Burnishing

About Burnishing

Burnishing is an alternative to engraving on trophy brass and aluminum (as opposed to diamond dragging). Typically, trophy brass is coated with a thin layer of paint that must be engraved through to expose the brass underneath. Aluminum can be either be coated with the same paint (as brass) or anodized. Either way, the idea is to remove the top color to expose the underlying color of the brass or aluminum without actually engraving into the metal.

Burnishing is achieved using a special engraving tool called none other than a burnisher. At first glance, a burnisher looks like a regular engraving cutter. Further inspection of the tip will reveal the subtle difference. Rather than having a sharpened tip like those designed to actually cut through plastic, a burnisher has more of a blunt end. This blunt end is designed to simply 'polish' the surface of the material rather than cut into it. This polishing process is forceful enough to remove the upper layer material. In this case, the upper layer of material is simply the paint or anodizing on the brass or aluminum. Because the burnisher does not cut into the brass, this type of engraving provides a smoother appearance and feel as compared to diamond dragging. By the way, this is a rotary process, meaning the spindle motor WILL be running while burnishing, unlike diamond drag.

Additional Accessories

As mentioned above, one of the added benefits of burnishing is a smoother finish of the engraving on the material. However, smaller sized burnishers, because of the nature of a smaller, more pointed tip will have the tendency to 'gouge' into the metal with too much down pressure. The down pressure is, of course provided by the main Tension Spring on the Z Axis assembly. Even with the Brass Spring Tension Knob set to its lightest setting, burnishers smaller than 35 thousandths (0.035) will gouge the metal, creating a less than 'smooth' finish. Rather than replacing the Tension Spring with one having a lighter spring rate, there is an easier solution: the Light Touch Burnishing Adaptor. The Burnishing Adaptor simply replaces the brass cutter knob typically found on the top of engraving cutters (and burnishers). The Burnishing Adaptor contains a spring with a much lighter spring rate than that of the main Tension Spring on the Z Axis assembly. This lighter spring rate will provide enough down pressure to remove the paint or anodizing, yet not gouge the material when using small burnishers.

NOTE: Using a Light Touch Burnishing Adaptor by-passes the main Tension Spring; in other words the main Tension Spring is NOT USED. When the main Tension Spring is not used while engraving, Full Automatic Cutter Set at Start CANNOT be used as well. Manual Cutter Set at Start must be used to set the necessary Z Axis travel associated with this procedure.

Setting up the Engraver to Burnish

Engraver Preparation

• Remove the standard brass knob from the burnisher and install the Light Touch Burnishing Adaptor (LTBA) close to the top of the burnisher.

• Install the burnisher into the spindle as you would a standard cutter.

NOTE: A top load spindle or a solid collet spindle is necessary when using a Light Touch Burnishing Adaptor.

• Nose cones and the micrometer are not necessary when burnishing. Removing your nose cone will provide you with a better view for steps 17 - 22.

• Using a cutter wrench or the wrench supplied with the LTBA loosen the set screw on the LTBA to position the height of the cutter in the spindle so that at least 1/4 inch of the bottom end of the burnisher (the tip) extends below the lowest part of the spindle.

• Tighten the set screw to secure the burnisher within the LTBA.

• With your finger, push up on the tip of the burnisher. It should move up in the spindle, compressing the spring in the LTBA. Removing your finger from the tip of the burnisher should allow it freely come back down with no hang ups. If it does hang up, loosen the set screw on the LTBA and rotate the cutter approximately 30 degrees and re-tighten. Repeat this step until burnisher moves up and down freely with no hang ups. This is important.

For Job Download (within software)

• Open or prepare a job layout.

• Select 'To Engraver' under the File Menu (or press F1).

• Optional - Make a mental note of the current value of the Z Home (later this value will change as a result of the following steps).

• Select 'Manual Cutter Set at Start'.

• 'Click' on 'OK' to download the job.

At this point there should be a green ready light on the pendant indicating the job has been downloaded to the engraver.

Setting Cutter (using Pendant as 'joystick')

1. Place the "Pause/Continue" switch in "Continue". (This is just to demonstrate the fact that during Manual Cutter Set at Start, the engraver will pause automatically, regardless of the "Pause/Continue" switch)

2. Place the Motor Speed Control (MSC) switch in the "Auto" position.

3. Press "Start" on the Pendant. (The engraver will move to the first position of the job and pause)

4. Turn the "Z Feed" knob on the Pendant to approximately 12 o'clock (halfway). This is to slow down the speed of the Z Axis for the next step.

5. Watch the Z Axis as you press and hold the "Cutter" switch to the "Down" position. You may readjust the "Z Feed" knob to a comfortable speed as it is coming down, slowing it as it gets closer to the material.

6. With your focus on the tip of the cutter, bring the cutter down to approximately 1/16 of an inch (0.062) from the surface of the material.

7. Place the "Spindle" switch on the MSC to the "Off" position (this is just temporary).

8. Rotate the spindle by hand until the set screw of the Light Touch Burnishing Adaptor is facing you.

9. Now with your focus on the set screw, press the "Cutter" switch to the down position until you see the set screw move up no more than approximately 1/32 of an inch (0.031). This is setting some float to allow for possible low spots in the material.

10. Press "Home Retain" to retain this setting (your new Z Home). The Z Axis will raise back to its Z Home location.

11. Place the "Spindle" switch on the MSC back to the "Auto" position.

12. Place the "Cutter" switch in "Auto".

13. Press "Start" to begin engraving.

After the job has been completed, the engraver will 'talk' back to the software, transferring two pieces of information: the newly found Z Home, and it turns Manual Cutter Set at Start to No Cutter Set at Start. To verify this go back to 'To Engraver', and look at the Z Home value. Except for the slight possibility of coincidence, the Z Home should have changed from its original value as noted in step 3. This new value is one that was determined mechanically in steps 17 - 22. Also, take a look at No Cutter Set at Start, it now has the focus. This is done on purpose to allow multiple engraving of the same job, on the same type of material, without having to set the cutter depth for every plate.