amination Fixtures (also referred to as Press Plates or Caul Plates) are often the last part of the tooling system considered, yet they play a major role in the final registration of the multilayer. Specifying the correct plates for purchase cn be as important a decision as which type of registration system, or what press to use.

Considerations such as types of materials and tolerances such as flatness and parallelism must all be addressed. Lamination fixtures have many functions in the lamination process. The most important function of the lamination fixture is to insure layer to layer registration of circuit pads. This is accomplished by pinning the layers on the lamination pins which are accurately located by bushings in the lamination plates.

Separator plates are used against the lamination fixtures and between each panel. Separator plates allow the lay-up of several multilayer panels in one set of lamination fixtures, providing a smooth contact surface against the panels. These separators also prevent the pattern from one board from being transferred or telegraphed to the next board.

The complete package of lamination fixtures, separator plates, lamination pins, innerlayers and prepreg is often referred to as the lamination book.

When purchasing lamination fixtures there are many criteria to be completed, the most important being the locational accuracy of the tooling positions. The lamination fixture tooling must match the positional location of the innerlayer punch (and the resultant tooling positions of the innerlayers) within a strict tolerance usually +/-0.001" (0.25mm). The bushed lamination plates preferred by Multiline's customers are usually stress relieved 1018 HRS or 4140 Steel with a thickness of 0.275" (7mm) or 0.375" (9.5mm). Multiline recommends the hardened 4140 material because of it's unique metallurgical properties which minimize plate warpage during lamination cycles.

The lamination plates should be sized as close to the panel size as possible. Multiline normally recommends a 1/2" border (i.e. 18" x 24" (457mm x 610mm) Panel) would be a 19" x 25" (482mm x 635mm) Plate. On combination plates where more than one panel size is tooled in the outer lamination plates thicker material is recommended 0.375" (9.5mm) thick.

Multiline offers two types of Separator plates, 304 or 630 Stainless Steel. In most of our customers applications we strongly recommend the 630 S.S. which is hardened and therefore provides a high wearing resistance to scratching and denting. This harder material assures you a longer life expectantcy and prevents defects in panels during lamination. We manufacture all our own Bushings and Lamination plates in house to strict quality control standards. This allows us to inspect the plates, pins and bushings numerous times during fabrication and assures consistancy and accuracy not available from other suppliers.

Multiline has a complete accessory product line dedicated to "Lamination". We feature "Soft Tooling Plugs" which we call our Delrin Plugs. They have become widely accepted as the best tooling system for drilling multilayers. In hard tooling plates there can be variations between the drill spindles and the tooling pins. In a soft tooling system the variation can be corrected since the drill is used to position the tooling pins in precise registration to the spindles. These tooling plugs are easy to use and very inexpensive. Multiline also provides the aluminum tooling plates which are mounted on the drilling machine and have tapped holes which correspond to the tooling positions of all the multilayer panel sizes.

After the plugs are inserted in the tooling plates. The tooling holes are then drilled into the Delrin Plugs and the tooling pins inserted. The Delrin material offers a tight fit and does not allow the pins to shift even with repeated use. The drill spindle will now be zeroed to the pins of the soft tooling system. A special spanner wrench is utilized for insertion and removal of the Delrin Plugs. The plugs should be replaced periodically. This soft tooling system can be designed to fit many machines and configurations. If you would like to receive free samples of Delrin Plugs please feel free to call us direct or send an Email to: SScheinpflug@multiline.com.

Multiline also has a multitude of "Lamination Pins" and "Lamination Fixture Bushings" to fit all your lamination needs. Call or Email us for a free Multilayer Accessories Catalog.

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