Leveling sheet metal: how to eliminate internal stress in the workpiece after laser cutting
Leveling sheet metal: how to eliminate internal stress in the
workpiece after laser cutting
Businesses, industries and commerce primarily focus on three
things: quality, delivery time and efficiency. Only companies in control of
their processes will successfully prevail against the competition over the
long term. The same applies to the metalworking industry. Raw materials in
ideal condition for further processing are a key factor here. However, sheets
are often out-of-flat and have internal stresses. These defects impair the
efficiency of downstream processing. That is why leveling the parts after
processing, for example laser cutting, is essential. Read this article and find
out all about leveling sheet metal along with the factors you need to consider.
Out-of-flat sheets with internal stresses
Stress-relieved sheets are
essential for all downstream production processes in sheet metal
fabrication. However, internal stresses are an almost inescapable byproduct of
the processing. Laser cutting in particular is notorious for creating and
releasing these stresses. The cutting laser generates a vast amount of heat
where it hits the material. This, in turn, creates a massive temperature
gradient resulting in internal stresses. In addition, this cutting process also
hardens the edges. The consequence: deformed parts. These are problematic when
it comes to efficient downstream processing. The only solution: you have to
level the sheets.
Leveling sheets which are
about to be laser cut is important in order to minimize scrap and the amount of
effort involved in rework. The objective is to significantly reduce both
internal stresses and flatness defects. Roller leveling is a proven
approach in this regard. But remember: not all roller levelers are made equal.
Specific characteristics and features of the machines ensure consistent
leveling quality. These include the block design of the leveling unit, the
correct roller configuration, the amount and quality of the support rollers,
and the number and diameter of the leveling rollers. Small leveling rollers, a
small roller pitch, a large number of leveling rollers, and very good support
are essential to fulfill the demanding flatness requirements.
Leveling sheet metal with the roller leveler –
How it works
In the field of forming
technology, roller leveling generally refers to a bending process using
rotating tools. In other words, roller leveling is a bending process that
utilizes rollers. It is an excellent means of rapidly and easily flattening
sheet metal. This approach reduces the stresses and flatness defects by means
of elastic-plastic alternating bending. When using a roller leveler, the panels
run through a series of alternating bends. The machine’s leveling rollers are
arranged with an offset from the infeed to the outlet. As a result, a roller
can always sit in between two opposite rollers, subjecting the material to
large and then progressively smaller alternating bends. This bending process
resembles a diminishing sine wave.
The alternating bending
movements when using a roller leveler achieve flat parts which are nearly free
of internal stresses. This is critical for efficient and problem-free
downstream processing. It is important that the bending of the part at the
machine infeed is larger than the largest existing bend. This is the only way
to ensure that the alternating bending has optimum sufficient effect on the
material being leveled. The leveling process eliminates the internal stresses
and flatness defects, creating a leveled part. At the same time, the roller
leveler has no effect on flat sections of the part. These remain unchanged.
Roller leveling for greater efficiency
Roller leveling is the
cost-effective approach for material thicknesses between 0.1 mm and 50 mm
(0.004” – 2”). Panels with reduced internal stresses can generally be leveled
in one run in a matter seconds. Multiple runs may also be necessary depending
on the geometry. Yet even if a part has to be run through the leveler twice,
roller leveling is still a rapid and, thus, cost-effective process. For
Imagine that you had to level
30,000 parts per year. Manual leveling carried out by an employee with a press
brake would require 10 minutes per part. In contrast, a roller leveler
completes the task in less than one minute. At a cost of $65 per hour for the
manual leveling and $150 per hour for machine leveling, this would deliver a
cost reduction of $250,000 per year. A quarter of a million simply by leveling
your parts with the proper machine. It is obvious that roller leveling
represents a simple, rapid and, above all, economical approach to sheet
metal leveling in comparison to other methods.
Leveling sheet metal and achieving the highest
In addition to the cost
aspect, the quality of manual sheet metal leveling can also be a disadvantage.
People are not machines. Their working processes cannot be 100% standardized
and therefore no two parts will have the same flatness results. Leveling
manually, which relies on human capabilities, cannot guarantee consistent
quality. Additionally, the specialists who can accomplish this task are also
rare. In comparison, a roller leveler ensures reliable results. The leveler
should also ideally be equipped with overload protection to guarantee a long
service life. Hydraulic systems have proven their value in this regard. These
hydraulics enable a safe work environment while dealing with extreme forces.
They also enable essentially wear-free leveling gap control. These systems hold
the machine in position during the leveling process, regardless of the forces
generated. This ensures the best-possible results.
All of the characteristics of
high-quality levelers combine to ensure rapid and good quality leveling results
with reliable processes. Modern roller levelers automatically calculate the
right settings so that the operator only needs to make minor corrections.
Machines are now also capable of checking the flatness, which enables automated
leveling for numerous applications.
Eliminate internal stresses to create
high-quality parts In summary, leveling parts with a roller leveler
is one of the fastest, easiest and cost-efficient methods of leveling. It
ensures high-quality sheet metal parts. This is a key factor for sheet metal
We hope you would have found the above article interesting , In
case you need any further information, Please contact us.
HEATLY & GRESHAM Ltd, U.K. commenced their activities in India in 1892 Importing for the Railways. The company gradually diversified into Machine Tools, Metrology Equipments, Construction Equipment, Thermal and Combustion Engineering, Air Ventilation & Pollution Control System & Equipments.