Mini Polisher Standard Operating Procedure

The front panel of the mini polisher has controls for speed, downward load, and a timer.

Mini polisher with the components labeled

1. When not in use, the lapping plate, collar, and sample holder should not be installed. If they are, read further on for removal instructions.
2. Clean parts if needed:
   1. Use the tongs to hold the part over the DI water sink behind the workstation.
   2. Scrub the parts clean with one of the small brushes.
   3. Dry parts with clean room wipes. For sanding pads, PAT them dry because they will collect long fibers from the wipes.
3. Determine the grit/pad and fluid that you will use:
   • The following 3" diameter pads are available: silicon carbide grits varying from 60 up to 3000, and soft polishing pads.
   • The following polishing materials are available: diamond paste in syringes at 5um, 3um, 1um, 0.5um, 0.25um, as well as 50nm and 20nm colloidial silica in bottles for the finest level of polish.
4. Choose from one of the available lapping plates which may already have the desired grit or polishing pad mounted. If none of the lapping plates have the desired pad/sandpaper mounted, then change it out:
   1. Note that because the pads are adhesive-back, a pad should only be removed from a lapping plate when it is too worn to be used anymore.
   2. Use tweezers or small pliers to peel up an edge of the existing pad. If needed to overcome the adhesive, twist the pad around the tweezers to peel it back, revealing the glass surface.
   3. Throw the old pad away.
   4. Clean the glass surface of the lapping pad if needed.
   5. Peel off the adhesive film from the new pad, and stick the pad onto the lapping plate.
5. Install the lapping plate, collar, and a spare sample holder to protect the lapping plate from the nose of the arm:
   1. Lift up the metal arm to make vertical space.
   2. Being careful not to scratch the pad on the tip of the arm, rotate the lapping plate to the correct orientation and move it in and down.
   3. Still lifting the arm, fit a rubber collar around the lapping plate.
   4. Insert the sample holder under the arm.
6. Prepare the sample on the sample holder:
   1. Ensure the sample holder is totally clean and free of wax, clean if needed.
   2. Secure your sample(s) to the sample holder:
      • (If your sample is very small or highly irregular, it may require use of a cold-mounted or hot-compressed sample mount. I.e., mtixtl.com for P/N EQ-CM-Mold-SR-125-LD. Special equipment for mounting may be required.)
      • For small samples, it is recommended to mount multiple in a pattern that evenly distributes the downward pressure from the polishing arm.
      • Using a heat gun:
        1. Place the sample holder facing up on a heat-resistant surface (metal table or stone slab).
        2. Place a small piece of bonding wax onto the surface, use sparingly.
        3. Heat the wax with the heat gun until it spreads thin.
        4. Apply the samples to the holder, then reapply heat.
        5. Use tweezers to apply slight pressure to the edges of each sample to secure the bond OR use a flat, very clean plate or glass to push down on the samples.
      • Using a hot plate:
        1. Prepare five 6"x6" clean room wipes, folding or rolling them to allow the handling of a hot sample holder.
        2. Place the sample holder on a hot plate that is at least 60C.
        3. Apply wax to the surface as soon as it will melt. Use sparingly.
        4. Apply the samples to the sample holder, pushing them around with tweezers to spread the wax thin.
        5. Remove the sample holder from the hot plate with the folded-up wipes as thermal insulation.
   3. If desired, measure your sample(s) height while mounted to the sample holder, using the Mitutoyo height gauge to the left of the polisher (use the wire handle to actuate the tip up). This can be used to measure sanding rate.
7. Prepare the polishing fluid:
   1. Ensure that a lapping plate, polishing or sanding pad, rubber collar, and spare (empty) sample holder are installed.
   2. If using polishing paste:
      1. Each syringe is 10g. Use 1g to start, applying to the pad.
      2. Apply an equal or greater amount of DI water to the pad.
      3. Use any small implement to mix, and spread evenly across the pad. If there is not enough to spread across the pad, use more paste and water.
   3. If using the blue 50nm colloidial silica slurry:
      1. Wet the polishing pad with DI water first, as little as possible to wet the entire pad and remove the surface tension.
      2. Pour enough of the slurry onto the pad that it can be spread across the entire pad.
8. Install the sample holder with your sample(s) on it:
   1. Lift up the metal arm to make vertical space.
   2. Remove the empty spare sample holder.
   3. Move the sample holder face down under the arm and lower the arm tip into the sample holder.
9. Polish/sand the sample(s):
   1. Turn the SPEED knob all the way to the left until it stops turning.
   2. Set the LOAD value by pushing in the knob and rotating it to one of seven possible positions between MIN and MAX.
      • The change in loading force by this adjustment is not very significant.
   3. Set the TIMER to a value between 0 and 30 minutes.
   4. Press the ON button. The machine will not polish immediately.
   5. Turn the SPEED knob 7 full turns to the right, or until it starts moving.
      • If the polishing arm stops and starts, it is likely that the sample holder is catching on the pad, either due to insufficiently balanced sample arrangement or due to sharp edges on the samples cutting into the polishing/sanding pad.
   6. Increase the SPEED knob as desired, keeping track of the number of turns from the zero position.
   7. Monitor the polishing fluid level and reapply DI water and paste or slurry if it begins to dry.
   8. As desired, stop operation with the ON/OFF button to remove the sample(s) and measure on the height gauge, always placing the empty sample holder on the polishing arm in order to protect the pad underneath.
10. Wrap up:
    1. Turn power off to the polisher and turn SPEED all the way counterclockwise. Turn LOAD counterclockwise if it was increased.
    2. Use a clean room wipe to pat the polishing area dry.
    3. Remove all parts from the polisher:
       1. Lift up the metal arm and continue to hold it while removing all the components.
          • Warning! Do not drop the arm after removing the sample holder, or else it will mar the polishing pad/sandpaper!
       2. Remove the sample holder from the polisher. The sample holder should easily drop from the sample arm.
       3. Remove the rubber collar.
       4. Being careful not to scratch the pad on the tip of the arm, lift the lapping plate up and out.
    4. Remove the sample from the sample holder with the heat gun or hot plate.
    5. Clean all parts:
       1. Use the toothbrushes, the brass tube brush, and dry wipes to clean and dry any residue inside the holes of the base.
       2. Use the tongs and toothbrushes to clean the lapping pad and the rubber collar and the sample holder in the DI water faucet.
       3. Remove all bonding wax from the sample holder.
       4. Clean the black workstation tray if needed.
       5. Pat parts dry and place in the POLISHER PARTS drawer on the workstation.