Talk:Hobby injection molding

Notability

This was split from the injection molding article, and I don't know if it should have been. I don't know if this topic has enough notability to warrant its own article. Wizard191 (talk) 20:39, 26 February 2009 (UTC)

I think this is notable for its separate readership, if still only a stub.

Just looked it up and was really happy to find it: just the kind of thing that someone would be likely to look for in an encyclopaedia rather than a technical college library. Merged or not, it has a separate readership of startups, hobbyists, teachers, people doing work in-house, and so-on. I believe it deserves expanding and when expanded would stand by itself - the trouble is I don't know enough about the topic to help.

I believe there is a UK table-top machine that's fairly manual and makes parts up to something like 15g. It is often available second-hand. I've just found another more automated machine at STVConnect in the UK with a max.15g shot. A connection in the footwear industry tells me that resin moulds are possible for only £3-400 a size but tend to be rough and break in the machine. Then there's the question of home-casting of aluminium and whether a hobbyist can make an aluminium mould. My next search is for the online web estimator of how much a professionally-made mould costs and people running online courses in moulding.Veganline (talk) 09:29, 18 July 2009 (UTC)

Fact checking, and a neutral POV

This topic wasn't so much "Hobby injection molding" as it was "Kevin Regan's injection molder". Unfortunately, the result is a great deal of bias and misinformation. Here's what I deleted, or should have deleted.

1. I removed the "copypaste" tag. Piano non troppo confused author and plagiarist; the page cited as source is parked, and is filled with snippets of text taken from other web pages, including apparently this one.
2. I removed the "unreferenced" tag. The article now has references, though not as many as you'd expect for such an interesting topic.
3. "Typical sizes range anywhere from 1-6 tons." Deleted. Writer has confused either clamping force, which holds the halves of the mold together, or nozzle force, which holds the injection nozzle against the mold, with injection pressure, which squirts the goo into the mold. Injection force (injection pressure x piston area) of an Engel ES80, is 36lb for up to 5oz shots of polymer and 54lb for up to 8oz shots.
4. "Injection capacity can range from 1-4 ounces of molten thermoplastic". Not unreasonable, but the Galomb injector is the only benchtop injector that specified capacity (2/3oz).
5. "roughly 200-300 pounds of downward force" Wayne Pearson's injector uses a 3ft lever, but actuation force isn't specified.
6. "scissor jacks" Deleted. Only Regan's design uses scissor jacks, probably because he misunderstood the design issues. In his YouTube video, he appears to clamp the mold together with wood clamps.
7. "Power requirements". Deleted. The heat capacity of polymers is extremely low; the power required by the heating element is determined by the amount of metal in the injector, which isn't a general property of benchtop injectors but of one particular design.

Perhaps the prose generally relevant to injection molding and not particularly relevant to hobby injection molding should be repatriated. Yappy2bhere (talk) 07:30, 25 October 2009 (UTC)

A few last thoughts. Kevin Regan has a Yahoo group and a website. His project seems derailed for now, but no doubt when his bugs are worked out you'll want to link this article to one or the other. figNoggle is also developing a home-brew injector, but until it's complete there's no point in citing it in the main article. Finally, Miniature Plastic Molding offers inexpensive injectors, but they start at $10K which in my opinion puts them out of the range of even avid hobbyists. However, opinions differ. Yappy2bhere (talk) 07:57, 25 October 2009 (UTC)

My compliments to yappy2bhere and other editors for making this article much more comprehensive and neutral.Jetlag44 (talk) 19:48, 30 October 2009 (UTC)

RE: Citations

I've restored the deleted reference to Galombs resins page. An inventor's claim is good enough for the USPTO, so it should satisfy Wikipedia, barring contrary evidence. Perhaps there's a better choice; Galomb claims PE, PS, and PP are suitable substrates on the resins page and again on the injector specifications page, and sells all the materials listed for use with the injector. The catalog page is comprehensive, but it only implies suitability, and since it's a catalog page it's likely to change, so I cited the resins page because it specified suitable substrate families and linked to the catalog. In any case, the claim that Galomb has used all these materials seems well supported.

I agree that the Gingery links are less than ideal. They weren't included for what is in the pamphlets, but because each page includes a picture that clearly illustrates the design, clearly enough certainly to understand how it works. There is a wireframe model of the lever actuated design, and photos of the drill press (rack and pinion) actuated design. Also, though essentially sales brochures, they include a surprising amount of useful detail about the designs, substrates, and technique.

Regan also reported success with polystyrene and "hot glue". It wasn't cited because Regan seemed to be designing to commercial specifications that he had misunderstood, so his success was understated. Really, "hot glue" should have been included as an acceptable substrate, and Regan's post cited. It just seemed too diffuse at the time, what with the Wikiwonks on their current pedantic tear to appear "encylopaedic". Yappy2bhere (talk) 04:36, 28 October 2009 (UTC)

I have opened a thread about his at the reliable source noticeboard, which can be found here: Wikipedia:RSN#Hobby injection molding. Wizard191 (talk) 17:37, 28 October 2009 (UTC)

I, Kevin Regan have no doubt used this page in a bias matter to direct them toward my machine for the sole reason of selling products and informing the public to my research. However, I don’t think it was necessary to call me a plagiarist. All of the content was original and from my own work in hobby injection molding. The use of a scissor jacks is completely relevant because it is the least expensive form of pressure attainable without the use of hydraulics or air pressure. A scissor jack can be bought for less then $20 and can generate roughly 1200 – 1500 pounds of downward linear injection force. Regarding my project and research being derailed, that is simply wrong. I simply no longer post everything I learn because my design was copied within weeks of posting my original video. My newer machine uses a fraction of the metal and is unlike anything out there. All of my research will reside at my workshop site at backyardengineer.com I apologize for any wrong doing and it was not my intention to breach any rules regarding hobby injection molding. However, if you need some help feel free to shoot me an email. Kevin@backyardengineer.com —Preceding unsigned comment added by 69.183.19.51 (talk) 20:40, 14 December 2009 (UTC)

Whoa, whoa, whoa, Kevin! No one is accusing you of plagiarism on this page. An earlier editor found a web page with text taken from this article. S/he flagged this article for possible plagiarism, assuming that this article had copied text from that web page, but s/he was wrong. That page is parked. It's filled with snippets of text from Wikipedia articles, including this article. S/he was correct that text had been copied, but that's all s/he got right, and clearly s/he didn't read the web page before tagging this article. I deleted the tag and explained why here, but neglected to link the offending edit, so of course you couldn't make heads or tails of who was being accused of what. I've emended point #1 of "Fact Checking and a Neutral POV" above; the external link will take you to the offending edit, and you'll find the offending URL in the edit summary.

Please accept my apology. I realize how serious it is to charge plagiarism, which is why I investigated the accusation and deleted it when I found it without foundation, and I should have made it clear as crystal exactly who was in the wrong, and why. For the record,

I do not believe, nor have ever believed, that Kevin Regan plagiarized any part of this article, nor have I found any evidence that suggests otherwise.

Sorry, Kevin. Yappy2bhere (talk) 23:59, 14 December 2009 (UTC)

I don't think it matters what your motives were in writing this article, nor do I think you have anything to apologize for. On the contrary, a surprising number of people are interested in this topic, and you've done them all a service by expanding this article. Indeed, I'd welcome your further help in improving it. If you don't want to divulge details about your own design, then perhaps you have insight into other designs, or into process issues that don't compromise any of your own trade secrets. I think there enough eyes on this article that peer review can be trusted to temper any editorial bias or original research that might slip in. Please remember that I only commented on those passages that I modified or thought ought to be modified. Most of what you added remains, unpraised perhaps but evidently of value.

Now to the engineering. I removed the statements about pressure and shot size because the numbers given were substantially larger than those for other successful hobby injectors. Reasons for the differences would be best, the rationale for a particular set of values would be second-best, but I lacked sources that supported either sort of statement. Do you know of some, or is it completely trial and error?

It's also not clear to me why Regan's scissor jack design uses pressure so much higher than, say, Gingery's drill press design. Is it simply a matter of shot size, or is there another issue? Again, insight is always helpful but it requires a source to include it in the article and make it stick. Yappy2bhere (talk) 02:01, 15 December 2009 (UTC)

Thank you for the apology. It means a lot. I have spent an absurd amount of time and money on my project, so much so that I should probably be committed to a mental facility. That being said I will be diligent in posting unbiased information regarding bench top injection molding. Thanks again. Kevin —Preceding unsigned comment added by 69.183.19.51 (talk) 20:21, 15 December 2009 (UTC)

Mattel toy machine

Back in the 1960s, I believe that the Mattel toy company offered both a vac-former and an injection molder as toys. US-market only, sadly. Anyone know more details? Andy Dingley (talk) 17:44, 28 October 2009 (UTC)

You mean the Mattel Vac-u-form. They also sold Creepy Crawlers, a thermoplastic casting toy. Both featured heated surfaces on which to cook children, hotter and more dangerous than Kenner's Easy-Bake Oven. Kids were tougher then, and strict liability was still but a gleam in an ambulance chaser's eye. Yappy2bhere (talk) 11:57, 29 October 2009 (UTC)

No, I mean injection moulding: hot melt polyethylene(?), with a hand-worked pressure ram. There's web coverage of it out there. Seems that it might originally have been a Kenner product. Andy Dingley (talk) 17:39, 29 October 2009 (UTC)

You were right, my friend. In this ad for Mattel's "Injector featuring The Western World" you can clearly see the ram and a two-piece mold. Do you know what the brown sheet of material is for? In photos of the toy there are what appear to be vacuum formed saddles made out of the material. (Nice photos; I'll ask if the seller will release them into the public domain.) There is a clear description of the process at Make. Mattel seems to have reincarnated it as the "Hot Wheels Factory", right down to the trademarked "Plastix" feed stock; there's a detailed description here.

You were also right about Kenner's "Electric Mold Master" (photo) In this ad for "Electric Mold Master" you can see that injection is performed with a plunger and not a lever, but the long throw suggests a reducing gear of some sort inside. (No, there was no "reducing gear". Plastic pellets were placed directly into the tubular chamber which was heated on all sides of the chamber. After loading the chamber with plastic pellets to the top the pellets were allowed to melt - usually ten minutes - then the plunger was forced down the tube and the liquid plastic was forced into the two sided plastic mold which slid sideways into and locked in the bottom of the chamber. A small hole in the plastic mold aligned with a hole in the bottom of the tubular chamber and the liquid plastic was simply forced in by pressing the plunger down. It took some force for a small kid and invariably more force if you were impatient and didn't wait long enough for the plastic to entirely heat up. A small amount of residue always lined the inner chamber and added resistance. The formed plastic article had to cool in the mold a good few minutes otherwise it didn't completely harden and came out gooey.)

Toymax's Superinjector is supposedly still made. The molds feature radial injection ports, perhaps so that clamping force is normal to injection force, allowing the two to be managed independently in the design. Very clever. Toymax was apparently reprising old Mattel designs in the late 1990s, but their website is parked now, and I don't know if Toymax failed or was acquired.

The Melt-O-Matic (tres retro, a 2000 toy with "matic" in its name) was powered by dry cells; perhaps this is the polyvinyl injector you recall, or perhaps I'm underestimating the energy in a D-cell battery.

Mattel's "Toot Sweets" (photo at TimeWarpToys) appears be either an injection molder or a compression molder, with downward force on the lever forcing Tootsie Roll upwards into a mold fitted into the top of the machine. There isn't much information available about it online, but the ad features cartoon children doing just that. If so, a real eye-popper.

I don't know what materials were used with these kits. A patent search might help, but full text search is only available for U.S. patents issued after 1975, and the trade name would only be found in the description. Toymax attempted to trademark "Plastix" but abandoned the application. Oddly, Mattel appears to have registered "Plastigoop" but not "Plastix", even though they claim registration on their packaging.

Dare we include these toys in this article? The copy for Mattel's "Injector" specifies "For Kids Only". I'm too young and pretty to go to Barbie's Jail House. Yappy2bhere (talk) 18:40, 31 October 2009 (UTC)

Article title & sub-category revision

I think this article would provide a better framework to build on if it was re-titled and organized as follows:

Revised main title: BENCHTOP INJECTION MOLDING

Sub-categories:

HISTORY

Cite various early machines. For example: Arburg's first machine

MACHINE TYPES

1. Toy machines (e.g. Mattel & Kenner)
2. Home made machines (e.g. Gingery's book)
3. Hand-operated machines (commercially sold)
4. Pneumatic machines (i.e. more sophisticated air driven machines, but still small enough for benchtop use)

APPLICATIONS

1. Hobbies: (e.g. popular hobbies such as making fishing lures, toy figurines, model railroad parts, custom LEGO's).
2. Research & development (e.g. materials testing & making prototypes)
3. Academic (e.g. teaching high school & college students about mfg. process). Cite various course curriculum of schools.
4. Manufacturing: actual commercial products produced with benchtop machines

MATERIALS

Discuss why some plastics are suitable for benchtop molders, but others are not because they require more sophisticated process controls, higher injection pressures and/or clamping forces, colorant & additive mixing capability, etc. Also cite websites such as Matweb.com where people can find technical data and process requirements for many different types of thermoplastic materials.

MOLDMAKING

1. Hand-made molds - (e.g. epoxy, plaster of paris). Cite websites that explain how to make them, such as Freeman Supply
2. Machined molds - discuss issues about machining molds, such as proper venting, gates, etc. & equipment that can be used to machine molds (i.e. benchtop CNC machines).
3. Unicast process molds. The cast to size conversion of sculptures into injection molds. I beleive it is relatively new.

Unicast molding can convert a sculpture into a metal castable injection mold. I don't know if this is new but I personally have only recently descovered it, although I personally have not yet tested it. It would allow for hobbiests to create metal injection molds for less then $500.00 eliminating the need for cnc equipment and would allow the average sculptor the ability to create complex metal injection molds. just an FYI - Kevin. BackyardEngineer.

HOW TO OPERATE

Provide links to various websites describing how to use benchtop machines or showing a video.

For example:

youtube video

youtube video

youtube video

instructables.com - step by step tutorial

Jetlag44 (talk) 17:30, 31 October 2009 (UTC)

Sure. There are some references to toy injectors above, but I don't know of a hobby pneumatic injector. The nearest I've seen is Miniature Plastic Molding's Model 45, which at US$9,800 with pneumatic clamping and automatic injection seemed of a different class from the hand injected units with screw clamps described here. Is it still a hobby at that point, or an obsession? Perhaps you're suggesting that this article provide a segue from one-off hobby machines to short run production machines.

Do you know of someone who's made Legos? I'd have guessed you need pressure to get enough definition for the little clicky receptacles on the bottom of them to work properly? Yappy2bhere (talk) 19:11, 31 October 2009 (UTC)

I support the idea of moving the article to benchtop injection molding. My only note is that we can't have a "how to operate" section because of WP:HOWTO. Wizard191 (talk) 20:13, 31 October 2009 (UTC)

I don't know that's what Jetlag44 intended. The content is useful and appropriate, whether subsumed under i.e. a Current Practices or a Techniques heading or listed, with brief descriptions, as External Links. Discussion of how technique influences temperature, flow rate, injection pressure, etc. and how these factors in turn affect the molded product isn't a "how to" guide. Given the variety in hobbyist designs, I don't believe that one "how to" guide could cover them all anyway.

I neglected to ask earlier, but is changing the article title somehow better than redirecting benchtop injection molding? Yappy2bhere (talk) 21:37, 31 October 2009 (UTC)

I feel that benchtop injection molding is more encompassing than hobby injection molding, because benchtop injection moldering is use for other reasons than hobbies, such as outlined above (R&D, manufacturing, acedemia, etc.) Wizard191 (talk) 23:01, 31 October 2009 (UTC)

I'd prefer "hobby", as a closer match to the content than "benchtop" - I've had some very expensive kit on my bench before now. "R&D" is also more likely to be using 3D printing these days, and that's out of the price bracket of the equipment described here.

The crucial factor here seems to be "injection moulding with limited ram pressure". That's what limits the capabilities, that's what is limited by the budget. The simplest way to word this would seem to be "hobby" rather than "benchtop". Andy Dingley (talk) 23:58, 31 October 2009 (UTC)

I suggested "benchtop" for the reason wizard191 alluded to. That is, because it's not descriptive of any one "type" of user, but rather simply implies injection molding on a small scale (for whatever purpose). I also believe a more diverse pool of contributors will be able to provide information that some hobbyists may be unaware of, but could still benefit from.

As yappy2bhere suggests, creating a separate article is also an option. My only intent was to avoid redundant content because much of same information that applies to "hobby" injection molding also applies to small scale injection molding in general.

The debate may be academic anyway since Wikipedia articles seem to be connected more like a spider web than a hierarchy. So if I do write a new article, I guess the hobby injection molding article could simply be revised if necessary to not duplicate whatever generalized information is already provided under benchtop injection molding. Jetlag44 (talk) 04:48, 4 November 2009 (UTC)

I wasn't suggesting a new article. I was suggesting an alias for an existing article. If you type pie fight into the search box you will be taken to an article on Pieing (really!) where you'll see printed beneath the article title "(Redirected from Pie fight)". Wikipedia recognizes Pie fight as an article title but there is no separate article for it, only a link to Pieing. I don't know how to do that, only that it can be done. What I asked was, does it matter which is the link and which is the article. If it matters to you, then "yes". It's all the same to me, as long as I can still find it. Yappy2bhere (talk) 15:25, 4 November 2009 (UTC)

Yappy, what you are referring to is a redirect, and they are quite easy to create. As to the title of the article, I fully think that the naming is important. As stated above, I still think the article should be moved to benchtop injection molding for the reasons listed by jetlag. If we move the article to that title a redirect will automatically be created. Wizard191 (talk) 15:57, 4 November 2009 (UTC)