Injection Molded Parts: Newsletter Challenge (04/10/07)

Well, I always used to say of my Alma Mater (University of Missouri at Rolla, formerly Missouri School of Mines and Metallurgy), that UMR stood for Universal Misery in Rolla. Now they are going to change the name of the institution (seriously, dude!) to Missouri University of Science and Technology, or, in short form, Missouri S&T, or MST.

Hmmmm, could it be......Miserable, Sad, and Tragic?

By the way, where did your St. Louis friend go to High School?

Struth Cobber.

Point One: Calm down

Point Two: Actually I made a flat screwdriver a Phillips head screwdriver, a BBQ egg flip and a BBQ Fork.

Point Three: Read the Question.

The question stated "You are working on a factory dock"

I know female secretaries that work on factory docks.

It doesn't state whether the person is an experienced factory worker, secretary or the janitor.

Point Four: At no stage in the question was it stated that the parts were produced en mass in a factory. "You are working on a factory dock when a pallet loaded with large injection-molded plastic parts is delivered."

It could have taken 6 months for the pieces to be made. You don't know. They are not made in your factory "delivered"

I worked on a factory dock once, we delivered bread.

Question didn't state what the factory produced.

Point Five: Who said that the person on the factory dock was a factory worker or whether they had even come across anything like this before? The question didn't mention whether the person on the factory dock was experienced or not.

"The parts described were much lighter than what "you", an experienced factory employee who has handled many other plastic parts, would have expected given the size, shape, and design of the parts."

Point Six: I didn't read in the Question whether the person on the factory dock considered design or not.

Point Seven: Yes it is relative but if I had a choice I'd rather get hit by plastic than steel.

Point Eight: You wrote that the parts came from "a modern, high-pressure injection molding process?" This wasn't stated in the Question, more of your assumptions.

Point Nine: "dancy" is the last name for a pretty boy English Actor. You figure that one out.

Point Ten: "but you are the only one giving your "answer"." But does that mean I'm wrong? Check out POST #4.

Point Twelve: So KISS my Yank bum, you Limey! . Why insult my heritage? Did I start the insults? Yes my forbears came from the UK. No they weren't given Limes, because they were convicts. So you get your data from movies? That doesn't sound unusual does it? Didn't "All" of your forbears get kicked out of the UK for their wayward religious beliefs? Yes, I can generalize too.

You get your signoff from a fictional character. Mmmmm

Point Thirteen: What I was trying to get across you sanctimonious twit was that you should consider a simple answer first. Why do you assume that the answer is complex?

Point Fourteen: This is a discussion page. I'm not out to impress anyone. I don't have to or care what you think. No one knows me; I just put in my two cents because that is how things are achieved in the real world. The more discussion the better we can define the problem. If my post isn't correct in relation to the question so what? So you know my experience do you. That would be a good trick as I haven't given you my resume.

Point Fifteen: Glad that you weren't the engineer on the Apollo 13 mission that redesigned the CO scrubber. Or they astronauts would still be floating around up there until you thought of a really, really good idea.

"Point One: Calm down"

Point One: Lighten up!

"Point Two: Actually I made a flat screwdriver a Phillips head screwdriver, a BBQ egg flip and a BBQ Fork."

I really don't care what you made. You could have made a whole plastic BBQ grill for all I care, it has nothing to do with the question.

"Point Three: Read the Question. The question stated "You are working on a factory dock" I know female secretaries that work on factory docks.It doesn't state whether the person is an experienced factory worker, secretary or the janitor."

Do you not understand the concept of inference? Things do not always have to be spelled out in black and white.

"Point Four: At no stage in the question was it stated that the parts were produced en mass in a factory."

Let's see, how often do factories buy multiple parts from tech schools made in a manually clamped mold, with hand-cranked plastic injection? Read between the lines!

"It could have taken 6 months for the pieces to be made. You don't know. They are not made in your factory "delivered" IRRELEVANT

"I worked on a factory dock once, we delivered bread." IRRELEVANT

"Question didn't state what the factory produced." IRRELEVANT

"Point Five: Who said that the person on the factory dock was a factory worker or whether they had even come across anything like this before? The question didn't mention whether the person on the factory dock was experienced or not."

Point Five? It sounds exactly like Point 3! If you are going to number your points to try to impress people with how much you know, at least do not repeat yourself.

"Point Six: I didn't read in the Question whether the person on the factory dock considered design or not."

Oh, wow! Good point! I will give you that one. BIG DEAL!

"Point Seven: Yes it is relative but if I had a choice I'd rather get hit by plastic than steel."

Good, hold still so I drop this (solid) plastic bowling ball on your head!

"Point Eight: You wrote that the parts came from "a modern, high-pressure injection molding process?" This wasn't stated in the Question, more of your assumptions."

Yes, and pretty good ones I would say. No worse than your assuming the parts were made by hand-cranking pasty low-temp plastic goo!

"Point Nine: "dancy" is the last name for a pretty boy English Actor. You figure that one out."

Well, if you are going to be nit-picky, at least I know that proper names require capitalization!

"Point Ten: "but you are the only one giving your "answer"." But does that mean I'm wrong? Check out POST #4."

You are using #4 as an example? At least your answer had some imagination to it. (Sorry about the "Lame" part. I was only kidding about that, but you are still wrong.) Post #4 only describes the basics of simple injection molding in the most general of terms. It begs the question. It also, like your answer, does nothing to explain why the parts are lighter than usual.

"Point Twelve: So KISS my Yank bum, you Limey! . Why insult my heritage? Did I start the insults? Yes my forbears came from the UK. No they weren't given Limes, because they were convicts. So you get your data from movies? That doesn't sound unusual does it? Didn't "All" of your forbears get kicked out of the UK for their wayward religious beliefs? Yes, I can generalize too."

Uh, geomech, if you noticed, I placed a Smiley icon after that statement. It was intended to be humorous and not to be taken personally, but I see you are a person of very little humor.

Actually, all my forbears left Europe (different parts of it) between 100 and 250 years ago, not because they were convicts, or religious fanatics, but because there was no opportunity to better themselves in the Old Country, which clung to a Medieval social system that prevented people from benefiting from hard work and ingenuity.

"You get your signoff from a fictional character. Mmmmm"

Oh, that image gets you hot, does it? So what if I use a fictional character? What the heck is a "geomech"?

"Point Thirteen: What I was trying to get across you sanctimonious twit was that you should consider a simple answer first. Why do you assume that the answer is complex?"

Sanctimonious twit? Ouch, that hurt, you meanie! I am going to tell your Mum on you! I never assumed the answer was complex, but your "simple answer" did not answer the question completely or correctly.

"Point Fourteen: This is a discussion page. I'm not out to impress anyone. I don't have to or care what you think. No one knows me; I just put in my two cents because that is how things are achieved in the real world. The more discussion the better we can define the problem. If my post isn't correct in relation to the question so what? So you know my experience do you. That would be a good trick as I haven't given you my resume."

"...not out to impress anyone." Is that why you wrote out 15 long points and numbered all of them, because you weren't out to impress anyone? Hey, if anyone believes that, I have this bridge in Brooklyn I would love to sell at a fair price! Discussion is one thing, drawing a conclusion is another. It wasn't up to you to define the problem. That was done my the author of the question. Maybe not done very well, but then that's when you have make some assumptions and try to understand what was implied by other clues in the question. It is a "Challenge Question" after all. Can't make it too easy, or too simple! If you draw a conclusion, you need to be able to defend your answer and yours is indefensible because it is wrong! Again, see the correct answer that has been posted by the author.

"Point Fifteen: Glad that you weren't the engineer on the Apollo 13 mission that redesigned the CO scrubber. Or they astronauts would still be floating around up there until you thought of a really, really good idea."

Oh, ya' got me again! Stabbed right in the heart! This is a "Point"? Looks to me just like an insult and has nothing to do with the problem. And you didn't even use a smiley to let me know you were just kidding, so I have to assume (oh, there I go again!) that you are serious. Are you?

Well, I may not have been the engineer that redesigned the CO scrubber, but I was the engineer who redesigned a world-class, state-of-the-art eye surgery system, so if you or one of your loved ones ever needs cataract surgery,....well, you will just have to wonder (hee, hee).

O'kay.STL Engineer. You Win. I'll admit defeat. You made some very good points, well alot of good points. Sorry i was having a crap week. No i was not serious about the Apollo scrubber, I'll use the smilies in the future. Thanks for the time you took to reply. I think I needed that. It was like a slap in the face with a wet fish. Everybody should have it done regularly, just to keep your feet on the ground . Actually I'm working on a whole plastic BBQ at the moment. I am so used to working with people who need to be told in black and white what to do that i'm starting to dumb down. Maybe I need a good bang on the head. Yes, I'll concede that my humour level was at an all time low last week.

Can we please forget about the last couple of entries. I think i might go and have a bit of a lie down. My eye-sight is starting to fade.

P.S. If your in the same game as the late Dr Fred Hollows. Cool.

Geomech is short for Geomechanical.

couple of additional thoughts -

a) both exothermic and endothermic reactions in structural foam molding can be counted on for weight reductions - on the order of 5-30% by volume, so if the part by volume weighs less than 70% or so of what a corresponding solid plastic part weighs, then it is likely that the walls are hollow as postulated earlier - probably with an open hollow gas pushed core area (or <GASP> lost water [ICE] insert - no mention was made that every surface of the part was closed). Another couple clues would be how 'stiff' the walls were and a hollow sound when rapped with the knuckles -

b) large "Structural Foam" machines actually are similar to "Injection Molding" machines in the sense that both use a screw to plasticate the material and deliver material to an accumulator. The Structural foam machine has an extruder that plasticates material and delivers it to the shot accumulator, then usually a hydraulic ram delivers the material. The Injection molding machine rotating screw retracts as material is delivered to the tip of the screw filling the accumulator - then the Injection screw rotation is stopped and it is pushed forward to fill the mold with the material in the accumulator. In either - at temperature the thermal foaming agents begin to act to reduce weight by volume during the plastication with cellular entrainment. The Injection Molding machine distributes the material through an orifice at HIGH PRESURE through the gate into the sprues (feeding manifold) area - and fills basically the whole mold at once requiring high tonnages of injection and clamping pressure to hold the mold closed during fill and pack. On the other hand, the Structural Foam machine distributes the material at LOW PRESSURE through a sequential manifold and only fills a portion of the mold at a time and sequentially fills the mold.

c) The major difference is that much larger parts can be made in a machine with much smaller tonnages of mold clamping pressures using the structural foam method using a cheaper machine which generally reduces the machine time portion of the manufacturing cost. The lower pressures allow the material to push, and move slightly until foaming packs, and the ability to creep slightly along the mold surfaces slightly during cooling allows for some 'swirling'. Interestingly there is an additional gas process that inserts inert gas between the foam and the mold until the mold is pushed full that reduces the 'swirling' in structural foam parts and increases part finish quality - lack of swirling doesn't automatically mean injection molding.

My guess is that it is more likely that that the parts with such thick walls are structural foam in nature.

the PLASTIC portion of your forum was interesting -

Jim Wilson

This is most likely roto-molded but is decieving because "injection molded" is also stated. In roto-molding you dump (by hand) plastic pellets into the mold before heating and rotation which results in a hollow structure part.

The injection moulded part is probably made with a plastic material that has a foaming agent added. Essentially as the plastic granuals are heated in the moulder, the foaming agent is activated. Activation will be a chemical reaction causing a gas to form within the molten plastic ( foam ). This is injected into the mould at a reasonable pressure & reasonably fast speed. The swirling pattern created on the mould surface is due to the filling pattern & the various densities of plastic that freeze on the mould surface. The darker colours will be of plastic with little or low foam & the lighter colours with be of lower density foamed plastic. Generally large pallets & crates are made with this method. If I get out of the gate with out hitting anything, it's a good day!

Yadda,yadda,yadda.

oops I mean, Yoda,Yoda,Yoda.Luke....Use the fork......

So let me get this all straight: The light sabers are used to form the swirls in the injection mold mirrors?

Nitrogen injection

space, or other gravitationally challenged environment

how, not where

Well, then, I'll bet the Keebler elves were involved!

Injection molding is a little bit like elfin magic.

I believe the parts are made using Gas Assisted Injected Moulding (GAIM) process, that creates one or more hollow channels using compressed nitrogen while the parts are injected.

There are few advantages using this process like: reduced cycle time, raw material savings and weight reduction. This explains why the parts are relatively light.

PT

This article on Structural Foam Molding seems to cover it:

http://www.pslc.ws/macrog/mpm/composit/fiber/process/foammold.htm

"Structural foam molding is a modification of the injection molding process previously discussed. Many large structural parts require thicker walls than standard injection molding can produce. Structural foam molding allows for the injection molding of thick wall parts through the addition of a foam agent. Any injection moldable thermoplastics can be foam molded. To produce the thicker wall part, a small amount of nitrogen or chemical blow agent is introduced into the plastic material. Under pressure inside the injection screw, the foaming agents do not expand. When the melted plastic enters the mold cavity, foaming occurs. As the foaming plastics fill the mold cavity, the wall of the part solidifies against the cold mold wall. A thin layer of plastic solidifies without foaming along the mold wall. This thin layer forms a skin structure over the foamed inter core. The thin solid wall is supported by the interior cellular foamed structure.".........................................."But, the foaming of plastics causes a swirling blemish on the surface of the plastic part. ".........................................

This article has pictures:

http://www.trexel.com/AnwendTechnik2005.pdf

No math this time, just googling.

This Q seems to have collapsed rather than frothed up . If anybody is bored at the weekend , they might want to think how an Aero chocolate bar is made - smooth surface , evenly distributed bubbles in a chocolate matrix within . I don't have a clue because Nestle own the patent. At least you can eat the results of experimenting.

If there is a patent on this process, then it is available for all of us to read...have you got the exact title? Or patent number? Were Nestle the originator of the patent (or were Aeros part of the Cadbury's stable before Nestle bought them?)?

The great thing about patents is that the price you pay for the 20 year monopoly is having to tell everyone how it's done!

And I think you'll find it's a two stage process - the bubbly bit is made in one machine, cut & shaped and then coated with solid chocolate. This is obvious if you eat the mint ones...

I think it's based on cocoa-butter that is aerated while in the semi-solid state, and the other ingredients mixed in later. Rather different from foaming plastics...

CH450131 or US3542270 should give you some idea.

I tried eating one once when it first appeared - decided it was a way to sell air to the toothless. (Give me dark chocolate any day).

Fyz

I tried eating one once when it first appeared - decided it was a way to sell air to the toothless. (Give me dark chocolate any day

Agreed , milk-chocolate is for amateurs .Still , when did they make it , why , how , the questions keep on coming. At least this is one you can get stuck into with justification. Galaxy is for a sugar rush , dark chocolate , well..

Will you sign in Fyz ! I have to do frequency analysis of letters to check it's you !

I'll fight you for the dark choc!

I scavenged the fact from a book ('Does Anything Eat Wasps') which I don't have to hand , but apparently the patent held in the UK does not divulge the secret (that was made clear by a response from the patent office ) - It is entirely possible to patent a process without revealing the 'how'. If I'm back here tomorrow (OK , when) I'll post more info. I wasted a good hour looking at US patent records this morning , so have to make amends for a while .An Aero is way more interesting than the original question , especially since the exact answer is not published and those who can get one can enjoy it.

Nearly forgot :

Description of GB459583

lSecond Edition l

PATENT SPECIFICATION

459,583 Complete Specification Left: Mareh 26, 1936.

Complete Specification Accepted: Jan 11, 1937.

PROYISIONAL SPECIFICATION.

-Improved Process for Nianufactqring Articles of Food or Confectionery.

We, JOHN WILLIAM TODD, of 131, Fifth Avenue, Tang Hall, in the City of York, British Subject, and ROWNTREE AND COMPANY LIMITED, whose registered office is at the Cocoa, Works, Wigginton Road, in the City of York, a British Company, do hereby declare the nature of this invention to be as follows This invention relates to a process for manufacturing articles of food or confectionery which possess, at ordinary atmospheric temperatures in England, that is, at temperatures up to about 750 F, throughout or in part a cellular structure or porous formation and which are formed from a food or confectionery substance consisting of an edible fatty medium, which is fluid, liquid, semiliquid, or molten, at temperatures exceeding about 90 F, and which may contain one or more edible ingredients, such as, for example, sugar, cocoa, milk, nuts and fruit The term " cellular structure or porous formation'" is in this specification to be understood to mean a structure or formation comprising an exceedingly large number of more or less spherical cavities located comparatively close together and readily visible to the eye The average distance between the cavities may be as much as three or four times the average width of the cavities, but preferably their distance apart is much less than their width.

The process according to the present invention consists in distributing or dispersing in the food or confectionery substance, while in a fluid or like state, a very large number of separate but closely associated bubbles of air or other gas, in inflating or distending the substance to give it a cellular structure or porous formation by the expansion of said bubbles and in cooling the substance either artificially or naturally while in its cellular or porous condition in order that it may set and solidify in this condition and not collapse back into its original deflated state.

The method used does not require the elimination of any moisture or other substance whihmay be volatile under the conditions described in the method of manufacture 55 One method of carrying out the process according to the present invention consists in mechanically introducing air or gas in the form of innumerable minute bubbles, into the substance while 60 in a molten condition by means of a whisk, centrifuge, or other known means of aeration, under atmospheric pressure, and in reducing the external pressure on the substance, so as to cause said bubbles 65 to expand to a size easily visible to the eye, thus imparting to the substance a cellular formation The size of the expanded bubbles and the nature of the cellular structure may be varied by vary 70 ing the external pressure and also bv varying the temperature In order that the cellular formation may remain permanent at ordinary atmospheric temperatures normally experienced in 75 Pngland it is necessary to chill or to set the material or to allow it to cool, while still maintaining an external pressure less than atmospheric pressure.

One example, with variations, of 80 this method will now be described with particular reference to a, substance consisting of cocoa, sugar, milk, and cocoa butter, such as is used for the manufacture of milk chocolate This 85 substance is taken simply as an example of a substance consisting of a fatty medium containing a number of ingredients.

The chocolate is warmed and well 90 mixed until it takes a liquid or semiliquid form It is then thoroughly aerated by being passed through a wbisk, or centrifuge, or other known means of aeration After the material has been 95 treated in this way, it is tempered in any of the ways commonly known in the chocolate industry and then deposited either by hand or mechanically into moulds in any of the ways commonly 100 known The external pressure on the chocolate is now reduced, say to a pressure of two inches of mercury This may be effected by providing each mould with a cover plate and exhausting the interior 105 of the mould, or by placing the moulds if Application Date: July 11, 1935 No 19,884/35.

a vacuum chamber and applying to the chamber the necessary degree of vacuum.

On the external pressure being reduced the bubbles of air inside the chocolate expand and distend the chocolate and produce a cellular formation Some of the bubbles may coalesce The reduced external pressure is maintained until the chocolate has become inflated or distended and has set or solidified sufficiently to retain its cellular formation at atmospheric pressure Preferably during this period the moulds or the vacuum chamber are subjected to a cooling operation, by means of a cold air blast, or by direct or indirect contact with a cold liquid The chocolate may be either completely solidified whilst under the influence of the vacuum, or it may be solidified just sufficiently to retain the cellular construction when the external pressure rises to the atmospheric pressure.

The final stages of solidification may then take place under atmospheric pressure These final stages of solidification may be accomplished by passing the moulds through an ordinary cooling chamber or by any of the known methods in the chocolate industry The cakes of material are then knocked out from the moulds in the standard way as employed for chocolate moulding.

Another method of carrying out the process according to the present invention comprises aeration by means of a whisk, centrifuge, or other known means of aeration, at pressures greater than atmospheric pressure, and expanding the bubbles by reducing the superatmospheric pressure to any desired extent, and chilling, or setting, the material.

Dated this 5th day of January, 1937.

CLEMENT LEAN, B Sc, A.M I Mech E, Chartered Patent Agent, Thanet House, 231/2, Strand, London, W C 2.

COMPLETE SPECIFICATION.

Improved Process for Manufacturing Articles of Food or Confectionery.

We, Jo HN Wi L Li Am TODD, of 131, Fifth Avenue, Tang Hall, in the City of York, a British Subject, and ROWNTREE AND Co Mi PANY Ln Lr ED, whose registered office is at the Cocoa Works, Wiggington Road, in the City of York, a British Company, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:-

This invention relates to a process for manufacturing articles of food or confectionery which, at ordinary atmospheric temperatures in England, that is, at temperatures up to about 90 F or 320 C, possess throughout or in part a rigid cellular structure or honeycombed formation readily visible to the eve and the cellular portions of which are formed from a food or confectionery substance consisting of an edible fatty medium, which becomes fluid, or semifluid, at temperatures exceeding about F or 320 C, and tends to become more rigid at temperatures below said temperature, for instance, cocoa-butter, and which may contain one or more edible ingredients, such as, for example, sugar, cocoa, milk, and like materials.

Said ingredients may have been ground with the medium to form a homogeneous paste at temperatures exceeding about 900 F or 320 C Said rigid cellular structure is lost at a temperature not greatly exceeding the aforesaid temperature The articles may have embedded in them such materials as for instance, 80 biscuits, nuts, or raisins, which remain whole, or in fractions or portions of comparatively considerable magnitude.

The articles may contain fondant cream.

The term " cellular structures" is in 85 this specification to be understood to mean a honeycombed structure or formation comprising an exceedingly large number of separate closed noncommunicating cavities, the vast 90 majority of which are substantially spherical, globular or ellipsoidal in shape, or are of an irregular (for instance, polygonal) shape in crosssection, and the dimensions of which in 95 any three directions at right angles to one another are in the vast majority of cases substantially the same (in contradistinction to the elongated cavities of stratified material or to tubular cavities) Any two 100 cross-sections, at right angles to one another, of material possessing cellular structure as herein defined will present somewhat similar honeycombed appearances The more the fatty medium 105 contains permanently solid materials of irregular shapes such as biscuits, nuts or raisins and of a size more or less comparable to the size of the cavities the more irregular will the shapes of the 110 459,583 for forming the parts of non-cellular structure may be added to the aircontaining material for forming the parts of cellular structure as a core or covering or such like integral parts, and the whole 70 in a fluid or semi-fluid condition can then be subjected to reduced pressure as above set forth, the part of cellular structure being thereafter allowed or caused to become solid It is possible accurately to 75 control the relative proportions of the portions of cellular structure and the portions of non-cellular structure by means of partitions or moulds.

The size of the expanded bubbles and 80 the nature of the cellular structure may be varied by varying the external pressure, or by varying the consistency of the substance, or by varying the temperature of the substance, or that of the 85 material of the mould or holder which carries the molten substance In order that the cellular formation may remain permanent at ordinary atmospheric temperatures normally experienced in 90 England, it is necessary to chill or set the material or to allow it to cool, while still maintaining a reduced external pressure.

One example, with variations, of the 95 carrying out of our said invention will now be described with particular reference to a substance consisting of cocoa, sugar, milk, and cocoa-butter, such as is used for the manufacture of milk 100 chocolate This substance is taken simply as an example of a substance consisting of a fatty medium containing a number of ingredients.

The chocolate is warmed and well 105 mixed until it takes a liquid or semiliquid form It is then thoroughly aerated by being passed through a whisk or centrifuge, or other known means of aeration After the material has been 110 treated in this way, it is tempered in any of the ways commonly known in the chocolate industry and then deposited either by hand or mechanically into moulds, in any of the ways commonly 115 known If desired, nuts and raisins, or other solid ingredients may be mixed into the chocolate before or after the tempering operation The chocolate may be deposited into moulds which have been 120 lined with chocolate by any method known in the chocolate industry Alternatively the mould may be lined with any other edible product, or with layers of chocolate and layers of other edible 125 material, or with mixtures of chocolate and other edible material, or with a nonedible material such as foil, card, or paper The external pressure an the chocolate is now reduced, say to a 130 cavities tend to be The cavities though small are readily visible to the eye and the majority of the cavities will vary from a quarter of a millimetre to three millimetres in length or width The average distance between the cavities may be as much as three or four times the average width of the cavities, but preferably their distance apart is much less than their width The cavities will normally be of substantially uniform size.

The articles in question are defined and described in the Complete Specification of our co-pending Patent

Application No 19883 of 1935 (Serial No.

459582).

When one of the articles in question is eaten the cellular structure of the whole article or of part of the article makes the article easier and pleasanter to bite, through making its ofter, that is, structurally weaker, and the cellular structure also makes the article more capable of rapidly melting or breaking down in the mouth.

The process according to the present invention consists in distributing or dispersing or producing in the edible fatty medium, or in the same mixed with edible ingredients as aforesaid, while the medium is in a fluid or like state, a very large number of separate but closely associated bubbles of air or other gas, small in size but readily visible to the eye, which imparts to the medium a cellular structure, and in cooling the medium either artificially or naturally while possessing the said cellular structure in order that it may set and solidify while having this structure and not collapse back into its original deflated state.

One method of carrying out the said process is by taking as a starting material an edible fatty medium which is in a fluid or like state, and which may contain one or more edible ingredients and which as the result of deliberate preliminary aeration or as the result of ordinary methods of preparation and mixing has distributed or dispersed throughout its volume a very large number of separate but closely associated bubbles of air or other gas, which are mostly so minute as to be invisible to the eye, and by reducing the pressure on the said medium to a pressure below atmospheric pressure, producing therein the cellular structure as hereinbefore defined.

In some cases in which it is desired to produce articles integral parts of which have a cellular structure and integral parts of which have a non-cellular structure, the substantially air-free material a 4 o 9,583 pressure of two inches of mercury This may be effected by providing each mould with a cover plate and exhausting the interior of the mould, or by placing the i moulds in a vacuum chamber and applying to the chamber the necessary degree of vacuum, On the external pressure being reduced the bubbles of air inside the chocolate, expand to a size readily visible to the eye and distend the chocolate and produce a cellular formation.

Some of the bubbles may coalesce The reduced external pressure is maintained until the chocolate has become infiated or distended to the desired degree aqnd has set or solidified sufgciently to retain its cellular formation at atmospheric pressure Preferably during this period the moulds or the vacuum chamuber are subjected to a cooling operation, by means of natural air or by means of a cold air blast, or by direct or indirect contact with a cold liquid The chocolate may be either completely solidifed w list under the influence of the vacuum, or it may be solidified just sufficiently to retain the cellular construction when the externa L pressure rises to the atmospheric pressure.

The final stages of solidification may then take place under atmospheric pressure These final stages of solidification may be accomplished by passing the moulds tbrough an ordinary cooling chamber or by any of the known methods in the chocolate industry The cakes of material are then knocked out from the moulds in the standard way as employed for chocolate moulding It will be understood of course that when solid pieces, such as nuts and raisins -have been introduced just before or after the tempering operation, such pieces do Rot become cellular in structure, but remain solidly compact.

Tn those cases in which the moulds containing the chocolate of cellular structure are lined with chocolate or other ediblematerial, the chocolate of,cellular structure, before the cakes are knocked out of the moulds, way be covered with layersof chocolate of non-cellular structure andthe cakes -not be knocked out of the moulds until after the said chocolate of noncellular structure has cooled.

The moulds may be of metal or of any material normally used in the chocolate -industry Alternatively, the moulds may be of some edible material, such as eonfectionery or biscuit, so that a combined product is made comprising chocolate of cellular structure ' Or chocolate of cellular structure may be sandwiched with chocolate of noni-eellujlar structure or with some other edible product.

Articles, made by the process according to the present invention (whether of chocolate or of other material) may be readily produced in the form of tablets of any required weight and shape, whether the whole article be of cellular 71) strpetre or whether the interior be of cellular structure and the external port Qn be of non-cellular structure Moreover the material for forming the portions of cellular structure may be treated while 75 possessing very various degrees of consistency according to the desired nature of the article to be produ Qed.

is the manufacture of ch Qcolate there is usually sufficient air introdu-ced, 8 (F mostly in a form invisible to the eye, toenable the chocolate in a liquid or semi liquid form to be taken as the starting material so that in the manufacture, according -to the present invention, d o 85:

chocolate articles it is usually unnecessary to perform a separate aerating operationby passing the material through a whisk, or centrifuage, or other knowt means of aeration, Another method of carrying -out the process according to the present invention comprises aeration so as to produce' minute or barely visible bubbles by means of Qa wbisk, centrifuge, or other known 9 Y means of aeration, at pressures greater than atmospheric pressute, and expanding the bubbles by reducing the superatmospheric pressure to any desiredextent, and ch Iling or setting, the 100 YR Material.

liaving now particularly described and ascertained the-naturie of our said inven tion and in what manner the same is to be performed, we declare that -what we 105claim is 1 Process for manufacturing from anedible fatty medium of the character hereinbefore described (with or without other edible ingredients) an article of 110 W food or confectionery of the nature:claimed in claim l 'of our ico-pending Specification No 19883/35 (Serial No.

459,582), the said pro-cess being characterised by (a) distributing or dispersing 115 or producing in the material which is to be given the said celiular structure, wbile the material is in a fluid or semi-fluidstate, a very large number of small butreadily -visible -and separate closely 120 assoeiated -bubbles of air or other gas, and thereafter (b) cooling the material either artifieially or najt-urally while in sluch aerated condition so that it sets and forms a rigid cellular structure 1252 Method of carrying out the process claimed in claim 1, in which air or gas, in the form of innumerable minute bubbles, is introduced into the material which is to be given the said cellular 13 GI 459,583 459,583 structure while the said material is in a fluid or semi-fluid state, by means of a, whisk, centrifuge or other means of aeration, under atmospheric pressure or super-atmospheric pressure, the said external pressure being subsequently reduced so as to cause the said bubbles to expand to a size readily visible to the eye.

3 Mode of performing the method claimed in claim 2, in which the material which is to be given the said cellular structure is chilled, or allowed to cool, while the external pressure is reduced.

4 Method of carrying out the process claimed in claim 1, in which there is taken as a starting material an edible fatty medium which is in a fluid or semi-fluid state, and which may contain one or more edible ingredients and which already contains distributed -or dispersed in itself a very large number of separate but closely associated bubbles of air or other gas, which are mostly so minute as to be invisible to the eye, and thereafter reducing the pressure on the said medium to a pressure below atmospheric pressure so as to produce a cellular structure as hereinbefore defined.

Process for manufacturing an article of food or confectionery as claimed in claim 1, or claim 2, or claim 3, or claim 4, in which the material which is to be given the said cellular structure is put into moulds which have been lined with an edible material, for instance, chocolate, or with any other edible material, or with a non-edible material, such as for instance, foil, card or paper.

6 Process for manufacturing an article of food or confectionery as claimed in claim 1, or claim 2, or claim 3, or claim 4, in which the material which is to be given the said cellular structure is put into moulds which consist of an edible material, for example, confectionery or biscuit.

7 Process for manufacturing an article of food or confectionery, as claimed in any of the claims 1 to 6, in which the material which is to be given the said cellular structure is subjected to the cellforming process while associated with material, in a fluid, or semi-fluid state, which is to form integral parts of noncellular structure, and which may or may not thereafter become solid.

8 Process for manufacturing an article of food or confectionery, as claimed in any of the claims 1 to 7, in which the material which is to be given the said cellular structure is subjected to the cell-forming process while containing embedded in it solid bodies, for example, nuts or fruit.

9 Process for manufacturing an article of chocolate as claimed in claim 1, 2 or 3, substantially as described in the foregoing example.

Dated this 5th day of January, 1937.

CLEMENT LEAN, B Sc, A.M I Mech E, Chartered Patent Agent, Thanet House, 23112, Strand, London, W.C 2.

Abingdon: Printed for His M Iajesty's Stationery Office, by Burgess & Son.

lWt 8031 B-250/2/1937 l

Thats a long way of roughly describing low pressure formation of bubbles in chocolate . This thread has dried up , so hopefuly nobody wil mind the pasted waffle.

Blowing agent is dry-blended with the resin to produce density reductions of 20-25%

(Structural Foam Molding)

I would suggest they are vacuum formed

Did you read the question? "Vacuum forming" is not injection molding. It only stretches an existing sheet. It cannot produce thick sections. It does not generally produce a surface pattern.

Your answer does not provide a definition of why the swirling pattern exists, which is assumed to be one of the identification factors to the process.

I am a Production Manager of a Structural Foam Plant. The swirling pattern are flow lines.

Thanks for the answer, I learned something, that's always good. What about the "swirling pattern in the surface"? Next, can the surface be structured, meaning not flat, smooth, but with a "surface enlargement" pattern.

Looking forward to the answer, best regards, Joseph

Any part that made by True Injection can have Blowing agent added. But if the wall thickness is to small you will not get any benefit (less than .150 in)

Just curious, what kind of Injection Molding would not be "True Injection"? Or do you just mean other kinds of plastic molding, like rotomolding, liquid epoxy casting, sheet thermoforming, parasol or injection blowmolding, etc., powdered thermoset molding, etc.?

I should of said conventional injection or straight injection.

Grammar, grammar, grammar!

"I should have said...", not "Ishould of said...".

Blimy! there's two of us pedants on CR4!

GrammarWatch UK: Have you seen a crime against the English Language being committed? Phone this number now and report it. And remember...stay safe out there.

Try "Blimey" for size. The number for the action line (on a current UK style 'phone) is 4355 427 376936 6837

ROFLMAO (when do we get moving emoticons?)