This document provides essential technical data on shear strength and recommended die clearance for a wide range of materials including steels, aluminum alloys, copper alloys, bronzes, brasses, stainless steels, and titanium, serving as a quick reference guide for engineers, tool designers, and manufacturing professionals involved in sheet metal design, stamping, punching, and die-making to ensure accurate clearance selection, improved tool life, and optimized production quality.
Showing posts with label Press Tool. Show all posts
Showing posts with label Press Tool. Show all posts
Blanking Tool
A blanking tool is a type of press tool used in metalworking to cut out a specific shape or "blank" from a sheet of material, typically metal. The tool consists of a punch and die that shear the material as it passes through the press. It is commonly used in industries like automotive and electronics to produce flat parts with precise dimensions and shapes, such as washers, discs, and other flat components. The blanking process is essential for high-volume production and helps ensure accuracy, speed, and consistency in part manufacturing.
Standard data sheet of Guide Bushes and Guide Pillars in Press Tools
Guide bushes and guide pillars are essential components in press tools that ensure precise alignment and stability during stamping and forming. Made from durable hardened steel, guide bushes provide fixed support for movable guide pillars, optimizing the alignment of upper and lower dies. This setup allows for smooth operation, minimizing vibrations and wear, which enhances the quality of stamped parts. Regular maintenance is crucial for maintaining performance and extending the tool's lifespan. Overall, guide bushes and pillars are vital for efficient and accurate press tool operations, significantly improving manufacturing quality.
Economic Factor: Stock Material Conservation in Manufacturing
In the realm of manufacturing, efficient stock material
conservation is a critical economic factor that can significantly influence
overall production costs and profitability. This approach focuses on optimizing
material usage without compromising the integrity and quality of individual
components, or piece parts. Understanding how to effectively manage stock
materials is essential for manufacturers looking to enhance their operational
efficiency.
Why Stock
Material Conservation Matters
✔ Cost
Reduction: By minimizing waste, companies can lower material costs, which
is especially
important in industries where raw materials are expensive or
subject to fluctuating prices.
✔ Sustainability: Conserving stock materials not only helps in reducing costs but also supports
sustainability initiatives by minimizing waste and promoting eco-friendly practices.
✔Efficiency: An optimized strip layout can enhance production efficiency, leading to quicker turnaround
times and increased output.
Calculating
Economy of Strip Layout
To quantify
the economy of a strip layout, manufacturers can use the following formula:
Examples:
1. Calculate the economy factor to punch the mild steel component in single row feeding?
Solution:
Number of rows = 1
Area of blank = 1314.16 mm2
Scrap Bridge = 1.2t =1.2
X 2 = 2.4 mm
We know that,
A. Wide Run
Economic Factor = 78.43%
B. Narrow Run
Economic Factor = 73.19%
2. Calculate the economy factor to punch the mild steel component in single row feeding?
Solution:
Number of rows = 1
Area of blank = 2525.8 mm2
Scrap Bridge = 1.2t =1.2 X 2 = 2.4 mm
We know that,
Economic Factor = 62.47%
3. Calculate the economy
factor to punch the mild steel component in single row feeding?
Solution:
Number of rows = 1
Area of blank = 2024.96 mm2
Scrap Bridge = 1.2t =1.2 X 2 = 2.4 mm
We know that,
Economic Factor = 77.33%
Technical Insights into Strip Layout for Blanking Tools
In the realm
of manufacturing, blanking tools are integral for producing precise blanks from
strip or unit stock. The layout of these strips is critical, as it directly
influences production efficiency, material utilization, and overall dimensional
accuracy. This article delves into the technical aspects of various strip
layout methodologies, considering the critical factors that affect tool design
and operational performance.
Significance
of Strip Layout Design
The strip
layout delineates the sequence of operations necessary for blank production. An
improperly designed layout can lead to errors that manifest during press
trials.
Key considerations
for designing an effective strip layout include:
1. Blank
Geometry
The
geometric profile of a blank plays a crucial role in determining its
positioning within the strip layout. Several considerations must be addressed
to optimize material utilization and ensure production efficiency:
✔ Angular
Arrangements: Certain blanks may require angular layouts to maximize
material usage and reduce waste. By positioning these blanks at specific
angles, manufacturers can take advantage of the strip's width and minimize
scrap material, ultimately leading to a more cost-effective process.
✔ Contoured
Blanks: For blanks with complex geometries, careful attention must be given
to the layout to maintain structural integrity while minimizing waste. The
arrangement should allow for efficient cutting paths, ensuring that intricate
shapes can be produced without excessive material loss. This may involve
strategic placement of the blanks to facilitate optimal cutting sequences and
tool access, thus enhancing the overall efficiency of the blanking process.
2.
Production Volume
Production
volume is a critical factor that significantly impacts the design of strip
layouts. Different production scenarios necessitate tailored approaches to
balance efficiency and cost-effectiveness:
✔ Low
Demand: When production requirements are low, conserving material becomes
paramount. In such cases, the layout must focus on maximizing material usage
while keeping tooling costs in check. Strategies may include optimizing the
arrangement of blanks to minimize scrap and ensuring that tooling is designed
for versatility, allowing for adjustments without incurring significant expenses.
✔ High
Volume: In high-volume production environments, utilizing gang dies can
greatly enhance throughput. Gang dies enable the simultaneous production of
multiple components in a single press stroke, significantly increasing
production efficiency. This method reduces cycle times and minimizes the need
for multiple setups, thereby lowering overall operational costs. The design of
the layout in this context should accommodate the complexities of gang die
configurations, ensuring that the tool path and positioning facilitate maximum
output.
3.
Material Grain Direction
Understanding
the grain direction in rolled sheets is essential for optimizing strip layout
design and ensuring the structural integrity of the blanks produced. The grain
orientation can significantly affect material behavior during processing:
Grain
Orientation: The grain direction refers to the alignment of fibers in the
material, which is established during the rolling process. This orientation
impacts the mechanical properties of the material, including its strength,
ductility, and fracture resistance.
Bending
Considerations: Bending the strip against the grain can lead to micro
fractures and significant defects in the finished blanks. Such fractures not
only compromise the integrity of the components but can also result in costly
rework or scrap material.
To mitigate
these risks, the strip layout design must take the following into account:
✔ Respecting
Grain Direction: Operations should be oriented to align with the grain
direction whenever possible. This minimizes the risk of defects and enhances
the durability of the final products.
✔ Strategic
Placement: Blanks that require bending or forming should be positioned in a
manner that utilizes the material’s strength effectively, thereby reducing the
likelihood of cracking or failure during processing.
4. Burr
Formation
Burr
formation is a critical consideration in strip layout design, as it influences
both the manufacturing process and the quality of the final product.
Understanding the position of burrs can guide layout decisions to optimize
efficiency and minimize post-processing.
✔ Blanking:
In blanking operations, burrs typically form on the punch side of the blank.
This occurs as the punch shears through the material, resulting in raised edges
that may require additional finishing steps to achieve desired surface quality.
✔ Piercing:
Conversely, during piercing operations, burrs are found on the die side. This
happens as the punch pushes material through the die, creating uneven edges on
the exit side.
5. Stock
Material Conservation
Maximizing
the use of stock material is a critical factor in optimizing manufacturing
efficiency and cost-effectiveness. Effective conservation strategies not only
reduce waste but also enhance the overall sustainability of the production
process. Key considerations include:
✔ Material
Utilization: A well-designed strip layout prioritizes efficient use of
material, ensuring that every inch of stock is effectively converted into
usable blanks. This is essential for minimizing scrap and maximizing yield,
particularly in industries where material costs are a significant portion of
overall expenses.
✔ Double
Pass Layouts: Implementing a double pass layout can significantly enhance
material conservation, particularly when dealing with complex geometries or
when the initial layout results in substantial waste. Although this method may
require a higher upfront investment in tooling and setup, the reduction in
material waste can offset these costs over time.
✔ Operational
Efficiency: In a double pass layout, the strip is fed through the tool
twice, allowing for a more optimized cutting sequence that can accommodate
intricate designs and reduce scrap production.
✔ Cost
Justification: The potential savings from reduced material waste can
justify the initial tooling costs associated with double pass layouts, making
them a financially viable option in high-precision manufacturing scenarios.
Economic
Efficiency of Strip Layouts
The economic
viability of a strip layout can be quantitatively assessed. The efficiency
percentage is calculated based on material conservation metrics relative to
production costs.
Single
Row One Pass Layout
The single
row one pass layout is a commonly used method in blanking operations, valued
for its operational simplicity and efficiency. In this layout, blanks are
arranged in a linear fashion, with the strip fed through the tool only once.
This approach can be tailored to different production needs through two primary
configurations:
✔ Narrow
Run
In a narrow
run configuration, the blanks are spaced closely together, resulting in a
narrower strip width. This layout is particularly beneficial for aligning with
the material's grain direction, which can enhance the mechanical properties of
the blanks. While it optimizes grain alignment, the narrow spacing often leads
to lower output due to limited utilization of the strip length, resulting in
increased scrap material.
✔ Wide Run
The wide run
configuration involves arranging the blanks in a wider layout, maximizing the
use of the strip’s width. This method is more effective for increasing blank
output per unit of strip length. The shorter advancement distances promote
easier feeding and reduce cycle times, leading to higher overall productivity.
By accommodating more blanks within a single pass, manufacturers can
significantly decrease the number of strips handled, optimizing workflow and
reducing handling costs.
The choice
between narrow and wide run configurations in a single row one pass layout
should be guided by production requirements and material characteristics. While
narrow runs may be suitable for specific applications requiring grain
alignment, wide runs generally offer greater efficiency and higher output,
making them preferable for many high-volume production scenarios.
Parallel
Edge Blanks
For blanks
featuring parallel edges, the strip width must align precisely with the
distance between these edges. This alignment is crucial for optimizing material
utilization and minimizing waste during production. The primary operations
involved include:
✔ Cut-off
Operation: This method is ideal for producing blanks with two parallel
edges. It efficiently removes the material without generating scrap, thus
minimizing waste and enhancing overall material conservation.
✔ Parting
Operation: When only one set of edges is parallel, a parting operation is
necessary. This method results in the creation of a scrap strip that must be
managed, making it less efficient than the cut-off process. Careful planning is
needed to handle the resulting waste effectively.
Notching
and Trimming Operations
✔ Notching:
This operation entails the removal of small sections from the edges of the
strip. Notching is essential for achieving precise shapes and ensuring that
components meet exact specifications. It is particularly useful in preparing
blanks for further processing.
✔ Trimming:
In contrast, trimming involves the removal of larger sections of material to
refine the dimensions of the blank. This operation helps achieve the desired
shape and size, enhancing the overall quality of the final product.
Considerations
for Irregular Contours
When
positioning blanks with irregular geometries, several factors must be
meticulously evaluated to ensure optimal production outcomes:
Contour
Analysis: For blanks with two parallel sides, cut-off operations provide
significant advantages, including:
✔Minimal
Material Wastage: Efficiently utilizing stock material reduces overall costs.
✔Reduced Tool
Costs: Simplifying operations leads to lower tooling expenses.
✔Elimination
of Scrap Handling: Less scrap material simplifies post-production processes.
Dimensional
Accuracy: It is important to note that sheared strips generally have an
accuracy limit of ±0.2 mm. For applications requiring tighter tolerances,
employing a dedicated blanking tool is highly recommended to achieve the
necessary precision.
Flatness
and Tool Selection
For
applications where flatness is a critical requirement, blanking tools are
preferable. They produce components with superior flatness compared to other
methods, ensuring that the final products meet stringent quality standards. Proper
tool selection plays a vital role in maintaining the integrity and dimensional
accuracy of the blanks, ultimately enhancing the reliability of the
manufacturing process.
Advanced
Layout Methods
In modern
manufacturing, optimizing strip layouts is crucial for maximizing efficiency
and minimizing waste. Here, we explore advanced layout methods, including the
single row two pass layout, double row layout, and gang die systems.
Single
Row Two Pass Layout
The single
row two pass layout involves feeding the strip through the tool twice, which
significantly enhances material utilization. This method is particularly
beneficial when:
✔Material
Conservation: By strategically planning the cutting paths over two passes,
manufacturers can minimize scrap material and improve overall yield.
✔Stop
Mechanisms: Careful consideration must be given to the design of stop
mechanisms to prevent interference during the second pass. Effective stop
designs ensure smooth operation and reduce downtime, allowing for seamless
transitions between passes.
This layout
is particularly advantageous in scenarios where intricate shapes or tight
tolerances are required, as it allows for greater control over the cutting
process.
Double
Row Layout
The double
row layout positions blank in two rows, effectively increasing economic
efficiency and production rates. Key benefits include:
✔Enhanced
Material Conservation: By maximizing the use of strip width, this layout
reduces scrap material and improves yield.
✔Increased
Production Rates: The ability to produce more blanks in a single operation
enhances throughput, making it an ideal choice for high-volume production
environments.
This
configuration is particularly useful in applications where speed and efficiency
are paramount, allowing manufacturers to meet higher demand without
compromising quality.
Gang Die
Systems
Gang die
systems incorporate multiple tool sets within a single press stroke,
facilitating the concurrent production of several components.
This method
offers several advantages:
✔Increased
Production Efficiency: By producing multiple parts simultaneously, gang dies
can significantly reduce cycle times and improve output rates.
✔Cost Offset:
Although the initial investment in gang die systems may be higher due to the
complexity of design and tooling, the resultant increase in production
efficiency can justify these costs over time.
However, it
is important to note that gang dies are not recommended for highly complex
geometries. The intricacy involved in designing gang dies for complicated
shapes can lead to increased production challenges and potential
inefficiencies..
Manufacturers can boost production efficiency and reduce
costs by optimizing strip layouts that thoughtfully consider blank geometry and
production volume. Prioritizing grain direction and strategically positioning
components to minimize burr formation enhances product quality and reliability
while reducing post-processing needs. This careful planning not only improves handling
and finishing but also promotes sustainable practices through material
conservation, ultimately strengthening competitiveness in the market. By
selecting the right layout, manufacturers achieve superior operational
efficiency and performance in their blanking processes.
DETERMINATION OF FORCES IN SHEARING OPERATIONS
In design of a press tool for shearing operation, all the various
forces involved in its construction will be considered. These two major forces
must be considered and become part of the design,among which two major forces,
namely cutting force and stripping force.
A. Cutting
Force (Fc)
Cutting
force is that force which is applied to shear the material in the course of the
cutting operation. Blanking, punching, and shaving are some of the operations,
it plays a very critical role since it acts as an indicator of the efficiency,
quality, and safety of the processes involved in manufacturing.
The
following are some factors which influence the magnitude of this force:
1. Material: This will depend upon the shear strength of material to be cut, which again is dependent on the nature itself - mild steel, aluminum, or composite material. Usually, a higher tensile strength will require more cutting force.
2. Material Thickness: It is a requirement of more force to actually shear this material. In comparison to the applied force and thickness, normally it is a straight line but varies with the material properties.
The cutting force plays an important role in the design of the press tool in shearing operations (i.e. Blanking, Piercing, Punching, Trimming etc.). Either way, it is a problem either in lifting the production process or hindered by it. Proper calculations of the force involved in cutting to ensure appropriate sizing of the tooling and suitable free operations without lots of risks of stress ensure that it will never be prone to early failure and wear and tear.
Cutting Force is Calculated as;
Where,
Fc=
Cutting Force, N
L= Cutting
Length, mm
t=
Thickness of sheet, mm
τmax
= Shear strength of Sheet Material, N/mm2
B.
Stripping Force (Fs)
It is the
force that would have to be applied for the withdrawal of the cut workpiece
from punch or die after the process of shearing has taken place, and it is
denoted as Fs. Among the vital forces that carry out a clean separation without
damaging the material or the tooling, this is one of them.
The
factors involved are:
1. Material
Adhesion: Owing to friction and elastic properties of material, the material
gets stuck in die on shear cut. The stripping force must overcome adhesion
forces, so that it is easily ejected from the die.
2. Die
Geometry: The stripping action depends a lot on the die geometry. This would
include clearance between workpiece and the die as well as the design of
stripping plates or mechanisms.
3. Surface
Finish: Finish on the die as well as on the workpiece is friction-related. That
is, the smoother the surface, the lesser would be the friction. With it comes
decreased stripping force.
4. Material
thickness: It affects the amount of stripping force just as it does with the
cutting force. The bigger the thickness, the bigger the pulling out force is,
especially when the material becomes liable to deformation at the point of
cutting.
Where,
Fs=
Stripping Force, N
Fc=
Cutting Force, N
Total Force: Total force is helpful to
determine the amount of right tonnage that needs to use for press tool operation.
It is calculated as,
Total Force = Cutting Force + Stripping Force
Where,
P = Required
Press Tonnage, N
Fs =
Stripping Force, N
Fc =
Cutting Force, N
Examples:
1. Calculate the required press tonnage for following data:
Operation : Blanking
t =Sheet Thickness, 2mm
τ = Shear strength, 400 N/mm2
Solution:
A. Cutting Force:
t =Sheet Thickness, 2mm
τ = Shear strength, 400 N/mm2
Cutting Length(L) = 197.08mm
Fc = 197.08 X 2 X 400
Fc = 157664 N
Fc = 15.8 Ton
B. Stripping Force
Fs= 10% of 157664
Fs= 15766.4 N
Fs= 1.6 Ton
C. Total Force
P= 157664+15766.4
P= 173430.4 N
P= 17.3 Ton
Required Press Tonnage for above operation is 17.3 Ton.
2. Calculate the required press tonnage for following data:
Operation : Blanking
t =Sheet Thickness, 2mm
τ = Shear strength, 280 N/mm2
Solution:
A. Cutting Force:
t =Sheet Thickness, 2mm
τ = Shear strength, 280 N/mm2
Cutting Length(L) = 205.66 mm
Fc = 115169.6 N
Fc = 11.5 Ton
B. Stripping Force
Fs= 10% of 115169
Fs= 11516.9 N
Fs= 1.2 Ton
C. Total Force
P= 115169.6+11516.9
P= 126686.5 N
P= 12.7 Ton
Required Press Tonnage for above operation is 12.7 Ton.
3. Calculate the required press tonnage for following data:
Operation : Blanking
t =Sheet Thickness, 1.5 mm
τ = Shear strength, 400 N/mm2
Solution:
A. Cutting Force:
t =Sheet Thickness, 1.5mm
τ = Shear strength, 400 N/mm2
Cutting Length(L) = 267.04 mm
Fc = 267.04 X 1.5 X 400
Fc = 160224 N
Fc = 16.02 Ton
B. Stripping Force
Fs= 10% of 160224
Fs= 16022.4 N
Fs= 1.6 Ton
C. Total Force
P= 160224 + 16022.4
P= 176246.4 N
P= 17.6 Ton
Required Press Tonnage for above operation is 17.6 Ton.
4. Calculate the required press tonnage for following data
Given;
Operation : Piercing
t =Sheet Thickness, 1.5 mm
τ = Shear strength, 530 N/mm2
Solution:
A. Cutting Force:
t =Sheet Thickness, 1.5 mm
τ = Shear strength, 400 N/mm2
Cutting Length(L) = 78.54 mm
Fc = 78.54 X 1.5 X 400
Fc = 47124 N
Fc = 4.7 Ton
B. Stripping Force
Fs= 10% of 47124
Fs= 4712.4 N
Fs= 0.4 Ton
C. Total Force
P= 47124 + 4712.4
P= 51836.4 N
P= 5.2 Ton
Required Press Tonnage for above operation is 5.2 Ton.
5. Calculate the required press tonnage for following data
Given;
Operation : Piercing
t =Sheet Thickness, 2 mm
τ = Shear strength, 530 N/mm2
A. Cutting Force:
t =Sheet Thickness, 2 mm
τ = Shear strength, 530 N/mm2
Cutting Length(L) = 2(πd) = 2(78.54) = 157.08 mm
Fc = 157.08 X 2 X 530
Fc = 166505 N
Fc = 16.7 Ton
B. Stripping Force
Fs= 10% of 166505
Fs= 16650.5 N
Fs= 1.7 Ton
C. Total Force
P= 166505 + 16650.5
P= 183155.5 N
P= 18.32 Ton
Required Press Tonnage for above operation is 18.32 Ton.
6. Calculate the required press tonnage for following data
Given;
Operation : Blanking and Piercing
t =Sheet Thickness, 2 mm
τ = Shear strength, 400 N/mm2
Solution:
A. Cutting Force:
t =Sheet Thickness, 2 mm
τ = Shear strength, 400 N/mm2
1. Blanking Operation
Cutting Length(L) = 371.76 mm
Fc = 371.76 X 2 X 400
Fc = 297408 N
Fc = 29.74 Ton
2. Piercing Operation
Cutting Length(L1) = 69.28 mm
Cutting Length(L1) = 38.11 mm
Fc = (69.28+38.11) X 2 X 400
Fc = 85912 N
Fc = 8.6 Ton
Total Force (Fc)= 29.74+ 8.6 =38.34 Ton
B. Stripping Force
Fs= 10% of 38.34
Fs= 3.8 Ton
C. Total Force
P= 38.34+3.8
P= 42.14 Ton
Required Press Tonnage for above operation is 42.14 Ton.
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