GB2139944A - Bending and moulding wood fibreboard - Google Patents

Abstract

Medium Density Fibreboard is bent or moulded by a process comprising softening, bending or moulding, setting and protection. Softening may be achieved by dry or wet heat. The softened sheet can be pressed or moulded by thermo forming technique or bent using clamps or straps. It can be set by heating or at ambient temperature.

Description

SPECIFICATION Bending and moulding of medium density fibreboard This new process is concerned with the bending and moulding of a wood composite sheet product called Medium Density Fibreboard (MDF). The product is composed of ligno-cellulosic based materials which has been reduced by mechanical or chemical processing into a fibrous consistency and is normally bonded with applied organic or inorganic materials to form a compressed woody composite product.

MDF possesses bending and moulding qualities which can be utilised at a later stage after the flat sheet composite of any thickness has been manufactured. The bending and moulding qualities refer to both single or double curvature of the sheet when processed in contact by applied pressure with a single tool or mould requirement; pressed between a two or more part tool or moulded by thermoforming techniques as applied to plastics processing.

MDF can also be bent by retaining clamps or strap supports so as to produce curvature.

A softening technique is required on the MDF prior to bending or moulding and this is carried out by the use of dry to wet heat ot any cyclic combination either as a surface softening effect or softening completely through the section of the woody composite.

The MDF is finally set to the required shape by the application of heat with a temperature in a range up to 300"C which could be induced by a heating mechanism such as conduction, infra red, dielectric heating, low voltage; alternatively allowing the bend or moulding to set under normal ambient temperature conditions is included.

The bent or moulded material could be further processed to have an applied low pressure film plastics overlay or wood veneer or a plastics based film transfer to be applied to the surface of the MDF.

These operations can be carried out during the initial moulding of the MDF sheet or subsequently applied after bending or moulding of the sheet product.

Description illustrating applications ofthe invention General For all the following applications identified forthe bending and moulding of medium density fibreboard, the radius of curvature can be low to high with a minimum radius of curvature of 1 cm depending on the thickness of the MDF. The curvature for a single bend can form an arc of a circle or can be processed to form a complete tube and then jointed with an appropriate wood joint (butt or scarf) bonded with an adhesive or glue.

It is claimed that the process can be used for: 1. Furniture applications.

(a) Manufacture of cabinet furniture in which the MDF components have single or double curvature in their construction. The sheet material can be used for drawer construction where single or double curvature applies. This furniture application would include kitchen, dining room and bedroom, built-in furniture and work tops for both domestic and industrial use.

(b) Manufacture of chair furniture in which the complete chair can be built or formed in a single operation or components bent or moulded and then assembied to form the chair structure.

(c) Within the furniture industry other applications would include bending and moulding of MDF in bed construction for head boards, slats, tubular legs.

2. Building applications.

(a) MDF could be used in the manufacture of stair construction where curvature is essential to the design concept and could include single curvature of MDF to replace traditional manufacture of treads and risers.

(b) Replacement of traditional window and door construction using MDF for bow front windows and doors.

(c) Involvement of the sheet product in roof construction where a single bend curvature is required usually involving a large radius of curvature and using many sheets of MDF.

3. Audio Visual Units can be produced using the moulding concept to basically produce a box-like unitforT.V., stereo and speaker units.

4. Used in the musical instrument industry for piano lids, drum construction, cases for musical instruments where curvature is required using MDF.

5. Manufacture of coffins in which MDF is bent in a single curvature to produce the long and narrow box.

6. Sports goods could use the MDF product for rackets which are used with a very soft spongy ball, roulette wheels and snooker tables which would involve mainly single curvatures.

7. Interior linings and instrument panelling of vehicles in which MDF would be bent using mainly a single curvature but double curvature could be involved.

1. A process for bending and moulding of Medium Density Fibreboard (MDF) comprising of softening, bending or moulding, setting and protection.

2. The essential steps in claim 1 are as follows: (a) Softening.

The process requires that the flat sheet of medium density fibreboard is subjected to a softening technique through the use of dry or wet heat or any cyclic combination either as a surface softening effect or softening completely through the thickness of the wood composite.

(b) Bending or Moulding.

This process uses softened medium density fibreboard (2a) and bends or moulds the wood based sheet material into a single or double curvature when processed by applied pressure from a single or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Bending and moulding of medium density fibreboard This new process is concerned with the bending and moulding of a wood composite sheet product called Medium Density Fibreboard (MDF). The product is composed of ligno-cellulosic based materials which has been reduced by mechanical or chemical processing into a fibrous consistency and is normally bonded with applied organic or inorganic materials to form a compressed woody composite product. MDF possesses bending and moulding qualities which can be utilised at a later stage after the flat sheet composite of any thickness has been manufactured. The bending and moulding qualities refer to both single or double curvature of the sheet when processed in contact by applied pressure with a single tool or mould requirement; pressed between a two or more part tool or moulded by thermoforming techniques as applied to plastics processing. MDF can also be bent by retaining clamps or strap supports so as to produce curvature. A softening technique is required on the MDF prior to bending or moulding and this is carried out by the use of dry to wet heat ot any cyclic combination either as a surface softening effect or softening completely through the section of the woody composite. The MDF is finally set to the required shape by the application of heat with a temperature in a range up to 300"C which could be induced by a heating mechanism such as conduction, infra red, dielectric heating, low voltage; alternatively allowing the bend or moulding to set under normal ambient temperature conditions is included. The bent or moulded material could be further processed to have an applied low pressure film plastics overlay or wood veneer or a plastics based film transfer to be applied to the surface of the MDF. These operations can be carried out during the initial moulding of the MDF sheet or subsequently applied after bending or moulding of the sheet product. Description illustrating applications ofthe invention General For all the following applications identified forthe bending and moulding of medium density fibreboard, the radius of curvature can be low to high with a minimum radius of curvature of 1 cm depending on the thickness of the MDF. The curvature for a single bend can form an arc of a circle or can be processed to form a complete tube and then jointed with an appropriate wood joint (butt or scarf) bonded with an adhesive or glue. It is claimed that the process can be used for:

1. Furniture applications.

(a) Manufacture of cabinet furniture in which the MDF components have single or double curvature in their construction. The sheet material can be used for drawer construction where single or double curvature applies. This furniture application would include kitchen, dining room and bedroom, built-in furniture and work tops for both domestic and industrial use.

(b) Manufacture of chair furniture in which the complete chair can be built or formed in a single operation or components bent or moulded and then assembied to form the chair structure.

(c) Within the furniture industry other applications would include bending and moulding of MDF in bed construction for head boards, slats, tubular legs.

2. The essential steps in claim 1 are as follows: (a) Softening.

The process requires that the flat sheet of medium density fibreboard is subjected to a softening technique through the use of dry or wet heat or any cyclic combination either as a surface softening effect or softening completely through the thickness of the wood composite.

(b) Bending or Moulding.

This process uses softened medium density fibreboard (2a) and bends or moulds the wood based sheet material into a single or double curvature when processed by applied pressure from a single or double tool or mould requirement. The softened MDF sheet can be pressed between 2 or more part tools or moulded by thermoforming techniques as applied to plastics processing. MDF can also be bent by retaining clamps or strap supports so as to produce curvature.

(c) Setting.

This process requires that the bend or moulding (2b) will be set to the required shape by the application of heat. A temperature in a range up to 300"C would be needed which could be induced by a heating mechanism such as conduction, infra red, dielectric or low voltage. Alternatively the bends or mouldings could be allowed to set more slowly under normal ambient temperature conditions.

(d) Protection.

This process requires that the bent or moulded material (2c) could be protected so as to improve aspects of durability of the MDF material. An applied low pressure film plastics overlay, or wood veneer or a plastics based film transfer or wood preservative could be applied.

(e) Additional Processing.

It may be necessary during the processing requirements as identified above to include a machining operation to be carried out on the MDF sheet product. This extra process will be possible either prior to softening or after setting has been carried out.

2. Building applications.

(a) MDF could be used in the manufacture of stair construction where curvature is essential to the design concept and could include single curvature of MDF to replace traditional manufacture of treads and risers.

(b) Replacement of traditional window and door construction using MDF for bow front windows and doors.

(c) Involvement of the sheet product in roof construction where a single bend curvature is required usually involving a large radius of curvature and using many sheets of MDF.

3. Audio Visual Units can be produced using the moulding concept to basically produce a box-like unitforT.V., stereo and speaker units.

4. Used in the musical instrument industry for piano lids, drum construction, cases for musical instruments where curvature is required using MDF.

5. Manufacture of coffins in which MDF is bent in a single curvature to produce the long and narrow box.

6. Sports goods could use the MDF product for rackets which are used with a very soft spongy ball, roulette wheels and snooker tables which would involve mainly single curvatures.

7. Interior linings and instrument panelling of vehicles in which MDF would be bent using mainly a single curvature but double curvature could be involved.

1. A process for bending and moulding of Medium Density Fibreboard (MDF) comprising of softening, bending or moulding, setting and protection.