A
Th e
Component Manufacturing dverti$ dverti $ er
Don’t Forget! You Saw it in the
Adverti$$er
November 2021 #13268 Page #51
Can Lasers Do It All? By Glenn Traylor
W
ith the introduction of lasers, setting up a truss while accurately controlling its perimeter and profile has never been quicker or easier. But do lasers do the job by themselves? The answer is no. They cannot. Here is why.
Lasers provide excellent and accurate information to truss builders about where the lumber needs to be as the truss is pressed; however, without proper blocking and properly located stops, the truss is at the mercy of the gantry. As the gantry rolls the connectors into place, the lateral force exerted by the roller attempts to push the truss from side to side. Hard, fast stops and blocking or jigging (see photo) prevent the truss from moving, thus inhibiting the distortion of the truss profile. This is also the reason that automatic jigging must be designed to prevent this lateral motion. Supplemental manual jigging must be used too. No existing system totally prevents some motion, although the closest exception is likely the vertical hydraulic press system. Some machinery requires additional blocking to prevent lateral movement while the truss is being pressed. This also is exacerbated each time another similar truss is pressed. Each roll loosens the jigging until the umpteenth truss is sloppy in the jig. The best way to prevent this migration is to install significant heel stops on all trusses including and especially scissor trusses. Some plants depend on stapling chord transitions, hoping this will resolve the problem; but unless you are building one and one and one, the lack of proper blocking can create variations between trusses. Also keep in mind that, if the gantry is pressed from left to right, then right to left on the next truss, the variations will double from truss to truss. These variations result in waviness which is revealed in the finished product application and resulting finished surfaces.
Continued next page
PHONE: 800-289-5627
Read/Subscribe online at www.componentadvertiser.com
FAX: 800-524-4982