Manufacturer of Hydraulic Presses

Straightening Press Applications

April 23, 2019

Straightening large shafts that are used in aerospace, oil, marine, and automotive industries rely on heat treatment, machining and forming processes. However, since these processes make these shafts warp, hydraulic straightening presses are the ideal choice. Hydraulic straightening presses control the straightening process well thus resulting in parts that are accurate and well-functioning at an affordable cost. Even though other processes can be used, straightening can be the only option when it comes to conditioning or preparing the material if you are looking to machine the component properly.

A hydraulic straightening press can be used to straighten shafts, plates, and large weldments. Nevertheless, since large weldments can either be warped or deformed by the heat produced during the welding process, it is advisable to straighten these weldments before you continue with the secondary production process. Working with shafts is quite complicated because they have different sizes. There are those that have large diameters (they are usually several inches in diameter) and even there are larger shafts. Therefore, the availability of different sizes of shafts makes it hard to automate the straightening process.

What you need to know about choosing the right press design

Fabricators usually choose a press design from these two choices i.e. the fixed head or the moving gantry. Plate and weldment applications need a moving gantry press because it has the ability to move its head over the work from right to left or front to back regardless of its location on the press bed. It is important to understand that straightening press that’s used on a shaft usually has one axis only. The axis is located at the center with the shaft for easy movement.

Straightening large drive pipes and shafts that can be difficult to manipulate e.g. those used in oil field applications, using a press that can locate to the high spot end is highly recommended. This means that these presses can bend in the shaft while still applying tonnage to straighten it. However, depending on the size of the shaft or the pipe you are working on, the shaft can be moved accordingly to ease the entire process.

In case the shaft is too heavy and large to be loaded manually by an operator, an overhead crane is used to lift and gear the shaft into place. After the shaft/gear has been placed into the right place, the gantry will move it to the right spot and apply the straightening force. The traveling carriages are operated using hydraulic force to raise and lower the pipes/shaft on and off to the V blocks. In addition, the operator lifts and rotates these shafts accordingly during the entire process until they fall into acceptable tolerances.

To straighten large diameter shafts, traveling gantry presses are used. These presses only move in the X-axis while the main cylinder provides the Z-axis downward movement to engage the shaft. All the straightening work is centered under the main ram as the gantry press move over the area that needs to be straightened. Traveling gantry press also allows the gantry to move to the end of the press so that the operator can load shafts form the overhead crane with ease. After loading the shafts, the operator can drive the gantry nose tool over the high spot during the straightening process.



What you need to know about straightening process.

When the operator chooses the right selected for an application, the metal former gains complete control over ram movement while still applying tonnage. In case there is less control, more hits are needed to straighten the metal. However, a good press can make it possible for an operator to dial in-ram depth with increments of 0.001 in. Here are some control features you should know:

i. AUX Power Unit – the unit is used during shaft works only because it supplies the carriage and the lift assemblies with power. Therefore, the unit can be shut off when working on plate or weldment works.

ii. Carriage up or down switch - lifts and lower carriage assemblies so that it can rotate the part and find its high spot.

iii. Lift assy up or down switch – moves the live centers where the shafts are usually mounted.

iv. Head and gantry lock – it is used to lift the gantry up against the bottom of the press bed during the straightening process. This is important to hold the gantry in place thus preventing it from tipping or moving off to the center of the table.

v. Down pushbutton – it is used for anti-tide down and anti-repeat dual hand controls. According to OSHA requirements, the operator’s both hands should be engaged at the start of each cycle, i.e. one hand should be on the start cycle button while the other hand should be on the joystick that controls the ram movement.

vi. The motor on or off – it’s used to turn the motor on and off.

vii. Gantry movement joystick –it's used to move the cylinder assembly front and back whilst allowing the gantry to move either right or left.

viii. Main ram joystick control – the joystick controls retraction and the main-ram extension. In addition, the ram can also be controlled proportionally for speed and pressure.


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