Chip handling

The metal removal process produces metal chips that must be dealt with. They must be processed and salvaged. With as many as 4,000 tons of chips per month at a single plant, it's not hard to see the challenge these chips present.

This huge volume of chips, along with their oily carry-off, create housekeeping and environmental issues in plant aisles, salvage carts, and chip storage areas that require constant monitoring

manual chip handling

advantages
disadvantages

advantages & disadvantages

automatic chip handling

advantages
disadvantages

advantages & disadvantages

How are chips handled?

There are two ways to handle chips: manually, or by means of automated systems. Each method has advantages and disadvantages.

Currently, virtually all chips are handled manually. Chip carts are stationed at the point where they are discharged and towed across the plant to a salvage area. Chips should be segregated by material type to maintain salvage value. The carts are grouped by material type and allowed to drain. The chips are then emptied into salvage cars and removed from the site.

Why do so many plants use manual chip handling?

Manual chip handling, while creating housekeeping problems and requiring extensive cart handling, is widely used due to its very low facility cost investment. Manual chip handling can be successful if management enforces a rigid program to eliminate oily and chip-laden floors.

There are two main requirements for manual handling: (1) conscientiously maintaining leak-proof chip carts, and (2) a disciplined program for timely replacement of full chip carts at process discharge points. Additionally, as process locations change, the handling plans should be revised to ensure that all pick-up points are scheduled into specific salvage routes.

Advantages:

Low initial capital investment

Simple equipment—less risk of down time

Reduced equipment maintenance

Less need for MRF flushing and less mist generation

Disadvantages:

Chip carts should be changed frequently.

When carts are allowed to over-fill, chips and MRF are spilled throughout the plant.

Chip carts should be monitored and repaired to eliminate leaking.

Chip carts contain excessive oil, which should be allowed to drain before dumping into salvage carts.

Material in chip carts could be a fire hazard.

Plant area is used to marshal chip carts.

Open chip carts tend to accumulate miscellaneous trash from employee discards.

Carts must be frequently shuttled.

Why do some plants choose automatic chip handling?

The alternative to manually handling chips is to install automated systems that process chips from their point of origin to the point of removal from site. Automatic chip handling systems result in better housekeeping and increased salvage value from dry chips. In addition, this method resolves the environmental problem of chip oil lost in transit.

These systems employ chip shredders/crushers, wringers (to remove oil by centrifugal separation), and blowers that transport the chips through thick-walled piping to the removal site.

A well-designed, well-tuned automatic system will provide a complete "hands off" approach to chip removal. But like all potential solutions, these systems also have limitations. The major disadvantage is the high initial capital investment. Also, different chip materials (aluminum, steel, or cast iron) pose different problems, as does the type of MRF (soluble or straight oil). Additionally, these systems are subject to high abrasive wear and will "self-destruct" over time, requiring a relatively high amount of maintenance and downtime.

Advantages:

Eliminates many housekeeping problems associated with chip and oil spillage.

Eliminates labor required to shuttle chip carts.

Greater salvage value for dry chips (with oil removed).

Returns excessive MRF from chips to the system.

Reduced chip cart maintenance.

Disadvantages:

High initial capital investment.

System’s tendency to "self-destruct"—high maintenance potential.

Manual handling necessary upon breakdown of system.

May be less effective when used on straight oil system.

Often requires much larger MRF sumps.

Potential for dead areas where MRF can "spoil" (bacterial growth).

Much greater energy costs. (A sluice pump can cost over $30,000/year for a 60 HP pump -- sluice systems often have multiple pumps.)