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LAUFFER laminating machine: pressing method and analysis of PCB multilayer board

Published:

2022-11-23 15:46

LAUFFER laminator summarizes the pressing method and analysis of PCB multilayer boards for you:

The following is a summary of the terms of PCB multilayer pressing by LAUFFER laminator

Crease crease is often referred to as the crease of copper sheet when it is not handled properly in the lamination of multilayer boards. The thin copper sheet below 0.5 oz is easy to have this defect when laminated.  

Dent depression refers to the gentle and uniform depression on the copper surface, which may be caused by the local point protrusion of the steel plate used for pressing. If it presents a fault like edge neat descent, it is called Dish Down. Such shortcomings, if unfortunately, remain on the line after copper etching, will cause unstable impedance of high-speed transmission signals, resulting in Noise. Therefore, this kind of missing shall be avoided on the copper surface of the base plate as far as possible.  

Caul Plate clapboard is a kind of multilayer plate which is often stacked between each opening of the press when pressing; Volume; For bulk materials of plates to be pressed (e.g. 8~10 sets), each set; Bulk material; (Book) must be separated by flat, smooth and hard stainless steel plate. The mirror stainless steel plate used for such separation is called Caul Plate or Separate Plate. Currently, AISI 430 or AISI 630 are commonly used.  

Kraft Paper refers to the use of kraft paper as heat transfer buffer during lamination (lamination) of multilayer boards or substrate boards. It is placed between the hot plate and the steel plate of the press to ease the temperature rise curve closest to the bulk material. Between multiple substrates or multilayer boards to be pressed. Try to close the temperature difference of each layer of the plate, and the commonly used specifications are 90 pounds to 150 pounds. Since the fiber in the paper has been broken after high temperature and pressure, it is no longer flexible and difficult to function, so it must be replaced. The kraft paper is boiled with the mixture of pine wood and various strong alkalis, and then washed and precipitated after the volatiles escape and the acids are removed; After it becomes pulp, it can be pressed again to become rough and cheap paper.  

The LAUFFER laminator summarizes the pressing methods for PCB multilayer boards:

Cap Lamination refers to the traditional lamination method of multilayer PCB in the early days; Outer layer" Multiple thin substrates with single copper sheet were used for lamination and pressing. The current large or large copper sheet pressing method (Mss Lam) was not used until the output of MLB was greatly increased at the end of 1984. This early MLB pressing method using single-sided copper sheet thin base plate is called Cap Lamination.

Foil Lamination copper foil pressing plate method refers to the mass production multilayer board, in which the outer layer of copper foil and film is directly pressed with the inner layer, becoming the mass lam method of multilayer board, replacing the traditional pressing method of single sided thin substrate in the early days.  

Kiss Pressure and Low Pressure: When multilayer plates are pressed, when the plates in each opening are placed and positioned, they will be heated and lifted up from the lowest layer of the hot plate with a powerful hydraulic ram to press the loose materials in each opening for bonding. At this time, the combined film (Prepreg) starts to soften gradually or even flow, so the pressure used for the top extrusion cannot be too large to avoid the plate sliding or too much glue flow out. This initial low pressure (15~50 PSI) is called" Kiss". However, when the resin in each film bulk material is softened and gelled by heat, and is about to harden, the full pressure (300~500 PSI) shall be increased to make each bulk material closely combined to form a firm multilayer board.  

LAUFFER laminating: Before laminating multilayer circuit boards or baseplates, it is necessary to align the inner laminates, films, copper sheets and other bulk materials with steel plates, kraft paper padding, etc., up and down, align them, or register them, so that they can be carefully fed into the laminating machine for hot pressing. This kind of preparatory work is called Lay Up. In order to improve the quality of multilayer boards; Overlay; The work shall be carried out in a temperature and humidity controlled dust-free room. For the speed and quality of mass production, mass lam is generally adopted for the construction of those with less than eight floors, and even needs to be used; Automation; To reduce human error. In order to save plant and shared equipment, most factories will; Overlay; And" Folded plate; The two are combined into a comprehensive processing unit, so its automation project is quite complex.  

Mass Lamination: This is the abandonment of the lamination process of multilayer boards; Align the tip", And a new construction method of multiple rows of plates on the same surface. Since 1986, when the demand for four - and six ply boards has increased, the pressing method of multilayer boards has changed greatly. In the early days, only one shipping plate was arranged on a process plate to be pressed. This one-to-one arrangement has been broken through in the new method, and can be changed into one-to-two, one-to-four, or even more plates according to their size. The second new method is to cancel the registration tip of various bulk materials (such as inner sheet, film, outer single-sided sheet, etc.); The outer layer is replaced by copper foil, and the inner layer is pre fabricated first; Target", After pressing; Scan; Take out the target, and then drill a tool hole from its center, which can be sleeved on the drilling machine for drilling.

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