better and more versatile, but it is still a bench machine. the fact that it looks more sofisticated is that it has been improved. for those that have asked me for the plans , I have spend 3weeks to find the old drawings and redraw them on a cad so that people like yourself would learn a little about the subject, I am 74 years old, I have been retired for sometime, I have no ambition to become some sort of hero or expert on the subjuct, but to forward my experience to others.

Hello Harrybaldacc;

I would also like to see those plans and learn a little more. Thanks for sharing!

Best regards,

Kreutz.

To all wanaby build a Plastic injection molder, I have build 2 machines that will do polipropolene and up to Nylon 6 and glass filled nylon, the machine has the capacity of a 26 ton large molder, it makes professionally made parts, and has acapacity of 500grams.I have e-mailed many plans to most guys like you all over the world for this machine, soon the owners of these plans will surely want to talk about this. As for you guys, Plastic molding requires high pressures of 6500 tons approx and heating capacity of no less than 200degress celcies, so unless you want to mold choclate ,stay away from plastic

I would like a copy of the plans also.

Alan

Ok Harry with all due resepct then what was this bit all about on your previous post,

As for you guys, Plastic molding requires high pressures of 6500 tons approx and heating capacity of no less than 200degress celcies, so unless you want to mold choclate ,stay away from plastic

To me and others it reads like your attacking home made machines, if that is the wrong impression then i appolagise.

OK Guys

If you know have learned anything from other posts about Injection molding you would have known that the 6,500 that Harry said was tons should have been PSI not tons for the injection pressure you need the tons part to hold the mold closed which has been said before you need about 3 to 5 tons per square inch of part surface to hold the mold closed these pressure's are quite easy to achieve even with a hobby machine

No problem there, just seams like a communication problem....no worries!

if your giving the plans out for you bench top machine though i would love to see them....send me a PM or email em to me

We should probably refer to the two as:

Mold clamp pressure.

Injector pump pressure.

I'm assuming that is what we are arguing about. I've never see a machine...so, I'm only guessing.

Harrybaldacc....count me on the plans when you're able to get to them. Thanks!

In that case reading that anyone wanting to make a moulding machine should give up unless making chocolate gave me the wrong impression.
I am sorry if i offeneded Harry, to me i thought the statement was very clear and mould pressure or injection pressure was not the point or issue and certainly not the argument, being told that im only good enough to mould chocolate and should stay away from plastic, even though hes made a machine, grated on me a bit so i spoke out, obviously im on my own with these feelings, i wont post again. Good luck with your machines.

To all wannabe build a Plastic injection moulder, I have build 2 machines that will do polypropylene and up to Nylon 6 and glass filled nylon, the machine has the capacity of a 26 ton large moulder, it makes professionally made parts, and has a capacity of 500grams.I have e-mailed many plans to most guys like you all over the world for this machine, soon the owners of these plans will surely want to talk about this. As for you guys, Plastic moulding requires high pressures of 6500 tons approx and heating capacity of not less than 200degress Celsius, so unless you want to mould chocolate ,stay away from plastic 500 grammes sounds perfect! Have you any images I could have a look-see at? :cheers:

Hey guys,
Do you guys think from looking at my machine that it is capable of sustaining actual thermal injection with real plastic. I intend on testing ABS and poly Ethylene crystals. I have gotten an email saying my machine and plastic will explode. Is that true?? Either way im gunna risk it and im trying polyethelyne saturday. If you guys have any tips or advice i would love to here it. If you guys would like to check out my hobby site that would be wonderful. http://www.backyardengineer.com or email me at kevin@backyardengineer.com

How do you get plastic into your mold on your machine kevin? from the picture it looks like you pour it in from the top?

if its gravity fed there wont be and explosion.

To have and "explosion" you have to have enough pressure build up in the system to overcome one of your machines clamps or the actually machine body. If your pump cant do this then the system will just stall.

An explosion implies flying debris, if i just leaks then well....you know, no explosion.

although safety precautions should be taken for an explosion I think a more likely outcome is burnt plastic and no flow do to melt/viscosity issues.

But im not and expert...just and armchair engineer. Ignore me :)

anybody intrested in this machine? I was going to throw it on ebay

you can see the hopper to the left of the machine

http://www.telusplanet.net/public/shackner/new/machine1.jpg

http://www.telusplanet.net/public/shackner/new/machine2.jpg

http://www.telusplanet.net/public/shackner/new/machine3.jpg

Thanks for asking Miljnor,

Plastic is inserted from the top. You are right it is poured in. It is gravity fed however, I designed the machine to run on its side, for an easier conversion to automated thermal injection at a home workshop. For those who haven't seen my machine here you go.


http://www.backyardengineer.com/injection molding 002.jpg



I would love to hear what you guys have to say feel free to shoot me an email: kevin@backyardengineer.com or check out my site at http://www.backyardengineer.com

This is an exaggeration that is chemically inaccurate. Plastic explosives are a class of compounds which contain the element nitrogen in a form of chemical bond known as a nitrate bond with oxygen atoms or as an azide bond which is between multiple nitrogen atoms; these chemicals bonds are unstable and can react explosively. Many of the thermoplastics used for injection molding do not even have nitrogen atoms in their chemical make up and those that do have the nitrogen in totally different forms of chemical bonds which are stable and non-reactive.

This is not to say that the temperatures and pressures used in injection molding are not dangerous; they are. Overheated thermoplastics can de-polymerize and form flammable and/or toxic gases which can under the correct conditions explode. But this is not any different to the explosion hazard of propane gas or natural gas. The pressures and mechanical forces used in injection molding are comparable to those in heavy duty hydraulic systems and require similar attention to correct and safe procedures.

Using exaggeration and inaccurate analogies to dramatise dangers is not helpful. Sometimes it can be counterproductive because an inexperienced person does not have sufficient knowledge to know what is an exaggeration and what is not. When they discover that part of a warning is indeed exaggerated the tendency is to discount the whole warning including the parts that are reliable. There was a fable written many generations ago about the dangers of 'crying wolf' too often.


It takes a lot of pressure to fill a mold and even greater pressure to hold the mold closed on a real injection molding machine the cavity pressure is around 5000 psi. Bench top type machines will only do some of the easy flow, lower temperature plastics effectively. What you have to watch for is is getting sprayed by molten plastic, as it will continue to burn into the skin. PVC can be dangerous to process. You never would want to mix PVC and Acetal as that can create an explosion and dangerous gas.

I think that you are making a big deal out of all this, I simply meant in my reply, to an injrection machine that was not build strong enough and that if it wre going to be operated by air or hydrolic , it would simply break.As it turned out to be , that the person building this machine was HAND OPERATED, and your experience would have told you had you seen the machine, not to make such an extreme comment about plastic explosions, and if you had some 30 years of plastic like I had you would think better.
Harry

Harry;

I still want to see your machine's plans, if possible.

Merry Christmas and Happy New Year!!

Kreutz.

Now i see KREUTZ in injection mold business;)

Now i see KREUTZ in injection mold business;)

Hi Khalid, just trying to learn something new...:)

Best regards,

Kreutz.

So what happened to Rod.M ? He starts a thread and then disappears!

So what happened to Rod.M ? He starts a thread and then disappears!

Threads gain a life of their own; dying and then getting resurrected.

Seeing that this one has resurrected I have a question that someone may be able to answer; what plastic is used for the balls in track balls?

If this question is directed to me , I do not know what you are talking about.

Threads gain a life of their own; dying and then getting resurrected.

Seeing that this one has resurrected I have a question that someone may be able to answer; what plastic is used for the balls in track balls?

If you are talking about the ones in a mouse, they are polyurethane overmolded over a steel ball.

If you are talking about the ones in a mouse, they are polyurethane overmolded over a steel ball.

Not the ball in a mouse the ones such as described here:

http://www.trackballworld.com/

mouses turned upside down.:)

I want a quick/cheap and precise way to make rigid plastic balls 2.750" diameter that are accurate to +/-0.001 for size and concentricity.

Quick/cheap means less than $20.00 including material and labor costs.

The trackball that your referring to is some type of thermoset material, like a cellulosic, polyester or melamine. The print on the outside for the optics is in all likely hood is a water transfer graphic, then it has a polyurethane clear coat. Like anything the more you get the lower the cost, I'm not sure what kind of quantity your looking at.

The trackball.... I'm not sure what kind of quantity your looking at.

Initially a hundred or so, but I don't really expect to find anyone to supply the precision I am asking for at $20 each for this quantity. Which is why I am interested in finding out what is the material with the idea of injection molding blanks that could be machined to size and precision.

Hi Geof

Do you want it to be a solid or just a thick wall I did mold some ball's at one time around 1.750 dia after molding they were tumbled & polished they came out to be with in .0001 no machining needed a lot of hour's in the tumbler to size them

Hi Geof

Do you want it to be a solid or just a thick wall I did mold some ball's at one time around 1.750 dia after molding they were tumbled & polished they came out to be with in .0001 no machining needed a lot of hour's in the tumbler to size them

Rather than totally hijack this thread I started my own:

http://www.cnczone.com/forums/showthread.php?p=543964#post543964

Hi Geof

Do you want it to be a solid or just a thick wall I did mold some ball's at one time around 1.750 dia after molding they were tumbled & polished they came out to be with in .0001 no machining needed a lot of hour's in the tumbler to size them

What material did you use? Did you use nitrogen or a chemical blowing agent?

for those interested in building a homemade injection molding machine: on Ebay there is a Simplamatic (you can search it) that is for sale for $600. I medical company that I worked for had a couple of them, they were pretty good for small parts, prototyping.