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GB2145656A - Method of rotational casting - Google Patents
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GB2145656A - Method of rotational casting - Google Patents

Method of rotational casting Download PDF

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Publication number
GB2145656A
GB2145656A GB08422118A GB8422118A GB2145656A GB 2145656 A GB2145656 A GB 2145656A GB 08422118 A GB08422118 A GB 08422118A GB 8422118 A GB8422118 A GB 8422118A GB 2145656 A GB2145656 A GB 2145656A
Authority
GB
United Kingdom
Prior art keywords
mould
axis
rpm
rotational casting
oven
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08422118A
Other versions
GB8422118D0 (en
Inventor
Allan Gerald Arthur Coombes
Reginald Bernard Lawrence
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University College London
Original Assignee
University College London
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University College London filed Critical University College London
Publication of GB8422118D0 publication Critical patent/GB8422118D0/en
Publication of GB2145656A publication Critical patent/GB2145656A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/02Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
    • B29C41/04Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

A mould (1) is rotated about a single stationary inclined axis (5). The mould contains a thermoplastic material and is heated in an oven (6). A fan (F) is used to cool the mould (1) on its withdrawal from the oven (6). The angle of inclination of the axis (5) is variable. <IMAGE>

Description

SPECIFICATION Method of rotational casting The present invention relates to a method of rotational casting, in particular to a method of forming prosthetic limb parts by rotational casting.
Methods of rotational casting, for example for making plastic footballs or containers, are known wherein a mould containing a powdered thermoplastic material is heated and simultaneously rotated about two perpendicular axes or rotated about one axis the angle of which to the horizontal is then continuously varied.
The known methods have the disadvantage that complicated machinery is needed to hold and rotate the mould about the axes and that the machinery is required to be very large since a large volume is swept out by the rotating mould.
The method of the invention has the advantage of being simple and easy to use compared to the known methods.
According to the invention there is provided a method of rotational casting wherein a mould is rotated about one substantially stationary axis, which axis is tilted wtih respect to the horizontal.
An embodiment of the invention is described below, by example only, with reference to the accompanying drawing which is a schematic view of a rotational casting machine for use in the method of the invention.
As schematically shown in Figure 1, a mould 1 is clamped between two plates 2, 3 mounted on a rotating shaft 4. The shaft 4 rotates about a axis 5.
The mould 1 is for moulding a tapered temporary prosthesis or pylon, but the mould could be for articles of a variety of shapes.
An oven 6 is provided and this oven and the clamped mould are movable relative to one another so that the oven can surround the mould 1.
A fan 7 is provided for cooling the mould 1.
The angle which the axis 5 makes with the horizontal can be adjusted before casting by moving the shaft 4 about pivot 8.
In operation, the desired angle of tilt of axis 5 is adjusted, the mould 1 with an amount of powdered thermoplastic material therein is clamped between plates 2, 3 the oven 6 is moved over the mould and the mould is rotated at the same time as being heated.
As the mould is heated, the powdered thermoplastic material melts and forms a film or layer on the surface of the mould. This layer is, by virtue of the tilt of the axis of rotation, evenly distributed within the mould without the need for the mould to be simultaneously rotated about a different axis or for the axis of rotation to be varied.
Different distribution of the thermoplastic material within the mould may be obtained by varying the pre-set angle of tilt and/or the speed of rotation. Thus a varying or fixed wall thickness can be obtained along the length of the mould as required.
Typically the angle of tilt might be between 10 and 150 and the speed of rotation might be from 5 rpm up to 200 rpm, more preferably up to 70 rpm.
The temperature might be about 350 C.
After a sufficient amount of time, the heating is stopped by the removal of the oven 6, and the still rotating mould 1 is cooled in air blown by the fan 7.
When the mould has cooled it is unclamped and opened and the moulded article is removed.
1. A method of rotational casting wherein a mould is rotated about one substantially stationary axis, which axis is tilted with respect to the horizontal.
2. A method according to claim 1, wherein the angle of tilt is between 10 and 150.
3. A method according to claim 1 or 2, wherein the speed of rotation is between 5 rpm and 200 rpm.
4. A method according to claim 3, wherein the said speed is between 5 rpm and 70 rpm.
5. A method according to any preceding claim being for forming prosthetic limb parts.
6. A method of rotational casting substantially as herein described with reference to the accompanying drawing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method of rotational casting The present invention relates to a method of rotational casting, in particular to a method of forming prosthetic limb parts by rotational casting. Methods of rotational casting, for example for making plastic footballs or containers, are known wherein a mould containing a powdered thermoplastic material is heated and simultaneously rotated about two perpendicular axes or rotated about one axis the angle of which to the horizontal is then continuously varied. The known methods have the disadvantage that complicated machinery is needed to hold and rotate the mould about the axes and that the machinery is required to be very large since a large volume is swept out by the rotating mould. The method of the invention has the advantage of being simple and easy to use compared to the known methods. According to the invention there is provided a method of rotational casting wherein a mould is rotated about one substantially stationary axis, which axis is tilted wtih respect to the horizontal. An embodiment of the invention is described below, by example only, with reference to the accompanying drawing which is a schematic view of a rotational casting machine for use in the method of the invention. As schematically shown in Figure 1, a mould 1 is clamped between two plates 2, 3 mounted on a rotating shaft 4. The shaft 4 rotates about a axis 5. The mould 1 is for moulding a tapered temporary prosthesis or pylon, but the mould could be for articles of a variety of shapes. An oven 6 is provided and this oven and the clamped mould are movable relative to one another so that the oven can surround the mould 1. A fan 7 is provided for cooling the mould 1. The angle which the axis 5 makes with the horizontal can be adjusted before casting by moving the shaft 4 about pivot 8. In operation, the desired angle of tilt of axis 5 is adjusted, the mould 1 with an amount of powdered thermoplastic material therein is clamped between plates 2, 3 the oven 6 is moved over the mould and the mould is rotated at the same time as being heated. As the mould is heated, the powdered thermoplastic material melts and forms a film or layer on the surface of the mould. This layer is, by virtue of the tilt of the axis of rotation, evenly distributed within the mould without the need for the mould to be simultaneously rotated about a different axis or for the axis of rotation to be varied. Different distribution of the thermoplastic material within the mould may be obtained by varying the pre-set angle of tilt and/or the speed of rotation. Thus a varying or fixed wall thickness can be obtained along the length of the mould as required. Typically the angle of tilt might be between 10 and 150 and the speed of rotation might be from 5 rpm up to 200 rpm, more preferably up to 70 rpm. The temperature might be about 350 C. After a sufficient amount of time, the heating is stopped by the removal of the oven 6, and the still rotating mould 1 is cooled in air blown by the fan 7. When the mould has cooled it is unclamped and opened and the moulded article is removed. CLAIMS
1. A method of rotational casting wherein a mould is rotated about one substantially stationary axis, which axis is tilted with respect to the horizontal.
2. A method according to claim 1, wherein the angle of tilt is between 10 and 150.
3. A method according to claim 1 or 2, wherein the speed of rotation is between 5 rpm and 200 rpm.
4. A method according to claim 3, wherein the said speed is between 5 rpm and 70 rpm.
5. A method according to any preceding claim being for forming prosthetic limb parts.
6. A method of rotational casting substantially as herein described with reference to the accompanying drawing.
GB08422118A 1983-09-02 1984-08-31 Method of rotational casting Withdrawn GB2145656A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB838323613A GB8323613D0 (en) 1983-09-02 1983-09-02 Rotational casting

Publications (2)

Publication Number Publication Date
GB8422118D0 GB8422118D0 (en) 1984-10-03
GB2145656A true GB2145656A (en) 1985-04-03

Family

ID=10548260

Family Applications (2)

Application Number Title Priority Date Filing Date
GB838323613A Pending GB8323613D0 (en) 1983-09-02 1983-09-02 Rotational casting
GB08422118A Withdrawn GB2145656A (en) 1983-09-02 1984-08-31 Method of rotational casting

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB838323613A Pending GB8323613D0 (en) 1983-09-02 1983-09-02 Rotational casting

Country Status (1)

Country Link
GB (2) GB8323613D0 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0255284A1 (en) * 1986-07-22 1988-02-03 Gec-Marconi Limited Radar reflector
WO2010036130A1 (en) 2008-09-24 2010-04-01 Charles Caulder Bree Moulded, modular building

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB382024A (en) * 1930-09-26 1932-10-20 Martin Stuehler Improvements in or relating to centrifugal machines for making conical hollow bodies, particularly reinforced concrete masts or the like
GB576149A (en) * 1941-05-28 1946-03-21 Pont A Mousson Fond Centrifugated tubular bodies and process for their manufacture
GB914584A (en) * 1961-01-30 1963-01-02 Sterling William Alderfer Production of foamed plastic articles
GB1253315A (en) * 1968-10-02 1971-11-10 Howard Bryan Carter Process and apparatus for forming thermoplastic articles
GB1278137A (en) * 1970-08-26 1972-06-14 Stewart Pivar Improvements in or relating to apparatus for molding hollow objects from thermoplastic materials
GB1358360A (en) * 1972-08-15 1974-07-03 Usui F Method of forming a tapered pipe

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB382024A (en) * 1930-09-26 1932-10-20 Martin Stuehler Improvements in or relating to centrifugal machines for making conical hollow bodies, particularly reinforced concrete masts or the like
GB576149A (en) * 1941-05-28 1946-03-21 Pont A Mousson Fond Centrifugated tubular bodies and process for their manufacture
GB914584A (en) * 1961-01-30 1963-01-02 Sterling William Alderfer Production of foamed plastic articles
GB1253315A (en) * 1968-10-02 1971-11-10 Howard Bryan Carter Process and apparatus for forming thermoplastic articles
GB1278137A (en) * 1970-08-26 1972-06-14 Stewart Pivar Improvements in or relating to apparatus for molding hollow objects from thermoplastic materials
GB1358360A (en) * 1972-08-15 1974-07-03 Usui F Method of forming a tapered pipe

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0255284A1 (en) * 1986-07-22 1988-02-03 Gec-Marconi Limited Radar reflector
US4823131A (en) * 1986-07-22 1989-04-18 Bell Stephen W Radar reflector
WO2010036130A1 (en) 2008-09-24 2010-04-01 Charles Caulder Bree Moulded, modular building
JP2012503563A (en) * 2008-09-24 2012-02-09 コールダー ブリー チャールズ Molded modular building
AU2009297185B2 (en) * 2008-09-24 2016-04-28 Charles Caulder Bree Moulded, modular building

Also Published As

Publication number Publication date
GB8422118D0 (en) 1984-10-03
GB8323613D0 (en) 1983-10-05

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)