In this article on Reverse Tonnage also referred to as “Snap-Through” we will examine the root cause of this issue and its adverse effects on both your press and your tooling. The effects of Reverse Tonnage can be devastating.
If not addressed properly over time Reverse Tonnage will literally reduce the life of your tooling and destroy the drive train of your press. The results of ignoring Reverse Tonnage can mean a complete rebuild of your press which can be hugely expensive.
However, today Reverse Tonnage is a well understood side effect of performing “blanking” in a press and its harmful effects can be controlled.
Air Counterbalance Adjustment is Often Overlooked, Causing Damage to Your Press
Maintaining proper Air Counterbalance Pressure (ACP) on mechanical stamping presses is essential to prevent excessive wear and damage. It may be surprising to learn that damage resulting from improperly adjusted ACP, which can cost tens of thousands of dollars, often occurs due to human error and lack of proper training, even though ACP cylinders are a relatively inexpensive component. To avoid these costly damages and downtime, it is important to ensure that the ACP system is set up correctly. In my over 40 years in the stamping industry, I have seen many problems that could have been avoided with proper ACP maintenance. Here are some tips to ensure optimal ACP pressure settings for each die:
✔ ACP cylinders should be used to equalize the weight of the upper die and the pull-down points in the press drive system.
✔ Static pressure settings should be used when the ram is not moving, while dynamic pressure settings may need to be increased depending on the strokes per minute.
✔ Damage can occur when the ACP system is not set up correctly, such as when the pressure is too low, causing a hammering effect at the pull-down points, or when the pressure is too high, making the main motor work harder and consume more amps.
Mechanical Connection Points
A 600-ton metal stamping press is a large piece of industrial equipment used to shape and cut metal. The mechanical connection points in this type of machine are crucial to its operation and include:
1. Motor and Flywheel Connection: This is where the power from the motor is transferred to the flywheel. The motor shaft and flywheel are connected using a coupling that can be rigid or flexible. The choice of coupling depends on the alignment accuracy and torque requirements.
2. Flywheel and Clutch Connection: The flywheel is connected to the clutch mechanism. This connection allows the transfer of energy from the flywheel to the press. The clutch, when engaged, transfers the rotational energy of the flywheel into linear motion that powers the stamping press.
3. Clutch and Crankshaft Connection: The clutch is connected to the crankshaft. When the clutch is engaged, it transfers the rotational motion of the flywheel to the crankshaft. This rotation is converted into reciprocating motion by the crank mechanism.
4. Crankshaft and Ram (or Slide) Connection: The crankshaft is connected to the ram (or slide) using connecting rods. This connection converts the rotary motion of the crankshaft into the linear motion of the ram. The ram then moves up and down, stamping the metal workpiece.
5. Ram and Die Connection: The ram holds the top of the die set (punch). The punch descends onto the workpiece that is placed in the bottom of the die set (die). The punch and die are typically bolted to the bed and ram of the press respectively.
6. Frame Connections: The press frame holds all the components together and provides rigidity to the system. The frame is composed of the crown, uprights (or housing), and bed. The motor, flywheel, clutch, crankshaft are all mounted to the frame. The frame is typically bolted to the floor for stability.
7. Reinforcement Plate and Die Connection: The reinforcement plate is a large metal block on which the die is mounted. It is designed to withstand the high pressure of the stamping process and is typically bolted or clamped to the press bed.
These connection points must be well-maintained and regularly inspected for wear to ensure the safe and efficient operation of the press.
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UPGRADES & RETROFITS FOR PRESS CONTROLS
If you are considering modernizing the control systems of your presses, we strongly recommend the I-PRESS® & Automation Control System.
Our cutting-edge control system is built on the reliable software and hardware platform of Rockwell AB, ensuring exceptional reliability, safety, and easy availability of spare parts.
I-PRESS® & Automation controls are now available for upgrades and retrofits of controls in mechanical and forging presses of all brands and models.
Users receive a new main electrical panel (MEP) and a completely new main operator station (MOS), as well as a full set of electrical schematics as originally built.
In this article on Reverse Tonnage also referred to as “Snap-Through” we will examine the root cause of this issue and its adverse effects on both your press and your tooling. The effects of Reverse Tonnage can be devastating.
If not addressed properly over time Reverse Tonnage will literally reduce the life of your tooling and destroy the drive train of your press. The results of ignoring Reverse Tonnage can mean a complete rebuild of your press which can be hugely expensive.
However, today Reverse Tonnage is a well understood side effect of performing “blanking” in a press and its harmful effects can be controlled.
