MicroE Optira Installation Manual
Celera Motion
IM-1001 | REV181211
Page 44
©2018 Celera Motion
12.2 Benching Linear Glass Scales
'Benching' the scale means aligning the scale by using benching pins. Refer to the Optira
interface drawing for dimensions. The benching pins can be set up on either side of the glass
scale, but are oriented to the "D" reference edge as shown in the interface drawing.
Benching Guidelines
•
Two benching pins are recommended on the long side of the scale and one at the end.
•
Position the benching pins inward from either end of the scale. 20% of the overall scale
length is the recommended location from the edge.
•
Be sure the benching pins do not exceed the height of the scale to prevent mechanical
interference with the sensor or sensor mount.
12.3 Prepare Mounting Surface
Perform the following steps prior to mounting the glass scales (for non-adhesive backed scales).
Step
Action
1. Inspect the mounting surface for any machining irregularities. MicroE Systems recommends
a surface finish of better than 3.2 micrometers Ra.
2. MicroE Systems recommends a mounting surface flatness of 0.0001 inch/inch.
3. Thoroughly clean the scale mounting surface and reference edge using a cotton swab or lint-
free cloth dampened with isopropyl alcohol or acetone. Remove all dust and particles.
12.4 Install
Linear Glass Scales
Use the following instructions to install linear glass scales.
Linear glass scales should be permanently attached to the mounting surface using epoxy and
silicone adhesive attached to the back of the scale.
Note
: Use talc-free gloves or finger cots to handle the scales.
Step
Action
1. Make sure that the mounting surface is dry and clean.
2. Align the scale by placing the edges against the benching pins. Optionally, scale clamps may
be used to secure the scale while the adhesive cures.
3. Apply a hard epoxy, such as Tra-Bond 2116, at one point on the scale. If no end benching pin
is used, epoxy at the index mark. If an end benching pin is used, epoxy at the end of the scale
where the pin is located. Then apply 100% Silicone RTV adhesive around the edges of the
scale.
Caution
: Do not allow epoxy to seep under the scale; this will affect scale
flatness and therefore encoder accuracy.
4. After adhesive curing, remove optional scale mounting clamps, if any.
0.6L
0.2L
0.2L
Benching Pins
L
End Benching Pin (optional)
