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WIRTZ SYSTEM APPROACH TO AUTOMOTIVE GRID CASTING
Successful light weight grid casting is practically impossible without specific predetermined parameters. Wirtz Manufacturing Company launched a major development some time ago to establish such parameters, and our system approach is the direct result of this program.
Experimentation and research is continuing and it is expected that we will be achieving fuller progress in all areas of involvement.
Technological advances in the past few years have been numerous in areas such as:
1. Automotive type grid casting with low antimonial alloy as well as with calcium.
2. Special application grids for various type batteries. Calcium alloy panels containing as many as eighteen grids per panel were normally cast by hand. Today they are produced automatically.
3. Small, medium, and large size industrial panels, low antimonial or calcium, can now be produced faster than ever before.
The SYSTEM APPROACH involves a full consideration of the following steps which are vitally important for profitable high speed casting.
1. The alloy or casting material
2. The furnace and ventilation system
3. Alloy delivery system dispensing valve and ladle
4. Grid and grid mold design
5. Controlled mold heating
6. Controlled mold cooling
7. Mold coating and application technique
8. The casting machine
9. Maintenance, environmental effects and safety
10. Adequate training for operating personnel
The system approach is important to the battery manufacturers because all of the above items are interrelated.
We can not afford to understand just part of it; we must understand all of it.
COMMENTING ON EACH BRIEFLY:
1. THE ALLOY OR CASTING MATERIAL
There has been considerable progress in this area and I am sure we know more about it today than ever before. However, we do not know enough. We believe the near future will bring better and more consistent casting materials.
Suppliers and users must work closely together. Better quality control along with operator training is of great help, however, periodic casting alloy specification review is important to successful high speed light weight grid casting.
2. THE FURNACE & VENTILATION EQUIPMENT
The furnace and ventilation equipment of today must be designed for efficiency as well as for safety. To only satisfy functional requirements would be a mistake.
Efficiency with adequate controls can be improved and, at same time, overheating can be eliminated. Lower furnace temperature to produce less dross can now be achieved.
Better ventilation, along with improved furnace insulation to prevent excessive radiation and heat stress, cannot be overlooked.
3. ALLOY DELIVERY SYSTEM DISPENSING VALVE AND LADLE
To allow lower operating temperatures in the melting pot, the modern lead lines have to do more than just deliver the lead to the ladle. Today’s alloy delivery requirements are greater in scope and must comply with requirements such as:
A. Scale free materials for construction
B. Air tight to prevent oxidation
C. Capable of superheating, above the furnace temperature
D. The superheating alloy should not be returned into the furnace
E. Constant head pressure must be maintained against the valve to allow accurate dispensing.
F. The valve should be air tight and capable of constant dispensing automatically and it must be easy to maintain or replace.
G. Feedline should be insulated to prevent heat radiation to the casting room
H. Ladles should be hooded to prevent heat radiation and to carry off gas and lead fumes.
I. The ladle must retain the required pouring temperature without generating excessive dross and it must be designed in conjunction with the mold to allow proper venting and rapid filling.
4. GRID AND GRID MOLD DESIGN
It is not desirable to separate the two; therefore, engineers designing the product must be familiar with mold design, as well as with the entire process of cavity filling in general. Turbulence can be reduced and rapid filling can be achieved if the designer understands the process.
5. CONTROLLED MOLD HEATING
Experiments and production feedback’s clearly point to the fact that accurate mold temperature control is a major improvement over past practices. The casting operator, with the aid of controlling instruments knows what adjustments to make without guessing.
6. CONTROLLED MOLD COOLING
In the areas of large casting metal concentration, (such as the gate) without controlled mold cooling, high speed casting production would be impossible. Constant coolant input at elevated temperatures will not disturb the equilibrium of the mold and, it does provide the operator with the necessary means of control over the cooling process. The closed circuit system can also provide a coolant to prevent troublesome deposits in the cooling lines if the proper equipment is provided along with the cooling system. In addition, the automatic heating and cooling system is reliable, practically maintenance free, and it eliminates all of the problems normally associated with tap water cooling.
7. MOLD COATING AND APPLICATION TECHNIQUES
The person responsible for mold coat handling or mixing must understand its performance, also the person applying the coating must be well-trained and have at least a basic understanding of what mold coating is all about.
Millions of dollars are lost annually in overweight grids simply because the operators and line supervisors are not familiar with the modern weight control techniques.
8. THE CASTING MACHINE
The casting machine must be rugged and capable of providing trouble-free conveying of panels from the mold to the trim die and from the die into the stacker.
Heavy duty construction, ease of maintenance, accessible components, less moving parts, safety and simplicity are significant design requirements.
9. MAINTENANCE, ENVIRONMENTAL EFFECTS AND SAFETY
No casting operation can be successful without supporting services such as maintenance. No one can afford to have production equipment idle any longer than is absolutely necessary.
Preventative maintenance, can only enter the picture after maintenance in general is well established.
Environmental problems can be lessened by providing better insulated equipment resulting in lower heat generation into the casting room, not only to comply with OSHA regulations, but to provide a more productive atmosphere in general.
10. ADEQUATE TRAINING FOR OPERATING PERSONNEL
Operator training is essential to the adequate usage of the casting system with its ultimate payout.
New equipment, new process and cost reduction systems can only be justified by assuring knowledgeable operation.
Our experienced and highly qualified service personnel are ready to serve you anytime, any place.
The policy of our organization is to provide you with all of our technological advances by way of better equipment and training.
The "Wirtz System" approach to grid casting is an on-going project.
A close association with all phases of the battery industry enables our research and development programs to continue bringing to the battery manufacturers improved Grid Casting Systems.
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