Lesson 5
Metal Containers
第 5课 金属容器
Background
Steel is one of the older packaging materials,
- Originally used for round,square,and rectangular
boxes and canisters,
- The old-fashioned appearance of a fabricated metal
box is effectively used to create nostalgia for specialty
and gift-type containers,
- Sanitary food can,hand-soldered cylindrical metal cans
started in the early l800s,
- Metal cans’ advantages,
Background
being relatively inexpensive
capable of being thermally processed
rigid
easy to process on high-speed lines
readily recyclable
total barrier to gas and light
an important means of delivering a shelf-stable
product
- Food cans,three-piece construction (Figure 5.1),
Background
Figure 5.1 Three-piece (left) and two-piece(right) can construction
Background
Shallow drawn containers with friction or slip covers
- Two-piece shallow drawn cans with double-seamed
(folded) ends
- Two-piece cans (Figure 5.1),
reduced metal usage
improved appearance
elimination of a possible leakage location
more elaborate tooling required
- Deeper draws and multiple draws and draw-and-iron
process
-Impact-extrusion,tin,lead,and Al; collapsible tubes
(nearly Al); heavier gauge aluminum extrusions used for
pressurized aerosol containers
Common Metal Container Shapes
Three-piece steel sanitary food cans,
·Aerosol cans,made by two methods,(1) Three-piece
steel cans with a welded body and two ends,and (2)
one-piece,impact-extruded aluminum cans necked-in
to accept the valve cup,
·Steel or aluminum two-piece drawn-and-ironed
beverage cans,
·Two-piece steel or aluminum cans by drawing or by
draw and redraw,
Full-opening,ring pull-top cans
Double-seamed,conventional-top cans
·Cans with hinged lids,usually steel
Common Metal Container Shapes
Flat round cans of drawn steel or aluminum with slipcovers (Figure 5.2)
·Three-piece steel or aluminum ovals,typically fitted with a dispensing
spout (Figure 5.2)
·Traditional pear-shaped,three-piece steel ham cans
·Oblong steel three-piece F-style cans (Figure 5.2)
·Oblong key-opening cans,three-piece steel
·Multiple friction cans of three-piece steel,also referred to as double-
and
triple-tight cans
·Three-piece,square-breasted steel cans
Spice cans (smaller three-piece cans) with a perforated metal or
plastic top
· Industrial pails and drums
·Two-piece,low-profile steel or aluminum ovals,with full-opening ring
pull-tops
Common Metal Container Shapes
Figure 5.2 Examples of specialized can shapes
Three-Piece Steel Cans
Steel three-piece can bodies can be mechanically
seamed,bonded with adhesive,welded,or soldered
(Figure 5.3),
- Aluminum cannot be soldered and cannot be welded
economically,
- Welded sanitary three-piece can bodies are therefore
made exclusively of steel,
- Mechanical seaming or clinching is used only for
containers intended for dry product
Three-Piece Steel Cans
Figure 5.3 Mechanical,welded,and adhesive-bonded side
seams for three-piece cans
Three-Piece Steel Cans
Adhesive bonding,or cementing,uses a thermoplastic
adhesive extruded onto a hot can blank,Being an
attractive body-assembly method for not being subjected
to thermal processing having full wraparound lithography
i.e.,three-piece beverage containers,some frozen juice
concentrate and paint cans
- Soldered a can,(solders, 97.5% lead and 2.5% tin),
Lead extraction by food products and a potential problem
with soldered seams Being no longer permitted for food in
North America
- Welded cans,(strong and eliminate potential lead
hazards),
Three-Piece Steel Cans
Process,（ Notes,Soudronic-the global leader for
resistance and laser welding systems and key production
systems for the metal packaging industry (3-piece cans,
industrial packaging)
body sheet - a tube with a slight overlap - passing
between electrodes - an electrical current heats and
fuses the metal (Figure 5.4),
Welded seam,about 30% thicker than the two base
metal sheets,
- Sanitary food cans and bead,to improve resistance to
collapse (preventing collapse during pressure
differentials encountered during retorting and enables the
can to withstand an internal vacuum),
Three-Piece Steel Cans
Figure 5.4 The can-welding process
Three-Piece Steel Cans
Sidewall beading,
requires more material
reduces top-to-bottom compression strength
complicates labeling
- Can ends intended for thermal processing and a series
of circular expansion panels (Figure 5.5),
This allows for movement of the end panels so that the
contents are able to expand and contract without bulging
or otherwise distorting the can,
- Can-end compound applied around the perimeter curl
as a caulk or sealant (Figures 5.6 and 5.7),
Three-Piece Steel Cans
Figure 5.5 Typical can-end embossing pattern
Three-Piece Steel Cans
Figure 5.6 Double-seaming is the attachment of the can end to the
body,It involves two curling steps,
Three-Piece Steel Cans
Figure 5.7 The double seam is a critical can component,Every angle,radius,and
dimension must be correct to ensure a hermetic seal
Two-Piece Cans
Draw
·Draw and redraw (DRD)
·Draw and iron (D&I )
Draw Process,Shallow-profile cans（ whose
height is less than their diameter） can be drawn
directly from a circular metal blank,The process
is sometimes referred to as "shallow draw."
Blanks for drawn cans may be decorated prior to
drawing (Figure 5.8)
Two-Piece Cans
Figure 5.8 Straight lines become distorted in different directions
during drawing
Two-Piece Cans
Draw-and-redraw Process,The first draw produces a
shallow cup,The second reduces the diameter as the
can is deepened,Cans having a height significantly
greater than the can diameter would require a third draw,
Draw-and-iron Process,Carbonated beverage cans by
D&I process (Figures 5.9,5.10),The thin walls of the D&I
container’s usage,
not undergo severe thermal processing
lend support to the walls
i.e.,carbonated beverage cans,noncarbonated
juices,soft drink can use either steel or aluminum,beer is
particularly sensitive to traces of dissolved iron while
being relatively insensitive to aluminum,
Two-Piece Cans
Figure 5.9 The manufacturing sequence for a necked D&I can
动画
Two-Piece Cans
Figure 5.10 The second draw and the ironing stages are all
accomplished in one continuous movement,The punch and the
ironing rings are shown in this exaggerated illustration,The punch
finishes its stroke against the bottoming tool
Impact Extrusion
Impact extrusion forms ductile metals such as tin,lead,
and aluminum into seamless tubes,
- Tin's high cost prohibits its use except for collapsible
tubes for certain pharmaceuticals,
- Lead,is now used only for applications where its
chemical inertness is an asset,
- Most impact extrusions are made from aluminum,
- Impact-extrusion sequence (Figure 5.11)
slug - striking - metal flowing up - a round,cylindrical
shape(tube height up to seven times its diameter)
Impact Extrusion
Figure 5.11 Impact-extrusion sequence
Impact Extrusion
Figure 5.12 Typical impact-extruded tube tips
Impact Extrusion
Figure 5.12 shows some commonly used tips,
(A),the round end (the most common tip)
(B):Screw-eye openings
(C),Nasal tips
(D):Mastitis tips
(E):Neckless tubes
(F):Grease tips
Metal tubes’ distinctive characteristics,
·the best barrier to all gases and flavors,
·the best dead-fold characteristics (ability to be flattened or rolled up),
·being decorated in a manner that takes advantage of their metallic
character,
Impact Extrusion
having a wide range of lining options because of the
metal's ability to withstand high curing temperatures,
- Tubes normally coated with a white enamel base and
then cured,printed by dry offset (offset letterpress),
- A major application,aerosol products,where the sleek,
seamless appearance of these cans is an asset,
a stiff sidewall is desirable
those cylinders are not annealed
the sidewall trimmed to length,turned down,and curled
over to accept the spray nozzle base (Fig,5.13),
Impact Extrusion
Figure 5.13 Two impact-extruded aerosol can designs
(left,center)and a three-piece welded-steel aerosol
can(right),All aerosol cans have bottoms that are
domed upward against internal pressure
AEROSOLS
Aerosol packaging refers to products packaged in a pressurized
container having a valve that permits controlled product release as
required,
- Depending on the formulation,the valve system and the means of
pressurizing,aerosols can be designed to release product in forms
ranging from fine mists to heavy pastes,
- Usages,Personal care products(perfumes,shaving creams,
deodorants,and hair sprays),household products (polishes,
cleaners,and room fresheners),smaller market portions(paints,
automotive products,and insect sprays),food(limited),
- The advantage of aerosols,
·their ability to disperse product into much finer particles that stayed
suspended in the air for a much longer time than was available from
hand pumps and other systems,
AEROSOLS
Aerosol Propellants,
-A typical aerosol product has a liquid phase and a vapor
phase (Figure 5.14),
The liquid phase,contains the product to be expelled,
The vapor phase,at an increased pressure and will force
the product up the dip tube and expel it through the
nozzle whenever the valve is opened,
- The product typically occupies about 75%,but never
more than 92.5%,of the available space,
- Well-designed aerosol containers will deliver 95% or
better of the contained product,
AEROSOLS
Figure 5.14 In a two-phase aerosol,the propellant is
dissolved in the product,In a three-phase system,
the propellant forms a separate layer
AEROSOLS
Principle,
suitable propellant & driving pressure
head-space volume,vapor-phase pressure maintained
by gas coming out of the solution
- The ideal propellant,CFCs,hydrocarbons,vinyl
chlorides,and dimethyl ether
Other Pressurized Dispensers,
- a design variation wherein product and propellant are in
separate chambers,
- the two common systems,
One uses a collapsible inner bag to hold the product,
The other applies the pressure through a piston(Figure
5.15 ),
AEROSOLS
Figure 5.15 Aerosols with propellants in chambers separate
from the product
Metal Containers
第 5课 金属容器
Background
Steel is one of the older packaging materials,
- Originally used for round,square,and rectangular
boxes and canisters,
- The old-fashioned appearance of a fabricated metal
box is effectively used to create nostalgia for specialty
and gift-type containers,
- Sanitary food can,hand-soldered cylindrical metal cans
started in the early l800s,
- Metal cans’ advantages,
Background
being relatively inexpensive
capable of being thermally processed
rigid
easy to process on high-speed lines
readily recyclable
total barrier to gas and light
an important means of delivering a shelf-stable
product
- Food cans,three-piece construction (Figure 5.1),
Background
Figure 5.1 Three-piece (left) and two-piece(right) can construction
Background
Shallow drawn containers with friction or slip covers
- Two-piece shallow drawn cans with double-seamed
(folded) ends
- Two-piece cans (Figure 5.1),
reduced metal usage
improved appearance
elimination of a possible leakage location
more elaborate tooling required
- Deeper draws and multiple draws and draw-and-iron
process
-Impact-extrusion,tin,lead,and Al; collapsible tubes
(nearly Al); heavier gauge aluminum extrusions used for
pressurized aerosol containers
Common Metal Container Shapes
Three-piece steel sanitary food cans,
·Aerosol cans,made by two methods,(1) Three-piece
steel cans with a welded body and two ends,and (2)
one-piece,impact-extruded aluminum cans necked-in
to accept the valve cup,
·Steel or aluminum two-piece drawn-and-ironed
beverage cans,
·Two-piece steel or aluminum cans by drawing or by
draw and redraw,
Full-opening,ring pull-top cans
Double-seamed,conventional-top cans
·Cans with hinged lids,usually steel
Common Metal Container Shapes
Flat round cans of drawn steel or aluminum with slipcovers (Figure 5.2)
·Three-piece steel or aluminum ovals,typically fitted with a dispensing
spout (Figure 5.2)
·Traditional pear-shaped,three-piece steel ham cans
·Oblong steel three-piece F-style cans (Figure 5.2)
·Oblong key-opening cans,three-piece steel
·Multiple friction cans of three-piece steel,also referred to as double-
and
triple-tight cans
·Three-piece,square-breasted steel cans
Spice cans (smaller three-piece cans) with a perforated metal or
plastic top
· Industrial pails and drums
·Two-piece,low-profile steel or aluminum ovals,with full-opening ring
pull-tops
Common Metal Container Shapes
Figure 5.2 Examples of specialized can shapes
Three-Piece Steel Cans
Steel three-piece can bodies can be mechanically
seamed,bonded with adhesive,welded,or soldered
(Figure 5.3),
- Aluminum cannot be soldered and cannot be welded
economically,
- Welded sanitary three-piece can bodies are therefore
made exclusively of steel,
- Mechanical seaming or clinching is used only for
containers intended for dry product
Three-Piece Steel Cans
Figure 5.3 Mechanical,welded,and adhesive-bonded side
seams for three-piece cans
Three-Piece Steel Cans
Adhesive bonding,or cementing,uses a thermoplastic
adhesive extruded onto a hot can blank,Being an
attractive body-assembly method for not being subjected
to thermal processing having full wraparound lithography
i.e.,three-piece beverage containers,some frozen juice
concentrate and paint cans
- Soldered a can,(solders, 97.5% lead and 2.5% tin),
Lead extraction by food products and a potential problem
with soldered seams Being no longer permitted for food in
North America
- Welded cans,(strong and eliminate potential lead
hazards),
Three-Piece Steel Cans
Process,（ Notes,Soudronic-the global leader for
resistance and laser welding systems and key production
systems for the metal packaging industry (3-piece cans,
industrial packaging)
body sheet - a tube with a slight overlap - passing
between electrodes - an electrical current heats and
fuses the metal (Figure 5.4),
Welded seam,about 30% thicker than the two base
metal sheets,
- Sanitary food cans and bead,to improve resistance to
collapse (preventing collapse during pressure
differentials encountered during retorting and enables the
can to withstand an internal vacuum),
Three-Piece Steel Cans
Figure 5.4 The can-welding process
Three-Piece Steel Cans
Sidewall beading,
requires more material
reduces top-to-bottom compression strength
complicates labeling
- Can ends intended for thermal processing and a series
of circular expansion panels (Figure 5.5),
This allows for movement of the end panels so that the
contents are able to expand and contract without bulging
or otherwise distorting the can,
- Can-end compound applied around the perimeter curl
as a caulk or sealant (Figures 5.6 and 5.7),
Three-Piece Steel Cans
Figure 5.5 Typical can-end embossing pattern
Three-Piece Steel Cans
Figure 5.6 Double-seaming is the attachment of the can end to the
body,It involves two curling steps,
Three-Piece Steel Cans
Figure 5.7 The double seam is a critical can component,Every angle,radius,and
dimension must be correct to ensure a hermetic seal
Two-Piece Cans
Draw
·Draw and redraw (DRD)
·Draw and iron (D&I )
Draw Process,Shallow-profile cans（ whose
height is less than their diameter） can be drawn
directly from a circular metal blank,The process
is sometimes referred to as "shallow draw."
Blanks for drawn cans may be decorated prior to
drawing (Figure 5.8)
Two-Piece Cans
Figure 5.8 Straight lines become distorted in different directions
during drawing
Two-Piece Cans
Draw-and-redraw Process,The first draw produces a
shallow cup,The second reduces the diameter as the
can is deepened,Cans having a height significantly
greater than the can diameter would require a third draw,
Draw-and-iron Process,Carbonated beverage cans by
D&I process (Figures 5.9,5.10),The thin walls of the D&I
container’s usage,
not undergo severe thermal processing
lend support to the walls
i.e.,carbonated beverage cans,noncarbonated
juices,soft drink can use either steel or aluminum,beer is
particularly sensitive to traces of dissolved iron while
being relatively insensitive to aluminum,
Two-Piece Cans
Figure 5.9 The manufacturing sequence for a necked D&I can
动画
Two-Piece Cans
Figure 5.10 The second draw and the ironing stages are all
accomplished in one continuous movement,The punch and the
ironing rings are shown in this exaggerated illustration,The punch
finishes its stroke against the bottoming tool
Impact Extrusion
Impact extrusion forms ductile metals such as tin,lead,
and aluminum into seamless tubes,
- Tin's high cost prohibits its use except for collapsible
tubes for certain pharmaceuticals,
- Lead,is now used only for applications where its
chemical inertness is an asset,
- Most impact extrusions are made from aluminum,
- Impact-extrusion sequence (Figure 5.11)
slug - striking - metal flowing up - a round,cylindrical
shape(tube height up to seven times its diameter)
Impact Extrusion
Figure 5.11 Impact-extrusion sequence
Impact Extrusion
Figure 5.12 Typical impact-extruded tube tips
Impact Extrusion
Figure 5.12 shows some commonly used tips,
(A),the round end (the most common tip)
(B):Screw-eye openings
(C),Nasal tips
(D):Mastitis tips
(E):Neckless tubes
(F):Grease tips
Metal tubes’ distinctive characteristics,
·the best barrier to all gases and flavors,
·the best dead-fold characteristics (ability to be flattened or rolled up),
·being decorated in a manner that takes advantage of their metallic
character,
Impact Extrusion
having a wide range of lining options because of the
metal's ability to withstand high curing temperatures,
- Tubes normally coated with a white enamel base and
then cured,printed by dry offset (offset letterpress),
- A major application,aerosol products,where the sleek,
seamless appearance of these cans is an asset,
a stiff sidewall is desirable
those cylinders are not annealed
the sidewall trimmed to length,turned down,and curled
over to accept the spray nozzle base (Fig,5.13),
Impact Extrusion
Figure 5.13 Two impact-extruded aerosol can designs
(left,center)and a three-piece welded-steel aerosol
can(right),All aerosol cans have bottoms that are
domed upward against internal pressure
AEROSOLS
Aerosol packaging refers to products packaged in a pressurized
container having a valve that permits controlled product release as
required,
- Depending on the formulation,the valve system and the means of
pressurizing,aerosols can be designed to release product in forms
ranging from fine mists to heavy pastes,
- Usages,Personal care products(perfumes,shaving creams,
deodorants,and hair sprays),household products (polishes,
cleaners,and room fresheners),smaller market portions(paints,
automotive products,and insect sprays),food(limited),
- The advantage of aerosols,
·their ability to disperse product into much finer particles that stayed
suspended in the air for a much longer time than was available from
hand pumps and other systems,
AEROSOLS
Aerosol Propellants,
-A typical aerosol product has a liquid phase and a vapor
phase (Figure 5.14),
The liquid phase,contains the product to be expelled,
The vapor phase,at an increased pressure and will force
the product up the dip tube and expel it through the
nozzle whenever the valve is opened,
- The product typically occupies about 75%,but never
more than 92.5%,of the available space,
- Well-designed aerosol containers will deliver 95% or
better of the contained product,
AEROSOLS
Figure 5.14 In a two-phase aerosol,the propellant is
dissolved in the product,In a three-phase system,
the propellant forms a separate layer
AEROSOLS
Principle,
suitable propellant & driving pressure
head-space volume,vapor-phase pressure maintained
by gas coming out of the solution
- The ideal propellant,CFCs,hydrocarbons,vinyl
chlorides,and dimethyl ether
Other Pressurized Dispensers,
- a design variation wherein product and propellant are in
separate chambers,
- the two common systems,
One uses a collapsible inner bag to hold the product,
The other applies the pressure through a piston(Figure
5.15 ),
AEROSOLS
Figure 5.15 Aerosols with propellants in chambers separate
from the product
