The L-705 Laser is mounted into the gearbox through-hole (counter bore) by using a self-centering chuck. The chuck has a specially adapted plate with a 0.750" (19.05 mm) hole that is centered to the feet to within .0005" (0.01 mm). The laser projects the axis of rotation of the extruder gearbox using a method we call the NORMIN (NORmal and INverted) procedure.

The A-510 2-Axis Bore Target and A-510A Bore Adapter are specially designed to find the center of the bore, without any moving parts, to a tolerance of .0005" (0.01 mm); with care, tolerances of .0002" (0.005 mm) can be achieved. The bore adapters are customized for each barrel diameter, but can handle +/- .060" (1.52 mm) of diameter variance.

The A-510 and A-510A are designed so that the PSD is centered axially between the four feet of the adapter, 2 of which are offset axially from the other 2 (see A-510A Adaptor - howitworks for details). This, in effect, puts the PSD on the pivot point of the adapter and allows the angle of incidence to the laser beam to vary by up to 45º. The A-510 takes advantage of this property by making the adapter slightly larger than the bore. To insert the target into the barrel, a spring-loaded pole is attached to the target and the target cord is pulled. This tips the target forward, allowing it to easily slide into the bore. When the cord is released, the target and adapter "jam" into the bore, finding the center automatically. The weight of the pole keeps the target centered in the bore.

To perform an alignment, the A-510 is placed into the free end of the barrel. The user then performs Hamar Laser's NORMIN procedure which puts the laser beam on the axis of rotation of the gearbox. That axis of rotation is projected down the barrel to the target.

The reading produced from the NORMIN procedure is then a measure of the misalignment of the free end of the barrel to the gearbox axis of rotation. Leaving the laser and target in the barrel, it can then be shimmed/moved until the readout displays .000" in both axes. If there is more than one adjustment point for the barrel the target can be inserted into that point and it can be shimmed/moved until the readout reads .000".

Barrel Wear Measurements

The A-510A Bore Adapter can be placed on the A-510 Target in 2 ways. With the adapter placed on the target in Self-Centering Mode, it will center itself into the barrel. In Measuring Mode (the other mounting side of the adapter), the adapter will measure diameter changes in the bore. To measure barrel wear/diameter changes, a measurement is taken with an inside micrometer of a reference bore, usually at the free end of the barrel. The A-510 target and adapter in Measuring Mode are inserted into the reference bore. A measurement is taken with the target in the NORMal position and in the INverted position. The 2 readings are averaged and the result is the starting measurement for the laser. At each subsequent measuring point, 2 sets of readings, normal and inverted, are taken and averaged. Subtract the result from the reference measurement and the diameter change is produced.