Materials for Machining

Materials for Machining

Metals: metals such as aluminium, steel and stainless steel are available as "free machining": always buy this form.

Wood Products: natural wood (ie bits of real tree), man-made boards such as MDF (beware of hazardous dust). MDF is abrasive and wears HSS cutters quickly: use router cutters. They perform quite well even at the low maximum spindle speed of the F1 mill.

Plastics: acrylic, rigid PVC sheet, Foamex (PVC foam sheet) among others. For best results use cutters designed for these materials: the Trend catalogue lists a small selection.

New Materials: it might be worth trying:

Alternative Ivory: this is cast polyester which looks like the real thing but is much cheaper, kinder to elephants, finishes well and is used by ornamental turners who formerly worked in ivory. It comes in a wide range of shapes and sizes and might make a change from using metal, wood or acrylic. It, and other interesting imitations of natural products, are supplied in various forms: round bar, flats and sheet. For samples and health and safety data contact GPS Agencies, Units 3 and 3A, Hambrook Business Centre, Cheesmans Lane, Hambrook, Chichester, West Sussex, PO18 8XP. Telephone 01243 574444 Fax 01243 574313.

Cibatool Board Material: this is available in epoxy or polyurethane blocks and in various grades and can be shaped on a CNC mill. The most useful grade is likely to be 5460 (brown) but it is quite abrasive and wears HSS tools quickly: carbide cutters are more suitable. It is available from John Burn & Co. (B'ham) Ltd, 74 Albert Road, Stechford, Birmingham, B33 9AJ telephone 0121 783 4451. It is available in slabs 1.5m x 0.5m and in thicknesses 25, 50, 75 and 100mm. A 25mm thick slab costs about Ł76. Other thicknesses are pro rata. Health and Safety and machining data are available from the manufacturer, Huntsman Advanced Materials (UK) Ltd, Duxford, Cambs., CB2 4QA telephone 01223 832121 Fax 01223 493322. See www.huntsman.com

Modelling Wax: is a hard blue wax, easy to machine at high feeds and speeds to check designs, make models and prototypes. It can be used as a mould for vacuum forming and casting resin. Used material can be melted and re-cast and re-used. However, casting into rod form is difficult as the wax pipes dramatically as it solidifies. It is obtainable from various sources including TechSoft UK Limited. See www.techsoftuk.co.uk

Modelling Foam: high density, closed cell rigid modelling foam is a useful material for rapid prototyping and manufacturing product concept models by 3D machining. Feed rates can be high and there is minimal wear of cutting tools.

A good quality, but quite expensive, board is available from Technology Supplies Ltd, see www.technologysupplies.co.uk

An alternative material is urethane insulation board (Therma Slab) which is available in various grades from various sources - try a building materials supplier. While quite cheap, a disadvantage is that its surface is somewhat friable and little particles rub off and get everywhere. Two grades of this type of foam are available in several sizes from TechSoft UK Limited: see www.techsoftuk.co.uk The cheaper low density modelling foam is useful for making quick "look-see" models but the surface is easily abraded and does not hold fine detail very well.

When machined, these boards, especially the urethane insulation board, produce a fine dust. Dust extraction should be used to prevent it getting into the atmosphere and into the machine's moving parts.

Oasis: is used by flower arrangers, it can be impaled on a bed of nails bolted to the mill table. It is a cheap and handy way of proving cutting tool paths without the risk of damaging anything. It is supplied damp. Make sure it is thoroughly dry before machining it so that rusting of bright machine parts cannot occur.

Safety