In the metal industry, a stretch forming press is a very important machinery. Stretch Forming itself, is a technique used in metal shaping and can be very complex. This article will help you to understand how it works in the simplest way possible.
What is Stretch Forming?
Stretch forming is a method of bending and shaping metal. It makes use of a special kind of machine called a Stretch Forming Press. The press gently stretches and draws the metal over a mold called a die, which allows it to take the exact shape you want.
All of this is made possible by one particular machinery; the stretch forming press. This machine is what stretches the metal to match the precision of the die, making work easier.
There are two types of stretch forming presses which are
- Longitudinal Stretch Forming Press and
- Transverse Stretch Forming Press
Longitudinal Stretch Forming Press
Just as the name suggests, the longitudinal stretch forming press is used to shape metals in a longitudinal direction as opposed to its width. It is the perfect way to handle long linear parts with smooth edges. It’s the best choice if you’re looking for uniformly consistent shapes.
The LSFP works by clamping the metal sheet at both ends. After that, it stretches the metal across the length without making any adjustments to its width. At the same time, the metal is pressed over a pre-designed die which gives the metal its precise shape. Once this is done, the metal is unclamped and ready for use.
The major advantage of using Longitudinal Stretch Forming Press is that it reduces the time spent on welding different pieces together.
Transverse Stretch Forming Press
A Transverse Stretch Forming Press works the same way the longitudinal stretch forming press works. The only difference however, is that this is used to stretch metal into desired width instead of length.
You use a transverse stretch forming press when your aim is to have a broad, sweeping curve or complex shapes with uniform surfaces. Apart from being cost-effective, transverse stretch forming press allows you to produce large parts with minimal wastage.
Now that you know what types of Stretch Forming Presses we have, you need to also understand the components of the press. These components are very important as they help you to operate the machine properly.
Components Of A Stretch Forming Press
Die
A die is a crucial part of the stretch forming press that allows you to measure the dimension in which your metal will be shaped into. It is the part of the machine where the metal is stretched over during the forming.
Without the die, you won’t get an exact specification of the part you want to process. It is solely responsible for how accurate your metal stretch turns out.
The die wraps around the metal when it is stretched. When the press stretches the metal sheet, the die makes sure it takes the desired shape you need for your work.
Clamp
Clamps are what they are, literally. They hold your metal sheet in place during stretching, ensuring that you have precise control over the process in a bid to achieve the necessary result.
The metal sheet is usually placed between the clamps before stretching begins. This allows tension to be evenly distributed across the sheets, giving it a consistent stretch.
The Hydraulic System
To perform a metallic stretch, you need force and power. The hydraulic system is fitted for this role. It generates the needed power to ensure that your machine works perfectly.
The hydraulic systems consist of;
The Power Unit is made up of a motor, pump, and reservoir containing hydraulic fluid. The fluid is filled with pressure as the motor starts the pump, causing it to convert electric energy to hydraulic energy. This fluid is then directed to where it is needed.
- Hydraulic Ram
The hydraulic ram takes the hydraulic energy and converts it into mechanical force. It works in such a way that when the pressurized fluid moves into the ram’s cylinder, a piston is pushed into linear motion. This motion is what you use to stretch and shape the metal sheet.
Now you know all about your stretch forming machine. But how does stretching really work? Let’s find out.
How Stretch Forming Works
Step One:
The first step in stretch forming is to prepare for the job itself. You need to select the right type of materials to use. After choosing, you cut to the desired shape or size. You do this to make sure that the materials fit perfectly into the press. That way, the measurements are right for the end result.
Once this is done, you may also need to anneal your material as this makes it easier to stretch without breaking.
After this step comes loading.
Step Two:
Loading the material onto the press requires perfect placement. Otherwise, you won’t get the shape or dimension you need. Next, you align the material with the clamp and hold it firmly in place. Always check the alignment to make sure it is evenly distributed as this may cause the material to slip. You should also adjust the clamps to make sure the material doesn’t stretch unevenly during the process.
Step Three:
Once this is done, it is time to stretch your material over the die. The hydraulic systems kick into gear at this point, distributing energy where it is needed. The system controls the force and speed at this point, making sure that your final result is just as you want it to be. Once this has been achieved, you can then reduce the hydraulic pressure before you take the material out.
After all is said and done, you also need to understand that stretch forming presses are not used in all industries. There are certain places where these machines are important and we will go through them.
Application of Stretch Forming Presses
Aerospace
Wing Panels, fuselages, and structural supports are metal works which are made possible by stretch forming presses in the aviation industry. As these parts can not easily be welded together, they are required to go through stretch forming in order to ensure precision, strength, and conditioning.
Automobile
There are certain parts of your car that are only made possible through the works of a stretch forming press. Body panels like roofs, hoods, and fenders are made to go through this machine to ensure they are precisely cut to shapes or sizes.
Other parts like the chassis are also made from stretched metals which are durable.
Architecture
Special domes, arches, staircases, and railings are products of stretched metals. The dimensions of the metal needed for this kind of architectural design are very delicate and require precision. This makes it important for stretch forming to occur.
Some curved facades are also made possible through stretch pressing, making them unique in style.
Importance of Stretch Forming Presses
Enhance Material Properties
When materials are stretched and molded into shapes, they not only become stronger but also more durable. Stretching allows materials to become more resilient, increasing their tensile strength which makes it harder for them to break or crack under pressure.
Cost-effectiveness and Waste Reduction
Unlike traditional methods where materials are welded together or cut into different shapes and sizes, stretching allows for little to no wastage. Since there are no scraps, you can save up money from buying excess materials.
It is also a great way to reduce the excessive use of tools in the factory since the presses themselves need less tools.
Ability to Form Complex Shapes
Say bye-bye to sleepless nights that leave you exhausted as you worry about having to create 3D shapes or complex metal forms. With stretch forming presses, you can bend metal into any type of shape you want.
It also allows you to be creative with style.
Conclusion
Metal work shouldn’t be too difficult as long as you have a stretch forming press. And with this comprehensive guide, you have learned all you need to make your work stand out. Even if you’re not an engineer or a metal worker, knowledge of this machine helps you to understand how those wondrous designs came to be.
