Using a combination of laser and target from two systems, Hamar Laser has put together a package that works exceptionally well for twin-barrel extruders. It uses the L-700 Spindle Laser and the A-510 2-Axis Self-Centering Target to align twin-barrel extruders to within .0005" (.013 m) in 30 feet.
The L-700 Laser is affixed to the gearbox output shaft using a self-centering chuck with a specially designed plate that has a .500" (12.50 mm) hole (matches stud on back of laser) that has been aligned to the feet. The laser is attached to the chuck and it is placed over the output shaft (spline). A 4-axis target and NORMIN procedure are used to position the laser beam on the axis of rotation of the gearbox shaft. When removed, the laser will project the gearbox shaft centerline out to 100 feet (30.5 M).
An A-510STA Self-Centering Small-Bore Target Adapter Hub for 2" to5" (50 mm to 127 mm) bores or an A-510LTA Self-Centering Large-Bore Target Adapter Hub for 4.25" to 20" (110 mm to 500 mm) bores and pole are attached to the A-510 Target and the assembly is inserted into the free end of the barrel. The target automatically centers itself and it immediately provides a horizontal and vertical measurement of alignment(see A-510STA/LTA How it Works for details). If the twin-barrel is under construction, the system can be used to align each section of the barrel. This is a much better alignment method than using indicators on the outside of the barrel or relying on pins and manufacturing to perform the alignment, both of which are subject to significant stack up errors.
If the extruder to be aligned is already installed, the A-510 target can be inserted into the barrel and positioned over adjustment points. The digital readout displays the misalignment numbers dynamically. Simply adjust the barrel until the readout reads zero and that section is aligned.
If there is radial adjustment in each individual barrel section, then the same procedure can be followed for the other bore.