AU4067802A - Procedure and machinery for the moulding of an assembled object - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION DIVISIONAL PATENT Invention Title: Procedure and machinery for the moulding of an assembled object The following statement is a full description of this invention, including the best method of performing it known to us: .Cle: Prce~dure3 and rinachiriery mouldifag of an assemblied objedt 'The invention* concerns a procedure for the 'production of one n at least two subsequent castings mole1bet n1 ol consisting of. at least three mould parts, Cind a machine -for the performance of this procedure., 'It is a known technique to mould an object 'in two or more subsequent castings, e.g. an injection mou. ded obj.ect: in plastic in two different colours casted subsequently., This can be realized by first moulding the material !of one colour in one part of the for this purpose arranged Mould, g. a letter in a key in a keyboard. After the cooling ~fthe mAterial and removal -of. the core parts- of the mold, thel~nteriAl of the other colour -is moulded around the mioulded Ilte, which-*now itself *serves as a part of the mould, in t~le same mould,:*-for the final, key.- This procedure requires an i~ jection moulding machine with two injection units.

There are also known injection moulds whiph cnsists of- -more than two mould parts, a front part and a ba~k part., the so-called sandwich moulds which also consis-t of a Mov.able middle part placed between the two other* mozld parts 'The purpose .of such a mould i5 not to cast objeL-ts in two .or *more subsequent castings, but to cast more objec~ts at the -same time in the same' mould by using the in this way doubled' closing area of the mould.

Among injection moulds containing more tha ne rntpr one back part are further known the so-call d three pl-ate -tobls. Between -the front part and the back art is placed a third plate as a mould part. Due to the fact that the inlet channels in the mould are placed between th~ two foremost' mould parts and the objects between the twol hindmost you, achieve., that the inlet and the objects are! being ;orn of f ejected separately when the mould is openedr The advintage 3 5 hereby is that the inlet and the finished objects thut can and and There are also known moulds which~in their rant part or. their back part. has an insertion which can be turted while the muld is open. In -the hitherto known cases this insertion excliasively is turned around an axis which is paralll 1to the mutadal direction of miovement between the front par and the bacc paLrt, thus,'you can. achieve the same e f fect s by a: turning -table. The purpose o f this* turning movementj is to achieve some extra steps during the moulding cycle, so that rhire-e..g.. can be injected material in the mould and simuliaheously cooling the mould and thereby'saving cycle time.

The purpose of this procedure and machineryl-accrding- to, the invention' is that by the casting of multi c apnent objeqts a highly increased number of objects per time nit in a.-idetined mould are achieved. Also you can use a cons derable smaller moulding machine than, possible up till now hnd still aichieve the same number of objects per time unit.

The procedure according to the invention is,; characterized by the fact'that at least one middle part placid between the moulds preferably stationary front parn andj the movable back part after moulding of the first part of the object -are turned at least one time preferably 180 degrees arbuxid an* axis/axle Which preferably is in a right angle to the movement direction between the front part of the mould and the back part, before the moulding of the following part of the obJect.

Due to the. fact that the middle part after he mouilding of the first part, of the object are turned 180 de gees around an axcis which is not. parallel to, but in a right ankle to the zmovement direction between the front part and the batk part, a number of interesting possibilities are achieved, that has not yet been .possible' to achieve by the -hitherto 'knpwn designis of moulds.

As explanation of the principle in the procodure a simple example can be chosen where each cycle moulds a single object comprising two parts where the front and thel back of the middle part are identical. The moulding of the first part of the object are made in the cavity formed between the front part 'a nd the middle part. After a suitable ooling of theobje~ct, the mould is opened so that -the inid~le part can b turned 180 degrees- preferably around a* vertical axis. Doing this you. must secure that the f irst moulded Ipart of the object remains positioned on the part of the middle part f acing the front part during the moulding.

After turning the middle part 180 degrees t4 mould is closed again, now with the first, moulded part f aci~ig -the back part and. forming an integrated part of the mould f or the hereby achieved new cavity. Between the middle par and the .b~ck part you hereby can perform the following mouldi ig of material from another 'moulding. unit on the partly moulded object.- Suitable simultaneously with-tbis -final moulding on '-he first' object there can in 'the' now remade. cavity between 1ihe front .ptt and the middle. part be performed the first moulding on the next object form the first moulding unit.

After a suitable cooling and hardening of t ~e objects 'in.-both the .moulding parts, suitably using the sametpar of the cycle time,; the mould is' open d and the first cmplet mouldedobject is ejected from the back part. At th' same tim6 thie middle part is. turned, with the partly moul ~d next Object placed on its other ident ically surface,.ag in 180.degreps preferably back to, but possibly forwards t 'its qriqinil position. Hereafter--the mould. is closed aga in and there are, injected the respective materials from the *wo injectiobn uinits,' suitable simultaneously in the two mduld 'Cavities between r~spedtively the front part and the I middle ;Part, where the first part of the following object is mdiuldedt and: bezween the middle part and the back part where the isecond and' finished object is mouilded. Afterwords the dieicribed cycle can be repeated in a current produc..ion of finighed assembled objects.

The above described cycle concerns a. singleiaspembled object S. ejected from the mol ah time; but in'pr': ciple 'the, same will be the case for a-larger quantity of c'vities per mOuld part. In the example above it is only neces~ary with a. single turnable middle part because the assembled object only consists of two parts..

If the assembled object consists of more patts, the procedure also in principle is the same. Should more stations be needed due to this, an extra turnable middle part or more can be added..

It can possibly be of advantage that the t*I'nng movemenit of the middle! part is performed outside the space between the front part And the back part. This can be roalized, through some kind of cassette system where the middl-e plate in a running cycle can be replaced with a corresponding mi~ddle plate and- turned between the single rnouldinOs outside the actual moulding area between the front part and the back part.

The procedure according to. the invention can in this wa.y result in a considerable time- and costreductiofl by the moulding of assembled objects in relation to the hitherto known procedures. of moulding in sequence two or more assembled objects.

If the objects to be moulded not as foreseeh in the above described example are su .itably symmetrical,! you can achiEe the sae effect due to the front and the ba~3c of the turnable middle part of the mould are each others re flectioh. The two surfaces of -the middle part can also possibly correspond in another way..

By the designing of the moulding equipment -it as mentionedmust be considered, that the object or set )of objects at the opening of the mould af ter the first m ouldi ag are releas ed mould part -and remains po stioned. in/on the turnable middle part and thereby being removed. to: the? space between the middle part and the or-he mould 'part. This removal* cahi simplest be achieved by a bette~ hold-down in, the middle part than in the front part and res ectively a better hold-down in the back part than in the middle part..

The necessary removal of the olbject from t~e front part, where the'first part of the material is injeced via tilt ki~dd.2e part to the back part where the fintal port ifon. of the material ist injected, as well as Where the 4je juan of0 th~e f1ished assembled object takes place, can also be 4chieved in. audther Way. This e.g. can be realized by an ejet* .,cr ul or jaw. system placed in the turnable middle pdt The ejector syste .m e.g. can be of a new design especiafly aeveluped 'for Pg. 06 4 the iddle part where 'the eJectors has a diJect connection bet ween the opposing cavities in the middle~ipart:. Eere~by the ejectors through a ball screw system placed in the Middle of the ejector in the middle plate can move;:.the ejectors. forth Sand backwards in the Part of the middle plate facing the back part. While the ejectors have a direct connco betweenth opposing cavities- or cores in the middle plate it herebybecomes possible to eject the objects, there are positioned on a core. or in another way are placed on the iiiddle part, iOwithout :using any.considerable space in the~imould f or this purpose.-..

in a special design of the machinery for the: performance of the procedure-according to the invention, at least :one of the 1 5 turnable. middle parts arIhral ni~a~ .g iha insullating plate between the front and the iack of the middle part. It* can hereby be achieved, that e.g. in the cavities between the front part and the middle part, ;a considerably higher temperature can be sustained, than in- the -cavities 2between the middle part and the back part. This in pr ihciple can also. be realized by the* traditional inde~c mould/turnm m ould where e.g. the one part -of the movable plate' is insulated opposed to the. other part.

For the be-st possible utilization of the insuqlated miiddle. part the following minor changes of the above-menitioned procedure can be recormmended: When the partly moulded I object or Objects are. remoVed f rom the hot area between the f zjbnt -part and the middle part to the cooler area -between the rnovable middle part and the back *part, the middle part is turned Immediate after the bbject/objects hereby has been transferr d to be positioned in the back part, and 180 degrees ba ckwards again.

Hereby the hottest part of the middle plate ;il. awayi be pushed again st the hot front -part, whereby i~ e. g. becomes.

easier to sustain a considerably higher temperature in the area at the front paxrt than in the area at the *back part.

The advantage in sustaining a constant and'high differenc-e in temperature in the mentioned areas is that y~u hereby achieve the possibility to mould two different materials together, which normally is not possible by the us e of l.a traditional mould. it -can e.g. be a thermo plastic material and an elastomer, a thermo plastic ma 'terial and a silicone plsia Silicone and a -metal and so'forth.

This method to sustain a considerable differ~nce in temperature between two areas in the mould on the contra.rywill har dl'y be necessir'whe''''using the proc~dur6 &~cciingto the invention to mould a thermo plastic. material together with metal or two different metals together. This because 'both metals and thermoQplastic materials are ejecied in cooled conditions.

Using the procedure according to the invention you e.g. can mould a metal as aluminium in the front part and a-polyolefine in the back part.. Hereby there also can be obtained the Advantage that when the plastic .is moulded #'round the ~netal, :the plastic material can cover the rough edges that a'ppear by the moulding' of metals. These rough edges th1at normaly appear when moulding- metal, therefore need not be i-emoved, but on the contrary they can contribute with a better connection the plastic to the metal. This give .possibilit±is to develop-.'a according to the invention that is 6apable ofmoldn plastic and 'metal together. But such a combined pstcand metal moulding machine can also be utilized:in connection with existing mould constructions.

The- more precise advantages and designs Of t~hi invention. will appeajr from the drawing and the connected d~scription.

Fig. 1 shows a design with a closed mould wid, the first part of the object .moulded Fig. 2 shows the same during opening F ig. 3 sh ows the same in fully opened condition with the middle part turned 90 degrees Fig. 4 shows the same during closing Fig. 5 shows the same fully closed Fig. 6 shows.the same after the moulding in iboth sides of the middle part Fig. 7 shows the same after opening and ejection of the f-irst finished object Fig. 8 shows a design with an insulation in 1the middle part Fig. 9.shows a design with the middle part dperating in sections.

In f ig. 1' is shown f rom above a section of an example of a closed mould to. perform the procedure according to the: invention. -The mould consists of a stationa' front. part and a. movable. back pat2, as well as a movable mdleprt 3, that further can be turned around an in thi~ case -vertical placed axis/axle In the shown example is 1just moulded 'as the first part 5 of the object a screw cap I xtnded- to be moulded separably together 4ith a matching thr~aded: tuzbe neck for serving as. a Closure on a. glass f or pilij.: on the irpont WQP~t 1 Is also a not shown in @Ctidft unit.- Cin then tofl Pert is -shown. the threaded Leares P an nteb~ at2ae shown the cores 7, which are smaller -than the threladed co~es; to allow 'the followi *ng moulding of the threaded tube neck,! which nere Is the last mouldeo part or the aSsembl~ed objeCt.- in. themiddle-part 3 i~s shown the in-both ends ideivtically designed cavities/mould cavities B.

Fig.- 2 shows the same mould during opeig where -the back 2 is moving left with the double speed. of the middle part 3, which carrie the first moulded parts of the object positioned in the cavities B.

In f ig. ~3 is shown the same mould fully opehed, where the 1 0 middle part 3 now is performing its turningl'and is tuined *degrees which means half-way around its axis;/axie 4.

On .f ig.- 4 is seen the same mould in the proes* of glos .ing, and wheare the middle part 3 has fulfilled its turning of 180: l 5 degrees, so that -the first moulded parts 5 6f the object. nowface tbe back part.

Fig. 5 shows the mould in closed condition i7here the first moulded parts 5 of the object*, here the coo~.ea scre-w cap, are 2 0 ready to perf orm as a part o f the mould, dsj they in connection with the. cores 7 in the back part 2, which ha a smaller: dia- meter than the cores 6 in the f ront part 1, f 0rms cavities R.

In'fig. 6 are shown the same mould also in closed condition where' the second part of the assembled obje~t 10, the2-* 'eae tube neck, now are moulded in mould cavitiei 9 in the back part 2. Simultaneously the first parts of the 2nexz set of assembled objects are being moulded in the tront par-, The -injection in the two surfaces of the middlei part as* well as the cooling, has occurred at the same time,: saving. a consi ,derable amount of cycle time.

In f ig-. 7 are seen the finishing of the firit :cycle, where the mould is opened and the cooled, assembled oiject 10) now is being ejected -from the back part 2 by meAns of ejectors not shown-on the figure. As the last mouldeded j~rs of the objects 10, here the threaded tube necks, moulded innermost, they has shrunk a little bit comoared to thesce 4caps, whereby the two parts- afterwards easily :can be separated i and reas5sembled 'manually. In the right partlotf the middle. part 3 the first 'parts. of the next portion of objecqts are :passing from. the front part 1, after a tarning of 180 idegriees,, to .be placed in the' back part 2i so. that the foll~winq ccle_ i continued and the process can proceed.

In fig. a is shown a special design of the turnable middle part 3 supplied in the middle with an insuli.ting plate: 11 or -similar, which can cause, that in 'the area -the- ioul'd 'at the front part I a higher temperature can be ma4.ntained, than in ~the area at the back part 2. *This is achieved especijJlly when the turnable middle part 3, having delivere~i a set :of the first moulded part of the object to the back part 2, immi-diate are turned back again.

Fig. 9 .shows A special design of the turnabe middle part 3 where it for practical reasons is se'ae'i w rmore slim,. preferably. identically and vertical ly j.plated sections.

Here. -is only shown two sections each able to turxn a- vertical axis/axle The iesser maximum turning radius' of each-of the slim sections dduses that the necessary' distance between -the front part ilad thi back part 2 at the opening will be considerably reduced. A considera4bly larger distance. between the front part and -hback part: would he 'necessary. if a single middl -e part with the same-.number *of cavities and width equal to the sum of thle widtli ofi the single. sections, should be able to -turn 180Qi'degrees in the space between the front part I and the. backi part 2.

S.heon the drawing shown designs of-the mac1~ine according to *the invention are only a part of the possibie~exam'ples. Yet they should be able to show the fundamental! principles of the invention, Besides the shown there also could have beeidisplayed the special ejectors in the middle part 3, that; connects the co nnecting cavities or cores on the two oppbs~te surfaces of the middle part. Using a ball screw or anot~er mechanism in the Middle of the ejectors, they can be movefd forth and backwards, and thus utilized for ejecting the :assembled *objects if the objects after the last moulding ar-e to 'be ejected from the middle part 3.

Claims (19)

1. A method for sequential injection moulding of an object using a mould including at least three mould parts, in which at least one central mould part is placed between a first mould part and a second mould part, said method comprising the steps of: moulding a first portion of an object in the cavity formed between said first mould part and said central mould part; opening said mould; rotating said at least one central mould part, including said first portion of the moulded object, about a central axis such that said first portion of the moulded object is positioned between said at least one central mould part and said second mould part; closing the mould; and moulding a second portion of the moulded object in a cavity formed between said first portion of the object and said second mould part.

2. A method for sequential injection moulding of an object according to claim 1, wherein subsequent to moulding of said first portion of the object, said at least one central mould part is rotated 180 degrees about said central axis prior to moulding said second portion of the object.

3. A method for sequential injection moulding of an object according to claim 1 or 2, wherein said first mould part remains stationary, said second mould part moves to open and close the mould, and said at least one central mould part is rotatable about an axis at right angles to the direction of movement of said second mould part.

4. A method for sequential injection moulding of an object according to any one of claims 1 to 3, wherein said at least two moulded portions of the object are composed of the same material. A method for sequential injection moulding of an object according to any one of claims 1-3, wherein each of said at least two moulded portions of the object are composed of different materials.

Freehills Sydney\004156600

6. A method for sequential injection moulding of an object according to any one of the preceding claims, wherein a temperature differential is maintained between the cavity in which said first portion of the object is moulded and the cavity in which said second portion of the object is moulded by said at least one central mould part being thermally insulated..

7. A method for sequential injection moulding of an object wherein a temperature differential is maintained between the cavity in which said first portion of the object is moulded and the cavity in which said second portion of the object is moulded by the at least one central mould part being thermally insulated, such that the moulding of said first portion and said second partion of the moulded object are performed at different temperatures, said method comprising the steps of: moulding a first portion of an object in the cavity formed between said first mould part and said central mould part; opening said mould; rotating said at least one thermally insulated central mould part, including said first portion of the moulded object, about a central axis such that said first portion of the moulded object is positioned between said at least one thermally insulated central mould part and said second mould part; closing the mould; transferring said first portion of the moulded object to said second mould part immediately opening the mould and rotating said at least one thermally insulated central mould part 180 degrees; closing the mould; and moulding a second portion of the moulded object in the cavity formed between said first portion of the object and said second mould part. Freehills Sydney\004156600

8. A method for sequential injection moulding of an object according to claim 7 wherein moulding of said first portion of the object occurs at a higher temperature than moulding of said second portion of the object.

9. A method for sequential injection moulding of an object according to claim 7 wherein moulding of said first portion of the object occurs at a lower temperature than moulding of said second portion of the object.

A machine for the sequential injection moulding of an object by a method according to any one of the preceding claims, said machine including a mould consisting of a first mould part, at least one central mould part and a second mould part, wherein said at least one central mould part is located between said first mould part and said second mould part and is adapted to be rotatable about a central axis, said machine being further adapted to contain cavities between said first mould part and said at least one central mould part, and between said at least one central mould part and said second mould part when said mould is closed.

11. A machine for the sequential injection moulding of an object according to claim wherein said first mould part is stationary, said second mould part is movable, and said at least one central mould part is rotatable about an axis at right angles to the direction of movement of said second mould part.

12. A machine for the sequential injection moulding of an object according to claim 10 or 11 wherein said at least one central mould part is thermally insulated.

13. A machine for the sequential injection moulding of an object according to any one of claims 10 to 12 wherein two opposing faces of said at least one central mould part are identical to one another.

14. A machine for the sequential injection moulding of an object according to any one of claims 10 to 13 wherein said at least one central mould part contains ejectors for the removal of objects from said at least one central mould part, said ejectors being adapted to eject said moulded object from said central mould part, and being further adapted to provide a direct connection between corresponding cavities formed between said first mould part and said central mould part and between said central mould part and said second mould part.

Freehills Sydney\004156600 A machine for the sequential injection moulding of an object according to any one of claims 10 to 14 wherein said machine contains multiple central mould parts each of which rotates on a separate axis, whereby the radius of the axis of rotation of each central mould part is less than the radius of the axis of rotation of a single central mould part with the same total surface area.

16. A machine for the sequential injection moulding of an object according to any one of claims 10 to 15 wherein said mould opens in two steps, including a first step activated via a clinch-pull which activates a core pull with a steep pitch in said first mould part such that said moulded object lies freely in said at least one central mould part when the mould is totally open.

17. A machine for the sequential injection moulding of an object according to any one of claims 10 to 16 wherein said machine is adapted to allow metal to first be moulded in the cavity formed between said first mould part and said at least one central mould part by means of a metal moulding unit before plastic is added to said moulded metal in a subsequent moulding step in a cavity formed between said at least one central mould part and said moulded metal.

18. A method substantially as herein described with reference to the accompanying drawings.

19. An injection moulding machine substantially as herein described with reference to the accompanying drawings. Dated this 16 day of May 2002 Jes Tougaard Gram by his attorneys Freehills Carter Smith Beadle Freehills Sydney\004156600