Die Casting Lubricants: Delivery Systems and Maintenance

SKILL BUILDER DIE CASTING LUBRICANT DELIVERY SYSTEMS AND MAINTENANCE BY: ZACH WHITE, DIE CASTING PRODUCT MANAGER Die Casting Lubricants High pressure die casting (or simply die casting) is a large throughput manufacturing process for casting non-ferrous metal parts, in which parts are formed by forcing molten metal into a die cavity at high pressure. An important aspect of die casting is proper delivery and application of die lubricants. Die lubricants are multi-functional fluids that are used to: a barrier coating on the surface of the die steel • Provide to prevent the molten alloy from coming into direct contact with the surface of the die.

the die between casting cycles to help maintain a • Cool consistent working temperature. ubricate moving parts of the dies to ensure proper • Lfunction and extend tool life.

Generally, die lubricants are water-dilutable emulsions of natural and synthetic components. These lubricants are typically diluted between 50:1 to 150:1 in water prior to application.

Types of Lubricant Delivery Systems The systems that are used to mix and deliver die lubricant to die cast machines vary between facilities and process, but typically consist of the same general components.

Die lubricant concentrate is held in a bulk container. From this container, the concentrate is pumped and mixed with water at the desired dilution via either a water-driven or electromechanical chemical proportioning pump. This pump will be used to fill a holding tank, typically called a “day tank” that provides a buffer of mixed lubricant – this is important for delivering lubricant at the correct dilution since many chemical proportioning pumps will provide pulses of concentrate. From this day tank, mixed lubricant is typically delivered to the die cast machines using a diaphragm pump in order to minimize shear on the die lubricant.

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Facilities may use one of two types of permanent delivery systems:

• Central Distribution Systems • Individual Mix Stations

Central distribution systems are constructed to deliver lubricant to multiple die cast machines. These systems are generally found in larger facilities with a high number of die cast machines and allow for efficient operation, consistent dilution ratio across operations, and eases fluid analysis by reducing the amount of samples to be collected. Since mixed lubricant is pumped to multiple machines, there is a significant amount of piping that is required to be maintained.

Individual mix stations are smaller systems located at each die cast machine. These systems allow the operators to use different die lubricant products and/or dilution ratios for each machine. Smaller systems are easier to maintain, but multiple systems require more time to monitor, maintain, and collect fluid samples.

The advantages and disadvantages must be weighed when selecting which type of system is more effective and efficient for a die cast facility and operation. In many cases, a facility may choose to use a combination of both types of systems. Additionally, there are portable proportioning systems that can typically be moved with ease that are used for trial purposes.

Maintaining Lubricant Delivery Systems Proper lubricant delivery and application are imperative in effective and optimized die cast operations. Ensuring that die cast machines are receiving adequate lubricant flow and pressure includes routine inspection and maintenance of all components as well as flushing. Flushing the lubricant system is the act of physically and/or chemically cleaning the surfaces of the delivery system that are in contact with die lubricant, and are typically conducted for several reasons:

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DIE CASTING LUBRICANT DELIVERY SYSTEMS AND MAINTENANCE Maintenance – It is recommended that die • Preventive lubricant delivery systems are flushed at least twice a

year as part of a preventive maintenance program to ensure that the system is in satisfactory condition. These flushes are usually conducted during summer and winter shutdowns.

Change – When a die cast operator decides to • Product use a different die lubricant, it is recommended to flush

2. Drain all old die lubricant and fluids out of all headers, lines and drop lines.

3. Add water (HOT if available) with FORMULA FX THUNDER at 5% concentration and thoroughly circulate through the system for a minimum of 2 hours.

During circulation, power wash all spray manifolds.

4. Drain cleaner.

the system to remove all of the old product. This ensures no unintended reactions between chemical differences between products and allows for effective dilution monitoring through colorimetry.

5. Water (HOT if available) rinse and flush out cleaning solution.

hard water scale, or general dirt and debris collected from the foundry environment.

8. Fire the sprayers and inspect. Ensure the fresh DIE SLICK® die release agent is being sprayed through the lines.

Build-Up – Over time, residues may develop in • Residue tanks and plumbing as a result of product evaporation,

– While die lubricants are formulated with • Microbiology preservatives to protect the concentrate from microbial

attack, dilution to very low concentrations creates an environment for bacteria and fungi to grow in delivery and application systems. Uncontrolled microbiology can result in:

• Damage to lubricant chemistry and product splitting • Biofilm accumulation on surfaces • Plugged filters that restrict flow and pressure • Worker health concerns and putrid odor

When microbiological activity has reached a point where it cannot be controlled through microbiocide additions, it is recommended to physically clean hard surfaces and flush the system.

Central Delivery System Flushing Procedure Example

6. Recharge system with DIE SLICK® die release agent.

7. Fill drop lines and system lines, headers, etc. with fresh charge of DIE SLICK® die release agent.

9. Re-install all manifolds, strainers, spray heads and anything else that may have been removed, repaired, replaced, etc.

10. Cycle all spray equipment to insure all spray heads are firing and hitting proper locations.

Inspect all die cast machines to make sure the machines are ready and receiving adequate flow and pressure before production starts back up.

Safety All Safety Data Sheets (SDS) for cleaners and biocides should be reviewed at the pre-meeting, noting any special personal protective equipment (PPE). In many cases, the cleanout chemicals are higher in pH than normal parts cleaners and need to be handled with appropriate precautions. Similarly, all regulations and safety measures concerning the use of biocides will need to be followed.

Die cast machine operators will be tasked with cleaning out die cast machines, strainers, nozzles, spray heads, machine cavities, and all lines from the drop lines into the machines.

1. Remove all spray manifolds from each die cast machine and scrape residue off die faces.

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