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Common Terminology Used for Metal Stamping
The stamping industry has developed a number of terms that may be a little
strange if you are not familiar with them.
Terms That Refer to....... (click topic to jump to section)
The Parts
The Setup
The Tool
The Punch Press
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Terms That Refer to the Parts:
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Blank: (1) Sheet metal stock from which a product is to be made.
(2) Work
piece resulting from a primary stamping operation.
Breakage: (Breakout) Fractured portion of the cross section of a cut edge
of stock. A condition occurring during shearing, blanking, or punching.
Burr: Raised sharp edge inherent in cutting operations such as shearing,
blanking, punching, and drilling.
Burr Side: That side of the blank where the burr is evident.
*Deburr: A process to remove the burr. Burrs can be removed by
tumbling, sanding, spanking, coining, or hand deburring.
*Draus: The burr / slag created when you laser cut.
Form: (1) The action of bending metal.
(2) That feature that is bent from
a large blank may be referred to as the formed ear, or the formed side.
Form Radius: Radius found at the base of the form. Normally, but not
always, identified on the inside of the form.
Lance: (shear form) Tab formed out of a blank without using any prior
cutting around
it.
Land: Smooth or shiny area below the cut edge and above the
breakout. Also called shear, or cut band.
Nesting: (1) Orienting parts so that they will fit together to conserve
material during blanking.
(2) Packaging parts so one fits into another to conserve packaging space.
Nibble Marks: Slight irregularities on the periphery of a part made by
repeated punching, such as is done by a turret press.
Over Form: (1) that condition where a formed feature measures a more
acute angle than is specified on the blueprint.
(2) Opposite of under form
or less acute angle)
Pierce: The punching of openings causing slots and holes in material.
A pierced hole will be surrounded by material. If it is not, it will be
called a notch.
Piece Part: Individual stamping
*Plate: (Plating) Coating applied to a stamping to prevent corrosion or to
enhance appearance.
Punch Side: (roll side) (pull down side) The side of a pierced
hole
opposite the burr. This is the side that the pierce punch enters. The punch side
is the burr side for a blank.
*Preplated material: Material that is painted or plated prior to
stamping. A common example is galvanized steel.
Score Marks: Forming tools that rub the stock surface, cause score marks
if not properly maintained, they will make a rub mark in the direction of the
form.
Short Run: (small lot) Those lots or quantities of parts that will have
either small quantities or the life of the product is short.
Slug: The resulting scrap material from piercing an opening.
Stampings: The resulting parts which are manufactured using a punch and die in a
power press.
Stencil: An identifying number or logo impressed into the material
surface. This makes a permanent mark on the part.
Stock Strip: That strip of production material found engaged in a
progressive tool.
Strip Stock: Material that is sheared from sheets into strips. This is
often used for blanking small quantities of parts. (short run)
Tool Marks: Marks left by the tool on the piece part. These marks will
almost always tell how the part was produced, and the condition of the tool.
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Terms That Refer to the Setup:
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Air Cushion: Used primarily under pressure pads on
forming tools.
Back off the hit: Raise the ram so as to not impact the bottom so hard.
Bottom out: Lower the ram until you start to increase tonnage. Tool marks
and a tonnage meter will tell you when you are bottomed out.
Clamps: Devices used to secure the lower tool onto the bolster plate.
Cushion Pressure: The cushion pressure is the amount of air pressure
applied to an Air Cushion.
Feeder: The device used to automatically advance the stock into various
operations. The blanking tool feeders advance the stock strip. Feed bowls on the
hardware insertion machines advance hardware to the point of operation.
Hit it harder: Lower the ram in order to impact the part with more
pressure.
Move the nest: The device that locates the part is called the
nest. Move
the nest means that the location of the part is wrong and needs to be changed.
Raise / Lower the Cushion: The air cushion is adjustable in its pressure
and in the height of its top. Raising or lowering the top (the cushion) has an
effect on how the tooling operates.
Spread the Rails: As material thickness changes, the rails that do the
forming may need to move. Spreading the rails means make more clearance between
the punch and the rails.
Squeeze the Rails: Bring the rails closer to the punch. This reduces the
clearance.
Spring Box: Device used usually on the top of a tool to apply spring
pressure to the stripper plate of a piercing tool.
Tonnage: The amount of pressure applied to the piece part is measured in
tons. Punch presses are rated by tonnage capacity.
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Terms That Refer to the Tool:
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Alignment: If you enter a punch into a
die, there will be a gap between
them. This gap is called the clearance. The gap must be the same all around.
This is called alignment.
*CAD: Computer aided design or drafting. This software is used In tool
design and receiving and using a customer’s data base. Also used by modern
stampers for automated devices measuring dimensional accuracy for quality
statistics.
*CAM: Computer aided manufacturing. This software, for example, tells the
turret press, the machining center, the laser what to do.
*CAD-CAM: Computer aided design and manufacturing. The term used to
encompass the use of CAD and/or CAM.
Cap Screw: The type of screw that takes an Allen wrench to turn it.
Clearance: The distance between a punch and die. Could be a
form punch
and die, blanking, or piercing punch and die.
Compound tool: Blanking tool that blanks and pierces at the same time.
Customer Tool: Occasionally a customer will provide their tool. This is
known as a customer tool. How these tools are serviced may be different than
those that are built and owned by the stamping company.
Die: (1) Normally the die will be the female part of a tool.
(2) The
entire tool can be called a die.
Die Holder: That plate that holds the die. Normally will be the lower
half of a tool when it is mounted in the press.
Gauling: Buildup of material on the tool caused by lack of lubricant or
severe rubbing action.
Knock-Out: The device built into the ram of the punch press that can be
actuated at the top of the stroke to remove parts from the tool.
*Laser: An alternative to making a stamping usually used for
short runs,
large parts, and prototypes. No tooling is necessary.
Leader Pins: (guide pins) Pins that are installed in a tool to guide the
two halves of a tool together. They should assure proper alignment.
Nest: The feature in a tool that locates the piece part. It may be pins
that match holes in the part, or it may be "nest pieces". They are movable
pieces bolted onto the die that locate the part.
Permanent Tool: Type of tool normally mounted in a die set. This tool is
designed to run a large quantity of parts before needing any service. The
tolerance and alignment capabilities of this tool exceed the temporary tool.
Pinned Nest: A nest that locates the part with pins either in holes in
the part, or around the parts edges.
*Precision leveler: A machine that is able to make stampings flat.
Progressive Die: (Prog. die) Normally a permanent type tool. Multiple
operations such as trimming, piercing, and
forming may occur simultaneously in
this type of tooling.
Punch: The male portion of a tool. The punch determines the size of a
pierced hole. The die determines the size of the slug.
Punch Holder:
(punch pad) (1) The portion of a tool assembly that retains
the punches.
(2) The top half of a die set.
Shank Top: A top holder that has a large round shaft attached to it. The
shaft is called a shank and is used to secure the top assembly onto the punch
press ram.
Sharpen: Tools that cut will get dull with use, and start leaving more
and more burr on the part. To repair a small amount of stock
is ground off the surface of the punch and die. This is called sharpening the tool.
Sheared: if a punch enters a die so far out of alignment that its edge
interferes with the edge of the mating die opening, the cutting edges strike
each other and damage occurs. This damage is called shear.
Stock Guide: The detail that guides the stock through the tool. Usually
you only find stock guides on blanking type tools
Stripper: (1) Plate that strips stock off the punches (blank punches or
pierce punches)
(2) Device that drags the part off a forming punch sometimes called a hook
stripper or outboard stripper.
Stripper Bolt: (shoulder screw) Fastener that attaches one plate to
another but lets it travel to the stripper bolt length.
Temp Tool: (stage tool) (soft tool) Tooling that is designed and built in a
short period of time and will run a relatively short quantity of parts. This
type of tool is recommended when the customer needs:
1) Fast delivery of parts
2)
Good quality
3) Lower cost
Also may be obtained from a stock inventory of tooling maintained by the stamper
to allow zero or very low tooling cost stamping. Larger stampers who
have been in business longer may have more stage tool availability.
Turret press: A punching machine that uses tooling that is standard and
can be used for many different parts. Allows for low volume blanking
and piercing without custom tooling but sometimes incurs a small programming
charge. See also "Turret Press" in the next
section.
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Terms That Refer to the
Punch Press:
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Ball Seat: The ram and connection are attached together with a ball and
socket arrangement. The socket is called the ball seat.
Bar: To "bar the press" means using a bar to rotate the
flywheel by hand.
Normally this is done during setup
Bed: That part of the press frame that the bolster plate is attached to.
Blanker: A punch press dedicated to blanking only. This is done for the
most economical way to setup and run the blanking tools.
Bolster Plate: Heavy steel plate, attached to the press bed. The tooling
is mounted directly to this
plate.
Brake: (1) Clam shell or disk type, used to stop the rotation of the
crank shaft and motion of the ram. (2) Machine designed for
forming only.
Brake Monitor: Sensing device used to time the actuation of the brake so
the ram stops at the top of the stroke.
Cage: Safety guard built around the point of contact to prevent hands
from entering, but allowing material to enter. Will not block visual inspection.
Crankshaft: Off-set shaft used to change the circular motion/energy into
linear motion/energy that makes the ram travel in a straight line.
Clutch: Device between the flywheel and the
crankshaft. When the clutch
is closed the crankshaft turns making the ram travel up and down. When the
clutch opens, all motion stops except for the flywheel.
Connection: The part between the crankshaft and the top of the
ram. The
ram adjusting screw is part of this assembly.
Cushion: (Air cushion) That unit normally mounted under the
bolster
plate. Used to apply pressure to pressure pads and stripper plates when used on
the lower half of the tool.
Feeder: (See
setup terms)
Foot Peddle: Means of engaging the clutch using your foot. Safety
cages
or pull-outs are a must when you use foot peddles.
Flywheel: Heavy wheel driven by a motor is used to store energy. This
stored energy is used when you trip the punch press.
Frame: The structure that holds all of the press components together and
bears the "load" and "snap-through" that the stamping action develops.
Gap Press: ("C" frame) Press
frame design that resembles a C. The work is
accessible from
the front as well as the sides.
Jog: To engage the press for only a portion of the stroke. Used for set
up.
Knock Out: An assembly that works through the ram, used to activate the
knockout feature that is built into some tools.
Light Curtain: Electrical safety device used to guard the press opening. It uses
a beam of light. If the beam is interrupted, the press will not operate.
OBI Press: OBI means "Open Back Inclinable" press. This is a
gap press
that is designed to incline or "lay back".
Palm Buttons: Usually there are 2, one for each hand,
away from the operational surfaces of the press. Both buttons must
be pressed at the same time for the press to cycle. A safety feature on
the press.
Pit: Hole built under a press. The pit is used to access the
cushion, or
to lower the press to a height that makes operation easier.
Pull-Outs: Cables that are attached to the operator’s hands
as a safety measure to ensure
that his or her hands cannot be near a pinch point. These are used on presses
that have a frill revolution clutch.
Ram: (Slide) The part of the punch press that slides perpendicular to the
bolster plate.
Ram Face: That surface of the ram that a tool will mount to.
Shut Height: The distance between the ram face and the bolster plate at
the bottom of the stroke.
Single Stroke: The setting on the press control that allows one complete
cycle of the press for each press of the palm buttons.
Slide Adjust: A large screw that is part of the connection makes the
height of the ram (slide) adjustable. This large screw and its locking mechanism
is called the slide adjust
Straight Side Press: Description of a press that has rigid sides. The
work area is
accessible from the front and rear only.
Stroke: (1) That distance that the ram travels in one direction when the
press cycles
(2) Another name for a press cycle. You might also say "stroke the press" or "cycle
the press".
Tonnage: Measure of press capacity, or how hard a press is hitting.
Top Dead Center: The position of the crankshaft where the offset portion
is at the farthest
Point from the bolster.
Turret Press: A CNC controlled punch press with multiple tools mounted in
a turret. Various pieces and shapes of metal are punched out of the
material stock in succession - often in small increments resulting in line
cutting actions.
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