The Lubricating Effects of Electroosmosis on Drill Bits

Abstract:

The purpose of this project was to determine if applying negative potential to a drill bit used to drill concrete would significantly increase its drilling performance. Negative potential was required for a current to attempt to flow since the concrete samples were already positively charged by natural processes in the concrete.

A pulley was attached to the arm of the drill press to provide a constant and even application of force to the drill bit. The pulley was constructed by positioning a coffee can around the arm of the drill press and tying a weight to it with a long string wound around it. Uniform concrete test blocks were created by pouring concrete into Styrofoam cups.

For the trials with a negative potential applied to the drill bit, a wire was run from a power supply through a wire looped around the upper exposed end of drill bit. The drill press was insulated from the charge by wrapping emery paper around the part of the drill bit in the chuck. Each trial lasted exactly one minute. For the trials without a negative potential applied, the same procedure was used excluding the wire setup. In all of the trials, uniform concrete test blocks were drilled into.

After organizing the data it became apparent that the drill bit with negative potential applied did significantly better in drilling depth than the drill bit without the negative potential applied in almost every instance.

INTRODUCTION

The purpose of this project was to determine if applying negative electrical potential to a drill bit would significantly increase drilling performance when used in drilling in concrete. Negative potential was required for a current to even attempt to flow, since the concrete samples are positively charged. My hypothesis is that electroosmosis will not significantly increase the drilling performance.

PURPOSE

The purpose of this investigation was to determine if the lubricating effect of electroosmosis significantly increased average drilling performance. If there is a significant increase in the drilling depth attained in a standard length of time, then the use of electroosmosis on drill bits would present many benefits in drilling.

PROCEDURE

1. Materials must be acquired:
   • Drill Press
   • 2 Masonry Drill Bits
   • 78 Uniform Concrete Drilling Samples
   • Force Applicator (Pulley)
     • Coffee Can
     • Cord
     • 10 lbs of weights
   • 12 volt power supply
   • Wires for connection
   • Copper Staff
   • Measuring Length
   • Emery Paper
2. The concrete drilling samples were poured using a standard styrofoam coffee cup as the mold, and left to set for 22 days until up to strength.
3. The drill press was prepared for drilling by setting up a coffee can as the force applicator. The can was secured to the arm of the drill press with duct tape. Weights were then attached to the cord which was wrapped around the coffee can several times to supply the constant downward force.
4. A negative potential of 12 volts was applied to the drill bit by channeling electricity from the negative side of the power supply to the drill bit. The same drill bit was used 39 times, each time with the negative potential applied, and only for one minute, with a constant downward force of ten pounds.
5. For the trials without negative potential applied to the drill bit, a new drill was used. The same drill bit was used for all of the trials without negative potential applied, each time only for one minute with a constant downward force of ten pounds.
6. Measurements were taken. Each hole made in the concrete was measured in depth to the nearest 32nd of an inch by marking how far down the staff went and then measuring that length. All measurements were recorded and compared.

Note:

Here is the Concrete Mix Design That I Used

DISCUSSION

During testing the two bits seemed to vary in performance with no noticeable pattern other than a slight decrease, probably due to wear, in both. Once the data was organized in a table, a pattern of increased performance of the drill bit with the negative potential applied began to emerge. When graphed, the results were far more obvious. The results of this experiment stayed fairly consistent throughout all of the experimentation. While several times the results differed from the “normal” pattern, it was not made any more difficult to reach my conclusions.

It was possible to tell the increased performance of the drill bit with negative potential applied directly off the raw graph, but to better interpret the data, trendlines were used. A moving average trendline of two, three and ten were used. A moving average smoothes out fluctuations in data and shows patterns and trends more clearly. With a moving average of two, the drill bit without negative potential applied peaked above the other drill bit only three times. With a moving average of three and of ten the drill bit without negative potential applied did not peak above the other drill bit at all.

Five times on the same drill bit usage the drill bit without negative potential applied performed better in drilling on the same trial than the drill bit with negative potential applied. This can be attributed to a random event such as the drill bit striking a rock, giving each drill bit the same chances and not affecting the overall results. There are no results for trials one, two, and seven for the drill bit with negative potential applied because of a failure in the setup.

CONCLUSION

From the data that I have collected, I can conclude that electroosmosis, when applied to a drill bit drilling in concrete does significantly increase drilling performance. In almost every instance, the drill bit with a twelve volt negative potential applied to it drilled a deeper hole in one minute than the drill bit without a charge applied. Comparisons were made between equal numbers of times the drill bits were used. Therefore, I can confidently conclude that electroosmosis applied to a drill bit does significantly increase drilling performance in concrete.

BIBLIOGRAPHY

Math, Irwin. Wires & Watts. New York City: Charles Schribner’s Sons, 1981.

Raloff, Janet. “Current Affairs: Managing water and pollutants in soil with electric currents.” Science News September 9, 1995:168,169.

Vogt, Gregory. Electricity and Magnetism. New York City: Franklin Watts, 1985.