August 28, 2003
Just as office managers look for the most efficient way to store files, shop managers must look for efficient ways to store heavy, expensive dies. Many offices have file cabinets with an index system for locating files quickly. The shop equivalent for storing and retrieving dies may be air-powered rollout shelf units.
These units typically are used in conjunction with overhead cranes, roller arms, and powered conveyors located at the press. The operator pushes a button that rolls out a shelf, picks up the dies with an overhead crane, and takes them directly to the press.
Rollout shelves can be manual or air-powered, and they usually have capacities from 400 to 40,000 pounds per shelf, lengths up to 40 feet, and depths up to 8 ft. Some systems have lock-in and lock-out devices while others have safety interlocks that lock the other shelves when one is rolled out.
Some shelves have pans that catch oil before it drips on the floor to help keep the shop clean. Dies also can be stored on inverted angles welded to the pans, and the oil is removed from the pan through a drain plug or a vacuum.
Numbering each shelf and designating a location on the shelf for each die helps to eliminate downtime associated with searching for dies.
Before you can reach this point, however, it is important to understand your company's operations thoroughly. You'll need to take an inventory of all dies, recording information on their width, depth, height, weight, and die name or number. Many companies have some or all of this information already available. However, many shops don't realize that taking the time to inventory and organize their dies will save money in the long run.
If a company doesn't have any recorded die information, it can take two to 20 minutes to measure, calculate weight, and assign a unique number to each die. For example, a company with an inventory of 50 dies would need about eight hours to catalog them.
The best person to catalog the dies usually is the foreman or someone who can determine how often each die is used, what presses it is used in, and whether it is obsolete or needs repair. After taking an inventory, many shops discover that about 25 percent of their dies are obsolete.
When your die inventory list is complete, make a list of all die handling problems you have with your current system. Be specific, and make sure the new system addresses and solves your die handling problems.
If a crane will be used with a shelf rollout system, its capacity will determine if it can lift the largest die, and the shop's floor print will establish the best location for the die handling system. The crane's hook height must be known to determine the maximum height of the new unit. Because the shelves roll out, the system can be placed in previously unused space, such as under the crane's rails.
Generally, 90 percent of the solution to any problem is to understand the problem thoroughly. In die handling and storage, a complete inventory of dies will solve most of the problem. Many shops have no idea how many dies they have or a designated location for them. Die chaos results in time lost searching for dies that are stored "somewhere" or being repaired.
The remaining 10 percent of the die handling solution is understanding die storage options and determining which one best suits your requirements.
Once you have an accurate die inventory list and have identified current storage problems, you are ready to have a new system designed. Some companies design their own system and some hire a consultant that specializes in material handling. On average, it takes about 40 labor-hours to create a CAD layout drawing with locations for 200 dies. Some vendors offer this as a free service to their customers.
Once a storage system is chosen, evaluate it for your shop's future as well as current needs. For example, all shops have combinations of dies, such as 2-ft.-sq. dies, 4-ft.-sq. dies, and 8- by 4-ft. dies. A shelf designed to store the largest die also should be able to accommodate any combination of existing or new dies.
Although air-powered rollout shelves in conjunction with an overhead crane may be an efficient and safe way to handle and store dies, this method takes the most time to design because all the units are custom-made to suit each application. Time is needed to plan the proper place for every die.
Custom systems can include not only air-powered rollout shelf units but also cranes, lifting devices, powered conveyors for inserting the dies into presses, and other items needed for a turnkey operation.
If the best die storage system is too expensive for your current budget, look for systems that can be phased in in stages. This may involve purchasing and setting up several units at a time and adding units as the budget allows.
Although floor space and changeover time are important, the main emphasis should be on safety. All employees should be trained in the proper use of the new system and have a step-by-step procedure manual for reference.
Any prospective die storage and handling system generally should take 50 percent less floor space than the current one, cut die handling time in half, and improve safety. An organized die storage and retrieval system will reduce the amount of time spent searching for needed dies and therefore increase press uptime.