Selection Of Material And Hardware Used In Press Tool

Module 3 Selection of Material and Hardware used in press tool

MATERIALS USED IN PRESS WORK

• GALVANISED IRON – Zinc-coated iron is known as "galvanized iron"'. This soft steel sheet is popularly known as Gl sheet. – Applications: pans, buckets, furnaces, heating ducts, cabinets, gutters, etc. are made mainly from GI sheets. • STAINLESS STEEL – This is alloy of steel with nickel, chromium, and traces of other metals. It has good corrosive resistance and can be welded easily. – Applications: fuel tanks, rims, bus bodies, canneries, dairies, food processing and chemical plants, kitchen wares, etc. • COPPER – Copper sheets are available either as cold-rolled or hot-rolled sheets. – Application: Radiators, bearings, brakes, Gutters, expansion joints, roof flashing and hoods are some of the common examples of copper sheet.

• ALUMINIUM – Aluminum cannot be used in pure form, but it is used with a very small amount of copper, silicon, manganese and iron. – Applications: Engine block, engine head, piston, Household appliances, refrigerator trays, lighting fixtures, windows, in the construction of airplanes. • TIN PLATE – Tin plate is sheet iron coated with the tin to protect it against rust. – Applications: Oil can for automobiles, Roofs, food containers, dairy equipments, furnace fittings cans and pans.

Selection of materials for press tool components : • The selection of materials for press tool components for a given application depend on which die failure mechanisms dominates. Step1. Identify the type of wear: • This is the most fundamental step because it will determine which wear resistance profile the die material should have. • The following factors are considered to establish the dominating wear (abrasive, adhesive or mixed) to be expected: – Type of sheet material – Hardness of sheet material – Presence of hard particles in the sheet material.

Step4. Number of parts to be produced: Very long runs often demand the use of a high performance tool steel to obtain optimum press tool economy. On the other hand, short runs can be made with lower alloy grade tool steel.

Step2. Occurrence of chipping or plastic deformation: • The following factors determine the extent of the risk for chipping and/or plastic deformation, i.e. whether high ductility and/or high hardness are needed: • Type of operations to be performed on press tool • Thickness and hardness of sheet material • Geometrical complexity of parts to be produced. The die designer normally uses his vast experience here. • Step3. Risk of cracking: • The following factors give an indication of the risk for cracking, i.e. whether tough material and/or moderate hardness levels have to be used: • Type of operations to be performed on press tool • Geometry of part to be produced • Die design and die size • Thickness and hardness of sheet material

• To obtain longer die life and hence higher productivity, tool steels are being widely used as materials for die components. • The selection of a proper material for press tool components has become one of the important aspects of press tool design because long tool life has become a necessity for achieving higher productivity and reducing cost of sheet metal parts. • Appropriate tool material selection is essential for the functionality and manufacturability of a product. • One of the most important advantages of using steels as cutting tool materials is that they are originally soft and machinable. by applying suitable heat treatment, they become extremely hard and wear resistant. • Within tool steels, there are various classifications : such as – – – – – –

air-hardening die steels, high-carbon high chromium die steels, water-hardening tool steels, oil hardening tool steels, hot-work die steels, shock resisting tool steels, etc.

Selection of correct quality of steels results in • Increased in productivity • Life of punches and dies will be increased