A press tool, also known as a stamping tool or die, is a
specialized device used in manufacturing processes to shape and cut materials
into specific forms. It is typically used with a mechanical or hydraulic press
that applies force to the tooling, thereby transforming a flat sheet of
material into a desired shape.
Primary Components of a Press Tool:
Press tool is divided into
two halves
A. Fixed half / Stationary
half.
B. Moving half / Floating
half.
Bottom plate, Bottom back
plate, die plate, fixed stripper plate etc. are mounted on stationary half.
&Top plate, thrust plate/
Punch back plate, Punch holding plate, Punch, floating stripper plate etc. are
mounted on floating half.
A press tool consists number of elements with its type and function, Some basic
essential elements of simple blanking / Piercing tool (cutting tool) are discussed
as follows:-
Top Plate:-
Top plate is used for
assembly purpose. The Punch assembly including the Punch, Punch holder &
Thrust plate is mounted on the top plate with screws and dowels. The shank is
also screwed into the top plate. It is top portion of the complete tool
assembly. Mild steel/ cast iron is generally used to
manufacture top plate. This plate should be of sufficient thickness to prevent
bending.
Thrust Plate:-
This plate is also called
punch back plate. it is used to absorb shock and avoid digging into the soft
top plate during cutting operations. Generally, 6 mm to 8 mm thickness thrust
plate with OHNS material is used. Mild Steel is
also very commonly used to make this plate. But in this case, plate thickness
is increased with respect to cutting force.
Punch holding plate:-
This plate is used to
holding the punch. The punch is usually fixed with a light press fit H7/p6 in
the punch holder. It is generally made up of OHNS.
Stripper plate: -
Stripper plate is used to
strip the work piece or strip from the punch. It is used to avoid sticking
between punch and strip. This plate restricts the up and down movement of
strip. It is also support and guide the punch. Stripper Plate are usually made
up of mild steel. When high production is required they are
made of Medium carbon steel and hardened to 45-50 HRC.
Types of stripper plate: -
A. Fixed / close/ box
stripper.
B. Travelling / Floating
stripper.
Die plate:-
Die is a female part of the tool. It gives required shape of opening for blanking and piercing
holes. When this required shape of opening is gives in single solid matal block, it is called
solid die and when it is made is two or more pieces, then it is called split die.
Die blocks are made up of non shrinkaable tool steel like HCHCr.
Bottom back plate :-
Bottom back plate is
generally used to increase the height of tool and reduce the impact of force on
bottom plate. This plate is made up of mild steel.
Bottom plate:-
Bottom plate is used for
assembly purpose. All stationary elements i.e. fixed half of tool is
assembled on this plate. The bottom plate gives a cushion effect to the die It
provides space for the tool to be clamped to the press bed. Its main function
is to provide a rigid foundation or base to the assembly. The bottom plate is
made of mild steel or cast iron. It should be
thick enough to prevent deformation under pressure.
Punch:-
Punch is a male member of
complete die. It acts in conjunction with the female die to give the desired
effect upon on the strip / work piece.
Punches are classified in
three categories:-
- Cutting punch
- Non- cutting punch
- Hybrid punch.
Punches are generally made
up of HCHCr / D2 material with HRC 58-62.
Strip:-
Metal strips are the thin
metal sheets which are transformed into desired product after applying
the number of press tool operations.
Guide Bush:-
Guide bush is a circular flange made up of case hardened steel (HRC 56 - 58).
These are generally mounted on top plate to provide smooth sliding contact
between pillars and top plate.
Guide pillar:-
Guide pillars are
cylindrical pins also called guide pins are used to align the die set. The
guide pillar and guide bush align the fixed & moving halves of tool in each
cycle. A close running fitment H7/g6 is maintained between
contact surfaces of guide pillar and guide bush. The length of pillar should be
enough to guide minimum 10 to 15% of pillar length before touching the punch to
strip / work piece.
Fasteners and Dowels:-
The screws are used to hold the die parts tightly together. Dowels are the cylindrical rods which are used to align the tool parts having no relative motion.
Shank:-
Shank is used to locate
and clamp the tool to the press ram. Diameter of the shank for a particular
tool depends only on the diameter of the corresponding hole size in the press
ram on which it is to be mounted. Shanks are standardized to suit different
presses.
Stoppers:-
The stopper is a plain
cylindrical pin. This pin is mounted on the die block. It is used to arrest the
movement of the strip when strip is fed forward to one pitch length.
Strip Guide:-
Strip guider are used to
guide the strip when strip is fed throughout on the die surface.
Strip guider are two parallel plates which are mounted on die surface by screw and dowels and properly aligned with the die parameters.
Strip guider are two parallel plates which are mounted on die surface by screw and dowels and properly aligned with the die parameters.