Issue link: https://iconnect007.uberflip.com/i/1473479
JULY 2022 I PCB007 MAGAZINE 93 layer registration, while optical registration measures each layer to get the front to back image registration as well the geometry shape of each core and can align inner layers with a tolerance of ±15 µm (using direct digital imaging). is is possible because each core is individually inspected and can be rejected as quality control according to a tolerance specification. is new generation of the induction bonders provides a capability to place multiple numbers of bonding points in any location of the multilayer stack for best registration. ose bonding spots work as virtual pins to help the scale constrain, similar to multiple tooling pins around a single PCB. e bond- ing points can be placed anywhere in the CAD design, the machine is capable to read and decode the CAD file jobs, and automatically know the coordinates for each bonding loca- tion of the panel. Four bonding heads with independent movement in X and Y axes allow the move- ment of each head to any location and pro- vide fast speed for complex panels that require many bonding locations for best registration and multilayer handling. With cores being as thin as 25-50 µm, and sub-laminations com- mon, the welding process can accommodate these variations as well as coppers from one- third to three ounces. Optionally, the regis- tered and bonded multilayer panel could be automatically unloaded at a rear unloading sta- tion that could be equipped with a trolley. Also, one plastic protection sheet can be automati- cally inserted between each panel. e welded coupon bonding process is seen in Figure 4. e welded book can withstand the dilations and shrinkage of the hot press cycles, thereby providing the best possible linear movement of all layers in a multilayer stackup, reduc- ing the internal stress that causes warping and deformations, and moreover reducing the distortions and misalignments between inner layers. e welded stackup multilayer can be X-rayed to check before and aer lamination for compensation adjustments. Figure 3: Stackup plates with welded panel, foil, and laser lines used as a guide.