GB2518856A

GB2518856A - Pressure casting apparatus and method

Info

Publication number: GB2518856A
Application number: GB1317449.5A
Authority: GB
Inventors: Christopher Moore
Original assignee: PCL CERAMICS Ltd
Current assignee: PCL CERAMICS Ltd
Priority date: 2013-10-02
Filing date: 2013-10-02
Publication date: 2015-04-08
Anticipated expiration: 2033-10-02
Also published as: GB2518856B; GB201317449D0; WO2015049486A1; EP3122525A1

Abstract

A ceramic pressure casting machine for casting articles such as sanitary ware 2 comprising an elongate support 4, a mould 8, an attachment 6, and a mould transport 10. The mould 8 comprises at least two portions an attached half 12 and a flying half 14. Slip is introduced to the mould in a first casting position where the attachment 6 overlies the mould and where the mould is compressed by the pressing of the attachment onto the mould for a given casting period. After the casting period the mould is moved along a linear path to a second position along the elongate support 4 by the mould transport 10 so that the attachment does not overlay the mould. In this second position the mould may be opened and demoulding may be undertaken using a portion of the mould as a demoulder head and the mould may subsequently be moved back along the elongate support 4 by the mould transport 10 to the first position. The opening of the mould and demoulding may be accomplished by a single robot arm.

Description

Rnvention The invention relates to an apparatus and a method for pressure casting articles such as sanitary ware -including toilet howls -in ceramic materials.

flckgmtn4indirirAtt Pressure casting of ceramics is a well established method of the production of tableware, sanitary ware and technical ceramics, offering an effective way of turning liquid slip into an acceptably firm, moulded body, far more quickly than is possible using traditional casting methods.

This process operates thus: a preformed, microporous mould is closed using mechanical means and filled with slip or slurry. The sbp/ slurry is then subjected to pressure, which serves to push the water out of the siip/ slurry and through the pores of the mould, leaving cast pieces of sufficient strength to support their own weight. These cast pieces are then removed from the mould, with the assistance of compressed air blown through the pores of the mould, then subsequentLy assembled and finished.

Typical pressure casting machines require sufficient opening distance between the two mould halves to allow removaL of the cast object from the mould. The consequence of this voi is that the dosing and clamping mechanisms tend to be heavy and/or complex and costly, they take up a large amount of room and are wastefuL There is therefore a real need for a smaller, smpler and more ener efficient casting machine.

It is these problems. amongst others, to which the invention attempts to provide one or more solutions.

fthenvention The invention has particular and immediate application to the production of toile.t howls, sinks and similarly large, multipart pieces of ceramic sanitary ware and as such will be discussed at length in relation to them, but has general application to all spheres in which 1 5 pressure casting is utilised, n a first, broad, independent aspect, the invention comprises a ceramic pressure casting machine, said machine comprising an elongate support, a mould, an attachment, and a mould transport, wherein the mould comprises at least two portions, and wherein in use, sUp is introduced to the mould in a first, casting position, in which position the attachment overlies the mould and wherein the mould is compressed by the pressing of the attachment onto the mould for a given casting period and wherein, subsequent to the casting period, the mould is moved along the support by the mould transport, such that the attachment no longer overties the mould, to a second, position, wherein the mould may he opened whereby demoulding may be undertaken and wherein the mould may subsequentLy be moved hack along the support by the mould transport to the first position.

The newly devised ceramic pressure casting machine advantageously allows for a machine with a small clamping mechanism typical pressure casting machines require sufficient opening distance between the two mould halves to allow removal of the cast object from the mould. The consequence of this is that the dosing and clamping mechanisms can become heavy and/or complex and costly; here, because the mould is transportable into and out of the clamping mechanism, there is no need for this large space. The mould can be removed from the area of the attachment and as such the mould clamping mechanism comprised by the attachment needs very Little travel in some instances as little as 5mm.

As such, a much smaller machine can be made and smaller size saves on space. but also on resources used to make the machine and energy used to power it; as such, the environmentaL impact of the making and operation of the machine is lessened.

Preferably, during movement from the first pOsition to the second position, the mouki is slid along the support.

ihe sliding movement ensures continuous contact between mould and attachment which in turn Leads to the saving of space and wear on the components of the pressure casting machine.

Preferably, the support is arranged, in use, such that it is vertical or offset from the vertical by an amount in the order of 20 degrees and in use, the second position is above the first position.

The vertical disposition of the new machine ensures that it has a smaller footprint -such a small footprint allows for exampLe for multiple pressure casting machines to he grouped around a single robot, thereby allowing for the creation of an efficient multiple casting system.

Preferably, the movement of the mould from the casting position is along a board, said board comprising at Least a mould contacting layer of tow friction materiaL Preferably, the path of the mould from the first position to the second position and vice versa is a substantially straight, Linear path The implementation of the straight linear path saves space and energy due to economy of movement.

Preferably, the mould comprises a conduit for the introduction of services to the interior of the mould and the machine fLrther comprises a coupling, said coupling comprising an aperture in the surface of the hoard and a flange, the said components being so arranged that when the mould is in the first position, the conduit of the mould and the flange and aperture of the machine form a fluid connection, The conduit and aperture/flange combination dispenses with the need for a slip hose. The slip hose has been used in all previous pressure casting machines. Using a slip hose requires the manual hooking and unhooking of the hose to the mould. Not only is the hose perishable and unwieldy with a tendency to break, injure the user and generally to leak and make a mess around the work area, but the very fact that it requires manuaL intervention means that the sUp hose is costly in terms of time and in that it requires human intervention to utilise, Preferably, the attachment comprises at least a Layer of lay fiat tubing and wherein, in use the said Layer is attached to a fluid source and wherein, in use, the lay fiat tubing is expanded by the introduction of fluid into it, such that the attachment expands and in so doing compresses the mould.

Lay flat tubing is particularly useful in the context of the expanding/compressing Layer because it can compress down virtually flat and takes up very lithe space in its compressed phase. Second, such tubing is cheap and easy to repair and replace.

Preferably, the attachment is attached to the machine by way of a series of height adjustable attachments, More preferably, the height adjustable attachments comprise a plurality of threaded tieS bars.

Adjustable height attachments allow for quick changes to be made in order to accommodate different mouLds within the pressure casting machine; this suits the machine to experimental moulding particularly well.

Preferably, the mould comprises at least an attached half and a removable half and wherein the removable half is so sized and shaped as to he suitable for use as a demoulder head during demoulding.

This configuration saves space, the number of items required in an end*-toend casting process as such. aLso saves energy and speeds up the process.

The invention also comprises a pressure casting machine substantially as described herein, with reference to and as ilkstrated by any appropriate combination of the text and/or drawings.

in a second broad, independent aspect, the invention comprises a method ol pressure casting using a mould comprising at Least two portions and an eLongate support comprising the steps, in this order, of casting in a first position, moving the mould along a Linear path along the elongate support to a second position, in use, above the first position, opening the mouLd in the second position; and demoulding in the second position, using a portion of the mould as a demoulder head.

This method confers the advantages of claimsi and 10 and generally saves time, space and resources.

PreferabLy, the opening of the mould and the demoulding are accomplished by a single robot arm, Again, the utilisation of a single robot arm saves space, energy and resources.

The invention also comprises a method at pressure casting substantially as described herein, with reference to and as illustrated by any appropriate combination of the text and/or drawings.

onoftlieDrawin The invention will he described in relation to the drawings, of which: Figure 1 is a diagrammatic side etevational view of a pressure casting machine in a first, casting position, Figure 2 is a diagrammatic side elevational view of a pressure casting machine in a second, open position, Figure 3 is a dilagrammatic side elevational view of a pressure casting machine in a third, demou [ding position, accompanied by an appropriate robot, and Figure 4 is a diagrammatic front eievational transparent view of a pressure casting machine.

At Figure 1 there is a cerarriic pressure casting machine indicated generally at 2. The machine 2 comprises in its essential elements an elongate support 4, an attachment 6, a mould 8 and a mould transport 10. In use, the operation of the machine 2 is thus: the mould 8 is tilled with day slip and is then compressed by attachment 6. The attachment 6 continues to compress the mould 8 until the casting process is finished, after which the attachment 6 releases the mould 8 such that transport 10 moves the mould verticalLy up the support 4 into the opening position, as illustrated in Figure 2, This process may be manual or fully or partially automated.

Figure 3 shows the mould 8, which in this embodiment is a twopart mould comprising an attached halt 1? and a flying half 14 which can be split apart such that the flying half 14 is removed -here by a robot 16 -from the attached half 12. In this instance, where automated demoulding is employed, an additional advantage is that the robot 16 can use the flying half 14 as a dernoulder head, avoiding the need for a custom designed demoulder head.

Returning to Figure 1, the support 4 comprises a ground engaging base 18 which in preferred embodiments will be firmly fixed to the ground with bolts or the Like, The base 18 has a pedestaL 20 projecting from ft in an upwards direction, The pedestal 20 has a vertical back edge 22 and an angled front edge 24 such that in crosssection the pedestal can be seen to be of a frustoconicai shape. The pedestal 20 may be a single, solid object or may consist of a plurality of plates and bars. The angled front edge 24 may be vertical, it is Likely to be offset from the vertical by an amount of the order of 20°, aUowing the rest of the machine to be orientated similarly offset or obliquely to the vertical. The pedestal 20 also comprises a conduit 26 through which services including clay slip can be fed into the mould, The conduit 26 runs through the pedestal 20 and lurther through fascia board 28, terminating in coupling 30. Coupling 30 series to couple with aperture 32 of attached half 12; it is through this aperture 32 that clay slip is introduced into the mould 8. The coupling 30 comprises a resilient sealing arrangement 34 at its exit face, essentially comprising a rubber sealing element 36 and a flat flange 38. These serve to co align the conduit 26 with the aperture 32 in the attached half 12 of the mould 8, allowing

the introduction of slip, in use.

JO The support 4 comprises a central plate 40 onto which fascia board 28 is mounted. The central plate 40 is of a metal or alloy construction. Fascia board 28, which runs essentially along three quarters of the length of the machine 2 is made of a water repelling substance such as a slippery plastic. ft is on the central plate 40 that attachment 6 is mounted, via tie bars 42. The tie bars 42 comprise threaded bofts such that the attachment 6 may be mounted on said bars 42, nearer or further away from the fascia board 28, such that machine 2 can accommodate moulds 8 of different sizes. Attached to the back of the central plate 40 are damps 44 which grip upright tube 46. Upright tube 46 projects upwards and upon upright tube 46 is mounted rodless cylinder 48, which is mounted to the upright tube 46 via cylinder mounts 50 at either end, To rodless cylinder 48 there is attached a service pipe/energy chain 52, which in turn is attached to blade 54; rodless cylinder 48, service pipe 52 and blade 54 comprise the transport 10, and serve to provide the means ot moving mould 8 from the casting position wherein mould 8 is disposed towards the bottom end 56 of the machine 2, to an open position wherein the mould 8 is disposed towards the top end 58 of the machine, Blade 60 moves up and down rodless cylinder 48, thereby transporting mould 8.

The attachment 6 comprises an outer layer 62, which is preferably steel, and an inner layer 64, which in this embodiment is of aluminium. The outer layer 62 and the inner layer 64 surround expanding / compressing layer 66. In preferred embodiments this expanding / compressing layer 66 which comprkes the clamping means is flattened flexible tubing also known as layflat tubing although compression during the casting process can be achieved by hydraulic, pneumatic or mechanical means -in the Latter case by means such as one or more screw threads. During clamping fluids are pumped into the lay fiat tubing, thus expanding it. The fluids are then drained out in order to return it to its original state.

The lay flat tubing expanding/compressing Layer 66 is made of high pressure polyester textile piping reinforced with a coextruded polyurethane sheath. Other materials may be appropriate. Other clamping means can be used, for example one or more short travel hydraulic cylinders.

Although the example here shows a pneumatic rodless cylinder 48, hydraulic, electrical and mechanical means in the atter case such as a screw arrangement -may be used to Dropel the mould B up and down the support 4.

The service pipe 52 may carry switches, sensors, water electrici' or slip singularly and/or in combination as appropriate.

At Figure 3, a robot 16 is shown demoulding the moud 8 by removing the flying half 14 of the mould from the attached half 12 of the mouLd 8. The robot 16 may be substituted by manuaL means but an advantage of using the system of the machine 2 is that there is an improvement in predsion in positioning the demoulded product, which has benefits if the demoulded product is to he joined with other cast items. A single robot 18 may be used to open and demould the moulds B of a number of machines 2 pLaced around the robot.

In a different system, additional equipment could be used to remove the flying half 14 of the mould 8 whilst the robot 18 operates directly on the demoutded work piece (not shown) itself.

Demoulding may be done manually, automatically or via a combination of manual and automatic aspects. An automated demoulding system may be used with one or more of the machines 2 to create a larger, automatic casting system.

Claims

claims 1. A ceramic pressure casting machine, said machine comprising an elongate support a mould, an attachment, and a mould transport, wherein the mould comprises at least two portions.and wherein in use, slip Is Introduced to the mould in a first, casting position, In which position the attachment overiles the mould and wherein the mould is compressed by the pressing of the attachment onto the mould for a given casting period, and wherein, subsequent to the casting period, the mould is moved along the support by the mould transport, such that the attachment no longer overlies the mould, to a second, position, wherein the mould may be opened whereby demouldlng may be undertaken and wherein the mould may subsequently be moved back along the support by the mould transport to the first posFilon.
2. A machine according to claim 1, wherein, during movement from the first position to the second position, the mould is slid along the support.
3. A machine according to either cLaim 1 or claim 2, wherein the support is arranged.in use such that it is vertical or offset from the vertical by an amount in the order of 20 degrees and In use, the second position is above the first position.
4. A machine according to any of the preceding claims, wherein the movement of the mould from the casting position is along a board, said board comprising at least a mould contacting layer of low friction material.
S. A machine according to any of the preceding claims, wherein the path of the mould from the first position to the second position and vice versa is a substantially straight, linear path.
6. A machine according to any of the preceding claims, wherein the mould comprises a conduit for the introduction of services to the Interior of the mould and the

I

Imachine further comprises a coupling, said coupling comprising an aperture in the surfac.e of the board and a flange, the said components being so arranged that when the mould is in the. first position, the conduit of the mould and the flange and aperture of the machine form a fluid connection,
7. A machine according to any of the preceding claims, wherein the attachment comprises at [east a layer of Lay fiat tubing and wherein, in use the said layer is attached to a fiud source and wherein, in use, the lay fiat tubing is expanded by the introduction of fluid into it, such that the attachment expands and in so doing compresses the mould,
8. A machine according to any of the preceding claims, wherein the attachment is attached to the machine by way of a series of height adjustable attachments.
9. A machine according to claim 9 wherein the height adjustable attachments comprise a plurality of threaded ti&bars,
10. A machine according to any of the preceding claims, wherein the mould comprises at least an attached half and a removable half and wherein the removable half is so sized and shaped as to be suitable for use as a demoulder head during demoulding.
ii. A pressure casting machine substantially as described herein, with reference to and as illustrated by any appropriate combination of the text and/or drawings.
12. A method of pressure casting using a mould comprising at [east two portions and an elongate support comprising the steps, in this order, of: casting in a first position, moving the mould along a Linear path along the elongate support to a second position, in use, above the first position, opening the mould in the second position and demoulding in the second position, using a portion of the mould as a demoulder head. fl13. A method of pressure casting accordThg to darn 11 whers the openng of the mouLd and the demou[dng are accompLished by a sing'e robot arm, 14. A method of pressure castng substantiaRy as descrWed her&n, with reference to and as ULustrated by any aproprate combnatLon of the text arid/or drawLngs.