Friction Test Procedures

The following test procedures are for determining the static coefficient of friction between the Iris mineral samples and 6061-T6 aluminum. These coefficients are needed to determine the required clamping force to hold the samples during launch and operations.

Test Apparatus

The test apparatus, as seen in Figure 1 below, consists of a 6061-T6 aluminum ramp with an adjustable angle. The ramp is mounted onto a wooden base and includes adjustable rubber feet for leveling the unit. A protractor is mounted near the ramp pivot for angle measurements.

For fine angle adjustment, tighten the nut at the end of the adjustment rod until it is in contact with the end block. Then slowly rotate the nut counter clockwise while pushing the rod towards the endblock. This will move the ramp pusher forward one inch for every sixteen rotations of the nut.

Required Tools

● 2mm Allen key

● Needle nosed pliers or 5mm wrench

● Isopropyl Alcohol

● Clean cloth or kimwipe

● Pen

Test Set-Up

1) Before using the friction tester, make sure the test unit base is level. If the base is not level, level it using the adjustment feet.

2) Loosen the nuts on both sides of the stopping block to allow the ramp to move.

3) Clean the ramp surface using isopropyl alcohol and a clean cloth until the cloth comes away clean.

Test Procedures

1) Weigh the sample.

2) Record the sample weight in a chart like the one shown in Figure 3.

3) Repeat the following five times per sample:

a) Set the ramp to minimum possible angle.

b) Place the sample onto the centre of the ramp.

c) Slowly increase the ramp angle until the sample slides to the bottom of the ramp without stopping.

d) Record the ramp angle at which the sample began to move to the nearest degree.

Test Close-Out

1) Once testing is complete, tighten the nuts on either side of the stopping block to prevent the ramp from moving while in storage.

Friction Calculation

The coefficient of static friction for each sample is equal to:

Where is the coefficient of static friction and is the ramp angle.