Lesson 4 Corrugated Fiberboard Boxes
第 4课 瓦楞纸板箱
? Historical perspective
? Corrugated Board
? Properties and Tests
? Corrugated Boxes
? Carrier Rules
? Stacking and Compression
一, Historical perspective
1,Appearance of corrugated paper and the development
? First patents for making were recorded in England in 1856,
? First patents in US were granted to A.L.Jones in 1871
? Unlined corrugated sheet---packing lamp chimneys and fragile objects,
? The first user double-lined corrugated boxes was a cereal manufacturer
(obtained acceptance in 1903)
? Figures reversed from 20% to 80% between the world War I and II
2,The specialized produce
? Sheet plants buy combined board only printing and cutting,
? About 770 plants produce more than 17.3 billion worth in America
3,Rules for constructing corrugated containers
? To enhance the quality
? Rule of UFC and NMFC
二, Corrugated Board
? 1,Construction, linerboard and medium
Material,heavy paper ---containerboard
Facings---kraft linerboard
Medium---one-ply sheet,hardwood or recycled fiber
Linerboard (flat facing)
Medium
(fluted wavy)
二, Corrugated Board
? 2 Four types combined board
b,Single Wall
(Double Face)
one medium
two liner boards
a,Single Face
one medium
one liner board
(for protective wrapping)
二, Corrugated Board
c,Double Wall
two mediums
three liner boards
d,Triple Wall
three mediums
four liner boards
Direction,Machine Direction
Cross Direction ----flute direction
动画
二, Corrugated Board
3,Flutes
Profile,arches with proper curve---- the strongest way to span space
Flutes as arches--- resist bending and pressure,support weight,as cushion,
Proper curve,between U and V (Also has its advantages)
Flutes also as a insulator to protect sudden temperature changes
Vertical linerboard provides strength; protects from damage,
Several standard shapes
(A,B,C,E,F…),
Contrast,
A-flute ---- the largest profile
B-flute ----smaller than A
C-flute ----between A and B
E-flute ---- smaller than B
F-flute ---- micro-flute
New flute---Macro-flute
二, Corrugated Board
Combined board ---Different flute profiles combined in one board
one layer of medium might be A-flute while the other C-flute
Manipulate the compression and cushioning strength,total thickness of the board,
Standard flute configurations
Flute Flutes/ m Flutes/ ft Thickness * Factor
A 100~120 30~36 4.67 mm 1.54
B 145~165 44~50 2.46 mm 1.32
C 120~140 36~42 3.63 mm 1.42
E 280~310 86~94 1.19 mm 1.27
*Not including facings;
1foot = 0.3047999m
,Take-up factor” is the
length of medium per
length of finished
corrugated board
Described,the component of grammage or basis weight,from outside to inside
eg,corrugated board,205/127C/161”----Outside liner = 205grams;
Medium = 127 grams,formed to C-flute;
Inside liner = 161grams
二, Corrugated Board
4, Fiberboard Grades, Weight ; Thickness ; Material
Grammage,the mass in
grams per square meter,
Basis weight,the weight in
pounds per 1,000 square feet
( abbreviated lb/MSF),
The most commonly used
corrugating medium weights
Grammage/g Basis Weight/b
127 26
147 30
161 33
195 40
Meterial,
? Linerboard --- natural kraft ;Solid bleached white kraft ; Mottled white ; Oyserboard
Linerboard with a whiter surface provide better graphics,
? Recycled or secondary fiber ---producing both two components
Recycled board ---smoother surface finish ;low CoF; excellent printing surface,
二, Corrugated Board
The most commonly used linerboard grades,based on Mullen burst test grading,
North American Grades European Grades
Grammage Basis Weight Grammage
127g 26b 125g
161g 33b 150g
186g 38b --
205g 42b 200g
-- -- 225g
-- -- 250g
337g 69b 300g
Other grades -- 400g
-- -- 440g
1 kg = 2.2046 b
1 meter = 3.28084 foot
1 g/m2 = 0.205 b/MSF
A generation of newer linerboards has high-performance boards,meeting ECT rather
than Mullen burst test and basis weight requirements,
lighter grades of the high-performance boards to get satisfactory performance
二, Corrugated Board
5,Corrugating Adhesive
The corrugating machine forms the medium into a fluted pattern and bonds it
to the linerboard facings,usually with a starch-based adhesive
1) A starch-based adhesive applied at about 10 to 14 grams per square meter,
2) Requirements, not tolerant high moisture and loses strength quickly,
3) When higher resistance is needed,starches can be modified or
supplemented by the addition of various polymeric materials,
4) Weather-resistant adhesive would maintain box properties at a somewhat
higher level for a longer period,
5) Water-resistant adhesive would be required for those applications where
the finished container will be in actual contact with water for periods of time,
and the coating or waxed should be treated
二, Corrugated Board
6,Broad Manufacture
Corrugating machine is made up of a set of stations that take the appropriate
linerboards and mediums,shape the flutes,join fluted medium to linerboards,
Precondition
medium with heat
and steam
Pretreated
linerboards to the
same temperature
and moisture
Brass fingers
Flute tips adhesive
The single-facer of a corrugating machine is where the flutes are formed
and bonded to the inside liner
二, Corrugated Board
Bridge ---Draped in an overlapping wave pattern to the double-backer station
Purpose---Isolating the two ends of the corrugating machine; balance; slow down
The double-backer section of corrugating machine where a second linerboard
is applied to the single-faced material coming from the single-facer unit
二, Corrugated Board
? Manufacture,
? Adhesive --- On the other side of the medium to glue outer linerboard,
? Final heating and cooling section --- Between two long,flat belts,
? Trimming edges--- Slit board to required width and length and stack
? Balanced construction--- Outer and inner have identical grammage,
? Upgrading only one liner may gain performance,
? Unbalanced constructions --- more problems with board wrappage,
? Heavier liner is placed on the outside for better printing and on the
inside for better compression strength,
三, Properties and Tests
Most board tests are described in methods provided by TAPPI,
Standard corrugated board burst and crush tests,
1,Mullen burst test (TAPPI T 810)
Forcing a rubber diaphragm against the facing until it bursts
三, Properties and Tests
2,ECT (TAPPI T 811)
A small specimen is placed between the platens of a compression
tester and loaded until failure occurs,Values are a function of the
stiffness contributed by the facings and the medium,ECT values have
a direct relationship to the projected stacking strength,
3,Flat Crush Test (TAPPI T 808)
Similar to the edge compression test except the specimen is
compressed in the flat,The test provides a measure of flute rigidity,
4,Combined Weight of Facings
Describes the combined linerboard weight per 1,000 square feet of
corrugated board
5,Thickness of Corrugated Board (TAPPI T 411)
Reduced board thickness (caliper) is an excellent indicator of reduced
compression strength; Caliper can be reduced by improper
manufacture,excessive printing pressure,improper handling and
storage
三, Properties and Tests
6,Gurley Porosity (TAPPI T 460 and T 536)
Measures the time it takes for a given volume of air to pass through a
paper,The lower the number,the more porous the paper,The porosity of
paper is sometimes the culprit when problems occur at vacuum-cup
transfer points,
7,Flexural Stiffness (TAPPI T 820)
Rrelated to box compression strength,Reduced stiffness is a good
indicator of damage during fabrication,
8,Water Take-up Tests (TAPPI T 441)
The Cobb size test,measures the amount of water absorbed by the facing
in a given time,used to measure water absorption for materials specified
to be used for hazardous product containers
三, Properties and Tests
9,Puncture Test (TAPPI T 803)
Measures the energy required to puncture a board with a triangular
pyramidal point affixed to a pendulum arm,
Test the resistance and stiffness of triple wall corrugated
The box maker’s stamp on triple wall containers calls for a puncture test
10,Pin Adhesion (TAPPI T 821)
Pin adhesion quantifies the strength of the bond between the
medium's flute tips and the linerboard facings,
11,Ply Separation (TAPPI T 812)
Evaluates the board's resistance to ply separation when exposed to water,
12,Coefficient of Friction (TAPPI T 815 and ASTM 04521),
CoF can affect machinability and load stability,A stress/strain machine
method will give both static and dynamic CoF values
四, Corrugated Boxes
1,Selecting the Correct Flute
use a carrier classification and C-flute as good starting points,
Characteristic A-Flute* B-Flute C-Flute E-Flute
Stack strength best* fair good poor
Printing poor good fair best
Die cutting poor good fair best
Puncture good fair best poor
Storage space most good fair least
Score/bend poor good fair best
Cushioning best fair good poor
Flat crush poor good fair fair
Comparison of corrugated board characteristics
四, Corrugated Boxes
E- and F-flutes are not used in shipping containers but rather are
replacements for thicker grades of solid paperboard,Can be considered if a
folding carton design calls for boards thicker than 750(30 point),Also be used
to replace paperboard for heavier or special protective primary packs as
primary container while in distribution,
Such as small tools,hardware,small appliances,and housewares…
A-flute originally specified,not commonly use, almost 5 mm (1/4 in.)
Occupies more space,has significantly greater deflection before bearing a load
when compressed,The thicker section give it the highest top-to-bottom
compression strength,A-flute has the lowest flat crush resistance
B-flute is used where box stacking strength is not required,B-flute's has high flat
crush strength when supporting heavy goods,
C-flute --- 10% better stacking strength than the same weights of B-flute
四, Corrugated Boxes
Medium Grammage A- Flute C- Flute B- Flute
127g 0.70 1.00 1.15
161g 0.90 1.25 1.45
195g 1.10 1.50 N.A
Relative flute flat crush values
四, Corrugated Boxes
? 2,Box Style
? Many standard box styles can be identified in three ways,by a descriptive name,
by an acronym based on that name,or by an international code number,For
example,a Regular Slotted Container could also be referred to as an RSC or as
#0201,
? There are many standard corrugated box styles,Slotted Boxes,Telescope Boxes,
Folders,Rigid Boxes (Bliss Boxes),Self-Erecting Boxes and Interior Forms
“Regular Slotted Container”(RSC or #0201) is the workhorse corrugated
box style (Figure 4.10),All his flaps have the same length,and the two
outer flaps (normally the lengthwise flaps) are one-half the container's
width,so that they meet at the center of the box when folded,If the
product requires a flat,even bottom surface,or the protection of two full
layers,a fill-in pad can be placed between the two inner flaps,
四, Corrugated Boxes
Figure 4.10 Parts of a regular slotted container (RSC) blank
四, Corrugated Boxes
3,Manufacturer's joint
? A flat piece of corrugated fiberboard,which has been cut,slotted and
scored,is called box blank,For some box styles,in order to make a box,
the two ends of the box blank must be fastened together with tape,
staples or glue,The place where these two ends meet is known as the
manufacturer's joint,
Liquid adhesives are most often used to join the two surfaces,Often there is
a glue tab,extending along one end of the box blank,The tab can be
joined to either the inside or the outside of the box,If there is no tab,the
box must be joined using tape,Not all boxes have manufacturers joints;
for example,the bliss box does not,
四, Corrugated Boxes
Bliss style container Bliss-style box design variations
4,Dimensioning
Dimensions are given in the sequence of length,width and depth,
Dimensions can be specified for either the inside or the outside of the
box,Accurate inside dimensions must be determined to ensure the proper
fit for the product being shipped or stored,At the same time,palletizing
and distributing the boxes depends on the outside dimensions,The box
manufacturer should be informed as to which
四, Corrugated Boxes
Top Loading End Loading
五, Carrier Rules
1,Application
? The Uniform Freight Classification (UFC) and National Motor
Freight Classification (NMFC) were established to categorize articles
for shipment via common carrier with respect to value,density,fragility,
and potential for damage to other freight,
? The classifications specify the conditions under which specific
articles can be shipped and at what rates,When shipping by rail,refer to
UFC,When shipping by truck,refer to NMFC,UFC rule 41 and NMFC
item 222 are the most frequently used in describing corrugated
packaging,
? There are four basic steps for determining authorized packaging,
? 1,Fully identify the product,
? 2,Select the proper governing classification,
? 3,Use the "Index to Articles" to find the applicable item number,
? 4,Consult the proper article to find the required packaging,
五, Carrier Rules
? Failure to comply with regulations can subject the shipper to penalties
such as higher freight rates,refusal of acceptance by the carrier,or
nonpayment of damage claims,
2,Summary of Rules for Corrugated Box Construction
? Carrier rules for corrugated box construction can be summarized as
follows,
? Specified boards (using either Mullen burst test or ECT values) shall
be used for a given product weight,providing the box does not exceed a
specified dimensional limit,The dimensional size limit for a box is
determined by adding an outside length,width,and depth,
? Table 4.6 summarizes the construction requirements for corrugated
boxes,The rules also require that a box manufacturer’s certificate (BMC)
on the bottom of the container ( Figure 4.11),
五, Carrier Rules
Figure 4.11 Box manufacturer's certificates using burst test and ECT values
五, Carrier Rules
PART A* PART B*
Maximum
weight of
Box and
Contents(l
bs.)
Maximum
Outside
Dimension,
Length,
Width and
Depth
Added(in.)
Minimum Burst Test,
Single Wall,Double
Wall or Solid
Fiberboard(lbs.per sq.in.)
or
Minimum Puncture Test,
Triple Wall
Board(in.oz.per in.of
tear)
Minimum
Combined Weight
of
Facings,including
Center Facing(s) of
Double Wall and
Triple Wall Board
or
Minimum
Combined Weight
of Pliers,Solid
Fiberboard,
Excluding
Adhesives(lbs.per
1,000 sq.ft.)
Minimum Edge
Crush Test
(ECT)
(lbs,per in,
width)
Table 4.6 Summary of carrier rules for corrugated boxes
五, Carrier Rules
Single Wall Corrugated Fiberboard Boxes
20
35
50
65
80
95
120
40
50
60
75
85
95
105
125
150
175
200
250
275
350
52
66
75
84
111
138
180
23
26
29
32
40
44
55
Double Wall Corrugated Fiberboard Boxes
80
100
120
140
160
180
85
95
105
110
115
120
200
275
350
400
500
600
92
110
126
180
222
270
42
48
51
61
71
82
五, Carrier Rules
Triple Wall Corrugated Fiberboard Boxes
240
260
280
300
110
115
120
125
700
900
1100
1300
168
222
264
360
67
80
90
112
Solid Fiberboard Boxes
20
40
65
90
120
40
60
75
90
100
125
175
200
275
350
114
149
190
237
283
* Mullen(Part A) and ECT(Part B) are presented side-by-side,
but there is no correlation between the values
六, Stacking and Compression
1,McKee formula
? Stacking strength is defined as the maximum compressive load (pounds
or kilograms) that a container can bear over a given length of time,under
given environmental/ distribution conditions without failing,
? The ability to carry a top load is affected by the structure of the
container and the environment it encounters,and the ability of the inner
(primary) packages and the dividers,corner posts,etc,to sustain the load,
? The simplest and most common corrugated transport packages are
regular slotted containers (RSCs,Box Style 0201) in which the
corrugation direction is typically vertical-parallel to top- bottom stacking
forces,
? Compression strength of regular slotted containers is a function of,
·Perimeter of the box (two times length plus two times width)
·Edge crush test of the combined board
·Bending resistance of the combined board
·Aspect ratio (L:W) and other factors
六, Stacking and Compression
? When we know the above variables,we can estimate the compression
strength through an equation known as the McKee formula,
? BCT=2.028× (ECT)0.746× ((Dx× Dy)0.254)1/2 × BP0.492 (4.1)
Where,
BCT = RSC top-to-bottom box compression strength,kN/m2(lbf/in.2 or
p.s.i)
ECT = edge crush test,kN/m (lbf/in.)
Dx,Dy = flexural stiffnesses of combined board in the machine direction and
cross direction,kN/m(lbf/in.)
BP = inside box perimeter,m (in.)
六, Stacking and Compression
? The McKee formula can only be applied to RSCs,and only those with a
perimeter-to-depth ratio no greater than 7:1,
? McKee also created a simpler formula based on caliper of the
combined board instead of bending stiffness,
BCT=5.87× ECT× (T× BP)1/2 (4.2)
Where,T = caliper of combined board,m (in.)
Solving for ECT,the simplified McKee formula is,
ECT = BCT /[5.87× (T × BP)1/2] (4.3）
六, Stacking and Compression
? The ability of a container to perform in distribution is significantly
impacted by the conditions it encounters throughout the cycle,
? If the original box compression strength is known,we can factor it
by generally accepted multipliers to arrive at an estimated maximum
safe stacking strength (Table 4.7)
2,Distribution Environment and Container Performance
Compression Loss Multifliers
Storage time under load
10 days-37 percent loss 0.63
30 days-40 percent loss 0.6
90 days-45 percent loss 0.55
180 days-50 percent loss 0.5
Relative humidity,under
load(cyclical RH variation further
increase compressive loss)
50 days-0 percent loss 1
60 days-10 percent loss 0.9
70 days-20 percent loss 0.8
80 days-32 percent loss 0.68
90 days-52 percent loss 0.48
100 days-85 percent loss 0.15
?Table 4.7 Environmental Stacking Factors
Pallet Patterns Best Case Worst Case
Columnar,aligned Negligible loss
Columnar,misaligned 10-15 percent loss 0.9 0.85
Interlocked 40-60 percent loss 0.6 0.4
Overhang 20-40 percent loss 0.8 0.6
Overhang 10-25 percent loss 0.9 0.75
Excessive handling 10-40 percent loss 0.9 0.6
六, Stacking and Compression
3,Compression Requirement
If the compression strength and distribution environment is known,the
effective stacking strength of any given RSC can be reasonably estimated,
If the distribution environment,container dimensions and flute profile are
known,a compression requirement can be estimated,This can be of great
value,because once a compression requirement is determined,the ECT
requirement can be determined (and,therefore,board combination options as
well),
[Example] A box of 0.5 m × 0.25 m× 0.30 m （ outside dimensions） will
have 12 kg,stacked 3 m high in the warehouse,Boxes will be arranged in an
interlock pattern and will be required to hold the load for 180 days at 80%
R.H.,The pallets are in good condition; there will be no overhang,What
should the required compression strength of the box be?
六, Stacking and Compression
1),Determine maximum number of boxes above bottom box,3 /0.30 -1= 8
2),Determine load on bottom box,8× 12 kg = 96 kg
3),Determine Environmental Factor by multiplying together all factors
that apply,
180 days,0.50
80% R.H,0.68
Interlocked stack 0.50
Multiplier product(Environmental Stacking Factors) 0.17
4),Determine required box compression strength,
BCT = anticipated load/stacking factor=96 kg/0.17=564 kg
Now that the actual compression strength is know,this value can be
plugged into the McKee formula (4.3),and the required edge crush test
(ECT) value of the corrugated board can be calculated,
六, Stacking and Compression
4,Compression Solutions
Following are a variety of approaches to increase compression and
stacking strength,The most efficient and cost-effective approach will
depend on the product,package size and distribution environment,
? ·Stronger liners and medium(s)
? ·Load sharing
? ·Increase the number of corners
? ·Change corrugation direction
? ·Dimensions,Depth,Length to width,Perimeter,Panel size
? ·Multiwall corrugated fiberboard
? ·Partitions,inserts and interior packaging
? ·Lamination
? ·Treatments,impregnations and coatings
第 4课 瓦楞纸板箱
? Historical perspective
? Corrugated Board
? Properties and Tests
? Corrugated Boxes
? Carrier Rules
? Stacking and Compression
一, Historical perspective
1,Appearance of corrugated paper and the development
? First patents for making were recorded in England in 1856,
? First patents in US were granted to A.L.Jones in 1871
? Unlined corrugated sheet---packing lamp chimneys and fragile objects,
? The first user double-lined corrugated boxes was a cereal manufacturer
(obtained acceptance in 1903)
? Figures reversed from 20% to 80% between the world War I and II
2,The specialized produce
? Sheet plants buy combined board only printing and cutting,
? About 770 plants produce more than 17.3 billion worth in America
3,Rules for constructing corrugated containers
? To enhance the quality
? Rule of UFC and NMFC
二, Corrugated Board
? 1,Construction, linerboard and medium
Material,heavy paper ---containerboard
Facings---kraft linerboard
Medium---one-ply sheet,hardwood or recycled fiber
Linerboard (flat facing)
Medium
(fluted wavy)
二, Corrugated Board
? 2 Four types combined board
b,Single Wall
(Double Face)
one medium
two liner boards
a,Single Face
one medium
one liner board
(for protective wrapping)
二, Corrugated Board
c,Double Wall
two mediums
three liner boards
d,Triple Wall
three mediums
four liner boards
Direction,Machine Direction
Cross Direction ----flute direction
动画
二, Corrugated Board
3,Flutes
Profile,arches with proper curve---- the strongest way to span space
Flutes as arches--- resist bending and pressure,support weight,as cushion,
Proper curve,between U and V (Also has its advantages)
Flutes also as a insulator to protect sudden temperature changes
Vertical linerboard provides strength; protects from damage,
Several standard shapes
(A,B,C,E,F…),
Contrast,
A-flute ---- the largest profile
B-flute ----smaller than A
C-flute ----between A and B
E-flute ---- smaller than B
F-flute ---- micro-flute
New flute---Macro-flute
二, Corrugated Board
Combined board ---Different flute profiles combined in one board
one layer of medium might be A-flute while the other C-flute
Manipulate the compression and cushioning strength,total thickness of the board,
Standard flute configurations
Flute Flutes/ m Flutes/ ft Thickness * Factor
A 100~120 30~36 4.67 mm 1.54
B 145~165 44~50 2.46 mm 1.32
C 120~140 36~42 3.63 mm 1.42
E 280~310 86~94 1.19 mm 1.27
*Not including facings;
1foot = 0.3047999m
,Take-up factor” is the
length of medium per
length of finished
corrugated board
Described,the component of grammage or basis weight,from outside to inside
eg,corrugated board,205/127C/161”----Outside liner = 205grams;
Medium = 127 grams,formed to C-flute;
Inside liner = 161grams
二, Corrugated Board
4, Fiberboard Grades, Weight ; Thickness ; Material
Grammage,the mass in
grams per square meter,
Basis weight,the weight in
pounds per 1,000 square feet
( abbreviated lb/MSF),
The most commonly used
corrugating medium weights
Grammage/g Basis Weight/b
127 26
147 30
161 33
195 40
Meterial,
? Linerboard --- natural kraft ;Solid bleached white kraft ; Mottled white ; Oyserboard
Linerboard with a whiter surface provide better graphics,
? Recycled or secondary fiber ---producing both two components
Recycled board ---smoother surface finish ;low CoF; excellent printing surface,
二, Corrugated Board
The most commonly used linerboard grades,based on Mullen burst test grading,
North American Grades European Grades
Grammage Basis Weight Grammage
127g 26b 125g
161g 33b 150g
186g 38b --
205g 42b 200g
-- -- 225g
-- -- 250g
337g 69b 300g
Other grades -- 400g
-- -- 440g
1 kg = 2.2046 b
1 meter = 3.28084 foot
1 g/m2 = 0.205 b/MSF
A generation of newer linerboards has high-performance boards,meeting ECT rather
than Mullen burst test and basis weight requirements,
lighter grades of the high-performance boards to get satisfactory performance
二, Corrugated Board
5,Corrugating Adhesive
The corrugating machine forms the medium into a fluted pattern and bonds it
to the linerboard facings,usually with a starch-based adhesive
1) A starch-based adhesive applied at about 10 to 14 grams per square meter,
2) Requirements, not tolerant high moisture and loses strength quickly,
3) When higher resistance is needed,starches can be modified or
supplemented by the addition of various polymeric materials,
4) Weather-resistant adhesive would maintain box properties at a somewhat
higher level for a longer period,
5) Water-resistant adhesive would be required for those applications where
the finished container will be in actual contact with water for periods of time,
and the coating or waxed should be treated
二, Corrugated Board
6,Broad Manufacture
Corrugating machine is made up of a set of stations that take the appropriate
linerboards and mediums,shape the flutes,join fluted medium to linerboards,
Precondition
medium with heat
and steam
Pretreated
linerboards to the
same temperature
and moisture
Brass fingers
Flute tips adhesive
The single-facer of a corrugating machine is where the flutes are formed
and bonded to the inside liner
二, Corrugated Board
Bridge ---Draped in an overlapping wave pattern to the double-backer station
Purpose---Isolating the two ends of the corrugating machine; balance; slow down
The double-backer section of corrugating machine where a second linerboard
is applied to the single-faced material coming from the single-facer unit
二, Corrugated Board
? Manufacture,
? Adhesive --- On the other side of the medium to glue outer linerboard,
? Final heating and cooling section --- Between two long,flat belts,
? Trimming edges--- Slit board to required width and length and stack
? Balanced construction--- Outer and inner have identical grammage,
? Upgrading only one liner may gain performance,
? Unbalanced constructions --- more problems with board wrappage,
? Heavier liner is placed on the outside for better printing and on the
inside for better compression strength,
三, Properties and Tests
Most board tests are described in methods provided by TAPPI,
Standard corrugated board burst and crush tests,
1,Mullen burst test (TAPPI T 810)
Forcing a rubber diaphragm against the facing until it bursts
三, Properties and Tests
2,ECT (TAPPI T 811)
A small specimen is placed between the platens of a compression
tester and loaded until failure occurs,Values are a function of the
stiffness contributed by the facings and the medium,ECT values have
a direct relationship to the projected stacking strength,
3,Flat Crush Test (TAPPI T 808)
Similar to the edge compression test except the specimen is
compressed in the flat,The test provides a measure of flute rigidity,
4,Combined Weight of Facings
Describes the combined linerboard weight per 1,000 square feet of
corrugated board
5,Thickness of Corrugated Board (TAPPI T 411)
Reduced board thickness (caliper) is an excellent indicator of reduced
compression strength; Caliper can be reduced by improper
manufacture,excessive printing pressure,improper handling and
storage
三, Properties and Tests
6,Gurley Porosity (TAPPI T 460 and T 536)
Measures the time it takes for a given volume of air to pass through a
paper,The lower the number,the more porous the paper,The porosity of
paper is sometimes the culprit when problems occur at vacuum-cup
transfer points,
7,Flexural Stiffness (TAPPI T 820)
Rrelated to box compression strength,Reduced stiffness is a good
indicator of damage during fabrication,
8,Water Take-up Tests (TAPPI T 441)
The Cobb size test,measures the amount of water absorbed by the facing
in a given time,used to measure water absorption for materials specified
to be used for hazardous product containers
三, Properties and Tests
9,Puncture Test (TAPPI T 803)
Measures the energy required to puncture a board with a triangular
pyramidal point affixed to a pendulum arm,
Test the resistance and stiffness of triple wall corrugated
The box maker’s stamp on triple wall containers calls for a puncture test
10,Pin Adhesion (TAPPI T 821)
Pin adhesion quantifies the strength of the bond between the
medium's flute tips and the linerboard facings,
11,Ply Separation (TAPPI T 812)
Evaluates the board's resistance to ply separation when exposed to water,
12,Coefficient of Friction (TAPPI T 815 and ASTM 04521),
CoF can affect machinability and load stability,A stress/strain machine
method will give both static and dynamic CoF values
四, Corrugated Boxes
1,Selecting the Correct Flute
use a carrier classification and C-flute as good starting points,
Characteristic A-Flute* B-Flute C-Flute E-Flute
Stack strength best* fair good poor
Printing poor good fair best
Die cutting poor good fair best
Puncture good fair best poor
Storage space most good fair least
Score/bend poor good fair best
Cushioning best fair good poor
Flat crush poor good fair fair
Comparison of corrugated board characteristics
四, Corrugated Boxes
E- and F-flutes are not used in shipping containers but rather are
replacements for thicker grades of solid paperboard,Can be considered if a
folding carton design calls for boards thicker than 750(30 point),Also be used
to replace paperboard for heavier or special protective primary packs as
primary container while in distribution,
Such as small tools,hardware,small appliances,and housewares…
A-flute originally specified,not commonly use, almost 5 mm (1/4 in.)
Occupies more space,has significantly greater deflection before bearing a load
when compressed,The thicker section give it the highest top-to-bottom
compression strength,A-flute has the lowest flat crush resistance
B-flute is used where box stacking strength is not required,B-flute's has high flat
crush strength when supporting heavy goods,
C-flute --- 10% better stacking strength than the same weights of B-flute
四, Corrugated Boxes
Medium Grammage A- Flute C- Flute B- Flute
127g 0.70 1.00 1.15
161g 0.90 1.25 1.45
195g 1.10 1.50 N.A
Relative flute flat crush values
四, Corrugated Boxes
? 2,Box Style
? Many standard box styles can be identified in three ways,by a descriptive name,
by an acronym based on that name,or by an international code number,For
example,a Regular Slotted Container could also be referred to as an RSC or as
#0201,
? There are many standard corrugated box styles,Slotted Boxes,Telescope Boxes,
Folders,Rigid Boxes (Bliss Boxes),Self-Erecting Boxes and Interior Forms
“Regular Slotted Container”(RSC or #0201) is the workhorse corrugated
box style (Figure 4.10),All his flaps have the same length,and the two
outer flaps (normally the lengthwise flaps) are one-half the container's
width,so that they meet at the center of the box when folded,If the
product requires a flat,even bottom surface,or the protection of two full
layers,a fill-in pad can be placed between the two inner flaps,
四, Corrugated Boxes
Figure 4.10 Parts of a regular slotted container (RSC) blank
四, Corrugated Boxes
3,Manufacturer's joint
? A flat piece of corrugated fiberboard,which has been cut,slotted and
scored,is called box blank,For some box styles,in order to make a box,
the two ends of the box blank must be fastened together with tape,
staples or glue,The place where these two ends meet is known as the
manufacturer's joint,
Liquid adhesives are most often used to join the two surfaces,Often there is
a glue tab,extending along one end of the box blank,The tab can be
joined to either the inside or the outside of the box,If there is no tab,the
box must be joined using tape,Not all boxes have manufacturers joints;
for example,the bliss box does not,
四, Corrugated Boxes
Bliss style container Bliss-style box design variations
4,Dimensioning
Dimensions are given in the sequence of length,width and depth,
Dimensions can be specified for either the inside or the outside of the
box,Accurate inside dimensions must be determined to ensure the proper
fit for the product being shipped or stored,At the same time,palletizing
and distributing the boxes depends on the outside dimensions,The box
manufacturer should be informed as to which
四, Corrugated Boxes
Top Loading End Loading
五, Carrier Rules
1,Application
? The Uniform Freight Classification (UFC) and National Motor
Freight Classification (NMFC) were established to categorize articles
for shipment via common carrier with respect to value,density,fragility,
and potential for damage to other freight,
? The classifications specify the conditions under which specific
articles can be shipped and at what rates,When shipping by rail,refer to
UFC,When shipping by truck,refer to NMFC,UFC rule 41 and NMFC
item 222 are the most frequently used in describing corrugated
packaging,
? There are four basic steps for determining authorized packaging,
? 1,Fully identify the product,
? 2,Select the proper governing classification,
? 3,Use the "Index to Articles" to find the applicable item number,
? 4,Consult the proper article to find the required packaging,
五, Carrier Rules
? Failure to comply with regulations can subject the shipper to penalties
such as higher freight rates,refusal of acceptance by the carrier,or
nonpayment of damage claims,
2,Summary of Rules for Corrugated Box Construction
? Carrier rules for corrugated box construction can be summarized as
follows,
? Specified boards (using either Mullen burst test or ECT values) shall
be used for a given product weight,providing the box does not exceed a
specified dimensional limit,The dimensional size limit for a box is
determined by adding an outside length,width,and depth,
? Table 4.6 summarizes the construction requirements for corrugated
boxes,The rules also require that a box manufacturer’s certificate (BMC)
on the bottom of the container ( Figure 4.11),
五, Carrier Rules
Figure 4.11 Box manufacturer's certificates using burst test and ECT values
五, Carrier Rules
PART A* PART B*
Maximum
weight of
Box and
Contents(l
bs.)
Maximum
Outside
Dimension,
Length,
Width and
Depth
Added(in.)
Minimum Burst Test,
Single Wall,Double
Wall or Solid
Fiberboard(lbs.per sq.in.)
or
Minimum Puncture Test,
Triple Wall
Board(in.oz.per in.of
tear)
Minimum
Combined Weight
of
Facings,including
Center Facing(s) of
Double Wall and
Triple Wall Board
or
Minimum
Combined Weight
of Pliers,Solid
Fiberboard,
Excluding
Adhesives(lbs.per
1,000 sq.ft.)
Minimum Edge
Crush Test
(ECT)
(lbs,per in,
width)
Table 4.6 Summary of carrier rules for corrugated boxes
五, Carrier Rules
Single Wall Corrugated Fiberboard Boxes
20
35
50
65
80
95
120
40
50
60
75
85
95
105
125
150
175
200
250
275
350
52
66
75
84
111
138
180
23
26
29
32
40
44
55
Double Wall Corrugated Fiberboard Boxes
80
100
120
140
160
180
85
95
105
110
115
120
200
275
350
400
500
600
92
110
126
180
222
270
42
48
51
61
71
82
五, Carrier Rules
Triple Wall Corrugated Fiberboard Boxes
240
260
280
300
110
115
120
125
700
900
1100
1300
168
222
264
360
67
80
90
112
Solid Fiberboard Boxes
20
40
65
90
120
40
60
75
90
100
125
175
200
275
350
114
149
190
237
283
* Mullen(Part A) and ECT(Part B) are presented side-by-side,
but there is no correlation between the values
六, Stacking and Compression
1,McKee formula
? Stacking strength is defined as the maximum compressive load (pounds
or kilograms) that a container can bear over a given length of time,under
given environmental/ distribution conditions without failing,
? The ability to carry a top load is affected by the structure of the
container and the environment it encounters,and the ability of the inner
(primary) packages and the dividers,corner posts,etc,to sustain the load,
? The simplest and most common corrugated transport packages are
regular slotted containers (RSCs,Box Style 0201) in which the
corrugation direction is typically vertical-parallel to top- bottom stacking
forces,
? Compression strength of regular slotted containers is a function of,
·Perimeter of the box (two times length plus two times width)
·Edge crush test of the combined board
·Bending resistance of the combined board
·Aspect ratio (L:W) and other factors
六, Stacking and Compression
? When we know the above variables,we can estimate the compression
strength through an equation known as the McKee formula,
? BCT=2.028× (ECT)0.746× ((Dx× Dy)0.254)1/2 × BP0.492 (4.1)
Where,
BCT = RSC top-to-bottom box compression strength,kN/m2(lbf/in.2 or
p.s.i)
ECT = edge crush test,kN/m (lbf/in.)
Dx,Dy = flexural stiffnesses of combined board in the machine direction and
cross direction,kN/m(lbf/in.)
BP = inside box perimeter,m (in.)
六, Stacking and Compression
? The McKee formula can only be applied to RSCs,and only those with a
perimeter-to-depth ratio no greater than 7:1,
? McKee also created a simpler formula based on caliper of the
combined board instead of bending stiffness,
BCT=5.87× ECT× (T× BP)1/2 (4.2)
Where,T = caliper of combined board,m (in.)
Solving for ECT,the simplified McKee formula is,
ECT = BCT /[5.87× (T × BP)1/2] (4.3）
六, Stacking and Compression
? The ability of a container to perform in distribution is significantly
impacted by the conditions it encounters throughout the cycle,
? If the original box compression strength is known,we can factor it
by generally accepted multipliers to arrive at an estimated maximum
safe stacking strength (Table 4.7)
2,Distribution Environment and Container Performance
Compression Loss Multifliers
Storage time under load
10 days-37 percent loss 0.63
30 days-40 percent loss 0.6
90 days-45 percent loss 0.55
180 days-50 percent loss 0.5
Relative humidity,under
load(cyclical RH variation further
increase compressive loss)
50 days-0 percent loss 1
60 days-10 percent loss 0.9
70 days-20 percent loss 0.8
80 days-32 percent loss 0.68
90 days-52 percent loss 0.48
100 days-85 percent loss 0.15
?Table 4.7 Environmental Stacking Factors
Pallet Patterns Best Case Worst Case
Columnar,aligned Negligible loss
Columnar,misaligned 10-15 percent loss 0.9 0.85
Interlocked 40-60 percent loss 0.6 0.4
Overhang 20-40 percent loss 0.8 0.6
Overhang 10-25 percent loss 0.9 0.75
Excessive handling 10-40 percent loss 0.9 0.6
六, Stacking and Compression
3,Compression Requirement
If the compression strength and distribution environment is known,the
effective stacking strength of any given RSC can be reasonably estimated,
If the distribution environment,container dimensions and flute profile are
known,a compression requirement can be estimated,This can be of great
value,because once a compression requirement is determined,the ECT
requirement can be determined (and,therefore,board combination options as
well),
[Example] A box of 0.5 m × 0.25 m× 0.30 m （ outside dimensions） will
have 12 kg,stacked 3 m high in the warehouse,Boxes will be arranged in an
interlock pattern and will be required to hold the load for 180 days at 80%
R.H.,The pallets are in good condition; there will be no overhang,What
should the required compression strength of the box be?
六, Stacking and Compression
1),Determine maximum number of boxes above bottom box,3 /0.30 -1= 8
2),Determine load on bottom box,8× 12 kg = 96 kg
3),Determine Environmental Factor by multiplying together all factors
that apply,
180 days,0.50
80% R.H,0.68
Interlocked stack 0.50
Multiplier product(Environmental Stacking Factors) 0.17
4),Determine required box compression strength,
BCT = anticipated load/stacking factor=96 kg/0.17=564 kg
Now that the actual compression strength is know,this value can be
plugged into the McKee formula (4.3),and the required edge crush test
(ECT) value of the corrugated board can be calculated,
六, Stacking and Compression
4,Compression Solutions
Following are a variety of approaches to increase compression and
stacking strength,The most efficient and cost-effective approach will
depend on the product,package size and distribution environment,
? ·Stronger liners and medium(s)
? ·Load sharing
? ·Increase the number of corners
? ·Change corrugation direction
? ·Dimensions,Depth,Length to width,Perimeter,Panel size
? ·Multiwall corrugated fiberboard
? ·Partitions,inserts and interior packaging
? ·Lamination
? ·Treatments,impregnations and coatings
