Do you need a die transport system?

Determining your requirements and choosing a system

By John Massenburg

May 9, 2006

A die transport system may be needed if current production requirements cannot be met with existing presses, and opportunities for additional contracts are limited by current equipment production volumes; parts can be produced competitively in large batches, but not if the part count is smaller; and shop safety needs to be improved.

If your current method for transporting 5- to 100-ton dies is causing injuries and you need to reduce downtime and costs to stay competitive, now might be the time to ask whether you need a die transport system.

Determining the Need

For a stamper, the primary indications that a die transport system might be necessary fall into three broad categories:

1. Current production requirements cannot be met with existing presses, and opportunities for additional contracts are limited by the current equipment's production volumes.
2. Parts can be produced competitively in large batches, but not if the part count is smaller.
3. Workplace safety needs to be improved.

In all three cases, lost production time should be considered. In the first and second categories, the stamper should consider the total press downtime caused by die changes and assign a value to the lost production capacity. In the third category, the stamper can determine the lost production time resulting from injuries.

Finding the Appropriate System

The die change process can be broken down into the following six steps:

1. Unload die from press and move to transporter.
2. Transport die from press area to storage or maintenance area.
3. Unload die from transporter to storage rack.
4. Load new die from storage rack to transporter.
5. Transport new die from storage area to press.
6. Load new die onto press from transporter.

The appropriate transporter type is determined by assigning a value to lost production or injury risk level to the load/unload operations and transport operations.

If the primary savings or injury risk decrease comes from reducing the transport time, then a simple flat deck-style transporter usually is the right choice.

If improvements to both the transport process and load/unload process have the highest value, then a transporter with a die load/unload mechanism can be justified.

Figure 1 A transporter with a flat deck is a style of transporter that provides a means to transport a die to and from a press.

Die Transporter Types

Simple Transporter With Flat Deck. This style of transporter (see Figure 1) provides a means to transport a die to and from a press. The current loading/unloading operation at the press might involve a crane or forklift and is not the primary justification for purchasing a specialized transporter.

The simple transporter offers a quick, safe alternative to forklifts and cranes for the majority of the travel distance.

Transporter With Roller Deck and Winch System. This style of transporter (see Figure 2) offers the means to load the die onto and off of the press in addition to transporting over distances. The top of the transporter has a roller deck to reduce the friction as the die moves over the transporter deck to and from the press. The winch system provides a simple way to perform the transfer process.

Figure 2 This style of transporter offers the means to load the die onto and off of the press in addition to transporting over distances.

For removing the die from the press, the cable from the winch is attached to the die, and the winch is energized to pull the die across the press bed onto the roller deck on the transporter. Once on the transporter, the die typically is secured by lowering the rollers so that it sets on a fixed or nonrolling surface.

To transfer the die to the press, the winch cable is run through a pulley on the back of the press and fed to the die on the transporter. Energizing the winch pulls the die from the transporter onto the press bed.

Transporter With Push-Pull Quick Die Change System. This type of system (see Figure 3) offers a high level of automation and provides fast die change times. It substitutes the winch system for a push-pull system for high-speed, accurate die placement.

The transporter also can be configured with two stations for die location to allow the existing die on the press to be removed and the new die placed in the press without the need for an additional trip.

Figure 3 A transporter with a push-pull quick die change system offers a high level of automation, which can decrease die change times.

Defining Transporter Requirements

Once a stamper has determined that a specialized die transporter is appropriate for its production process, the next step is to choose the right equipment from the right supplier.

The stamper should give as much information as possible about its process, presses, dies, and desired results to the supplier. A reputable transporter supplier typically will ask many questions before recommending a system, including:

• What are the weight and size ranges of the dies?
• What reach is required to load/unload the die from the press or storage rack?
• What is the height of the press bed, and is it the same for all presses?
• How many presses will the transporter be supporting?
• What is the average travel distance and number of trips per shift?
• What type of floor will the transporter travel on?
• What kind of transporter maneuverability is required?

This list is by no means complete, but it's a good starting point and should be considered a bare minimum to start the process of specifying the right transporter system.

John Massenburg is an applications engineer with AeroGo Inc., 1170 Andover Park W., Seattle, WA 98188, 206-575-3344, fax 206-575-3505, info@aerogo.com, www.aerogo.com.